CN102841268B - A kind of capacitance plate noise detecting method and system - Google Patents
A kind of capacitance plate noise detecting method and system Download PDFInfo
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- CN102841268B CN102841268B CN201210252658.2A CN201210252658A CN102841268B CN 102841268 B CN102841268 B CN 102841268B CN 201210252658 A CN201210252658 A CN 201210252658A CN 102841268 B CN102841268 B CN 102841268B
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Abstract
The present invention is applicable to electric digital data processing field, and provide a kind of capacitance plate noise detecting method, this detection method comprises the following steps: A, utilize Received signal strength data characteristics to carry out noise rough detection; B, noise rough detection is judged whether to there is noise, if there is noise, record the noise characteristic value of current noise rough detection; The detection of D, noise rough detection there is noise or noise changes, then utilize analysis noise spectrum and energy distribution to carry out noise examining survey to received signal; Described rough detection analyzes Received signal strength part or the overall situation, and short-term or long-term signal amplitude, frequency and signal intensity deviation judge whether to there is noise or noise changes, and judge whether that needing to do noise examining surveys accordingly; It is noise spectrum and the energy distribution of analyzing Received signal strength that described examining is surveyed; Described data characteristics, when touching generation, reacts the signal intensity on capacitance plate.By hierarchical detection noise, reduce complexity, detect timely, precision raising.
Description
Technical field
The invention belongs to electric digital data processing field, particularly relate to a kind of capacitance plate noise detecting method and device.
Background technology
Current, capacitance touch, becomes main flow, as smart mobile phone, and the consumer product of the types such as mobile internet surfing equipment.And the detection of capacitance plate touching, be generally the AC signal sending a certain amplitude certain frequency at transmitting terminal, this signal can be sinusoidal wave, square wave, trapezoidal wave or other waveforms, then the amplitude of the signal received by receiving end is judged.As Fig. 1, the first data-signal that transmitting terminal sends, after integrated operational amplifier amplifies, become the second new data-signal, the second data-signal is relevant with the mutual capacitance between transmitting terminal and receiving end with the amplitude of the first data-signal.Mutual capacitance can change along with the contact of finger.Second data-signal, after digital-to-analog converter quantizes, connects a detuner or frequency mixer usually, and detuner is used for recovering the amplitude information of the second data-signal.Certainly, detuner also before digital-to-analog converter, can utilize analogy method to realize, does not affect Detection results.
Fig. 2 is a kind of possible demodulator structure.An analogue low pass filtering is used as the frequency overlapped-resistable filter of digital-to-analog converter, or with the function of some radio-frequency component in filtering second data-signal.Signal after analogue low pass filtering converts digital signal to by digital-to-analog converter, and digital signal enters detuner demodulation.There is own demodulation signal in detuner, is the square wave having certain frequency, sinusoidal wave or other waveforms, and restituted signal can realize with look-up table or numerically-controlled oscillator.Restituted signal and the second data-signal are normally with the signal of frequency homophase.Like this, after multiplier, the second data-signal can be converted to the 3rd data-signal of band DC component by AC signal, the 3rd data-signal is the signal that we want to obtain.In Fig. 2, the 3rd data-signal is by a digital low-pass filtering, the high fdrequency component be used in filtering the 3rd data-signal.A kind of common implementation of digital low-pass filtering is, carries out multiple spot tire out with average the 3rd data-signal.This demodulation mode requires that restituted signal aligns with the phase place of the second data-signal.Fig. 3 is another kind of possible demodulator structure.An analogue low pass filtering is used as the frequency overlapped-resistable filter of digital-to-analog converter, or with the function of some radio-frequency component in filtering second data-signal.Signal after analogue low pass filtering converts digital signal to by digital-to-analog converter, and digital signal enters detuner demodulation.Detuner is provided with two digital low-pass filterings arranged side by side, and similar with low-pass filter structure.Restituted signal can be square wave, sinusoidal wave, trapezoidal wave or other waveforms.Restituted signal is generally and the second data-signal same frequency, and orthogonal two signals, they can be produced by the time delay of look-up table or signal.The output of digital low-pass filtering can recover the amplitude of the second data-signal.Because restituted signal is mutually orthogonal, now, the phase place of restituted signal not necessarily will be alignd with the second data-signal, also can recover correct signal amplitude.
