WO2024055301A1 - 一种信号测量电路及方法 - Google Patents
一种信号测量电路及方法 Download PDFInfo
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Definitions
- This specification relates to the field of circuit design, and in particular to a signal measurement circuit and method.
- Signal measurement circuits can often obtain data related to the user's physical condition by collecting physiological signals.
- the signal measurement circuit can monitor and use the information of myoelectric signals to make clinical diagnosis of muscle conditions such as muscle strength, muscle fatigue, and even myasthenia gravis, myotonia, and muscle atrophy.
- the signal measurement circuit collects physiological signals
- the quality of the collected physiological signals is often poor due to poor fit between the electrodes and the human body, and the skin is almost insulated in a dry environment, making it difficult to monitor accurately.
- the circuit includes: a plurality of electrodes used to fit the human body and collect physiological signals of the human body; a contact impedance detection circuit electrically connected to the plurality of electrodes, and the contact impedance detection circuit is used to measure the contact impedance between the electrodes and the human body; and The switch circuit is used to control the conductive state of multiple electrodes and the contact impedance detection circuit, so that only some of the plurality of electrodes and the contact impedance detection circuit remain in the conductive state at the same time.
- the plurality of electrodes include two electrodes attached to the same muscle, and the two electrodes attached to the same muscle are synchronously maintained in a conductive state with the contact impedance detection circuit.
- the plurality of electrodes include two electrodes attached to the same muscle, and the two electrodes attached to the same muscle maintain a conductive state with the contact impedance detection circuit at different times.
- the contact impedance detection circuit includes: an excitation source for providing excitation signals to two electrodes attached to the same muscle to generate a detection signal reflecting the contact impedance between each electrode and the human body; two voltage dividers The impedance is respectively coupled between the excitation source and each electrode, and is used to divide the voltage of the excitation source to form a detection signal; the two analog-to-digital converters are respectively used to perform analog-to-digital conversion of the detection signal.
- the contact impedance detection circuit includes: an excitation source for providing an excitation signal to each electrode to generate a detection signal reflecting the contact impedance between each electrode and the human body; a voltage dividing impedance coupled to the excitation source Between each electrode, it is used to divide the excitation source to form a detection signal; the analog-to-digital converter is used to perform analog-to-digital conversion of the detection signal.
- the excitation source is a DC excitation source or an AC excitation source with a frequency not less than 0.1 Hz.
- the voltage dividing impedance includes a resistor and/or a capacitor.
- a follower is coupled between the analog-to-digital converter and the voltage dividing impedance.
- the signal measurement circuit also includes a gain circuit for processing physiological signals, and the gain circuit and the contact impedance detection circuit maintain a conductive state with multiple electrodes at different times.
- the signal measurement circuit further includes a processing circuit for determining parameter information reflecting the fit state of each electrode to the human body based on the contact impedance of each electrode.
- One embodiment of the present specification provides a signal measurement method.
- the method includes: controlling the conduction state of multiple electrodes and the contact impedance detection circuit through a switch circuit, so that at the same time, only some of the multiple electrodes are in contact with the contact resistance detection circuit.
- the impedance detection circuit remains in a conductive state, with multiple electrodes used to fit the human body and collect physiological signals of the human body.
- the contact impedance detection circuit is used to measure the contact impedance between the electrodes and the human body; based on the contact impedance of each electrode, the response is determined Parameter information on the fit status of each electrode to the human body.
- the method further includes: determining the user's warm-up state based on a difference or ratio between contact impedances of two electrodes attached to the same muscle.
- the contact impedance between the electrode and the human body is measured, and the fit state between the electrode and the human body is determined based on the contact impedance, thereby ensuring the quality of the physiological signals collected by the electrode.
- the embodiments of this specification can also select different partial electrodes to maintain the conductive state with the contact impedance detection circuit at different times to collect the contact impedance corresponding to different partial electrodes in a time-sharing manner, thereby ensuring that different electrodes in the signal measurement circuit Quality of collected physiological signals.
- Figure 1 is a structural block diagram of a signal measurement circuit according to some embodiments of this specification.
- Figure 2 is a structural block diagram of a contact impedance circuit according to some embodiments of this specification.
- Figure 3 is a schematic diagram of a signal measurement circuit according to some embodiments of this specification.
- Figure 4 is a structural block diagram of a signal measurement circuit according to other embodiments of this specification.
- Figure 5 is a schematic structural diagram of a signal measurement circuit according to some embodiments of this specification.
- Figure 6 is a schematic diagram of the contact impedance curve corresponding to multiple electrodes when the user moves according to some embodiments of this specification;
- Figure 7 is an exemplary flowchart of a signal measurement method according to some embodiments of this specification.
- system means of distinguishing between different components, elements, parts, portions or assemblies at different levels.
- said words may be replaced by other expressions if they serve the same purpose.
- the signal measurement circuits and methods of one or more embodiments of this specification can be applied to devices that collect one or more physiological signals, such as smart wearable devices, medical detection devices, or signal analysis devices.
- smart wearable devices can be placed on various parts of the human body (for example, calves, thighs, waist, back, chest, shoulders, neck, etc.) to collect data from various parts of the user's body in different states. Physiological signals can be further processed later.
- smart wearable devices may include smart bracelets, smart shoes and socks, smart glasses, smart helmets, smart watches, smart clothes, smart backpacks, smart accessories, etc. or any combination thereof.
- physiological signals are signals that can be detected and can reflect body status.
- physiological signals may include respiratory signals, electrocardiogram signals (ECG), myoelectric signals, blood pressure signals, temperature signals, and other signals.
- ECG electrocardiogram signals
- the frequency range of the physiological signal may include 0.05 Hz to 2 kHz
- the frequency range of the ECG signal may include 0.05 Hz to 100 Hz
- the frequency range of the EMG signal may include 10 Hz to 850 Hz.
- the intensity of the physiological signal collected by the signal measurement circuit will be affected by a variety of factors, such as the contact impedance between the human body and the electrode, the degree of activation of human muscles, etc.
- Contact impedance is the impedance generated when the human body's skin comes into contact with the electrodes of the signal measurement circuit. Its impedance value will be affected by the dryness of the skin and the fit state of the human body and the electrodes, thereby affecting physiological signals. For example, the drier the skin, the greater the impedance value of the contact impedance, resulting in poorer quality of the collected physiological signals; conversely, the wetter the skin, the smaller the impedance value of the contact impedance, and the better the quality of the collected physiological signals. For another example, poor contact between the human body and the electrode will cause the impedance value of the contact impedance to increase, causing the quality of the physiological signal to deteriorate.
- the degree of muscle activation is the active state of the muscle during work, which can affect the intensity of the electromyographic signal released by the muscle.
- the degree of muscle activation For users, there are many daily movement monitoring needs (such as walking, standing, etc.). Compared with fitness monitoring needs (such as squats, running, etc.), daily exercise has a low degree of muscle activation, which will cause physiological
- the intensity of signal (eg, electromyographic signal) recognition is low, which affects subsequent recognition and processing.
- the contact impedance between the human body and the electrode is likely to be large, resulting in poor quality of the physiological signal collected and difficult to Accurately monitor users' physiology.
- the contact impedance between the electrode and the human body can be measured first through the contact impedance detection circuit, and the fit state between the electrode and the human body is determined based on the contact impedance, thereby ensuring that the electrode collects the quality of physiological signals. Furthermore, when you want to monitor the fit status of multiple electrodes to different parts of the human body, you can select different partial electrodes to maintain the conductive state with the contact impedance detection circuit at different times to collect the corresponding information of different partial electrodes in a time-sharing manner.
- the contact impedance can prevent interference between different electrodes and save resources in the contact impedance detection circuit.
- FIG. 1 is a structural block diagram of a signal measurement circuit according to some embodiments of this specification.
- the signal measurement circuit 100 may include: a plurality of electrodes 110 , a switch circuit 130 and a contact impedance detection circuit 120 .
- the plurality of electrodes 110 are electrically connected to the switching circuit 130
- the contact resistance detection circuit 120 is electrically connected to the switching circuit 130 .
- multiple electrodes 110 can fit the human body and collect physiological signals of the human body.
- the contact impedance detection circuit 120 can be used to measure the contact impedance between the electrode and the human body.
- the switch circuit 130 is used to control the conductive state of the plurality of electrodes 110 and the contact resistance detection circuit 120. In some embodiments, at the same time, only some of the electrodes 110 among the plurality of electrodes 110 remain in a conductive state with the contact resistance detection circuit 120 .
- the electrode 110 may be a circuit element that contacts to input or output current.
- the electrode 110 can be attached to the human body to collect physiological signals of the human body (such as myoelectric signal, ECG signal, blood pressure signal, etc.).
- the electrodes 110 can collect physiological signals of the human body within a target frequency range.
- the target frequency range may include the frequencies of most of the physiological signals produced by the human body, or may include the frequencies where the physiological signals are expected to be obtained.
- the electrodes 110 can be attached to different parts of the human body to collect physiological signals from different parts.
- the electrodes 110 can be attached to the user's chest, wrist, back, legs, arms, head, etc.
- one electrode can be used to collect physiological signals from one part, or two electrodes can be used as a group to collect physiological signals from the same part.
- the plurality of electrodes 110 may include two electrodes 110 that fit the same muscle.
- two electrodes 110 attached to the same muscle can be used as a set of electrodes to collect two physiological signals of the same muscle at the same time.
- the two physiological signals at the same time can be used to form parameters reflecting the motion state of the same muscle through operations such as difference and summation. In this way, inaccurate measurement of physiological signals caused by damage to an electrode or poor fit with the human body can be prevented.
- two electrodes 110 attached to the same muscle can also work in a time-sharing manner to collect two physiological signals of the site at different times. Two physiological signals at different times can reflect changes in physiological signals to monitor the user's physiological state.
- time-sharing operation reference may be made to other embodiments of this specification, such as switch circuits and related descriptions thereof.
- the contact impedance between the electrode 110 and the human body can generate a detection signal under external excitation (eg, an excitation signal), so that the contact impedance corresponding to the electrode 110 can be determined based on the detection signal.
- the detection signal may be a signal that reflects the magnitude of the contact impedance, and accordingly, may be used to reflect the quality of the physiological signal.
- the detection signal corresponding to an electrode indicates that the contact impedance between the electrode and the human body is greater than a certain threshold, it means that the electrode is not worn correctly or the user's skin is too dry.
- the difference between the corresponding detection signals of two electrodes is large, it means that the difference in contact impedance between the two electrodes and the human body is large, which means that at least one of the electrodes is not worn correctly or the user's skin is too dry.
- the quality of the physiological signals collected is poor; conversely, if the difference between the detection signals corresponding to the two electrodes is small, it means that the difference in contact impedance between the two electrodes and the human body is small, which means that the quality of the physiological signals collected is better.
- the detection signal can also reflect the user's electrode wearing status, body composition information, skin status and other other information.
- the corresponding contact impedances of two electrodes 110 attached to the same muscle can generate two detection signals at the same time. According to these two detection signals, the fit state of the two electrodes 110 and the human body at the same moment can be identified, thereby reflecting the quality of the physiological signals collected at that moment.
- the external excitations corresponding to the two electrodes 110 can provide excitation signals of different frequencies. Then, by performing signal processing on the detection signals of different frequencies, the impedance information of the human body at different frequencies can be obtained, thereby using To reflect the body composition information of the human body.
- two electrodes 110 attached to the same muscle generate two detection signals at different times. In some scenarios, the interval between the acquisition times of the two detection signals is very short.
- Processing these two detection signals can still reflect the fit state of the two electrodes 110 to the human body during this period, thereby reflecting the quality of the physiological signals during the same period.
- the electrode 110 may be in contact with the human body in the form of a flexible patch, which may be in a regular shape such as a circle, an ellipse, a rectangle, a rhombus, or other irregular shapes.
- the electrodes can be made of metallic conductive materials (such as copper, aluminum, nickel, chromium, alloys, etc.), non-metal conductive materials (such as conductive plastics, conductive rubber, conductive silica gel, conductive fabrics) or other conductive materials. .
- the signal measurement circuit 100 may also include one or more reference ground electrodes (not shown in FIG. 1 ), which may serve as a reference ground in the signal measurement circuit 100 .
- the one or more reference ground electrodes can be used to fit the human body, so that the aforementioned excitation signal can flow to the reference ground electrode through the human body to form a closed loop.
- the one or more reference ground electrodes can be disposed on a flat and relatively stable (less mobile) location, such as the back, head, etc. of the human body, thereby effectively reducing noise.
- the contact impedance detection circuit 120 may be a structural module with certain signal processing functions (such as amplification, rectification, A/D conversion, filtering, logic processing, etc.). In some embodiments, the contact impedance detection circuit 120 may determine the contact impedance between the electrode 110 and the human body based on the aforementioned detection signal corresponding to the electrode.
- the contact impedance detection circuit 120 can separately process the detection signal corresponding to a certain electrode 110, and thereby evaluate the physiological signal collected by the electrode.
- the contact impedance detection circuit 120 can perform analog-to-digital (A/D) conversion on the detection signal corresponding to the electrode 110, and the converted digital signal can individually reflect the relationship between the electrode 110 and the human body after further processing.
- the contact impedance reflects the fit state between the electrode 110 and the human body, thereby determining the quality of the physiological signals collected by the corresponding electrode 110.
- the contact impedance detection circuit 120 can combine detection signals corresponding to multiple electrodes 110 to comprehensively evaluate the physiological signals collected by these electrodes 110 .
- the contact impedance detection circuit 120 can perform calculations (for example, difference, sum) on detection signals corresponding to multiple electrodes 110 (for example, two electrodes 110 attached to the same muscle), and then calculate the calculated results. Perform analog-to-digital (A/D) conversion.
- the calculated detection signal can comprehensively reflect the difference in contact impedance between the two electrodes 110 and the human body, thereby reflecting the fit state of the two electrodes 110 and the human body, thereby determining the quality of the physiological signal.
- the contact impedance detection circuit 120 when the contact impedance detection circuit 120 is in a conductive state with the electrode 110, it can perform data transmission with the electrode 110.
- the contact impedance detection circuit 120 can simultaneously obtain the detection signal corresponding to the electrode 110 and the physiological data collected by the electrode 110. Signal.
- the contact impedance detection circuit 120 can also filter the detection signal corresponding to the electrode 110 to distinguish the detection signal corresponding to the electrode 110 from the physiological signal collected by the electrode 110 .
- the frequency of the excitation signal is different from the frequency of the physiological signal
- the frequency of the detection signal generated by the excitation signal is also different from the frequency of the physiological signal. Therefore, the detection signal and the physiological signal can be extracted separately by using a filter to facilitate subsequent analysis of the physiological signal and detection. The signal is evaluated.
- the contact impedance detection circuit 120 can distinguish based on the signal intensity through a follower and an analog-to-digital converter. The detection signal corresponding to the electrode 110 and the physiological signal collected by the electrode 110.
- the number of contact impedance detection circuits 120 may be one, and the contact impedance detection circuit 120 may be coupled with the switch circuit 130 .
- one or more of the plurality of electrodes 110 can be selected to be connected to the contact resistance detection circuit 120 at different times through the switch circuit 130 .
- the number of contact impedance detection circuits 120 may be multiple.
- the switch circuit 130 may select some of the contact resistance detection circuits 120 of the plurality of contact resistance detection circuits 120 to maintain a conductive state with some of the plurality of electrodes 110 .
- the switch circuit 130 can simultaneously select the electrode 110 that needs to be turned on and the contact resistance detection circuit 120 that needs to be turned on.
- each contact impedance detection circuit 120 may be coupled to one or more electrodes 120 through a switch circuit 130 , multiple switch circuits 130 can control multiple contact resistance detection circuits 120 and multiple electrodes to maintain a conductive state at the same time.
- the plurality of electrodes 110 and their corresponding contact resistance detection circuits 120 can be controlled to be conductive through the plurality of switch circuits 130 .
