CN112152578A - Modulation signal demodulation circuit, demodulation method and electronic equipment - Google Patents
Modulation signal demodulation circuit, demodulation method and electronic equipment Download PDFInfo
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Abstract
The invention discloses a modulation signal demodulation circuit, a demodulation method and electronic equipment, relates to the technical field of electronic circuits and aims to solve the problem that a shallow modulation signal is difficult to detect. The modulation signal demodulation circuit includes: an envelope detector and a dynamic bias control loop; the output end of the envelope detector is electrically connected with the input end of the dynamic bias control loop, and the output end of the dynamic bias control loop is electrically connected with the envelope detector; the envelope detector is used for detecting and amplifying the modulation signal to generate an envelope signal; and the dynamic bias control loop is used for generating a bias voltage of the envelope detector according to the envelope signal, wherein the bias voltage is used for controlling the envelope detector to be stabilized at a static operating point when the modulation signal changes. The modulation signal demodulation circuit provided by the invention is used for detecting a shallow modulation signal.
Description
Technical Field
The present invention relates to the field of electronic circuit technologies, and in particular, to a modulation signal demodulation circuit, a demodulation method, and an electronic device.
Background
The wireless internet of things node has the problem of energy limitation in the data transmission process, and in order to prolong the service life of a battery, a wireless energy acquisition technology can be adopted, and radio frequency signal energy in the surrounding environment is captured and converted into electric energy to provide power supply voltage required by work for a load. The technology realizes that the energy is collected from the same modulation signal received by the receiver and the modulation signal is demodulated, thereby reducing the use of off-chip elements and saving the cost of the receiver. Traditional modulation signals such as binary on-off keying modulation are not beneficial to energy transmission due to large modulation depth and large signal power variation. Therefore, the amplitude modulation signal with shallow modulation can transmit energy and data at the same time.
The existing detector has the following problems for shallow modulation signals: 1. since the envelope variation of the shallow modulation signal is small, it is difficult to detect the shallow modulation signal. 2. Because the amplitude of the input modulation signal is greatly influenced by the environment, the traditional detector can change the static working point of the transistor when the amplitude of the input modulation signal is greatly changed, so that the signal is distorted.
Disclosure of Invention
The invention aims to provide a modulation signal demodulation circuit, a demodulation method and an electronic device, which are used for detecting a shallow modulation signal.
In a first aspect, the present invention provides a modulation signal demodulation circuit, including: an envelope detector and a dynamic bias control loop; the output end of the envelope detector is electrically connected with the input end of the dynamic bias control loop, and the output end of the dynamic bias control loop is electrically connected with the envelope detector;
the envelope detector is used for detecting and amplifying the modulation signal to generate an envelope signal;
and the dynamic bias control loop is used for generating a bias voltage of the envelope detector according to the envelope signal, wherein the bias voltage is used for controlling the envelope detector to be stabilized at a static operating point when the modulation signal changes.
Compared with the prior art, in the modulation signal demodulation circuit provided by the invention, the output end of the envelope detector is electrically connected with the input end of the dynamic bias control loop, so that the envelope detector can amplify and detect modulation signals of different depths, and the dynamic bias control loop can generate the bias voltage of the envelope detector according to the envelope signals. Due to the fact that the amplitude of the input modulation signal changes, the envelope detector cannot stably work at a static working point, and the output envelope signal is distorted. Based on this, when the output end of the dynamic bias control loop is electrically connected to the envelope detector, the bias voltage output by the dynamic bias control loop is provided to the envelope detector, so that when the modulation signal changes, the envelope detector can be stabilized at a static working point under the action of the bias voltage, and the output envelope signal is ensured not to be distorted.
In a second aspect, the present invention also provides a modulation signal demodulation method, including:
the envelope detector detects and amplifies the modulation signal to generate an envelope signal;
and the dynamic bias control loop generates a bias voltage of an envelope detector according to the envelope signal, wherein the bias voltage is used for controlling the envelope detector to be stabilized at a static working point when the modulation signal changes.
Compared with the prior art, the beneficial effects of the modulation signal demodulation method provided by the embodiment of the invention are the same as those provided by the modulation signal demodulation circuit, and are not repeated herein.
In a third aspect, the present invention further provides an electronic device, which includes any one of the modulation signal demodulation circuits described above.