After being mixed into noise in whole system, this noise can be neighbourhood noise, RF noise, or the common-mode noise of charger, this noise is generally incorporated in system by the finger touching of user, this time, noise is after the demodulation of Fig. 2 or Fig. 3, can become an AC signal, the frequency of this AC signal, be the difference frequency of noise frequency and mixer frequency.In order to detect this AC signal, can in time domain, utilize wave characteristics to detect, such as, cross 0 detection, obtain frequecy characteristic, or detect the variable quantity of waveform in a period of time, or on frequency domain, utilize frequency selection network to detect, detect the energy value of a certain frequency.But it is general lower that noise produces difference frequency signal frequency, tim e-domain detection needs for a long time, and good frequency selection network, also need the stabilization time grown very much, therefore, aforesaid way all requires sufficiently long detection time.For some TP systems, shown in Fig. 4, such as traditional transmitting terminal sequential scan mode, the sweep time of each transmitting terminal is shorter, limits the accuracy of detection.
Traditional walkaway mode all does walkaway usually in normal use procedure always, because walkaway accurately needs longer detection time, causes system to need to waste the long period in walkaway always.
On the other hand, when noise frequency is consistent with sweep frequency, the above-mentioned time domain mentioned or frequency domain all cannot detect noise, and only way is the impact of removing sweep frequency, and common is exactly close transmitting terminal scanning or be switched to another transmitting terminal sweep frequency.The mode switching transmitting terminal sweep frequency is effective for mono-tone interference, if but also containing the frequency consistent with new transmitting terminal sweep frequency in noise, then also cannot detect.The mode of closing transmitting terminal scanning is beneficial to the interference detecting multifrequency point, but in normal scan, insert too much sky scanning, the entire scan speed of system can be reduced, and if only carry out sky scanning within certain a period of time, when noise is discontinuous occur time, likely can noise signal be detected.
Current most of technology is all only in hardware end detection noise, and method comprises various scheme above-mentioned.If the detection of hardware is only carried out in a frame a certain section, also there will be and miss walkaway situation, if hardware switched scan frequency repeatedly, or send several sweep frequency simultaneously, hardware complexity can be caused to strengthen.Meanwhile, at some under the environment of time requirement harshness, may have no time to do walkaway, thus reduce the noise immunity of system.In sum at present walkaway mode single exist system complexity high, detect not in time, there is the low technological deficiency of accuracy of detection in the system for some the limited time.
Summary of the invention
The object of the embodiment of the present invention is to provide a kind of capacitance plate noise detecting method and system, and being intended to solve increases system complexity, detects not in time, there is the low technical matters of accuracy of detection for the system of some the limited time.
The embodiment of the present invention is achieved in that a kind of capacitance plate noise detecting method, and this detection method comprises the following steps:
A, Received signal strength data characteristics is utilized to carry out noise rough detection;
B, noise rough detection is judged whether to there is noise, if there is noise, record the noise characteristic value of current noise rough detection;
The detection of D, noise rough detection there is noise or noise changes, then utilize analysis noise spectrum and energy distribution to carry out noise examining survey to received signal;
Described rough detection analyzes Received signal strength part or the overall situation, and short-term or long-term signal amplitude, frequency and signal intensity deviation judge whether to there is noise or noise changes, and judge whether that needing to do noise examining surveys accordingly;
It is noise spectrum and the energy distribution of analyzing Received signal strength that described examining is surveyed, and is the working frequency points that Systematic selection is suitable;
Described data characteristics, when touching generation, reacts the signal intensity on capacitance plate.