- the contact impedance detection circuit 120 please refer to other embodiments of this specification, such as FIG. 2 and its related descriptions.
- the switch circuit 130 may be a control structure that switches on-state and off-state between multiple devices.
- the on state may reflect whether data transmission between devices is possible, and the off state may reflect whether data transmission between devices is difficult.
- the input end of the switch circuit 130 is connected to the plurality of electrodes 110, the output end of the switch circuit 130 can be connected to the contact impedance detection circuit 120, and the switch circuit 130 can control the on and off of the input end and the output end. switch.
- the switch circuit 130 can select the input terminal corresponding to one or more electrodes 110 among the plurality of electrodes 110 to be connected to the output terminal of the switch circuit 130, thereby maintaining the conductive state between the electrode 110 and the contact resistance detection circuit 120.
- the switch circuit 130 can control part of the electrodes 110 among the plurality of electrodes 110 to be turned on at the same time to simultaneously measure the contact impedance corresponding to the part of the electrodes 110 .
- the contact resistance detection circuit 120 can measure the contact resistance corresponding to the part of the electrode 110 and other electrodes 110 in a time-sharing manner.
- the switch circuit 130 can also control each of the electrodes 110 to conduct time-sharing to measure the contact impedance corresponding to each electrode 110 .
- the switch circuit 130 can also control the electrodes 110 to collect physiological signals in a time-sharing manner and measure the corresponding contact impedance of this part of the electrodes 110 . The above three time-sharing measurements are described below respectively.
- the switch circuit 130 can control different parts of the electrodes 110 to maintain the conduction state with the contact impedance detection circuit 120 at different times, so as to measure the contact impedance between different parts of the electrodes and the human body in a time-sharing manner.
- the plurality of electrodes 110 may include two electrodes 110 attached to the same muscle, and the switch circuit 130 may control the two electrodes 110 attached to the same muscle to synchronously maintain a conductive state with the contact impedance detection circuit 120 .
- the contact impedance detection circuit 120 can simultaneously detect the contact impedance between the two electrodes 110 and the human body to determine the quality of the physiological signals (eg, myoelectric signals) collected by the two electrodes 110 .
- two electrodes 110 may be selected from the plurality of electrodes 110 to perform measurements at the same time, and other electrodes 110 may be selected to perform measurements at another or multiple time points.
- the contact impedance detection circuit 120 can simultaneously obtain detection signals corresponding to the two electrodes 110 attached to the same muscle, so that the contact impedance between the two electrodes 110 and the human body can be simultaneously detected to evaluate the quality of the physiological signals corresponding to the muscles. .
- the contact impedance detection circuit 120 can also determine the contact impedance corresponding to each electrode 110 based on the two detection signals, thereby separately evaluating the quality of the physiological signals collected by the two electrodes 110.
- the two electromyographic signals can be further operationally amplified through other processing circuits (for example, Differential amplification) to obtain parameter values reflecting muscle status.
- other processing circuits can calibrate or modify the two electromyographic signals according to the contact impedance between the two electrodes 110 and the human body to improve the accuracy of the electromyographic signals collected by the electrodes.
- the switch circuit 130 can capture the contact impedance information of the two electrodes of the same muscle at the same time by controlling the two electrodes 110 attached to the same muscle to synchronize and maintain the conductive state with the contact impedance detection circuit 120, thereby preventing the contact impedance from changing over time. Time fluctuations and interference from other signals (such as detection signals corresponding to other electrodes) can more accurately evaluate the quality of physiological signals.
- two electrodes 110 attached to the same muscle are used as an electrode group.
- the electrodes 110 can include multiple electrode groups, and the switch circuit 130 can control the conduction between one or more electrode groups and the contact impedance detection circuit 120 to simultaneously measure contact impedance. For example, assuming there are four electrode groups, the switch circuit 130 can control two electrodes 110 in one electrode group to maintain the conduction state with the contact impedance detection circuit 120 while the other three electrode groups are turned off. state, no data is transmitted with the contact resistance detection circuit 120.
- the switch circuit 130 can also control the electrodes 110 in two of the electrode groups to maintain the conductive state with the contact impedance detection circuit 120, while the other two electrode groups are in an off state and do not transmit data with the contact impedance detection circuit 120. Thus, the contact impedance information of the two electrode groups at the same time is obtained.
- the switch circuit 130 can control each electrode 110 to maintain a conductive state with the contact impedance detection circuit 120 at different times to measure the contact impedance between each electrode 110 and the human body in a time-divided manner.
- the switch circuit 130 can control two electrodes 110 attached to the same muscle to maintain a conductive state with the contact impedance detection circuit 120 at different times.
- the contact impedance detection circuit 120 can detect the contact impedance between the two electrodes 110 and the human body in a time-sharing manner to determine the quality of the physiological signals (eg, myoelectric signals) collected by the two electrodes 110 .
- the contact impedance detection circuit 120 can asynchronously acquire detection signals corresponding to the two electrodes 110 to evaluate the quality of the physiological signal corresponding to the muscle.
- the contact impedance detection circuit 120 can determine the contact impedance corresponding to each electrode 110 based on the two detection signals, thereby separately evaluating the quality of the physiological signals collected by the two electrodes 110. Since the acquisition time interval of the two detection signals is very short, in some embodiments, the contact impedance detection circuit 120 can also determine the contact impedance difference between the two electrodes 110 based on the difference between the two detection signals, and evaluate the two The quality of physiological signals collected by electrode 110.
- the contact impedance detection circuit 120 can asynchronously detect the contact impedance between the two electrodes 110 and the human body, reducing the burden of subsequent circuits processing the detection signals at the same time, for example, reducing the system's requirements for the sampling frequency in the subsequent analog-to-digital conversion process.
- asynchronous detection can save subsequent circuit costs and prevent mutual interference between the two electrodes 110, thereby further improving the quality of physiological signals.
- the contact impedance detection circuit 120 can acquire the detection signal corresponding to the first electrode at the first moment, and then wait until the detection signal corresponding to the second electrode is acquired at the second moment, and then based on the detection signal corresponding to the first electrode and The detection signal corresponding to the second electrode evaluates the quality of the physiological signals collected by the two electrodes 110 . It should be noted that, in order to ensure signal stability in the switching channel and prevent signal errors caused by asynchronous detection, the interval between the first moment and the second moment can be set very short.
- the interval between the first moment and the second moment can also be based on the AC excitation source. frequency to set.
- the interval between the first moment and the second moment may be 100 ⁇ s, 1 ms, 10 ms, 20 ms, etc.
- the switch circuit 130 can also control some of the contact impedance detection circuits 120 in the multiple contact impedance detection circuits 120 to be in a conductive state, and the other part of the contact impedance detection circuits 120 can be in a conductive state.
- the circuit 120 is in the off state, so that the part of the contact resistance detection circuit 120 that needs to be turned on can perform data transmission with the part of the electrode 110 that needs to be turned on.
- the contact impedance detection circuit 120 may have a corresponding relationship with the electrode 110, and the switch circuit 130 may select the contact impedance circuit 120 corresponding to part of the electrode 110, so that part of the electrode 110 may maintain conduction with its corresponding contact impedance circuit 120. Pass.
- each electrode 110 corresponds to a contact resistance detection circuit 120
- the switch circuit 130 can control each electrode 110 and its corresponding contact resistance detection circuit 120 to maintain a conductive state in a time-sharing manner.
- the switch circuit 130 can control different electrode groups and their corresponding control contact resistance detection circuits 120 to maintain a conductive state in a time-sharing manner.
- the switch circuit 130 may include a control terminal and a switch.
- the switch is used to electrically connect the electrode 110 and the contact impedance detection circuit 120 .
- the control terminal may be used to control the on and off of the switch.
- the switch circuit 130 may include a single-channel switch to implement the function of selecting multiple electrodes 110 .
- the number of channels of a single-channel switch may be related to the number of multiple electrodes 110
- the number of channels expected to be turned on may be related to the number of electrodes 110 expected to be turned on at the same time with the contact impedance circuit 120 .
- the switch circuit 130 may include a single-channel switch such as an 8-to-1 switch, an 8-to-2 switch, an 8-to-4 switch, or the like.
- the switch circuit 130 can use an 8-to-1 switch to select one of the eight electrodes 110 to be connected to the contact impedance circuit 120 at the same time.
- the switch circuit 130 may include a dual-channel switch to implement the function of selecting multiple electrodes 110 and multiple contact impedance circuits 120 . Similar to the single-channel switch, in some embodiments, the number of channels corresponding to the plurality of electrodes 110 in the dual-channel switch may be related to the number of the plurality of electrodes 110 , and the number of channels corresponding to the plurality of contact impedance circuits 120 in the dual-channel switch. The number of channels expected to be conductive may be related to the number of contact impedance circuits 120 , and the number of electrodes 110 expected to be conductive to the contact impedance circuit 120 at the same time may be related.
- the switch circuit 130 may include a two-channel switch of 2 out of 8 for the electrodes 110 and 1 out of 4 for the contact impedance circuit 120 .
- the switch circuit 130 may include a two-channel switch of 2 out of 8 for the electrodes 110 and 1 out of 4 for the contact impedance circuit 120 .
- the switch circuit 130 can also control the electrodes 110 to collect physiological signals in a time-sharing manner and measure the corresponding contact impedance of this part of the electrodes 110 .
- the switch circuit 130 can also control the electrode 110 to maintain a conductive state with the contact impedance detection circuit 120 and the gain circuit (used to process physiological signals) at different times.
- the contact resistance detection circuit 120 can obtain and process the detection signal corresponding to the electrode 110 to obtain the contact resistance information corresponding to the electrode 110 .
- the electrode 110 and the gain circuit are in a conductive state, the electrode 110 can collect physiological signals, and the gain circuit can process the collected physiological signals to obtain information reflecting the physiological state of the human body (such as muscle state, etc.).
- the switch circuit 130 controls the electrode 110 to asynchronously collect physiological signals and measure contact impedance, which can separate the detection signal and the physiological signal, thereby preventing the signals from interfering with each other and further improving the quality of the physiological signal.
- physiological signals and detection signals can also be processed simultaneously.
- filters can be used to extract physiological signals and detection signals respectively through the frequency difference between the two, so that the physiological signals and detection signals can be subsequently processed.
- Detection signals are evaluated. For example, a low-pass filter can be used to extract the analog-to-digital converted physiological signal, and a high-pass filter can be used to extract the analog-to-digital converted detection signal.
- FIG. 2 is a structural block diagram of a contact impedance circuit according to some embodiments of this specification.
- the contact impedance detection circuit 120 may include: an excitation source 121 , a voltage dividing impedance 122 and an analog-to-digital converter 123 .
- the excitation source 121 is connected to the voltage dividing impedance 122 for providing an excitation signal to the electrode 110 to generate a detection signal reflecting the contact impedance between the electrode 110 and the human body.
- the voltage dividing impedance 122 is connected to the plurality of electrodes 110 and is used to divide the voltage of the excitation source 121 to form the detection signal.
- the analog-to-digital converter is connected to the voltage dividing impedance 122 for analog-to-digital conversion of the detection signal.
- the excitation source 121 may be a circuit element that provides electrical energy.
- the excitation source 121 may be a current source or a voltage source.
- the excitation source 121 may provide an excitation signal to generate a detection signal reflecting the contact impedance between the electrode 110 and the human body.
- the excitation signal can be understood as forming a closed loop after flowing through the human body through the electrode 110.
- the detection signal can correspond to the contact impedance between the electrode 110 and the human body, and the partial voltage of the human body's impedance in the closed loop. The higher the intensity of the excitation source 121, the easier it is for the detection signal to be detected.
- the setting of the intensity of the excitation source 121 also needs to consider the safety voltage and current of the human body to ensure human body safety, and the intensity of the excitation source 121 should not be too high.
- the current intensity of the excitation source 121 may be less than 1 mA. Further, in some embodiments, the current intensity of the excitation source 121 may be less than 100 ⁇ A. Furthermore, in some embodiments, the current intensity of the excitation source 121 may be less than 10 ⁇ A.
- the voltage intensity of the excitation source 121 may range from 10 ⁇ V to 3.3V. Further, in some embodiments, the voltage intensity of the excitation source 121 may be in the intensity range of 100 mV to 9V.
- the excitation source 121 may be a DC excitation source or an AC excitation source.
- the excitation source 121 can be a DC excitation source or an AC excitation source.
- the frequency of the AC excitation source can be set so that the frequency of the detection signal and the frequency of the physiological signal are different, so that the subsequent processing can be based on The frequency difference between the detection signal and the physiological signal is used to extract the detection signal and physiological signal respectively.
- the frequency of the excitation source 121 can be set in a frequency range that is less susceptible to external interference (eg, power frequency interference) and has less interference with physiological signals.
- the excitation source 121 may be a DC excitation source or an AC excitation source with a frequency not less than 0.1 Hz.
- the number of excitation sources 121 may be one, and multiple electrodes 110 are connected in parallel to provide excitation signals for multiple electrodes 110 (for example, two electrodes 110 attached to the same muscle). In some embodiments, the number of excitation sources 121 may be multiple, and each excitation source 121 may be connected to one or more electrodes 110 respectively to provide an excitation signal for each electrode 110 . It should be noted that multiple contact impedance circuits 120 can also share one excitation source 121, and by connecting multiple electrodes 110 in parallel, the excitation source 121 can provide excitation signals for all electrodes 110.
- the excitation source 121 when the excitation source 121 is an AC excitation source, the excitation source 121 can generate multiple excitation signals with different frequencies at the same time, and can provide excitation signals with the same frequency or different frequencies to multiple electrodes 110. This produces detection signals of different frequencies.
- the excitation source 121 can provide excitation signals of different frequencies to the plurality of electrodes 110 to collect different detection signals. There may be a large distance between the multiple electrodes 110 (for example, greater than or equal to 5 cm), so that the closed loop through which the excitation signal flows can pass through different human tissues. In this arrangement, the multiple electrodes 110 correspond to detection signals of different frequencies. It can be used to reflect body composition information of the human body, such as body fat rate, bone density, body fluid content, etc.
- the excitation source 121 may provide a second excitation signal different from the excitation signal to generate a second detection signal.
- the second detection signal may reflect impedance information on the closed loop formed between each electrode and the human body at another frequency (ie, a frequency different from the frequency of the excitation signal), including the contact impedance between the electrode and the human body and the closed loop The impedance of human tissue in the circuit.
- body composition information of the human body can be determined using a first detection signal generated by a first excitation signal (eg, the aforementioned excitation signal) and a second detection signal generated by a second excitation signal.
- the excitation signal may be a voltage signal or a current signal. In some embodiments, the excitation signal may be a DC excitation signal or an AC signal, so that the frequency of the generated detection signal is related to the frequency of the excitation signal.
- the voltage dividing impedance 122 may be disposed between the excitation source 121 and the electrode 110 . Since the electrode 110 and the voltage-dividing impedance 122 are in the same circuit, the detection signal can correspond to the contact impedance between the electrode 110 and the human body, and the voltage division of the human body's impedance in the closed-loop circuit, or to the voltage division of the voltage-dividing impedance in the closed-loop circuit. pressure. Since the size of the detection signal is affected by the contact impedance between the electrode 110 and the human body, the size of the detection signal can reflect the size of the contact impedance, thereby reflecting the quality of the physiological signal.
- each electrode 110 may be connected to one voltage dividing impedance 122 .
- there may be only one voltage dividing impedance 122 which is connected to the conductive electrode 110 through the switch circuit 130 .
- the number of voltage dividing resistors 122 may be determined based on the number of electrodes 110 in the conductive state. For example only, when the two electrodes 110 synchronously maintain the conduction state with the contact resistance detection circuit 120 , the divided voltage impedance 122 may be two to synchronously maintain the conduction state with the two electrodes 110 . When the two electrodes 110 are in a conductive state with the contact resistance detection circuit 120 at different times, the voltage dividing impedance 122 may be one and is only connected to the electrode 110 in the conductive state.