Compared with the prior art, the electronic device provided by the embodiment of the invention has the same beneficial effects as those provided by the modulation signal demodulation circuit, and details are not repeated herein.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 illustrates a schematic structural diagram of an electronic device provided in an embodiment of the present invention;
fig. 2 illustrates a schematic diagram of a simple structure of a modulated signal demodulation circuit provided by an embodiment of the present invention;
FIG. 3 illustrates a waveform diagram of a shallow modulation signal provided by an embodiment of the present invention;
fig. 4 is a schematic diagram illustrating a specific structure of a modulation signal demodulation circuit according to an embodiment of the present invention;
fig. 5 is a schematic flowchart illustrating a modulated signal demodulation method according to an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise. The meaning of "a number" is one or more unless specifically limited otherwise.
In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.
In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Fig. 1 illustrates a schematic structural diagram of an electronic device according to an embodiment of the present invention, and as shown in fig. 1, an electronic device 110 according to an embodiment of the present invention includes a modulation signal demodulation circuit 111, a processor 112, and a memory 113 in communication with the processor 112.
Wherein the memory is used to store program codes and data of the base station. The program code and data described above are used to execute instructions executed by a computer that implements aspects of the present invention and are controlled by a processor for execution. The processor is used for executing the computer execution instructions stored in the memory, thereby realizing the method provided by the embodiment of the invention.
The memory may be, but is not limited to, a read-only memory (ROM) or other type of static storage device that may store static information and instructions, a Random Access Memory (RAM) or other type of dynamic storage device that may store information and instructions, an electrically erasable programmable read-only memory (EEPROM), a compact disk read-only memory (CD-ROM) or other optical disk storage, optical disk storage (including compact disk, laser disk, optical disk, digital versatile disk, blu-ray disk, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory may be separate and coupled to the processor via a communication link. The memory may also be integral to the processor.
The Processor may be a Central Processing Unit (CPU), a general purpose Processor, a Digital Signal Processor (DSP), an Application-Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, transistor logic, hardware components, or any combination thereof. Which may implement or perform the various illustrative logical blocks, modules, and circuits described in connection with the disclosure. The processor may also be a combination of computing functions, e.g., comprising one or more microprocessors, DSPs, and microprocessors, among others.
The electronic equipment receives the modulation signal from the modulation equipment, obtains an envelope signal through the modulation and demodulation circuit, outputs the envelope signal to the processor for processing, and stores final data obtained by processing in the memory. The electronic device including the modulation signal demodulation circuit has been exemplified above, but is not limited thereto.
The process of demodulating a low frequency signal from a modulated signal is called envelope detection. The envelope detection is amplitude detection, and the common method of envelope detection is to perform unidirectional filtering by using a diode and then perform low-pass filtering. The existing envelope detector has difficulty in demodulating a shallow modulation signal, and the detection cannot be successfully carried out due to the shallow modulation depth. And when the amplitude of the modulation signal changes greatly, the detected envelope signal is distorted.
In view of the above problem, an embodiment of the present invention provides a modulation signal demodulation circuit. Fig. 2 illustrates a schematic diagram of a simple structure of a modulation signal demodulation circuit according to an embodiment of the present invention, and as shown in fig. 2, the modulation signal demodulation circuit 20 includes: an envelope detector 21 and a dynamic bias control loop 22; the output of the envelope detector 21 is electrically connected to the input of the dynamic bias control loop 22, and the output of the dynamic bias control loop 22 is electrically connected to the envelope detector 21.
The envelope detector is used for detecting and amplifying the modulation signal to generate an envelope signal; the modulation signal may be a deep modulation signal or a shallow modulation signal. For a shallow modulation signal, the detection is performed by amplifying the demodulation signal while detecting, and the generated envelope signal is an amplified signal. The modulation depth is the ratio of the difference between the maximum amplitude and the minimum amplitude of the modulated wave to the sum of the maximum amplitude and the minimum amplitude of the carrier wave. In the modulation technology, a modulation coefficient is a parameter for measuring modulation depth, the modulation coefficient refers to the amplitude ratio of a modulation signal to a carrier signal, and formula (1) is a calculation formula of an amplitude modulation coefficient ma.
ma＝[(A-B)/(A+B)]×100％ (1)
A and B represent the maximum and minimum amplitudes in the vertical direction of the waveform, respectively.