Further technical scheme of the present invention is: after described step B, further comprising the steps of before D step:
C, judge whether the working frequency range of current noise rough detection is surveyed by examining, if surveyed by examining, current rough detection noise characteristic compares difference with the noise characteristic value of noise rough detection in data base, and as difference is greater than preset value, then noise changes.
Further technical scheme of the present invention is: also comprise step e after described D step:
E, by noise rough detection, examining survey noise characteristic value be updated to respectively noise rough detection, examining survey noise characteristic value data base in.
Further technical scheme of the present invention is: described noise rough detection comprises the Data Detection of local and the overall situation, local data detects and is completed by detuner, the overall situation is completed by host computer, final detection result using one be judged as main or two judge as combine criterion or two judge that weighted sum is as criterion.
Further technical scheme of the present invention is: described step B is divided into following steps:
B1, noise rough detection is judged whether to there is noise;
If B2 exists noise, record the noise characteristic value of current noise rough detection.
Further technical scheme of the present invention is: described step C is divided into following steps:
C1, judge whether the working frequency range of current noise rough detection is surveyed by examining;
If C2 is surveyed by examining, current rough detection noise characteristic compares difference with the noise characteristic value of noise rough detection in data base, and as difference is greater than preset value, then noise changes.
Another object of the embodiment of the present invention is to provide a kind of capacitance plate noise detection apparatus, and this pick-up unit comprises:
Noise rough detection module, the signature analysis of the data characteristics and whole frame data to received signal that detect Received signal strength waveform for utilizing detuner carries out noise rough detection;
Noise judges logging modle, for judging whether to there is noise to noise rough detection, if there is noise, records the noise characteristic value of current noise rough detection;
Noise examining is surveyed and is judged contrast module, for judging whether the working frequency range of current noise rough detection is surveyed by examining, if surveyed by examining, current rough detection noise characteristic compares difference with the noise characteristic value of noise rough detection in data base, and as difference is greater than preset value, then noise changes;
, there is noise for the detection of noise rough detection in the thin detection module of noise or noise changes, then utilize analysis noise spectrum and energy distribution to carry out noise examining survey to received signal;
Noise characteristic value memory module, in the noise characteristic value data base that the noise characteristic value for noise rough detection, examining being surveyed is updated to noise rough detection respectively, examining is surveyed.
Further technical scheme of the present invention is: described noise judges that logging modle comprises with lower module:
Noise judge module, for judging whether to there is noise to noise rough detection;
Noise recording module, if for there is noise, records the noise characteristic value of current noise rough detection.
Further technical scheme of the present invention is: described noise examining is surveyed and judged that contrast module comprises with lower module:
Judge module is surveyed in noise examining, for judging whether the working frequency range of current noise rough detection is surveyed by examining;
Noise vs's module, if for being surveyed by examining, current rough detection noise characteristic compares difference with the noise characteristic value of noise rough detection in data base, and as difference is greater than preset value, then noise changes.
The invention has the beneficial effects as follows: by the mode of hierarchical detection noise, effectively reduce the expense of system, find noise fast and accurately.Thus reduce the complexity of system, walkaway is timely, the systems axiol-ogy precision by time restriction is improved, mitigation system load, the consumption of reduction system resource.