- FIG. 3 is a schematic diagram of a signal measurement circuit according to some embodiments of this specification.
- the electrode 110 may include a first electrode 111 and a second electrode 112
- the voltage dividing impedance 122 may include a first voltage dividing impedance R4 and a second voltage dividing impedance R5 .
- the excitation source 121 (the excitation source shown in Figure 3) emits an excitation signal, it can flow through the first voltage dividing impedance R4.
- the first voltage dividing impedance R4 can divide the excitation signal to form a detection signal corresponding to the first electrode 111 .
- the excitation source 121 sends out an excitation signal, it can flow through the second voltage dividing impedance R5. After being divided by the second voltage dividing impedance R5, it can flow to the human body through the second electrode 112, and finally flow to the reference ground electrode, forming a third Two paths.
- the second voltage dividing impedance R5 can divide the excitation signal to form a detection signal corresponding to the second electrode 112 .
- the contact impedance R1 may refer to the contact impedance between the first electrode 111 and the human body
- the contact impedance R2 may refer to the contact impedance between the second electrode 112 and the human body
- the impedance R3 may include the impedance of the human body and the resistance between the reference ground electrode and the human body. impedance between.
- the first path and the second path may have certain symmetry.
- the first voltage dividing impedance R4 and the second voltage dividing impedance R5 may have the same parameters.
- the multiple excitation sources 121 may have the same parameters.
- one or more excitation sources 121 may generate excitation signals with the same frequency, and the first voltage-divided impedance R4 and the second voltage-divided impedance R5 have the same impedance under the excitation of the excitation sources 121 .
- the difference between the detection signal corresponding to the first electrode 111 and the detection signal corresponding to the second electrode 112 can be mainly derived from the first electrode 111 and the difference in contact impedance between the second electrode 112 and the human body. In this way, by comparing the difference between the detection signals, it can be reflected whether the fit between the two electrodes and the human body is good, and thus whether the physiological signals collected by the electrodes meet the requirements.
- the contact resistance detection circuit 120 and the gain circuit can remain on simultaneously with the electrode 110 .
- the subsequent input impedance will be too small due to parallel connection, resulting in the intensity of the collected physiological signal being too small and difficult to be monitored.
- physiological signals may be overwhelmed by various noises (including aliasing noise, thermal noise, etc.), causing the system to not work properly.
- the resistance values of the first voltage-dividing impedance R4 and the second voltage-dividing impedance R5 are too large, the partial voltage of the excitation signal will be too large, making the intensity of the detection signal too small to reflect the contact between the electrode and the human body. impedance.
- the voltage dividing impedance 122 may include a resistor to divide the voltage of the DC excitation source to an appropriate size to prevent voltage division due to excessive resistance of the voltage dividing impedance 122 Too large to ensure that the intensity of the detection signal is large, which can reflect the contact impedance between the electrode and the human body.
- the voltage dividing impedance 122 may include a resistor and/or a capacitor.
- the voltage dividing impedance 122 may have different impedances at different frequencies. With this arrangement, at the frequency of the excitation signal (i.e., higher frequency), the voltage dividing impedance 122 can have a smaller impedance, thereby reducing the voltage dividing of the excitation signal, so that the detection signal can better reflect the relationship between the electrode and the human body.
- the voltage dividing impedance 122 has a larger impedance, which avoids the subsequent decrease in input impedance due to parallel connection, so that the physiological signals can be more effectively Subsequent circuit pickup and processing.
- the contact impedance detection circuit 120 and the gain circuit maintain time-sharing conduction with the electrode 110 .
- the gain circuit when the contact resistance detection circuit 120 is connected to the electrode 110, the gain circuit is disconnected from the electrode 110, or when the gain circuit is connected to the electrode 110, the contact resistance detection circuit 120 is disconnected from the electrode 110.
- the gain circuit and the electrode 110 can remain conductive for a long time, and only the contact resistance detection circuit 120 and the electrode 110 are switched on and off. That is to say, the gain circuit and the electrode 110 do not need to be disconnected. Only when it is necessary to collect contact impedance information, the conduction of the contact impedance detection circuit 120 and the electrode 110 is controlled to collect detection information corresponding to the contact impedance.
- the contact resistance detection circuit 120 and the electrode 110 can be disconnected to save the number of switching times of the switch circuit 130 .
- the contact impedance detection circuit 120 will not affect the gain circuit that processes physiological signals, that is, the voltage-dividing impedance 122 will not be connected in parallel to the input end of the gain circuit. At this time, even if the voltage-dividing impedance 122 is used Smaller impedance values can also produce better quality detection signals.
- the voltage dividing impedance 122 when the excitation source 121 is a DC of 3.3V, the voltage dividing impedance 122 can be selected to be a resistance of 1 M ⁇ to 10 M ⁇ .
- the voltage dividing impedance 122 can be a capacitor of 1 pF to 50 pF.
- the analog-to-digital converter 123 may sample the detection signal to generate a digital signal corresponding to the detection signal.
- the sampling rate of the analog-to-digital converter 123 can be set in combination with the frequency of the excitation source 121 .
- the sampling rate of the analog-to-digital converter 123 may be greater than 2 times the frequency of the excitation source 121 .
- the sampling rate may be 4 times or more the frequency of the excitation source 121 .
- the signal measurement device 100 since the signal measurement device 100 has a large number of channels, most circuits cannot support the extremely high sampling rate of multiple channels, so the single-channel sampling rate and the frequency of the excitation source 121 should not be too high.
- the frequency of the excitation source 121 may be 1 kHz
- the single-channel sampling rate may be 8 kHz.
- different analog-to-digital converters may be selected based on resolution requirements for contact impedance detection. For example, when the power supply is 3.3V, the accuracy of a 12-bit analog-to-digital converter can reach 0.8mV, and the accuracy of a 16-bit analog-to-digital converter can reach 0.05mV.
- a follower may be coupled between the analog-to-digital converter 123 and the voltage dividing impedance 122 .
- the follower can be used to buffer or isolate components with different functions, such as isolating the voltage dividing impedance 122 and the analog-to-digital converter 123 (the analog-to-digital converter ADC shown in Figure 3), and keeping the input of the analog-to-digital converter 123 stable.
- the non-inverting input end of the follower U1 is connected to the first voltage dividing impedance R4 for receiving the detection signal, and the inverting input end of the follower U1 is connected to the output end of the follower U1.
- the non-inverting input end of the follower U2 is connected to the second voltage dividing impedance R5 for receiving the detection signal, and the inverting input end of the follower U2 is connected to the output end of the follower U2.
- the structure of the contact impedance detection circuit 120 (such as excitation source, voltage dividing impedance, analog-to-digital converter, etc.) can also be set differently according to different time-sharing measurement methods.
- the contact impedance detection circuit 120 may include an excitation source 121, two voltage dividing impedances 122, and two analog-to-digital converters 123.
- the excitation source 121 can provide excitation signals for two electrodes 110 attached to the same muscle to generate detection signals that reflect the contact impedance between each electrode 110 and the human body; the two voltage dividing impedances 122 are respectively coupled to the excitation source 121 and between each electrode 110, for dividing the voltage of the excitation source 121 to form a detection signal; the two analog-to-digital converters 123 can be used to perform analog-to-digital conversion of the detection signals corresponding to the two electrodes 110 respectively.
- the switch circuit 130 may control the first electrode and the second electrode that fit the first muscle to maintain a conductive state with the contact impedance detection circuit 120 respectively at the first moment.
- each voltage dividing resistance 122 in the contact resistance detection circuit 120 may be connected to the first electrode and the second electrode respectively.
- the switch circuit can disconnect the contact resistance detection circuit 120 from the first electrode and the second electrode, and control the third electrode and the fourth electrode that fit the second muscle to maintain conduction with the contact resistance detection circuit 120 respectively. On state to obtain detection signals corresponding to the third electrode and the fourth electrode.
- the switch circuit 130 can control two electrodes 110 attached to the same muscle to maintain the conductive state with the contact impedance detection circuit 120 at different times, that is, in a scenario where the two electrodes 110 asynchronously collect detection signals.
- the contact impedance detection circuit 120 may include an excitation source 121, a voltage dividing impedance 122 and an analog-to-digital converter 123.
- the excitation source 121 can provide an excitation signal for a certain conductive electrode 110 to generate a detection signal reflecting the contact impedance between the electrode 110 and the human body; the voltage dividing impedance 122 is coupled between the excitation source 121 and the conduction between the electrodes 110, used to divide the voltage of the excitation source 121 to form a detection signal; the analog-to-digital converter 123 can be used to perform analog-to-digital conversion of the detection signal corresponding to the conductive electrodes 110.
- the switch circuit 130 can control the first electrode and the contact resistance detection circuit to maintain a conductive state at the first moment to obtain the signal corresponding to the first electrode. detection signal.
- the switch circuit 130 can switch the electrode at the second moment and control the second electrode to maintain a conductive state with the contact resistance detection circuit to obtain a detection signal corresponding to the second electrode.
- FIG. 4 is a structural block diagram of a signal measurement circuit according to other embodiments of this specification.
- the signal measurement circuit 100 may also include a gain circuit 140, which may be used to process physiological signals.
- the gain circuit 140 and the contact impedance detection circuit 120 respectively maintain a conductive state with a certain electrode 110 at different times, or The conductive state is maintained with different electrodes 110 at the same time.
- the gain circuit 140 may be a signal processing circuit that amplifies the signal. In some embodiments, the gain circuit 140 can be used to provide gain for the physiological signal to improve the intensity and signal-to-noise ratio of the physiological signal and ensure the quality of the signal. In some embodiments, the gain circuit 140 and the contact impedance detection circuit 120 can maintain a conductive state with multiple electrodes 110 at different times, thereby controlling the electrodes 110 to asynchronously collect physiological signals and measure contact impedance through the switch circuit 130, thereby isolating Turn on detection signals and physiological signals to prevent signals from interfering with each other and further improve the quality of physiological signals.
- the number of gain circuits 140 may be one, and the gain circuit 140 may be connected to one or more electrodes 110 , and the switch circuit 130 controls the conduction state of the gain circuit 140 and the electrodes 110 . In some embodiments, the number of gain circuits 140 may be multiple, and the switch circuit 130 may select the electrode 110 and its corresponding gain circuit 140 to remain in a conductive state.
- the conduction method between the gain circuit 140 and the electrode 110 is similar to the conduction method between the contact impedance detection circuit 120 and the electrode 110. For specific implementation methods, please refer to the above-mentioned Figure 1 and related descriptions.
- the gain circuit 140 can provide gain for the full frequency band signal and can also provide gain for part of the frequency band signal. Taking the electromyographic signal as an example, most of the electromyographic signals are mainly distributed in the frequency band of 10Hz to 850Hz.
- the gain circuit 140 can provide gain for the electromyographic signal in the frequency band of 10Hz to 850Hz to avoid affecting other frequency bands (for example, except 10Hz). ⁇ 850Hz frequency band) provides gain, thereby suppressing the interference of noise on the EMG signal and improving the signal-to-noise ratio of the EMG signal.
- gain may be expressed as the degree of amplification of the electromyographic signal. For example, the greater the gain provided by the gain circuit 140, the greater the factor by which the myoelectric signal is amplified; conversely, the smaller the gain provided by the gain circuit 140, the smaller the factor by which the myoelectric signal is amplified.
- the size of the gain can be set according to the actual signal strength and the expected signal strength. In some embodiments, the gain size can be set according to the actual signal strength and expected signal strength of the electromyographic signal and the detection signal. For example, since the actual signal strength of the electromyographic signal is approximately 10 ⁇ V and below, and the resolution of a commonly used 12-bit analog-to-digital converter is approximately 0.8 mV (ie, the desired signal strength), the gain circuit 140 can be used to provide a signal from a hundred times to a thousand times. times the gain, so that the signal strength of the gain-enhanced myoelectric signal can reach 1mV ⁇ 1.65V.
- the gain at 10 Hz may be expressed as the gain of the motion artifact, and the ratio of the gain at 100 Hz to the gain at 10 Hz by the gain circuit 140 may be the first signal-to-noise ratio.
- the first signal-to-noise ratio may be set to not less than 4.
- the gain at 50 Hz may represent the gain of power frequency noise, and the ratio of the gain circuit 140 to the gain at 100 Hz and to the gain at 50 Hz is the second signal-to-noise ratio.
- the second signal-to-noise ratio may not be less than 2.
- a frequency of 1/2 of the sampling rate of the analog-to-digital converter can be expressed as the frequency of the aliasing noise, which is also called the first frequency.
- the frequency of aliasing noise can be 2kHz.
- the ratio of the gain at 100 Hz to the gain at the first frequency of the gain circuit 140 may be a third signal-to-noise ratio (ie, the aforementioned aliasing signal-to-noise ratio). In order to improve the gain signal-to-noise ratio of the gain circuit 140, the third signal-to-noise ratio may not be less than 10.
- the gain signal-to-noise ratio can also be used to measure the quality of the gain circuit.
- the gain circuit 140 may include a multi-stage amplifier sub-circuit, which is used to perform multi-stage amplification processing on the input signal (eg, physiological signal) to achieve the function of providing gain.
- the amplifier sub-circuit can be set up independently in the signal measurement circuit 100, or can also be set up as a component in a circuit with other functions (such as a filter circuit, etc.), and is set up as a whole with the circuits with other functions. It can also provide gains while realizing other functions.
- different stages of the multi-stage amplification sub-circuit may have different amplification gains for the input signal. For example, the gain of the amplifier subcircuit located in the front stage may be smaller than the gain of the amplifier subcircuit located in the subsequent stage.
- the gain circuit 140 may also be provided with a high-pass filter to filter out low-frequency noise such as motion artifacts and power frequency noise.
- the gain circuit 140 may also be provided with a low-pass filter to filter out interference signals with higher frequencies, such as high-frequency noise such as aliasing noise.
- the cutoff frequencies of the high-frequency filter and the low-pass filter can be set according to the frequency of the physiological signal.
- the gain circuit 140 can also be used to provide gain for the detection signal to increase the intensity of the detection signal and ensure subsequent accurate identification and processing of the detection signal. In some embodiments, the gain circuit 140 may provide gains for the physiological signal and the detection signal respectively in different time periods.
- the signal measurement circuit 100 may further include a processing circuit for determining parameter information reflecting the fit state of each electrode 110 to the human body based on the contact impedance of each electrode 110 .
- the processing circuit may be a module with certain signal processing functions, and the structure of the processing circuit.
- the parameter information may include impedance information between each electrode 110 and the human body, which may reflect the fit state between each electrode 110 and the human body, and further reflect the current wearing state of the wearable device and the fit degree of the size.
- the processing circuit can evaluate the fit state of the human body based on the parameter information and the amplitude range in which it is located. For example, when the parameter information is outside the target amplitude range, it may reflect that the quality of the physiological signal collected is very poor, and it is difficult to use the physiological signal for physiological monitoring in the future. Therefore, abnormal reminder information needs to be output to remind the user to check and adjust in time. When the parameter information is outside the target amplitude range, it can reflect that the quality of the physiological signal collected is very poor, and it is difficult to use the physiological signal for physiological monitoring in the future. Therefore, abnormal reminder information needs to be output to remind the user to check and adjust in time.
- the parameter information is within the target amplitude range, it can be determined that the current wearing status of the wearable device is well-worn, it can also be determined that the size fit of the wearable device is suitable for the size, it can also be determined that the user is in a fully warmed-up state, it can also be determined Or the skin where the current electrode is in contact with the human body is in a relatively moist state.
- the type of parameter information and the limit of the target amplitude range can be adjusted according to the measurement needs.
- the processing circuit can also use a signal processing algorithm to correct or compensate the physiological signal, thereby ensuring the quality or accuracy of the physiological signal.
- the signal processing algorithm may also include one or more of the following algorithms: signal filtering, wavelet transform, machine learning and other algorithms.
- the signal measurement circuit 100 can be applied to wearable devices.