Fig. 3 illustrates a waveform diagram of a shallow modulation signal provided by an embodiment of the present invention. As shown in fig. 3, since the envelope variation of the shallow modulation signal is small, the signal needs to be amplified to be detected, and the amplitude of the output detection signal is larger than that of the output detection signal.
For the above reasons, the above dynamic bias control loop is configured to generate a bias voltage for the envelope detector from the envelope signal, wherein the bias voltage is configured to control the envelope detector to settle at a static operating point when the modulation signal varies.
In practical applications, the envelope detector needs to have a large input dynamic range because the amplitude of the input signal of the envelope detector is greatly influenced by the environment. The amplifier formed by the transistors in the envelope detector is required to amplify the signal voltage without distortion, i.e. to set its quiescent operating point. The dynamic bias control loop enables the bias voltage input to the envelope detector to dynamically change along with the amplitude change of the modulation signal, so that the envelope detector still works at a static working point under the condition of large input dynamic range, and the detection is not distorted.
Fig. 4 illustrates a specific configuration diagram of the modulated signal demodulation circuit. As shown in fig. 4, the envelope detector comprises: a first high pass filter 211, a second high pass filter 212, a differential amplifier 213 and a low pass filter 214.
As shown in FIG. 4, the differential amplifier 213 has a first input terminal for receiving the modulated signal VRFIs electrically connected to the first high pass filter 211; second input terminal of differential amplifier 213And for accessing the modulated signal VRFThe second high pass filter 212 is electrically connected; the first supply terminal of the differential amplifier 213 is used for receiving the supply voltage VddThe second power supply terminal of the differential amplifier 213 is used for grounding; the output terminal of the differential amplifier 213 is electrically connected to the input terminal of the dynamic bias control loop; the input end of the dynamic bias control loop and the second power end of the differential amplifier 213 are both connected to the low-pass filter 214, and the output end of the dynamic bias control loop is electrically connected to the reference end of the first high-pass filter 211 and the reference end of the second high-pass filter 212, respectively.
The first high-pass filter and the second high-pass filter are respectively used for isolating direct current signals in the modulation signals and coupling the modulation signals to the differential amplifier. The differential amplifier is used for amplifying the modulation signal.
The differential amplifier 213 includes: a differential pair transistor 2131 and a load transistor 2132.
The first control electrode of the differential pair transistor is electrically connected with the output end of the first high-pass filter, and the second control electrode of the differential transistor is electrically connected with the output end of the second high-pass filter.
The first electrode of the differential pair transistor is used for connecting a power supply voltage, and the second electrode of the differential pair transistor is electrically connected with the second electrode of the load transistor; the second electrode of the load transistor is electrically connected with the input end of the dynamic bias control loop; the second electrode of the load transistor is also electrically connected with the input end of the low-pass filter, the grounding end of the low-pass filter is electrically connected with the first electrode of the load transistor, and the grounding end is grounded.
And a differential pair of transistors for amplifying the modulated signal. And a load transistor for keeping a current magnitude of the modulated signal of the method constant and outputting an envelope signal according to the demodulated signal from which the high frequency signal is removed. The low-pass filter is used for processing the amplified modulation signal to obtain a target signal. The differential amplifier is also used for generating an envelope signal according to the target signal. The first high-pass filter and the second high-pass filter are respectively used for stabilizing the envelope detector at a static operating point under the control of the bias voltage output by the dynamic bias control loop.
During specific work, the first high-pass filter carries out high-pass filtering on a modulation signal, isolates a direct current signal in the modulation signal, sends the obtained first filtered signal to the differential amplifier, the second high-pass filter carries out high-pass filtering on the modulation signal, isolates the direct current signal in the modulation signal, and sends the obtained second filtered signal to the differential amplifier. And the differential amplifier processes according to the first filtering signal and the second filtering signal to realize the amplification of the modulation signal. Meanwhile, the low-pass filter processes the amplified modulation signal to obtain a target signal; and generating an envelope signal according to the target signal by differential amplification, and transmitting the envelope signal to the dynamic bias control loop. The bias voltage generated by the dynamic bias control loop can control the first high-pass filter and the second high-pass filter, so that the generated first filtering signal and the second filtering signal smoothly enter the differential amplifier for amplification, the differential amplifier is stabilized at a static working point under the action of the bias voltage, and the first filtering signal and the second filtering signal are amplified without distortion.