- wearable devices may include smart bracelets, smart shoes and socks, smart glasses, smart helmets, smart watches, smart clothing, smart backpacks, smart accessories, etc. or any combination thereof.
- smart clothing such as fitness clothes or sportswear
- the signal measurement circuit 100 can acquire any two or two electrodes with a specific association (for example, two electrodes attached to the same muscle to receive the electromyographic signal of the same muscle).
- the physiological signals collected by any two electrodes or two electrodes with a specific correlation and evaluate the quality of the physiological signals based on the difference between the physiological signals collected by any two electrodes or two electrodes with a specific correlation, or evaluate the quality of the physiological signals between any two electrodes or two electrodes with a specific correlation The state of fit between the two electrodes and the human body.
- the signal measurement circuit 100 can also perform wearing status analysis, warm-up status analysis, size fit analysis, clothing life analysis, motion monitoring, skin status analysis, body composition analysis, etc. based on the evaluation results of the aforementioned physiological signals.
- An example signal measurement circuit 500 is provided below, and the specific implementation of time-sharing measurement is described in detail.
- FIG. 5 is a schematic structural diagram of a signal measurement circuit according to some embodiments of this specification.
- the signal measurement circuit 500 may include eight electrodes 510 , a contact resistance detection circuit 520 , and a switch circuit 530 .
- the contact impedance detection circuit 520 includes an excitation source 521 (the excitation source Source shown in Figure 5), voltage dividing impedances R1-R2, followers U1-U2, and analog-to-digital converters ADC1-ADC2.
- every two electrodes 510 among the eight electrodes 510 can be used as an electrode group and attached to the same muscle, and the two electrodes 510 are used to measure the physiological signal of the muscle.
- the eight electrodes 510 are respectively coupled to the switching circuit 530.
- One end of the voltage dividing impedance R1-R2 is coupled to the excitation source 521, and the other end is coupled to the switching circuit 530.
- the voltage dividing impedance R1-R2 can divide the voltage of the excitation source 521.
- the coupling end of the voltage dividing impedance R1-R2 and the switching circuit 530 is also connected to an analog-to-digital converter.
- the analog-to-digital converter is used to convert the detection signal into a digital signal for processing by subsequent equipment, such as calculating the contact impedance between the electrode and the human body. Identify the fit status of electrodes to the human body, etc.
- the followers U1-U2 can be set between the voltage dividing impedances R1-R2 and the analog-to-digital converters, and the followers U1-U2 can be used to stabilize the detection signals input to the analog-to-digital converters ADC1-ADC2.
- the switch circuit 530 can control 2 of the 8 electrodes 510 (select 2 from 8) while maintaining a conductive state with the contact resistance detection circuit 520, so that 2 electrodes 510 are simultaneously generated under the action of the excitation source 521.
- the contact impedance detection circuit 520 can receive detection signals reflecting the contact impedance between the two electrodes 510 and the human body, and perform analog-to-digital conversion on the two detection signals.
- the switch circuit 530 may include an 8-select-2 switch to achieve the above-mentioned function of selecting 2 electrodes 510 from the 8 electrodes 510 while maintaining a conductive state with the contact impedance detection circuit 520 .
- the switch circuit 530 can control two electrodes 510 among the eight electrodes 510 to maintain a conductive state with the contact impedance detection circuit 520 at different times, so that they are asynchronous under the action of the excitation source 521 Generates 2 detection signals. That is, at the same time, only one electrode 510 (select 1 out of 8) of the eight electrodes 510 remains in a conductive state with the contact resistance detection circuit 520 .
- the contact impedance detection circuit 520 can successively receive detection signals reflecting the contact impedance between the two electrodes 510 and the human body, and perform analog-to-digital conversion on the two detection signals.
- the switch circuit 530 may include an 8-to-2 switch to achieve the above-mentioned function of controlling two electrodes 510 among the eight electrodes 510 to maintain a conductive state with the contact impedance detection circuit 520 at different times. In some embodiments, the switch circuit 530 may also include an 8-to-1 switch to achieve the function of controlling only one electrode 510 among the eight electrodes 510 to remain in a conductive state with the contact resistance detection circuit 520 at the same time.
- the switch circuit 530 can also control some of the eight electrodes 510 to maintain conduction with the contact impedance detection circuit 520 and the gain circuit (not shown in Figure 5) at different times. To achieve asynchronous collection of physiological signals and detection of contact impedance.
- FIG. 6 is a schematic diagram of the contact impedance curve corresponding to multiple electrodes when the user moves according to some embodiments of this specification.
- the abscissa represents the number of sampling points
- the ordinate represents the contact impedance corresponding to the electrode.
- Figure (a) includes the curve 610 and the curve 620 of the contact impedance corresponding to the two electrodes attached to the left pectoralis muscle;
- Figure (b) includes the curve of the contact impedance corresponding to the two electrodes attached to the left triceps muscle.
- Figure (c) includes the curve 650 and curve 660 of the contact impedance corresponding to the two electrodes attached to the left biceps brachii;
- Figure (d) includes the two electrodes attached to the left oblique muscle The corresponding curves 670 and 680 of the contact impedance.
- the contact impedance difference between the two electrodes that fit different muscles for example, the difference between the ordinates of curve 610 and curve 620, the ordinate difference between curve 630 and curve 640
- the coordinate difference, the ordinate difference between curve 650 and curve 660, the ordinate difference between curve 670 and curve 680) are also different.
- the absolute value of the contact impedance (for example, the ordinate size of the curve 610-curve 680) becomes smaller, and the contact impedance difference also becomes smaller, so that it can It is determined that warm-up can help improve the fit between the electrode and the human body and improve the quality of the physiological signals collected.
- FIG. 7 is an exemplary flowchart of a signal measurement method according to some embodiments of this specification.
- the process 700 may be executed by the aforementioned smart wearable device, which may include a processor, a memory, and the signal measurement circuit 100 as described above, wherein the memory may store a computer program for executing the process 700,
- the processor may be part of the processing circuit in the signal measurement circuit 100, or may be an independently provided electronic device capable of realizing the functions of the processing circuit.
- the signal measurement circuit 100 please refer to the parts of FIGS. 1-6 and their related discussions.
- process 700 may include:
- Step 710 Control the conduction state of the plurality of electrodes and the contact resistance detection circuit through the switch circuit, so that at the same time, only some of the plurality of electrodes and the contact resistance detection circuit remain in the conduction state.
- step 710 may be implemented by the switching circuit 130 in the signal measurement circuit 100 .
- multiple electrodes in the signal measurement circuit 100 can be used to fit with the human body to collect physiological signals (eg, myoelectric signals) of the human body.
- physiological signals eg, myoelectric signals
- a detection signal reflecting the contact impedance between the electrode and the human body can also be obtained.
- the contact impedance detection circuit maintains a conductive state with part of the electrode, the contact impedance detection circuit can receive the detection signal corresponding to the part of the electrode, and the contact impedance detection circuit can perform operations (for example, difference, summation) on the detection signal to determine The contact impedance between the human body and some electrodes.
- the other part of the electrode can remain conductive with the contact impedance detection circuit at another time.
- the plurality of electrodes may include two electrodes attached to the same muscle.
- the switch circuit can control two electrodes attached to the same muscle while maintaining a conductive state with the contact impedance detection circuit, that is, the contact impedance detection circuit can capture two electrodes of the same muscle at the same time.
- Contact impedance information can be used to avoid fluctuations in contact impedance over time and interference from other signals (such as detection signals corresponding to other electrodes), and more accurately assess the quality of physiological signals.
- two electrodes attached to the same muscle can be controlled to maintain a conductive state with the contact impedance detection circuit at different times. That is, the contact impedance detection circuit can obtain two detection signals asynchronously, and the asynchronous detection detects the two The contact impedance between an electrode and the human body thereby reduces the burden of processing the detection circuit at the same time, for example, reducing the system's requirements for the sampling frequency in the subsequent analog-to-digital conversion process. In addition, asynchronous detection can save subsequent circuit costs and prevent mutual interference between the two electrodes, thereby further improving the quality of physiological signals.
- the switch circuit can control the electrode to remain conductive with the gain circuit and the contact impedance detection circuit at different times, that is, to asynchronously collect physiological signals and measure contact impedance, thereby isolating the detection signal and the physiological signal, preventing Signals interfere with each other, further improving the quality of physiological signals.
- Step 720 Based on the contact impedance of each electrode, determine parameter information reflecting the fit state of each electrode and the human body.
- step 710 may be implemented by the contact impedance detection circuit 120 or the processing circuit in the signal measurement circuit 100 .
- the parameter information may include impedance information between each electrode and the human body.
- the fit state between each electrode and the human body can be reflected, and thus the current wearing condition of the wearable device can be reflected.
- Condition and size fit may be based on the parameter information of the fit state of the electrode and the human body.
- the current wearing state, size fit, warm-up state, clothing life state, motion monitoring, and skin state where the electrode contacts the human body can also be evaluated. , one or more types of information in body composition information, or other wearing information.
- the contact impedance of the electrode when the contact impedance of the electrode is greater than a certain threshold, it may reflect that the electrode is not worn correctly or the user's skin is too dry, so that indication information can be sent to the user so that the user can refer to the indication information to determine the wearing status of the electrode. and size fit to check or adjust.
- a detection signal reflecting the quality of the physiological signal can also be obtained, the detection signal can be digitally sampled, and the index parameter value can be determined, which can be used to reflect the quality of the physiological signal.
- the processing circuit can determine the quality of the physiological signal based on the amplitude fluctuation of the index parameter value within a preset time period. For example, when the index parameter value is outside the target amplitude range, it may reflect that the quality of the physiological signal collected is very poor, and it is difficult to use the physiological signal for physiological monitoring in the future. Therefore, abnormal reminder information needs to be output to remind the user to check and adjust in time. In some embodiments, there are many factors that cause poor quality of physiological signals, such as electrodes detaching from human skin or lesions on the user's body. The user can check various factors in a timely manner based on the abnormality reminder information.
- the processing circuit may output first indication information indicating the user's movement. If the index parameter value is within the first amplitude range, it means that the quality of the physiological signal is still poor and it is difficult to accurately reflect the user's physiological state. Therefore, it is recommended that the user detect or adjust to improve the quality of the physiological signal.
- the user can exercise according to the first instruction information and reduce contact impedance through warming up, thereby improving the quality of physiological signals.
- the processing circuit may output second indication information instructing the user to adjust the fitting state of the electrode.
- the index parameter value is within the second amplitude range, it can indicate that there may be abnormalities in the fit state between the electrode and human skin, such as poor contact or incomplete fit, etc., resulting in poor quality of physiological signals and difficulty in accurately detecting them. Reflects the user's physiological state. At this time, the user can adjust the fitting state of the electrode according to the second instruction information, so that the user can change the size of the contact impedance.
- actions performed by the user may also cause the amplitude of the indicator parameter value to fluctuate.
- the user's motion actions can be monitored based on the amplitude fluctuation of the index parameter value within a preset time period. For example, when the index parameter value is less than a preset threshold, and the index parameter value has more than a preset number of peaks within a preset time period, it can be determined that the user performed exercise within the preset time period.
- the user's warm-up state can be determined based on the difference or ratio between the contact impedances of two electrodes attached to the same muscle.
- the difference or ratio between contact impedances may reflect the user's warm-up status. Referring to Figure 6, as time goes by, the smaller the difference or ratio between contact impedances, the better the warm-up state; conversely, the larger the difference or ratio between contact impedances, the worse the warm-up state.
- the contact impedance of each electrode can also independently reflect the user's warm-up status. For example, the smaller the absolute value of contact impedance, the better the warm-up state.
- detection signals of different frequencies corresponding to multiple electrodes 110 can also be used to reflect body composition information of the human body, such as body fat percentage, bone density, body fluid content, and other body composition information.
- Possible beneficial effects brought about by the embodiments of this specification include but are not limited to: (1) The contact impedance between the electrode and the human body can be measured through the contact impedance detection circuit, and the fit between the electrode and the human body is determined based on the contact impedance. status, thereby ensuring the quality of the physiological signals collected by the electrodes; (2) When it is necessary to monitor the fit status of multiple electrodes to different parts of the human body, it can be maintained by selecting different partial electrodes and contact impedance detection circuits at different times. The conduction state is used to collect the contact impedance corresponding to different partial electrodes in a time-sharing manner, which can prevent interference between different electrodes and save resources of the contact impedance detection circuit.
- numbers are used to describe the quantities of components and properties. It should be understood that such numbers used to describe the embodiments are modified by the modifiers "about”, “approximately” or “substantially” in some examples. Grooming. Unless otherwise stated, “about,” “approximately,” or “substantially” means that the stated number is allowed to vary by ⁇ 20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximations that may vary depending on the desired features of the individual embodiment. In some embodiments, numerical parameters should account for the specified number of significant digits and use general digit preservation methods. Although the numerical ranges and parameters used to identify the breadth of ranges in some embodiments of this specification are approximations, in specific embodiments, such numerical values are set as accurately as is feasible.