Illustratively, as shown in fig. 4, the first high-pass filter 211 includes: a first capacitor Cb1 and a first resistor Rb 1; the second high-pass filter 212 includes: a second capacitor Cb2 and a second resistor Rb 2; the first capacitor Cb1 is electrically connected to one end of the first input end of the differential amplifier 213, which is an output end of the first high-pass filter 211, the first capacitor Cb1 is used for receiving a modulation signal, which is an input end of the first high-pass filter 211, one end of the first resistor Rb1 is also electrically connected to the first input end of the differential amplifier 213, and the other end of the first capacitor Cb1 is connected to an output end of the dynamic bias control loop. The second capacitor Cb2 is electrically connected to one end of the second input terminal of the differential amplifier 213 as the output terminal of the second high-pass filter 212, one end of the second capacitor Cb2 for receiving the modulation signal is the input terminal of the second high-pass filter 212, one end of the second resistor Rb2 is also electrically connected to the first input terminal of the differential amplifier 213, and the other end is connected to the output terminal of the dynamic bias control loop.
As shown in fig. 4, the low-pass filter 214 includes: a third capacitor Co1 and a third resistor Ro 1; the end of the third resistor Ro1 electrically connected to the input end of the dynamic bias loop is the input end of the low-pass filter 214, the end of the third resistor Ro1 electrically connected to the control electrode of the load transistor 2132 is the output end of the low-pass filter 214, the output end of the low-pass filter 214 is further electrically connected to the first end of the third capacitor Co1, and the second ends of the third resistors Ro1 are electrically connected to the first electrodes of the load transistor 2132 and are all grounded.
The differential pair transistor comprises a first transistor and a second transistor, wherein the first transistor and the second transistor are in butt joint, and a first electrode of the first transistor is electrically connected with a first electrode of the second transistor and is respectively used for connecting power supply voltage; the second electrode of the first transistor is electrically connected with the second electrode of the second transistor and is respectively connected to the second electrodes of the load transistors, and the second electrodes of the load transistors are electrically connected with the input end of the dynamic bias control loop; the control electrode of the first transistor is electrically connected with the output end of the first high-pass filter, and the control electrode of the second transistor is electrically connected with the output end of the second high-pass filter; the second electrode of the load transistor is also electrically connected with the input end of the low-pass filter, the grounding end of the low-pass filter is electrically connected with the first electrode of the load transistor, and the grounding end is grounded.
During specific work, the positive electrode and the negative electrode of the modulation signal are respectively connected to the input ends of the first high-pass filter and the second high-pass filter, as shown in fig. 4, the high-pass filter is the simplest first-order high-pass filter, the modulation signal enters the input ends of the first capacitor Cb1 and the second capacitor Cb2, the modulation signal comprises a direct current signal and an alternating current signal, the alternating current signal comprises a low-frequency alternating current signal and a high-frequency alternating current signal, and only the alternating current signal in the modulation signal is left after the modulation signal passes through the first capacitor Cb1 and the second capacitor Cb2 due to the direct and alternating current separation characteristic of the first capacitor Cb1 and the second capacitor Cb 2. In the differential amplifier, transistors having the same characteristics are connected, the first high-pass filter and the second high-pass filter also have the same characteristics, the product of the first capacitor Cb1 and the first resistor Rb1 is taken as a first time constant, the cutoff frequencies of the first high-pass filter and the second high-pass filter are calculated according to the first time constant, so that the alternating current signals with the cutoff frequencies or higher pass through, and the first resistor Rb1 and the second resistor Rb2 attenuate the alternating current signals with the cutoff frequencies or lower in the modulation signals passing through the first capacitor Cb1 and the second capacitor Cb2, and prevent the alternating current signals from passing through.
Specifically, as shown in fig. 4, the modulation signal output from the output terminals of the first capacitor Cb1 and the second capacitor Cb2 is already a modulation signal that isolates a dc signal and attenuates an ac signal below a cutoff frequency, and is input to the control electrodes of the first transistor and the second transistor in the differential amplifier. According to the power supply voltage, two input signals respectively flow through the second electrodes of the first transistor and the second transistor and commonly flow into the load transistor, because the signals input by the control electrodes of the first transistor and the second transistor have the same amplitude and opposite polarities, namely the input signals are differential mode signals. The output terminal of the differential amplifier is based on the input signal V+ in、V- inDifferential mode gain A of a differential amplifierdAnd common mode gain AcIt can be obtained that equation (2) is the output value V of the differential amplifier when the two inputs are differential mode signalsOUTThe calculation formula of (2):
VOUT＝Ad(V+ in–V- in)+Ac(V+ in+V- in)/2 (2)
wherein, V+ in、V- inThe differential amplifier is used for improving the differential amplification factor and reducing the common-mode amplification factor, and a load transistor in the differential amplifier is used as an approximate constant current circuit with large internal resistance to replace a common resistor to reduce the common-mode amplification factor. V+ in、V- inTwo input signals respectively flow through the second electrodes of the first transistor and the second transistor and commonly flow into the input end of a third resistor Ro1 of the low-pass filter, the third resistor Ro1 is connected with a third capacitor Co1 in series, and the lower the frequency of the input signal is, the larger the capacitive reactance of the third capacitor Co1 is, the higher the output voltage is (the maximum voltage does not exceed the input voltage); the higher the input signal frequency, the smaller the capacitive reactance of the third capacitor Co1, and the lower the output voltage. The product of the third capacitor Co1 and the third resistor Ro1 is taken asAnd a second time constant, according to which the cutoff frequency of the low-pass filter is calculated so that a signal having a frequency lower than the cutoff frequency passes, and the third resistor Ro1 is constant in resistance, attenuating the signal having a frequency higher than the cutoff frequency, and preventing the signal from passing. The signal output by the low pass filter flows into the control electrode of the load transistor, so that the output end of the differential amplifier outputs an envelope signal which is amplified and filters a high frequency signal. The output end of the error amplifier is connected with a capacitor in parallel to adjust the envelope signal to smoothly enter the first input end of the error amplifier, the error amplifier dynamically obtains the bias voltage of the envelope detector according to the envelope signal input by the first input end and the peripheral reference voltage input by the second input end, and the bias voltage is input to the reference ends of the first high-pass filter and the second high-pass filter, so that the first transistor and the second transistor in the envelope detector work in an amplification state when the amplitude change of the modulation signal is large, namely work at a static working point, and stably output the envelope signal.
As an alternative, the dynamic bias control loop comprises: an error amplifier and a grounded capacitor Ce;
as shown in FIG. 4, the output terminal of the differential amplifier is electrically connected to the first input terminal of the error amplifier, and the second input terminal of the error amplifier is used for receiving the reference voltage Vref(ii) a The output end of the error amplifier is respectively and electrically connected with the reference end of the first high-pass filter and the reference end of the second high-pass filter.
And the error amplifier is used for generating a bias voltage of the envelope detector according to the envelope signal and the reference voltage.
The capacitor is used for adjusting the loop bandwidth of the dynamic bias control loop to be smaller than the baseband signal bandwidth of the envelope signal when the bandwidth of the dynamic bias loop is larger than the baseband signal bandwidth of the envelope signal.
In practical applications, if the loop bandwidth of the dynamic bias control loop is greater than the baseband signal bandwidth of the envelope signal, the envelope signal cannot enter the error amplifier to generate the bias voltage.
Therefore, the modulation signal demodulation circuit provided by the invention comprises an envelope detector and a dynamic bias control loop, wherein the envelope detector can amplify and detect modulation signals at different depths, particularly the detection of a shallow modulation signal; because the amplitude of the input modulation signal changes, the envelope detector cannot stably work at a static working point, the output envelope signal is distorted, and a dynamic bias control loop is connected behind the envelope detector, so that the bias voltage of the envelope detector can be generated according to the envelope signal output by a preceding stage, and the dynamic control includes that the detector works at the static working point, so that the output envelope signal is not distorted.
Fig. 5 illustrates a flowchart of a modulation signal demodulation method according to an embodiment of the present invention. The embodiment of the invention also provides a modulation signal demodulation method, which comprises the following steps:
step 101: the envelope detector detects and amplifies the modulated signal to generate an envelope signal.
Step 102: and the dynamic bias control loop generates a bias voltage of the envelope detector according to the envelope signal, wherein the bias voltage is used for controlling the envelope detector to be stabilized at a static operating point when the modulation signal changes.