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Abstract
本说明书实施例公开了一种信号测量电路及方法。该电路包括:多个电极,用于贴合人体并采集人体的生理信号;接触阻抗检测电路,与多个电极电连接,该接触阻抗检测电路用于测量电极与人体之间的接触阻抗;以及开关电路,用于控制多个电极与接触阻抗检测电路的导通状态,使得在同一时刻,仅有多个电极中的部分电极与接触阻抗检测电路保持导通状态。本说明书可以通过测量得到的电极与人体之间的接触阻抗,并基于该接触阻抗确定电极与人体之间的贴合状态,确保电极采集到的生理信号的质量。还可以通过在不同时刻下选择不同的电极与接触阻抗检测电路保持导通状态,以分时采集不同的部分电极对应的接触阻抗,从而确保采集到的生理信号的质量。
Description
本说明书涉及电路设计领域,特别涉及一种信号测量电路及方法。
随着人们对生理监测、疾病诊断、实验研究等领域的关注越来越高,对信号测量的电路结构的研究也越来越被重视。信号测量电路往往可以通过采集生理信号获取与用户身体状况相关的数据。例如,信号测量电路可以监测并利用肌电信号的信息对肌肉发力情况、肌疲劳性等肌肉状态,甚至重症肌无力、肌强直以及肌萎缩等多种疾病做出临床诊断。
然而,在信号测量电路采集生理信号时,常常会因为电极与人体之间贴合较差、在干燥环境下皮肤近乎绝缘等原因,导致采集的生理信号质量差,难以准确地进行监测。
因此,希望可以提出一种能够提高生理信号的质量的装置。
发明内容
本说明书实施例之一提供一种信号测量电路。该电路包括:多个电极,用于贴合人体并采集人体的生理信号;接触阻抗检测电路,与多个电极电连接,该接触阻抗检测电路用于测量电极与人体之间的接触阻抗;以及开关电路,用于控制多个电极与接触阻抗检测电路的导通状态,使得在同一时刻,仅有多个电极中的部分电极与接触阻抗检测电路保持导通状态。
在一些实施例中,多个电极包括两个贴合同一肌肉的电极,两个贴合同一肌肉的电极同步保持与接触阻抗检测电路的导通状态。
在一些实施例中,多个电极包括两个贴合同一肌肉的电极,两个贴合同一肌肉的电极分别在不同时刻保持与接触阻抗检测电路的导通状态。
在一些实施例中,接触阻抗检测电路包括:激励源,用于为两个贴合同一肌肉的电极提供激励信号,以产生反映每一电极与人体之间接触阻抗的检测信号;两个分压阻抗,分别耦接于激励源和每一电极之间,用于对激励源进行分压形成检测信号;两个模数转换器,分别用于对检测信号进行模数转换。
在一些实施例中,接触阻抗检测电路包括:激励源,用于为每一电极提供激励信号,以产生反映每一电极与人体之间接触阻抗的检测信号;分压阻抗,耦接于激励源和每一电极之间,用于对激励源进行分压形成检测信号;模数转换器,用于对检测信号进行模数转换。
在一些实施例中,激励源为直流激励源或频率不小于0.1Hz的交流激励源。
在一些实施例中,分压阻抗包括电阻和/或电容。
在一些实施例中,模数转换器与分压阻抗之间耦接跟随器。
在一些实施例中,信号测量电路还包括用于处理生理信号的增益电路,增益电路和接触阻抗检测电路之间分别在不同时刻与多个电极保持导通状态。
在一些实施例中,信号测量电路还包括处理电路,用于根据每个电极的接触阻抗,确定反映每个电极与人体的贴合状态的参数信息。
本说明书实施例之一提供一种信号测量方法,该方法包括:通过开关电路控制多个电极与接触阻抗检测电路的导通状态,使得在同一时刻,仅有多个电极中的部分电极与接触阻抗检测电路保持导通状态,其中多个电极用于贴合人体并采集人体的生理信号,接触阻抗检测电路用于测量电极与人体之间的接触阻抗;根据每个电极的接触阻抗,确定反映每个电极与人体的贴合状态的参数信息。
在一些实施例中,该方法还包括:根据两个贴合同一肌肉的电极的接触阻抗之间的差值或比值,确定用户的热身状态。
本说明书实施例中通过测量得到的电极与人体之间的接触阻抗,并基于该接触阻抗确定电极与人体之间的贴合状态,进而确保电极采集到的生理信号的质量。
再者,本说明书实施例还可以通过在不同时刻下选择不同的部分电极与接触阻抗检测电路保持导通状态,以分时采集不同的部分电极对应的接触阻抗,从而确保信号测量电路中不同电极采集到的生理信号的质量。
本说明书将以示例性实施例的方式进一步说明,这些示例性实施例将通过附图进行详细描述。这些实施例并非限制性的,在这些实施例中,相同的编号表示相同的结构,其中:
图1是根据本说明书一些实施例所示的信号测量电路的结构框图;
图2是根据本说明书一些实施例所示的接触阻抗电路的结构框图;
图3是根据本说明书一些实施例所示的信号测量电路的原理示意图;
图4是根据本说明书另一些实施例所示的信号测量电路的结构框图;
图5是根据本说明书一些实施例所示的信号测量电路的结构示意图;
图6是根据本说明书一些实施例所示的用户运动时多个电极所对应的接触阻抗的曲线示意图;
图7是根据本说明书一些实施例所示的信号测量方法的示例性流程图。
为了更清楚地说明本说明书实施例的技术方案,下面将对实施例描述中所需要使用的附图作简单的介绍。显而易见地,下面描述中的附图仅仅是本说明书的一些示例或实施例,对于本领域的普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据这些附图将本说明书应用于其它类似情景。除非从语言环境中显而易见或另做说明,图中相同标号代表相同结构或操作。
应当理解,本文使用的“***”、“装置”、“单元”和/或“模块”是用于区分不同级别的不同组件、元件、部件、部分或装配的一种方法。然而,如果其他词语可实现相同的目的,则可通过其他表达来替换所述词语。
如本说明书和权利要求书中所示,除非上下文明确提示例外情形,“一”、“一个”、“一种”和/或“该”等词并非特指单数,也可包括复数。一般说来,术语“包括”与“包含”仅提示包括已明确标识的步骤和元素,而这些步骤和元素不构成一个排它性的罗列,方法或者设备也可能包含其它的步骤或元素。
本说明书中使用了流程图用来说明根据本说明书的实施例的***所执行的操作。应当理解的是,前面或后面操作不一定按照顺序来精确地执行。相反,可以按照倒序或同时处理各个步骤。同时,也可以将其他操作添加到这些过程中,或从这些过程移除某一步或数步操作。
本说明书一个或多个实施例的信号测量电路和方法可以应用于采集一个或多个生理信号的设备,如智能穿戴设备、医疗检测设备或信号分析设备。在一些实施例中,智能穿戴设备可以设置在人体各个部位(例如,小腿、大腿、腰、后背、胸部、肩部、颈部等),用于采集用户在不同状态时其身体各个部位的生理信号,后续还可以进一步对采集的信号进行处理。在一些实施例中,智能穿戴设备可以包括智能手镯、智能鞋袜、智能眼镜、智能头盔、智能手表、智能衣服、智能背包、智能配件等或其任意组合。
在一些实施例中,生理信号为可以被检测的能够体现身体状态的信号,例如,生理信号可以包括呼吸信号、心电信号(ECG)、肌电信号、血压信号、温度信号等多种信号。在一些实施例中,所述生理信号的频率范围可以包括0.05Hz~2kHz,其中,所述心电信号的频率范围可以包括0.05Hz~100Hz,所述肌电信号的范围可以包括10Hz~850Hz。
在一些实施例中,信号测量电路采集到的生理信号的强度会受到多种因素的影响,如人体与电极之间的接触阻抗、人体肌肉的激活程度等。接触阻抗为人体的皮肤与信号测量电路的电极接触而产生的阻抗,其阻抗值会受到皮肤的干燥状态、人体与电极的贴合状态的影响,从而影响生理信号。例如,皮肤越干燥,接触阻抗的阻抗值越大,导致采集到的生理信号的质量越差;反之,皮肤越湿润,接触阻抗的阻抗值越小,采集到的生理信号的质量越好。再例如,人体与电极的接触不良会导致接触阻抗的阻抗值变大,使得生理信号的质量变差。
在一些实施例中,肌肉的激活程度是肌肉在工作时的活跃状态,其可以影响肌肉释放的肌电信号的强度。对于用户来说,存在很多日常的运动监测需求(如,走路、站姿等),相对于健身监测需求(如,深蹲、跑步等),日常的运动对肌肉的激活程度低,会造成生理信号(如,肌电信号)识别的强度较低,影响后续的识别和处理。这种情况下,若在生理信号采集过程中,用户佩戴电极不正确或是用户的皮肤过于干燥,则人体与电极之间的接触阻抗容易较大,导致采集到的生理信号的质量差,难以准确地对用户进行生理监测。
因此,根据本说明书的一些实施例,首先可以通过接触阻抗检测电路测量得到的电极与人体之间的接触阻抗,并基于该接触阻抗确定电极与人体之间的贴合状态,进而确保电极采集到的生理信号的质量。再者,当要监测多个电极与人体身体不同部位的贴合状态时,可以通过在不同时刻下选择不同的部分电极与接触阻抗检测电路保持导通状态,以分时采集不同的部分电极对应的接触阻抗,这样可以防止不同电极之间的干扰,并且节约接触阻抗检测电路的资源。
图1是根据本说明书一些实施例所示的信号测量电路的结构框图。信号测量电路如图1所示,信号测量电路100可以包括:多个电极110、开关电路130和接触阻抗检测电路120。多个电极110与开关电路130电连接,接触阻抗检测电路120与开关电路130电连接。在一些实施例中,多个电极110可以贴合人体并采集所述人体的生理信号。接触阻抗检测电路120可以用于测量电极与人体之间的接触阻抗。开 关电路130用于控制多个电极110与所述接触阻抗检测电路120的导通状态。在一些实施例中,在同一时刻,仅有多个电极110中的部分电极110与所述接触阻抗检测电路120保持导通状态。
电极110可以为通过接触以输入或导出电流的电路元件。在一些实施例中,电极110可以贴合人体,以采集人体的生理信号(例如肌电信号、ECG信号、血压信号等)。在一些实施例中,电极110可以采集人***于目标频率范围内的生理信号。目标频率范围可以包括人体产生的大部分生理信号的频率,也可以包括期望获取到的生理信号所在的频率。
在一些实施例中,电极110可以贴合在人体的不同部位,以采集不同部位的生理信号。例如,电极110可以贴合在用户的胸部、腕部、背部、腿部、手臂、头部等部位。在一些实施例中,可以利用一个电极采集一个部位的生理信号,或者利用两个电极作为一组共同采集同一部位的生理信号。
在一些实施例中,多个电极110可以包括两个贴合同一肌肉的电极110。在一些实施例中,两个贴合同一肌肉的电极110可以作为一组电极,以采集该同一肌肉在同一时刻下的两个生理信号。可选地,该同一时刻下的两个生理信号可以经过差分、求和等运算过程后形成反映该同一肌肉的运动状态的参数。如此,可以防止因某个电极损坏或与人体贴合状态不好而导致生理信号的测量不准确。在一些可替代的实施例中,两个贴合同一肌肉的电极110也可以分时进行工作,以采集该部位在不同时刻下的两个生理信号。不同时刻下的两个生理信号可以反映生理信号的变化,以对用户的生理状态进行监测。关于分时工作的具体描述,可以参考本说明书的其他实施例,例如开关电路及其相关描述。
在一些实施例中,电极110与人体之间的接触阻抗可以在外部激励下(如,激励信号)产生检测信号,从而可以根据该检测信号确定该电极110所对应的接触阻抗。在一些实施例中,检测信号可以为反映接触阻抗的大小的信号,相应地,可以用于反映生理信号的质量。通过分析单个电极110对应的检测信号,或者多个电极之间的检测信号的差异,可以评估单个电极或多个电极所采集的生理信号的质量。例如,如果某个电极对应的检测信号表示该电极与人体的接触阻抗大于某个阈值,意味着该电极没有佩戴正确或者用户的皮肤过于干燥。再例如,如果两个电极对应的检测信号之间的差异大,表示这两个电极与人体的接触阻抗的差异大,意味着其中至少有一个电极没有佩戴正确或者用户的皮肤过于干燥,则所采集的生理信号的质量较差;反之,如果两个电极对应的检测信号之间的差异小,表示这两个电极与人体的接触阻抗的差异小,意味着所采集的生理信号的质量较好。在一些实施例中,检测信号还可以反映用户的电极佩戴状态、体成分信息、皮肤状态等其他信息。
在一些实施例中,贴合同一肌肉的两个电极110对应的接触阻抗可以同时产生两个检测信号。根据这两个检测信号可以识别出同一时刻下所述两个电极110与人体的贴合状态,以此反映该时刻下所采集的生理信号的质量。可选地,所述两个电极110对应的外部激励可以提供不同频率的激励信号,则通过对不同频率的检测信号分别进行信号处理后,可以获得人体在不同频率下的阻抗信息,由此用于反映人体的体成分信息。在一些实施例中,贴合同一肌肉的两个电极110分别在不同时刻下产生两个检测信号。在一些场景下,这两个检测信号的获取时间的间隔很短,在这段时间内,仍然可以认为所述两个电极110与人体的贴合状态变化不大。对这两个检测信号进行处理,例如,差分或求和等运算,仍然可以反映这段时间内两个电极110与人体的贴合状态,由此反映同时段内生理信号的质量。
在一些实施例中,电极110可以以柔性贴片的形式与人体接触,该贴片可以为圆形、椭圆形、矩形、菱形等规则形状或其他不规则形状。在一些实施例中,电极可以采用金属导电材料(如,铜、铝、镍、铬、合金等)、非金属导电材料(如,导电塑料、导电橡胶、导电硅胶、导电织物)或其他导电材料。
在一些实施例中,信号测量电路100还可以包括一个或多个参考地电极(图1中未示出),该参考地电极可以作为信号测量电路100中的参考地。在一些实施例中,该一个或多个参考地电极可以用于与人体贴合,以使前述激励信号能够经由人体流向参考地电极,形成闭环回路。在一些实施例中,该一个或多个参考地电极可以设置在平坦且较为稳定(动作较少)的部位,例如人体背部、头部等,从而能够有效降低噪音。
接触阻抗检测电路120可以为具有一定的信号处理功能(如放大、整流、A/D转换、滤波、逻辑处理等)的结构模块。在一些实施例中,接触阻抗检测电路120可以基于前述与电极对应的检测信号,确定电极110与人体之间的接触阻抗。
仅作为示例,在一些实施例中,接触阻抗检测电路120可以单独对某个电极110对应的检测信号进行处理,并以此评估该电极所采集的生理信号。示例性的,接触阻抗检测电路120可以对与该电极110所对应的检测信号进行模数(A/D)转换,转换后的数字信号经过进一步处理后可以单独反映该电极110与人体之间的接触阻抗,从而反映电极110与人体的贴合状态,以此确定对应电极110所采集的生理信号的质量。
在一些实施例中,接触阻抗检测电路120可以结合多个电极110对应的检测信号,综合评估这些电极110所采集生理信号。示例性的,接触阻抗检测电路120可以对多个电极110(如,贴合同一肌肉的 两个电极110)所对应的检测信号进行运算(例如,差分、求和),然后对运算后的结果进行模数(A/D)转换。经过运算后的检测信号可以综合反映两个电极110与人体之间的接触阻抗的差异,从而反映两个电极110与人体的贴合状态,以此确定生理信号的质量。
在一些实施例中,接触阻抗检测电路120与电极110保持导通状态时,可以与电极110进行数据传输,接触阻抗检测电路120可以同时获取到电极110对应的检测信号以及电极110采集到的生理信号。在一些实施例中,接触阻抗检测电路120还可以对电极110所对应的检测信号进行滤波,以区分开电极110对应的检测信号与电极110所采集的生理信号。当激励信号的频率与生理信号的频率不同时,由激励信号产生的检测信号的频率与生理信号的频率也不同,从而可以利用滤波器分别提取检测信号和生理信号,以便后续对生理信号和检测信号进行评估。由于电极110对应的检测信号的强度大于以及电极110采集到的生理信号的强度,在一些可选的实施例中,接触阻抗检测电路120可以通过跟随器和模数转换器,基于信号强度区分开电极110对应的检测信号以及电极110采集到的生理信号。
在一些实施例中,接触阻抗检测电路120的数量可以是一个,该接触阻抗检测电路120可以与开关电路130耦合。在这种情况下,通过开关电路130可以在不同时刻选择多个电极110中的一个或多个与接触阻抗检测电路120导通。