As an implementation manner, the above-mentioned envelope detector detects and amplifies the modulation signal, and generating the envelope signal includes:
the first high-pass filter and the second high-pass filter respectively isolate direct current signals in the modulation signals and couple the modulation signals to the differential amplifier; the differential amplifier amplifies the modulated signal; the low-pass filter processes the amplified modulation signal to obtain a target signal; the differential amplifier also generates an envelope signal from the target signal. The first high-pass filter and the second high-pass filter respectively enable the envelope detector to be stabilized at a static working point under the control of the bias voltage output by the dynamic bias control loop.
Exemplarily, when the differential amplifier includes a differential pair transistor and a load transistor; the differential pair transistors amplify the modulation signal; the load transistor keeps the current magnitude of the amplified modulation signal constant and outputs an envelope signal according to a target signal.
In an alternative form, the dynamic bias control loop includes: an error amplifier and a capacitor connected to ground.
The error amplifier generates a bias voltage for the envelope detector based on the envelope signal and a reference voltage.
When the bandwidth of the dynamic bias loop is larger than the baseband signal bandwidth of the envelope signal, the loop bandwidth of the capacitance adjustment dynamic bias control loop is smaller than the baseband signal bandwidth of the envelope signal.
Compared with the prior art, the beneficial effects of the modulation signal demodulation method provided by the embodiment of the invention are the same as those provided by the modulation signal demodulation circuit, and are not repeated herein.
In the above embodiments, the implementation may be wholly or partially realized by software, hardware, firmware, or any combination thereof. When implemented in software, may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instructions are loaded and executed on a computer, the procedures or functions described in the embodiments of the present invention are performed in whole or in part. The computer may be a general purpose computer, a special purpose computer, a computer network, a terminal, a user device, or other programmable apparatus. The computer program or instructions may be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer program or instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wire or wirelessly. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that integrates one or more available media. The usable medium may be a magnetic medium, such as a floppy disk, a hard disk, a magnetic tape; or optical media such as Digital Video Disks (DVDs); it may also be a semiconductor medium, such as a Solid State Drive (SSD).
While the invention has been described in connection with various embodiments, other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a review of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the word "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
While the invention has been described in conjunction with specific features and embodiments thereof, it will be evident that various modifications and combinations can be made thereto without departing from the spirit and scope of the invention. Accordingly, the specification and figures are merely exemplary of the invention as defined in the appended claims and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (9)
1. A modulated signal demodulation circuit, characterized in that the modulated signal demodulation circuit comprises: an envelope detector and a dynamic bias control loop; the output end of the envelope detector is electrically connected with the input end of the dynamic bias control loop, and the output end of the dynamic bias control loop is electrically connected with the envelope detector;
the envelope detector is used for detecting and amplifying the modulation signal to generate an envelope signal;
and the dynamic bias control loop is used for generating a bias voltage of the envelope detector according to the envelope signal, wherein the bias voltage is used for controlling the envelope detector to be stabilized at a static operating point when the modulation signal changes.
2. The modulated signal demodulation circuit of claim 1 wherein the envelope detector comprises: the device comprises a first high-pass filter, a second high-pass filter, a differential amplifier and a low-pass filter;
the first input end of the differential amplifier is electrically connected with a first high-pass filter for accessing the modulation signal; the second input end of the differential amplifier is electrically connected with a second high-pass filter for accessing the modulation signal; the first power end of the differential amplifier is used for accessing a power supply voltage, and the second power end of the differential amplifier is used for grounding; the output end of the differential amplifier is electrically connected with the input end of the dynamic bias control loop;
the input end of the dynamic bias control loop and the second power supply end of the differential amplifier are both connected to the low-pass filter, and the output end of the dynamic bias control loop is respectively electrically connected with the reference end of the first high-pass filter and the reference end of the second high-pass filter;
the first high-pass filter and the second high-pass filter are respectively used for isolating direct current signals in the modulation signals and coupling the modulation signals to the differential amplifier;
the differential amplifier is used for amplifying the modulation signal;
the low-pass filter is used for processing the amplified modulation signal to obtain a target signal;
the differential amplifier is also used for generating an envelope signal according to the target signal;
the first high-pass filter and the second high-pass filter are respectively used for stabilizing the envelope detector at a static operating point under the control of the bias voltage output by the dynamic bias control loop.
3. The modulation signal demodulation circuit according to claim 2, wherein the differential amplifier comprises: a differential pair transistor and a load transistor;
the first control electrode of the differential pair transistor is electrically connected with the output end of the first high-pass filter, and the second control electrode of the differential transistor is electrically connected with the output end of the second high-pass filter;
the first electrode of the differential pair transistor is used for connecting a power supply voltage, and the second electrode of the differential pair transistor is electrically connected with the second electrode of the load transistor; a second electrode of the load transistor is electrically connected with an input end of the dynamic bias control loop; the second electrode of the load transistor is also electrically connected with the input end of the low-pass filter, the grounding end of the low-pass filter is electrically connected with the first electrode of the load transistor, and the grounding end is grounded;
the differential pair transistor is used for amplifying the modulation signal;
the load transistor is used for keeping the current of the amplified modulation signal constant and outputting the envelope signal according to the target signal.
4. The modulation signal demodulation circuit of claim 2 wherein the dynamic bias control loop comprises: an error amplifier and a grounded capacitor;
the output end of the differential amplifier is electrically connected with the first input end of the error amplifier, and the second input end of the error amplifier is used for accessing a reference voltage; the output end of the error amplifier is respectively and electrically connected with the reference end of the first high-pass filter and the reference end of the second high-pass filter;
the error amplifier is used for generating a bias voltage of the envelope detector according to the envelope signal and the reference voltage;
and the capacitor is used for adjusting the loop bandwidth of the dynamic bias control loop to be smaller than the baseband signal bandwidth of the envelope signal when the bandwidth of the dynamic bias loop is larger than the baseband signal bandwidth of the envelope signal.
5. A modulated signal demodulation method, characterized by comprising:
the envelope detector detects and amplifies the modulation signal to generate an envelope signal;
and the dynamic bias control loop generates a bias voltage of an envelope detector according to the envelope signal, wherein the bias voltage is used for controlling the envelope detector to be stabilized at a static working point when the modulation signal changes.
6. The method of claim 5, wherein the detecting and amplifying the modulated signal to generate the envelope signal comprises:
the first high-pass filter and the second high-pass filter respectively isolate direct current signals in the modulation signals and couple the modulation signals to the differential amplifier;
the differential amplifier amplifies the modulated signal;
the low-pass filter processes the amplified modulation signal to obtain a target signal;
the differential amplifier also generates an envelope signal according to the target signal;
and the first high-pass filter and the second high-pass filter respectively enable the envelope detector to be stabilized at a static working point under the control of the bias voltage output by the dynamic bias control loop.
7. The modulated signal demodulating method according to claim 6, wherein the differential amplifier includes: a differential pair transistor and a load transistor;
the differential pair of transistors amplifies the modulated signal;
the load transistor keeps the current magnitude of the amplified modulation signal constant, and outputs the envelope signal according to the target signal.
8. The method of claim 6, wherein the dynamic bias control loop comprises: an error amplifier and a grounded capacitor;
the error amplifier generates a bias voltage of the envelope detector according to the envelope signal and the reference voltage;
when the bandwidth of the dynamic bias loop is larger than the baseband signal bandwidth of the envelope signal, the capacitor adjusts the loop bandwidth of the dynamic bias control loop to be smaller than the baseband signal bandwidth of the envelope signal.
9. An electronic device, characterized in that the electronic device comprises the modulation signal demodulation circuit according to any one of claims 1 to 4.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202995523U (en) * | 2012-10-30 | 2013-06-12 | 珠海中慧微电子有限公司 | Linear dropout regulator (LDO) with ultra-low power consumption and without output filtering capacitor |
| US20180198424A1 (en) * | 2017-01-06 | 2018-07-12 | Skyworks Solutions, Inc. | Amplifier architecture using positive envelope feedback |
| CN109167577A (en) * | 2018-08-30 | 2019-01-08 | 复旦大学 | Low-noise amplifier with envelope detected function |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN202995523U (en) * | 2012-10-30 | 2013-06-12 | 珠海中慧微电子有限公司 | Linear dropout regulator (LDO) with ultra-low power consumption and without output filtering capacitor |
| US20180198424A1 (en) * | 2017-01-06 | 2018-07-12 | Skyworks Solutions, Inc. | Amplifier architecture using positive envelope feedback |
| CN109167577A (en) * | 2018-08-30 | 2019-01-08 | 复旦大学 | Low-noise amplifier with envelope detected function |
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