在一些实施例中,接触阻抗检测电路120的数量可以是多个。在这种情况下,开关电路130可以选择多个接触阻抗检测电路120中的部分接触阻抗检测电路120与多个电极110中的部分电极保持导通状态。也就是说,通过开关电路130可以同时对需要导通的电极110以及需要导通的接触阻抗检测电路120进行选择。在一些可选的实施例中,在接触阻抗检测电路120为多个时,开关电路130也可以为多个,每个接触阻抗检测电路120可以通过一个开关电路130与一个或多个电极120耦合,多个开关电路130可以在同一时刻控制多个接触阻抗检测电路120与多个电极保持导通状态。也就是说,通过多个开关电路130可以控制多个电极110与其对应的接触阻抗检测电路120导通。关于接触阻抗检测电路120的具体描述,可以参看本说明书的其他实施例,例如图2及其相关描述。
开关电路130可以为切换多个设备之间导通状态和关断状态的控制结构。在一些实施例中,导通状态可以反映设备之间是否能够进行数据传输,关断状态可以反映设备之间难以进行数据传输。在一些实施例中,开关电路130的输入端与多个电极110连接,开关电路130的输出端可以与接触阻抗检测电路120连接,开关电路130可以控制输入端和输出端的导通和关断的切换。开关电路130可以选择与多个电极110中的一个或多个电极110对应的输入端与开关电路130的输出端导通,从而实现电极110与接触阻抗检测电路120保持导通状态。
在一些实施例中,开关电路130可以控制多个电极110中的部分电极110同时导通,以同步测量该部分电极110对应的接触阻抗。在这种情况下,接触阻抗检测电路120可以分时测量该部分电极110与其他电极110对应的接触阻抗。在一些可选的实施例中,开关电路130还可以控制电极110中的每个电极分时导通,以测量每一电极110对应的接触阻抗。在一些可选的实施例中,开关电路130还可以控制电极110分时采集生理信号和测量该部分电极110对应的接触阻抗。下面分别对上述三种分时测量进行说明。
在一些实施例中,开关电路130可以控制不同部分的电极110在不同时刻保持与接触阻抗检测电路120的导通状态,以分时测量不同部分的电极与人体之间的接触阻抗。例如,多个电极110可以包括贴合同一肌肉的两个电极110,开关电路130可以控制两个贴合同一肌肉的电极110同步保持与接触阻抗检测电路120的导通状态。在这种情况下,接触阻抗检测电路120可以同步检测两个电极110与人体之间的接触阻抗,以此确定两个电极110所采集的生理信号(如,肌电信号)的质量。也就是说,可以从多个电极110中选择两个电极110在同一时刻进行测量,其他电极110在另一个或多个时刻进行测量。接触阻抗检测电路120可以同时获取到与贴合同一肌肉的两个电极110对应的检测信号,从而可以同步检测两个电极110与人体之间的接触阻抗,以评估该肌肉对应的生理信号的质量。在一些实施例中,接触阻抗检测电路120还可以分别根据两个检测信号,确定每个电极110对应的接触阻抗,从而分别评估两个电极110采集的生理信号的质量。在一些实施例中,如果两个贴合同一肌肉的电极100所采集的两路肌电信号的质量都较好时,可以通过其它处理电路进一步对这两路肌电信号进行运算放大(例如,差分放大),得到反映肌肉状态的参数值。可选地,其它处理电路可以根据两个电极110与人体之间的接触阻抗,对两路肌电信号进行校准或修改,提高电极采集肌电信号的准确性。
如此,开关电路130通过控制贴合同一肌肉的两个电极110同步与接触阻抗检测电路120保持导通状态,可以捕捉到同一时刻下同一肌肉的两个电极的接触阻抗信息,从而避免接触阻抗随时间的波动以及其他信号的干扰(如其他电极对应的检测信号),更准确地评估生理信号的质量。
在一些实施例中,以两个贴合同一肌肉的电极110为一个电极组,电极110可以包括多个电极组,开关电路130可以控制一个或多个电极组与接触阻抗检测电路120的导通以同时测量接触阻抗。示例性的,假设有4个电极组,则开关电路130可以控制其中1个电极组中的两个电极110同时保持与接触阻抗检测 电路120的导通状态,而其他3个电极组处于关断状态,不与接触阻抗检测电路120进行传输数据。开关电路130还可以控制其中2个电极组中的电极110同时保持与接触阻抗检测电路120的导通状态,而其他2个电极组处于关断状态,不与接触阻抗检测电路120进行传输数据,从而获取到同一时刻下的2个电极组的接触阻抗信息。
在一些实施例中,开关电路130可以控制每个电极110在不同时刻保持与接触阻抗检测电路120的导通状态,以分时测量每个电极110与人体之间的接触阻抗。例如,开关电路130可以控制两个贴合同一肌肉的电极110分别在不同时刻保持与所述接触阻抗检测电路120的导通状态。在这种情况下,接触阻抗检测电路120可以分时检测两个电极110与人体之间的接触阻抗,以此确定两个电极110所采集的生理信号(如,肌电信号)的质量。也就是说,接触阻抗检测电路120可以异步获取与两个电极110对应的检测信号,以评估该肌肉对应的生理信号的质量。在一些实施例中,接触阻抗检测电路120可以分别根据两个检测信号,确定每个电极110对应的接触阻抗,从而分别评估两个电极110采集的生理信号的质量。由于两个检测信号的获取时间的间隔很短,在一些实施例中,接触阻抗检测电路120也可以根据两个检测信号的差异,确定两个电极110之间的接触阻抗差值,评估两个电极110采集的生理信号的质量。
如此,接触阻抗检测电路120可以异步检测两个电极110与人体之间的接触阻抗,减少同一时刻后续电路处理检测信号的负担,例如,降低***对后续模数转换过程中的采样频率的要求。并且,异步检测可以节约后续电路成本,并且能够防止两个电极110的相互干扰,从而进一步提升生理信号的质量。
示例性的,接触阻抗检测电路120可以在第一时刻获取到第一电极对应的检测信号,然后等待直到第二时刻获取到第二电极对应的检测信号,再根据第一电极对应的检测信号和第二电极对应的检测信号,评估两个电极110采集的生理信号的质量。需要说明的是,为了保证开关通道中的信号稳定以及防止异步检测导致的信号误差,第一时刻和第二时刻之间的间隔时长可以设置得很短。在激励源为交流激励源时,由于接触阻抗检测电路120读取多个检测信号需要等待完整周期,在一些实施例中,第一时刻和第二时刻之间的间隔时长还可以根据交流激励源的频率进行设定。示例性的,第一时刻和第二时刻之间的间隔时长可以为100μs、1ms、10ms、20ms等。
在一些实施例中,在接触阻抗检测电路120的数量为多个时,开关电路130还可以控制多个接触阻抗检测电路120中的部分接触阻抗检测电路120处于导通状态,另一部分接触阻抗检测电路120处于关断状态,从而使得需要导通的部分接触阻抗检测电路120能够与需要导通的部分电极110进行数据传输。在一些实施例中,接触阻抗检测电路120可以与电极110存在对应关系,开关电路130可以选择与部分电极110对应的接触阻抗电路120,从而使得部分电极110可以与其对应的接触阻抗电路120保持导通。
仅作为示例,每个电极110分别与一个接触阻抗检测电路120对应,则开关电路130可以分时控制每个电极110与其对应的接触阻抗检测电路120保持导通状态。再例如,每个电极组与一个接触阻抗检测电路120对应,则开关电路130可以分时控制不同电极组与其对应的控制接触阻抗检测电路120保持导通状态。
在一些实施例中,开关电路130可以包括控制端和开关,开关用于电连接电极110和接触阻抗检测电路120,控制端可以用于控制开关的导通和关断。在一些实施例中,开关电路130可以包括单通道开关,以实现对多个电极110进行选择的功能。在一些实施例中,单通道开关的通道数量可以与多个电极110的数量相关,期望导通的通道数量可以与期望同一时刻与接触阻抗电路120导通的电极110的数量相关。示例性的,当存在8个电极110时,开关电路130可以包括8选1开关、8选2开关、8选4开关等单通道开关。开关电路130可以利用8选1开关,在同一时刻从8个电极中选择一个电极110与接触阻抗电路120连接。以此类推,也可以利用8选2开关,在同一时刻从8个电极中选择两个电极110(例如,贴合同一肌肉的两个电极)与接触阻抗电路120连接。
在一些实施例中,开关电路130可以包括双通道开关,以实现对多个电极110和对多个接触阻抗电路120进行选择的功能。与单通道开关类似,在一些实施例中,双通道开关中与多个电极110对应的通道数量可以与多个电极110的数量相关,双通道开关中与多个接触阻抗电路120对应的通道数量可以与接触阻抗电路120的数量相关,期望导通的通道数量可以与期望同一时刻与接触阻抗电路120导通的电极110的数量相关。仅作为示例,当存在8个电极110和4个接触阻抗电路120时,开关电路130可以包括对于电极110来说8选2,对于接触阻抗电路120来说4选1的双通道开关。关于双通道开关的具体实现方式,可以参看本说明书其他实施例,如图5及其相关内容,此处不再赘述。
在一些实施例中,开关电路130还可以控制电极110分时采集生理信号和测量该部分电极110对应的接触阻抗。在一些实施例中,开关电路130还可以控制电极110分别在不同时刻与接触阻抗检测电路120和增益电路(用于处理生理信号)保持导通状态。电极110与接触阻抗检测电路120保持导通状态时,接触阻抗检测电路120可以获取并处理与电极110对应的检测信号,以得到与电极110对应的接触阻抗信息。电极110与增益电路保持导通状态时,电极110可以采集生理信号,增益电路可以对采集到的生理信 号进行处理,以得到反映人体生理状态的信息(如,肌肉状态等信息)。
如此,通过开关电路130控制电极110异步采集生理信号和测量接触阻抗,可以隔开检测信号和生理信号,从而防止信号互相干扰,进一步提高生理信号的质量。
需要说明的是,生理信号和检测信号也可以同步进行处理,而为了区分生理信号和检测信号,可以通过两者的频率差异,利用滤波器分别提取生理信号和检测信号,以便后续对生理信号和检测信号进行评估。示例性的,可以利用低通滤波器提取模数转换后的生理信号,利用高通滤波器提取模数转换后的检测信号。
图2是根据本说明书一些实施例所示的接触阻抗电路的结构框图。如图2所示,在一些实施例中,接触阻抗检测电路120可以包括:激励源121、分压阻抗122和模数转换器123。其中,激励源121与分压阻抗122连接,用于为电极110提供激励信号,以产生反映电极110与人体之间接触阻抗的检测信号。分压阻抗122与多个电极110连接,用于对激励源121进行分压形成所述检测信号。模数转换器与分压阻抗122连接,用于对检测信号进行模数转换。
激励源121可以为提供电能的电路元件。在一些实施例中,激励源121可以为电流源或电压源。在一些实施例中,激励源121可以提供激励信号,以产生反映电极110与人体之间接触阻抗的检测信号。仅作为示例,激励信号可以理解为通过电极110流经人体后形成闭环回路,此时,检测信号可以对应电极110与人体之间的接触阻抗、以及人体的阻抗在该闭环回路中的分压。激励源121的强度越高,检测信号越容易被检测到。同时需要说明的是,激励源121的强度的设置还需要考虑人体的安全电压和电流,以保证人体安全,激励源121的强度不宜过高。在一些实施例中,激励源121的电流强度可以小于1mA。进一步的,在一些实施例中,激励源121的电流强度可以小于100μA。再进一步的,在一些实施例中,激励源121的电流强度可以小于10μA。在一些实施例中,激励源121的电压强度可以在10μV~3.3V的强度范围内。进一步的,在一些实施例中,激励源121的电压强度可以在100mV~9V的强度范围内。
在一些实施例中,激励源121可以为直流激励源或交流激励源。在分时处理生理信号和检测信号时,生理信号和检测信号难以互相干扰,此时激励源121可以采用直流激励源,也可以采用交流激励源。而在未分时处理生理信号和检测信号时,为了避免生理信号和检测信号的互相干扰,可以通过设置交流激励源的频率,使得检测信号的频率与生理信号的频率具有差异,以便后续可以根据检测信号与生理信号的频率差异,分别提取检测信号和生理信号。在一些实施例中,激励源121的频率可以设置在受外界干扰(例如,工频干扰)较小且对生理信号干扰较小的频率范围。示例性的,在一些实施例中,激励源121可以为直流激励源或频率不小于0.1Hz的交流激励源。
在一些实施例中,激励源121的数量可以为一个,通过并联多个电极110的方式,为多个电极110(如,两个贴合同一肌肉的电极110)提供激励信号。在一些实施例中,激励源121的数量可以为多个,每个激励源121可以分别与一个或多个电极110连接,为每个电极110提供激励信号。需要说明的是,多个接触阻抗电路120也可以共用一个激励源121,通过并联多个电极110的方式,该激励源121可以为所有的电极110提供激励信号。
在一些实施例中,激励源121为交流激励源时,激励源121可以分别同时产生多个具有不同频率的激励信号,并且可以给多个电极110提供具有相同频率或不同频率的激励信号,由此产生不同频率的检测信号。
例如,激励源121可以为多个电极110提供不同频率的激励信号以采集不同的检测信号。多个电极110之间可以具有较大的距离(例如大于或等于5cm),以使激励信号流经的闭环回路可以经由不同的人体组织,如此设置,多个电极110对应的不同频率的检测信号可以用于反映人体的体成分信息,如体脂率、骨密度、体液含量等等体成分信息。
具体地,激励源121可以提供与激励信号不同的第二激励信号,以产生第二检测信号。第二检测信号可以反映在另一频率(即,与激励信号的频率不同的频率)下每个电极与所述人体之间形成的闭环回路上的阻抗信息,包括电极与人体的接触阻抗以及闭环回路上人体组织的阻抗。在一些实施例中,利用通过第一激励信号(如,前述激励信号)产生的第一检测信号,以及通过第二激励信号产生的第二检测信号,可以确定人体的体成分信息。
在一些实施例中,激励信号可以为电压信号或电流信号。在一些实施例中,激励信号可以为直流激励信号,也可以为交流信号,以使产生的检测信号的频率与激励信号的频率相关。
在一些实施例中,分压阻抗122可以设置在激励源121与电极110之间。由于电极110和分压阻抗122处于同一回路中,检测信号可以对应电极110与人体的接触阻抗、以及人体的阻抗在该闭环回路中的分压,或者对应分压阻抗在该闭环回路中的分压。由于检测信号的大小受到电极110与人体之间接触阻抗的影响,检测信号的大小可以反映接触阻抗的大小,从而可以反映生理信号的质量。例如,某个电极110对应的检测信号的强度越大,表示对应的接触阻抗越大,意味着该电极所采集的生理信号的质量较差;反 之,如果检测信号的强度越小,表示对应的接触阻抗越小,意味着该电极所采集的生理信号的质量较好。
在一些实施例中,分压阻抗122可以有多个,每个电极110可以与一个分压阻抗122对应连接。在一些可选的实施例中,分压阻抗122也可以只有一个,通过开关电路130与导通的电极110连接。在一些实施例中,分压阻抗122的数量可以根据处于导通状态下电极110的数量确定。仅作为示例,在两个电极110同步保持与接触阻抗检测电路120的导通状态时,分压阻抗122可以为两个,以同步与该两个电极110保持导通状态。在两个电极110分时与接触阻抗检测电路120保持导通状态时,分压阻抗122可以为一个,只与导通状态下的电极110连接。
图3是根据本说明书一些实施例所示的信号测量电路的原理示意图。如图3所示,电极110可以包括第一电极111和第二电极112,分压阻抗122可以包括第一分压阻抗R4和第二分压阻抗R5。激励源121(如图3所示的激励源Source)发出激励信号后,可以流经第一分压阻抗R4,经第一分压阻抗R4分压后,可以通过第一电极111流向人体,最后流向参考地电极,形成第一路径。其中,第一分压阻抗R4可以对激励信号进行分压,从而形成第一电极111所对应的检测信号。
同理地,激励源121发出激励信号后,可以流经第二分压阻抗R5,经第二分压阻抗R5分压后,可以通过第二电极112流向人体,最后流向参考地电极,形成第二路径。第二分压阻抗R5可以对激励信号进行分压,从而形成第二电极112所对应的检测信号。其中,接触阻抗R1可以指第一电极111与人体之间的接触阻抗,接触阻抗R2可以指第二电极112与人体之间的接触阻抗,阻抗R3可以包括人体的阻抗以及参考地电极与人体之间的阻抗。
在一些实施例中,第一路径与第二路径可以具有一定的对称性。具体而言,即第一分压阻抗R4与第二分压阻抗R5可以具有相同的参数,当激励源121的数量为多个时,多个激励源121可以具有相同的参数。例如,一个或多个激励源121可以产生具有相同频率的激励信号,第一分压阻抗R4与第二分压阻抗R5在激励源121的激励作用下具有相同的阻抗。在一些实施例中,通过保证第一路径和第二路径的对称性,可以使得第一电极111所对应的检测信号与第二电极112所对应的检测信号的差值主要来源于第一电极111和第二电极112与人体之间的接触阻抗的差值。这样,通过比较检测信号之间的差异,即可体现两个电极与人体之间的贴合状态是否良好,进而反映出由电极所采集的生理信号是否满足要求。
在一些实施例中,接触阻抗检测电路120和增益电路可以与电极110保持同时导通。此时,当第一分压阻抗R4与第二分压阻抗R5的阻值过小时,会因并联造成后续的输入阻抗过小,导致所采集的生理信号的强度过小而难以被监测到,例如,生理信号有可能被各种噪音(包括混叠噪音、热噪音等)淹没,进而导致***不能正常工作。而当第一分压阻抗R4与第二分压阻抗R5的阻值过大时,会导致对激励信号的分压过大,使得检测信号的强度过小难以体现出电极与人体之间的接触阻抗。
在一些实施例中,当激励源121为直流激励源时,分压阻抗122可以包括电阻,以便对直流激励源进行适宜大小的分压,防止因分压阻抗122的阻值过大导致分压过大,确保检测信号的强度较大,可以反映出电极与人体之间的接触阻抗。
在一些实施例中,当激励源121为交流激励源时,分压阻抗122可以包括电阻和/或电容。分压阻抗122为电容时可以在不同频率下可以具有不同的阻抗。如此设置,在激励信号的频率(即较高的频率)下,分压阻抗122可以具有较小的阻抗,从而减小对激励信号的分压,使得检测信号可以更多体现出电极与人体之间的接触阻抗;而在大部分生理信号所对应的较低的频率下,分压阻抗122具有较大的阻抗,避免因并联而导致后续的输入阻抗的降低,使得生理信号可以更有效地被后续电路拾取和处理。
在一些实施例中,接触阻抗检测电路120和增益电路与电极110保持分时导通。在一些实施例中,接触阻抗检测电路120与电极110导通时,增益电路与电极110断开,或者增益电路与电极110导通时,接触阻抗检测电路120与电极110断开。在一些可选的实施例中,增益电路与电极110可以长时间保持导通,仅切换接触阻抗检测电路120与电极110的导通和断开。也就是说,增益电路与电极110可以不必断开,仅在需要采集接触阻抗信息的时候,才控制接触阻抗检测电路120与电极110的导通,以采集与接触阻抗对应的检测信息,不需要采集时可以控制接触阻抗检测电路120与电极110的断开,以节省开关电路130的切换次数。在分时导通的情况下,接触阻抗检测电路120不会对处理生理信号的增益电路产生影响,即分压阻抗122并不会并联到增益电路的输入端,此时分压阻抗122即使采用较小的阻抗值也可以得到质量较好的检测信号。在一些实施例中,当激励源121为3.3V的直流时,分压阻抗122可以选择1MΩ~10MΩ的电阻。当激励源121为交流时,分压阻抗122可以选择1pF~50pF的电容。
在一些实施例中,模数转换器123可以对检测信号进行采样,以便生成与检测信号对应的数字信号。在一些实施例中,当激励源121为交流激励源时,模数转换器123的采样率可以结合激励源121的频率进行设定。具体来说,为了对检测信号进行采样,模数转换器123的采样率可以大于激励源121的频率的2倍。为了减少误差,在一些实施例中,采样率可以是激励源121的频率的4倍及以上。需要说明的是,由于信号测量装置100的通道数目较多,大部分电路难以支持多通道的极高采样率,所以单通道采样率和 激励源121的频率也不宜过高。例如,激励源121的频率可以为1kHz,单通道采样率可以为8kHz。
在一些实施例中,可以根据接触阻抗检测的分辨率需求选择不同的模数转换器。示例性的,在供电为3.3V的条件下,分辨率为12位模数转换器的精度可以达到0.8mV,16位模数转换器可达到0.05mV。
在一些实施例中,模数转换器123与分压阻抗122之间可以耦接跟随器。跟随器可以用于缓冲或隔离不同功能的元器件,如隔离分压阻抗122和模数转换器123(如图3所示的模数转换器ADC),并保持模数转换器123的输入稳定。示例性的,参考图3,其中,跟随器U1的正相输入端与第一分压阻抗R4连接,用于接收检测信号,跟随器U1的反相输入端与跟随器U1的输出端连接。跟随器U2的正相输入端与第二分压阻抗R5连接,用于接收检测信号,跟随器U2的反相输入端与跟随器U2的输出端连接。
在一些实施例中,接触阻抗检测电路120的结构(如激励源、分压阻抗、模数转换器等)还可以根据不同的分时测量方式进行不同的设置。
在一些实施例中,在开关电路130控制贴合同一肌肉的两个电极110同步保持与接触阻抗检测电路120的导通状态,即在两个电极110同步采集检测信号的场景下,接触阻抗检测电路120可以包括激励源121、两个分压阻抗122和两个模数转换器123。其中,激励源121可以为贴合同一肌肉的两个电极110提供激励信号,以产生反映每一电极110与人体之间接触阻抗的检测信号;两个分压阻抗122分别耦接于激励源121和每一电极110之间,用于对所述激励源121进行分压形成检测信号;两个模数转换器123可以分别用于对两个电极110对应的检测信号进行模数转换。
示例性的,开关电路130可以在第一时刻控制贴合第一肌肉的第一电极以及第二电极分别与接触阻抗检测电路120保持导通状态。其中,接触阻抗检测电路120中的每一分压阻抗122可以分别与第一电极和第二电极连接。在第二时刻,开关电路可以断开接触阻抗检测电路120与第一电极以及第二电极的连接,而控制贴合第二肌肉的第三电极以及第四电极分别与接触阻抗检测电路120保持导通状态,以获取与第三电极和第四电极对应的检测信号。
在一些实施例中,在开关电路130可以控制贴合同一肌肉的两个电极110分别在不同时刻保持与接触阻抗检测电路120的导通状态,即在两个电极110异步采集检测信号的场景下,接触阻抗检测电路120可以包括激励源121、分压阻抗122和模数转换器123。其中,激励源121可以为某一导通的电极110提供激励信号,以产生反映所述电极110与人体之间接触阻抗的检测信号;分压阻抗122耦接于激励源121和所述导通的电极110之间,用于对激励源121进行分压形成检测信号;模数转换器123可以用于对所述导通的电极110对应的检测信号进行模数转换。
示例性的,以两个电极110(第一电极和第二电极)为例,开关电路130可以在第一时刻控制第一电极与接触阻抗检测电路保持导通状态,以获取与第一电极对应的检测信号。开关电路130在第二时刻可以切换电极,控制第二电极与接触阻抗检测电路保持导通状态,以获取与第二电极对应的检测信号。
图4是根据本说明书另一些实施例所示的信号测量电路的结构框图。在一些实施例中,信号测量电路100还可以包括增益电路140,其可以用于处理生理信号,增益电路140和接触阻抗检测电路120分别在不同时刻与某个电极110保持导通状态,或者在同一时刻与不同电极110保持导通状态。
在一些实施例中,增益电路140可以为对信号进放大处理的信号处理电路。在一些实施例中,增益电路140可以用于为生理信号提供增益,以提高生理信号的强度和信噪比,确保信号的质量。在一些实施例中,增益电路140和接触阻抗检测电路120可以分别在不同时刻与多个电极110保持导通状态,从而通过开关电路130控制电极110异步采集生理信号和测量接触阻抗,以此隔开检测信号和生理信号,防止信号互相干扰,进一步提高生理信号的质量。
在一些实施例中,增益电路140的数量可以为一个,增益电路140可以与一个或多个电极110连接,由开关电路130控制增益电路140与电极110的导通状态。在一些实施例中,增益电路140的数量可以为多个,开关电路130可以选择电极110以及与其对应的增益电路140保持导通状态。增益电路140与电极110的导通方式,与接触阻抗检测电路120与电极110的导通方式类似,具体实现方式可以参看上述图1及相关描述。
在一些实施例中,增益电路140可以为全频段信号提供增益,还可以为部分频段信号提供增益。以肌电信号为例,大部分肌电信号主要分布在10Hz~850Hz的频段内,则增益电路140可以为10Hz~850Hz频段内的肌电信号提供增益,以避免为其他频段(如,除10Hz~850Hz的频段)提供增益,从而抑制噪声对肌电信号的干扰,提高肌电信号的信噪比。
在一些实施例中,增益可以表示为对肌电信号进行放大的程度。例如,增益电路140提供的增益越大,肌电信号被放大的倍数越大,反之,增益电路140提供的增益越小,肌电信号被放大的倍数越小。
在一些实施例中,增益的大小可以根据实际信号强度以及期望信号强度进行设定。在一些实施例中,可以根据肌电信号和检测信号的实际信号强度以及期望信号强度设定增益大小。例如,由于肌电信号的实际信号强度大约在10μV及以下,而常用的12位模数转换器的分辨率大约为0.8mV(即期望信号强 度),则可以利用增益电路140提供百倍以上到千倍的增益,以使增益后的肌电信号的信号强度可以达到1mV~1.65V。
由于在信号测量过程中存在很多干扰信号,如前述运动伪迹、工频及其谐波、混叠噪声等。一方面,如果为前述干扰信号提供过大的增益,会造成增益后的干扰信号超出电路的测量范围,从而导致电路饱和丢失数据,难以通过算法恢复数据。另一方面,如果为高频噪音提供过大的增益,由于受到采样率的限制,导致超过采样率的高频噪音被混叠,从而提高了噪音基底使得高频噪音会与肌电信号重叠,难以进行区分和处理。
在一些实施例中,可以将10Hz处的增益表示为运动伪迹的增益,增益电路140对100Hz处的增益和对10Hz处的增益的比值可以为第一信噪比。为了提高增益电路140的增益信噪比,该第一信噪比可以被设置为不小于4。在一些实施例中,可以将50Hz处的增益表示工频噪声的增益,增益电路140对100Hz处的增益和对50Hz处的增益的比值为第二信噪比。为了提高增益电路140的增益信噪比,该第二信噪比可以不小于2。在一些实施例中,由于混叠噪声的产生与采样率有关,则可以将模数转换器的采样率的1/2频率表示为混叠噪声的频率,也叫做第一频率。如采样频率为4kHz时混叠噪声的频率可以为2kHz。增益电路140对100Hz处的增益与第一频率处的增益的比值可以为第三信噪比(即,前述混叠信噪比)。为了提高增益电路140的增益信噪比,该第三信噪比可以不小于10。
需要说明的是,增益信噪比还可以用于衡量增益电路的质量,信号测量装置的增益信噪比越高可以表明获取到的肌电信号的强度和质量越好,增益电路的质量也就越高。
在一些实施例中,增益电路140可以包括多级放大子电路,其用于对输入信号(如,生理信号)进行多级放大处理,实现提供增益的功能。在一些实施例中,放大子电路可以在信号测量电路100中独立设置,还可以作为组件设置在具有其他功能的电路(如滤波电路等)中,与其他功能的电路作为一个整体进行设置,在实现其他功能的同时还可以提供增益。在一些实施例中,多级放大子电路中不同级放大子电路对输入信号可以具有不同的放大增益。例如,位于前级的放大子电路的增益可以小于位于后级的增益。
在一些实施例中,增益电路140还可以设置有高通滤波器,以滤除运动伪迹、工频噪声等低频噪声。在一些实施例中,增益电路140还可以设置有低通滤波器,以滤除频率较高干扰信号,例如混叠噪声等高频噪声。其中,高频滤波器以及低通滤波器的截止频率可以根据生理信号所在的频率进行设定。
在一些可替代的实施例中,由于人体与电极的接触阻抗的阻抗值可能较小,导致分压产生的检测信号强度低,后续难以对检测信号进行识别和处理。增益电路140还可以用于为检测信号提供增益,以提高检测信号的强度,保证后续准确地对检测信号进行识别和处理。在一些实施例中,增益电路140可以在不同的时间段内分别为生理信号和检测信号提供增益。
在一些实施例中,信号测量电路100还可以包括处理电路,用于根据每个电极110的接触阻抗,确定反映每个电极110与人体的贴合状态的参数信息。
在一些实施例中,处理电路可以为具有一定的信号处理功能的模块,处理电路的结构。在一些实施例中,参数信息可以包括每一个电极110与人体之间的阻抗信息,可以反映出每一个电极110与人体之间的贴合状态,进而可以反映出穿戴设备的当前穿戴状态以及尺码合身度等情况。
在一些实施例中,处理电路可以根据参数信息与其所在的幅值范围,对人体的贴合状态进行评估。示例性的,当参数信息位于目标幅值范围之外,可以反映采集生理信号的质量很差,后续难以使用该生理信号进行生理监测,从而需要输出异常提醒信息以提醒用户及时检查、调整。当参数信息位于目标幅值范围之外,可以反映采集生理信号的质量很差,后续难以使用该生理信号进行生理监测,从而需要输出异常提醒信息以提醒用户及时检查、调整。若参数信息位于目标幅值范围之内,则可以确定穿戴设备的当前穿戴状态为穿戴良好,也可以确定穿戴设备的尺码合身度为尺码适合,还可以确定或者用户处于充分热身状态,还可以确定或者当前电极与人体接触处的皮肤处于较为湿润的状态。参数信息的种类、目标幅值范围的限定可以根据测量需求进行调整。
在一些实施例中,当生理信号的质量很差时,处理电路还可以利用信号处理算法对生理信号进行纠正或补偿,从而确保该生理信号的质量或准确性。在一些实施例中,信号处理算法还可以包括如下一种或多种算法:信号滤波、小波变换、机器学习等算法。
在一些实施例中,信号测量电路100可以应用到可穿戴设备上。在一些实施例中,可穿戴设备可以包括智能手镯、智能鞋袜、智能眼镜、智能头盔、智能手表、智能服装、智能背包、智能配件等或其任意组合。以智能服装(例如健身服或运动服)为例,信号测量电路100可以获取任意两个或者具有特定关联的两个电极(例如,贴合在同一肌肉上以接收同一肌肉的肌电信号的两个电极)所采集的生理信号,并基于该任意两个电极或者具有特定关联的两个电极所采集的生理信号的差值评估该生理信号的质量,或者评估该任意两个或者具有特定关联的两个电极与人体之间的贴合状态。
在一些实施例中,信号测量电路100还可以基于前述生理信号的评估结果进行穿戴状态分析、热 身状态分析、尺码合身度分析、服装寿命分析、动作监测、皮肤状态分析、体成分分析等。
下面提供一种示例的信号测量电路500,详细描述分时测量的具体实现方式。
图5是根据本说明书一些实施例所示的信号测量电路的结构示意图。如图5所示,信号测量电路500可以包括8个电极510、接触阻抗检测电路520、以及开关电路530。接触阻抗检测电路520包括激励源521(如图5所示的激励源Source)、分压阻抗R1-R2、跟随器U1-U2以及模数转换器ADC1-ADC2。其中,8个电极510中的每两个电极510可以作为一个电极组,贴合在同一肌肉上,两个电极510用于测量该肌肉的生理信号。8个电极510分别与开关电路530耦合,分压阻抗R1-R2的一端分别与激励源521耦合,另一端分别与开关电路530耦合,分压阻抗R1-R2可以对激励源521进行分压,以生成反映每个电极510与人体接触阻抗的检测信号。分压阻抗R1-R2与开关电路530的耦合端还与模数转换器连接,模数转换器用于将检测信号转换为数字信号,以便后续设备进行处理,例如,计算电极与人体的接触阻抗、识别电极与人体的贴合状态等。跟随器U1-U2可以设置在分压阻抗R1-R2与模数转换器之间,跟随器U1-U2可以用于稳定输入至模数转换器ADC1-ADC2的检测信号。
在一些实施例中,开关电路530可以控制8个电极510中的2个电极510(8选2)同时与接触阻抗检测电路520保持导通状态,以使在激励源521的作用下同时产生2个检测信号,接触阻抗检测电路520可以接收到反映2个电极510与人体之间接触阻抗的检测信号,并对2个检测信号进行模数转换。在一些实施例中,开关电路530可以包括8选2开关,以实现上述从8个电极510中选择2个电极510同时与接触阻抗检测电路520保持导通状态的功能。
在一些可选的实施例中,开关电路530可以控制8个电极510中的2个电极510分别在不同的时刻与接触阻抗检测电路520保持导通状态,以使在激励源521的作用下异步产生2个检测信号。即,同一时刻下只有8个电极510中的1个电极510(8选1)与接触阻抗检测电路520保持导通状态。接触阻抗检测电路520可以先后接收到反映2个电极510与人体之间接触阻抗的检测信号,并对2个检测信号进行模数转换。在一些实施例中,开关电路530可以包括8选2开关,以实现上述控制8个电极510中的2个电极510,分别在不同的时刻与接触阻抗检测电路520保持导通状态的功能。在一些实施例中,开关电路530也可以包括8选1开关,以便实现控制同一时刻下只有8个电极510中的1个电极510与接触阻抗检测电路520保持导通状态的功能。
在一些可选的实施例中,开关电路530还可以控制8个电极510中部分电极510分别在不同的时刻与接触阻抗检测电路520和增益电路(图5中未示出)保持导通状态,以实现异步采集生理信号和检测接触阻抗。
图6是根据本说明书一些实施例所示的用户运动时多个电极所对应的接触阻抗的曲线示意图。其中,横坐标表示采样点数,纵坐标表示电极对应的接触阻抗的大小。图(a)包括贴合在左胸肌的两个电极所对应的接触阻抗的曲线610和曲线620;图(b)包括贴合在左肱三头肌的两个电极所对应的接触阻抗的曲线630和曲线640;图(c)包括贴合在左肱二头肌的两个电极所对应的接触阻抗的曲线650和曲线660;图(d)包括贴合在左腹斜肌的两个电极所对应的接触阻抗的曲线670和曲线680。
由图6中的图(a)-图(d)所示,贴合不同肌肉的两个电极的接触阻抗差(如,曲线610与曲线620的纵坐标差值、曲线630与曲线640的纵坐标差值、曲线650与曲线660的纵坐标差值、曲线670与曲线680的纵坐标差值)也不一样。随着热身的进行(如,横坐标的增加表示时间增加),接触阻抗的绝对值(如,曲线610-曲线680的纵坐标大小)都在变小,接触阻抗差也在变小,从而可以确定热身能够帮助改善电极与人体的贴合状态,提升采集到的生理信号的质量。
图7是根据本说明书一些实施例所示的信号测量方法的示例性流程图。在一些实施例中,流程700可以由前述智能穿戴设备执行,该智能穿戴设备可以包括处理器、存储器以及如上所述的信号测量电路100,其中,存储器可以存储用于执行流程700的计算机程序,处理器可以是信号测量电路100中的处理电路的一部分,也可以是独立设置的、能够实现处理电路的功能的电子器件。关于信号测量电路100的更多细节可以参照图1-图6部分及其相关论述。
参照图7,在一些实施例中,流程700可以包括:
步骤710,通过开关电路控制多个电极与接触阻抗检测电路的导通状态,使得在同一时刻,仅有多个电极中的部分电极与接触阻抗检测电路保持导通状态。在一些实施例中,步骤710可以由信号测量电路100中的开关电路130实现。
根据以上信号测量电路100的描述,在一些实施例中,信号测量电路100中的多个电极可以用于与人体贴合,以采集人体的生理信号(如,肌电信号)。在设置激励源的情况下,还可以获取用于反映电极与人体之间接触阻抗的检测信号。当接触阻抗检测电路与部分电极保持导通状态时,接触阻抗检测电路可以接收与该部分电极对应的检测信号,接触阻抗检测电路可以对检测信号进行运算(例如,差分、求和),以确定人体与部分电极的接触阻抗。而另一部分电极可以在另一时刻与接触阻抗检测电路保持导通。
在一些实施例中,多个电极可以包括贴合同一肌肉的两个电极。相对应的,在一些实施例中,开关电路可以控制贴合同一肌肉的两个电极同时与接触阻抗检测电路保持导通状态,即接触阻抗检测电路可以捕捉到同一时刻下同一肌肉的两个电极的接触阻抗信息,从而避免接触阻抗随时间的波动以及其他信号的干扰(如其他电极对应的检测信号),更准确地评估生理信号的质量。
在一些可选的实施例中,可以控制贴合同一肌肉的两个电极分别在不同时刻与接触阻抗检测电路保持导通状态,即接触阻抗检测电路可以异步获取两个检测信号,异步检测对两个电极与人体之间的接触阻抗,从而减少同一时刻处理检测电路的负担,例如,降低***对后续模数转换过程中的采样频率的要求。并且,异步检测可以节约后续电路成本,并且能够防止两个电极的相互干扰,从而进一步提升生理信号的质量。
在一些可选的实施例中,开关电路可以控制电极分别在不同时刻与增益电路和接触阻抗检测电路保持导通,即异步采集生理信号和测量接触阻抗,从而隔开检测信号和生理信号,防止信号互相干扰,进一步提高生理信号的质量。
步骤720,根据每个电极的接触阻抗,确定反映每个电极与人体的贴合状态的参数信息。在一些实施例中,步骤710可以由信号测量电路100中的接触阻抗检测电路120或处理电路实现。
在一些实施例中,参数信息可以包括每一电极与人体之间的阻抗信息,通过该参数信息,可以反映出每一个电极与人体之间的贴合状态,进而可以反映出穿戴设备的当前穿戴状态以及尺码合身度等情况。在一些实施例中,根据电极与人体的贴合状态的参数信息,还可以评估穿戴设备的当前穿戴状态、尺码合身度、热身状态、服装寿命状态、动作监测、电极与人体接触处的皮肤状态、体成分信息中的一种或多种信息,或是其他穿戴信息。
在一些实施例中,当电极的接触阻抗大于某个阈值,可以反映该电极没有佩戴正确或者用户的皮肤过于干燥,从而可以向用户发出指示信息,以使用户可以参考指示信息对电极的佩戴状态以及尺码合身度进行检查或调整。
在一些实施例中,还可以获取反映生理信号质量的检测信号,对检测信号进行数字采样,确定指标参数值,其可以用于反映生理信号的质量。
在一些实施例中,处理电路可以根据指标参数值在预设时间段内的幅值波动,判断生理信号的质量。示例性的,当指标参数值位于目标幅值范围之外,可以反映采集生理信号的质量很差,后续难以使用该生理信号进行生理监测,从而需要输出异常提醒信息以提醒用户及时检查、调整。在一些实施例中,存在很多造成生理信号的质量很差的因素,例如电极与人体皮肤脱离或用户身体出现病变等,用户可以根据异常提醒信息及时检查各项因素。
当指标参数值位于第一幅值范围内,则处理电路可以输出指示用户运动的第一指示信息。指标参数值位于第一幅值范围内表示生理信号的质量仍较差,难以准确地反映用户的生理状态,从而建议用户检测或调整,以改善生理信号的质量。用户可以根据第一指示信息进行运动,通过热身减小接触阻抗,从而提高生理信号的质量。
当指标参数值位于第二幅值范围内,则处理电路可以输出指示用户调整电极的贴合状态的第二指示信息。指标参数值位于第二幅值范围内时,可以表示电极与人体皮肤之间的贴合状态可能存在异常,例如接触不良或未完全贴合等,导致生理信号的质量仍较差,难以准确地反映用户的生理状态。此时,用户可以根据第二指示信息调整电极的贴合状态,以使用户可以改变接触阻抗的大小。
在一些实施例中,当指标参数值较低,用户进行的动作也可以引起指标参数值的幅值发生波动。基于此,在一些实施例中,可以根据指标参数值在预设时间段内的幅值波动,对用户的运动动作进行监测。示例性的,在指标参数值小于预设阈值时,且指标参数值在预设时间段内具有超过预设数目的峰,则可以确定用户该预设时间内进行了运动动作。
根据上述图6可知,在一些实施例中,可以根据两个贴合同一肌肉的电极的接触阻抗之间的差值或比值,确定用户的热身状态。在一些实施例中,接触阻抗之间的差值或比值可以反映用户的热身状态。参考图6,随着时间的增长,接触阻抗之间的差值或比值越小,热身状态越好;反之,接触阻抗之间的差值或比值越大,热身状态越差。需要说明的是,每一个电极的接触阻抗也可以单独反映用户的热身状态。例如,接触阻抗的绝对值越小,热身状态越好。
需要说明的是,在一些实施例中,多个电极110对应的不同频率的检测信号还可以用于反映人体的体成分信息,如体脂率、骨密度、体液含量等等体成分信息。
本说明书实施例可能带来的有益效果包括但不限于:(1)可以通过接触阻抗检测电路测量得到的电极与人体之间的接触阻抗,并基于该接触阻抗确定电极与人体之间的贴合状态,进而确保电极采集到的生理信号的质量;(2)当要监测多个电极与人体身体不同部位的贴合状态时,可以通过在不同时刻下选择不同的部分电极与接触阻抗检测电路保持导通状态,以分时采集不同的部分电极对应的接触阻抗,这样可 以防止不同电极之间的干扰,并且节约接触阻抗检测电路的资源。
上文已对基本概念做了描述,显然,对于本领域技术人员来说,上述详细披露仅仅作为示例,而并不构成对本说明书的限定。虽然此处并没有明确,说明,本领域技术人员可能会对本说明书进行各种修改、改进和修正。该类修改、改进和修正在本说明书中被建议,所以该类修改、改进、修正仍属于本说明书示范实施例的精神和范围。
同时,本说明书使用了特定词语来描述本说明书的实施例。如“一个实施例”、“一实施例”、和/或“一些实施例”意指与本说明书至少一个实施例相关的某一特征、结构或特点。因此,应强调并注意的是,本说明书中在不同位置两次或多次提及的“一实施例”或“一个实施例”或“一个替代性实施例”并不一定是指同一实施例。此外,本说明书的一个或多个实施例中的某些特征、结构或特点可以进行适当的组合。
此外,除非权利要求中明确说明,本说明书所述处理元素和序列的顺序、数字字母的使用、或其他名称的使用,并非用于限定本说明书流程和方法的顺序。尽管上述披露中通过各种示例讨论了一些目前认为有用的发明实施例,但应当理解的是,该类细节仅起到说明的目的,附加的权利要求并不仅限于披露的实施例,相反,权利要求旨在覆盖所有符合本说明书实施例实质和范围的修正和等价组合。例如,虽然以上所描述的***组件可以通过硬件设备实现,但是也可以只通过软件的解决方案得以实现,如在现有的服务器或移动设备上安装所描述的***。
同理,应当注意的是,为了简化本说明书披露的表述,从而帮助对一个或多个发明实施例的理解,前文对本说明书实施例的描述中,有时会将多种特征归并至一个实施例、附图或对其的描述中。但是,这种披露方法并不意味着本说明书对象所需要的特征比权利要求中提及的特征多。实际上,实施例的特征要少于上述披露的单个实施例的全部特征。
一些实施例中使用了描述成分、属性数量的数字,应当理解的是,此类用于实施例描述的数字,在一些示例中使用了修饰词“大约”、“近似”或“大体上”来修饰。除非另外说明,“大约”、“近似”或“大体上”表明所述数字允许有±20%的变化。相应地,在一些实施例中,说明书和权利要求中使用的数值参数均为近似值,该近似值根据个别实施例所需特点可以发生改变。在一些实施例中,数值参数应考虑规定的有效数位并采用一般位数保留的方法。尽管本说明书一些实施例中用于确认其范围广度的数值域和参数为近似值,在具体实施例中,此类数值的设定在可行范围内尽可能精确。
针对本说明书引用的每个专利、专利申请、专利申请公开物和其他材料,如文章、书籍、说明书、出版物、文档等,特此将其全部内容并入本说明书作为参考。与本说明书内容不一致或产生冲突的申请历史文件除外,对本说明书权利要求最广范围有限制的文件(当前或之后附加于本说明书中的)也除外。需要说明的是,如果本说明书附属材料中的描述、定义、和/或术语的使用与本说明书所述内容有不一致或冲突的地方,以本说明书的描述、定义和/或术语的使用为准。
最后,应当理解的是,本说明书中所述实施例仅用以说明本说明书实施例的原则。其他的变形也可能属于本说明书的范围。因此,作为示例而非限制,本说明书实施例的替代配置可视为与本说明书的教导一致。相应地,本说明书的实施例不仅限于本说明书明确介绍和描述的实施例。
Claims (20)
- 一种信号测量电路,包括:多个电极,用于贴合人体并采集所述人体的生理信号;与所述多个电极电连接的接触阻抗检测电路,用于测量所述电极与所述人体之间的接触阻抗;以及开关电路,用于控制所述多个电极与所述接触阻抗检测电路的导通状态,使得在同一时刻,仅有所述多个电极中的部分电极与所述接触阻抗检测电路保持导通状态。
- 根据权利要求1所述的信号测量电路,其特征在于,所述多个电极包括两个贴合同一肌肉的电极,所述两个贴合同一肌肉的电极同步保持与所述接触阻抗检测电路的导通状态。
- 根据权利要求1所述的信号测量电路,其特征在于,所述多个电极包括两个贴合同一肌肉的电极,所述两个贴合同一肌肉的电极分别在不同时刻保持与所述接触阻抗检测电路的导通状态。
- 根据权利要求2所述的信号测量电路,其特征在于,所述接触阻抗检测电路包括:激励源,用于为所述两个贴合同一肌肉的电极提供激励信号,以产生反映每一电极与所述人体之间接触阻抗的检测信号;两个分压阻抗,分别耦接于所述激励源和每一电极之间,用于对所述激励源进行分压形成所述检测信号;两个模数转换器,分别用于对所述检测信号进行模数转换。
- 根据权利要求3所述的信号测量电路,其特征在于,所述接触阻抗检测电路包括:激励源,用于为每一电极提供激励信号,以产生反映每一电极与所述人体之间接触阻抗的检测信号;分压阻抗,耦接于所述激励源和每一电极之间,用于对所述激励源进行分压形成所述检测信号;模数转换器,用于对所述检测信号进行模数转换。
- 根据权利要求4或5所述的信号测量电路,其特征在于,所述激励源为直流激励源或频率不小于0.1Hz的交流激励源。
- 根据权利要求4或5所述的信号测量电路,其特征在于,所述分压阻抗包括电阻和/或电容。
- 根据权利要求4或5所述的信号测量电路,其特征在于,所述模数转换器与所述分压阻抗之间耦接跟随器。
- 根据权利要求1所述的信号测量电路,其特征在于,还包括用于处理所述生理信号的增益电路,所述增益电路和所述接触阻抗检测电路之间分别在不同时刻与所述多个电极保持导通状态。
- 根据权利要求9所述的信号测量电路,其特征在于,所述增益电路为所述生理信号提供增益。
- 根据权利要求10所述的信号测量电路,其特征在于,所述增益电路对100Hz处的增益和对10Hz处的增益的比值为第一信噪比,所述第一信噪比不小于4。
- 根据权利要求10所述的信号测量电路,其特征在于,所述增益电路对100Hz处的增益和对50Hz处的增益的比值为第二信噪比,所述第二信噪比不小于2。
- 根据权利要求10所述的信号测量电路,所述增益电路对100Hz处的增益和对第一频率处的增益的比值为第三信噪比,所述第一频率为与模数转换器的采样率的1/2对应的频率,所述第三信噪比不小于10。
- 根据权利要求1所述的信号测量电路,其特征在于,还包括处理电路,用于根据每个电极的接触阻抗,确定反映每个电极与所述人体的贴合状态的参数信息。
- 根据权利要求1所述的信号测量电路,其特征在于,所述信号测量电路设置在可穿戴设备中。
- 一种信号测量方法,包括:通过开关电路控制多个电极与接触阻抗检测电路的导通状态,使得在同一时刻,仅有所述多个电极中的部分电极与所述接触阻抗检测电路保持导通状态,其中所述多个电极用于贴合人体并采集所述人体的生理信号,所述接触阻抗检测电路用于测量所述电极与所述人体之间的接触阻抗;根据每个电极的接触阻抗,确定反映每个电极与所述人体的贴合状态的参数信息。
- 根据权利要求16所述的信号测量方法,其特征在于,还包括:根据两个贴合同一肌肉的电极的接触阻抗之间的差值或比值,确定用户的热身状态。
- 根据权利要求16所述的信号测量方法,其特征在于,还包括:获取反映每个电极与所述人体之间的接触阻抗的检测信号;对所述检测信号进行处理,确定反映所述人体的生理信号质量的指标参数值。
- 根据权利要求18所述的信号测量方法,其特征在于,还包括:当所述指标参数值位于第一幅值范围内,则输出指示用户运动的第一指示信息。
- 根据权利要求18所述的信号测量方法,其特征在于,还包括:当指标参数值位于第二幅值范围内,则输出指示用户调整电极的贴合状态的第二指示信息。
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