Accompanying drawing explanation
Fig. 1 is the hardware detection structural drawing that prior art provides;
Fig. 2 is the demodulator structure figure that prior art provides;
Fig. 3 is the demodulator structure figure that prior art provides;
Fig. 4 is the transmitting terminal order scanning sequence schematic diagram that prior art provides;
Fig. 5 is capacitance plate noise detecting method process flow diagram provided by the invention;
Fig. 6 is that the empty frame of capacitance plate noise detecting method provided by the invention inserts transmitting terminal order scanning sequence schematic diagram;
Fig. 7 is capacitance plate noise detecting method hardware structure diagram provided by the invention;
Fig. 8 is capacitance plate noise detecting method orthogonal modes hardware structure diagram provided by the invention;
Fig. 9 is capacitance plate noise detecting method walkaway mode hardware structural drawing provided by the invention;
Figure 10 is clean signal data dithering figure in capacitance plate noise detecting method provided by the invention;
Figure 11 adds noise signal data dithering figure in capacitance plate noise detecting method provided by the invention;
Low-pass filtering is designed to tired and device figure by Figure 12 in capacitance plate noise detecting method provided by the invention;
Figure 13 is that capacitance plate noise detecting method provided by the invention is with one-level pre-filtering hardware structure diagram;
Figure 14 is tired in capacitance plate noise detecting method noise provided by the invention and the corresponding spectrogram of device;
Figure 15 is the structural drawing of capacitance plate noise detection apparatus provided by the invention;
Reference numeral: 30 analogue low pass filtering 40 impact damper 50 digital signal processing module 60 A-D converter 70 detuner 701 multiplier 702 digital low-pass filtering 703 totalizer 704 squaring multipliers 80 tire out and the pre-filtering of device 90 one-level.
Embodiment
In order to make object of the present invention, technical scheme and advantage clearly understand, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, be not intended to limit the present invention.
Fig. 1 shows the flow process of the capacitance plate noise detecting method that the embodiment of the present invention provides, and details are as follows:
In step S101, touch capacitance plate and generate touch signal, transmitting terminal launches touch signal, and receiving end receives the touch signal that transmitting terminal is launched, noise can be mixed into, such as extraneous RF interference or the common mode interference of charger etc. in the touch signal that receiving end receives.Now just need to carry out noise rough detection to received signal, here noise rough detection is whether be mixed with noise in Received signal strength under preliminary judgement.Judge whether that there is noise is that two kinds of modes realize, the first utilizes the data characteristics form of detuner sweep waveform to received signal to judge whether to there is noise, and it two is utilize the feature of the whole frame data of Received signal strength to analyze the mode that whether there is noise to judge whether to there is noise.The process of these two kinds of mode detection noise can be carried out simultaneously or order is carried out in no particular order, can not affect the result of noise rough detection.When noise is discontinuous, Billy can be obtained with the faster more complete Detection Information of the feature detection of detuner sweep waveform feature by the mode of the data characteristics analysis of signal, strict to time requirement, detuner can not carry out in the system of walkaway, and data characteristics is analyzed detection noise and had more advantage.These two kinds of detection mode results, can, according to actual conditions, be judged as main with its one, or two judge as associating criterion, or two weighted sums judged are as criterion, thus the noise examining triggered below be surveyed.
Rough detection utilizes data characteristics to carry out walkaway to received signal.
Data characteristics, when touching generation, reacts the signal intensity on capacitance plate.
In step s 201, the result of noise rough detection carries out judging whether to there is noise to received signal.If judge to there is not noise, this walkaway will be terminated.If judge that there is noise can trigger next process.
In step S301, noise rough detection judges to there is noise to received signal, just extract current noise eigenwert, and this noise rough detection noise characteristic value record is got up, and this noise rough detection noise characteristic value is updated to noise rough detection eigenwert data base.
In step S401, when have recorded the eigenwert of noise, will judge the working frequency range of noise characteristic value, the working frequency range judging this noise characteristic value whether examining is surveyed, if this noise characteristic value is not carefully detected noise, then directly triggers noise examining and survey.
In step S501, current noise rough detection judges that the working frequency range of noise characteristic value is carefully detected, the size of difference will be compared to the noise characteristic in current noise eigenwert and data base, if do not have difference or difference very little, then ignore this walkaway, terminate this walkaway.If difference is greater than preset value, will think that this noise there occurs change, need that new noise examining is carried out to this noise and survey.
In step s 601, when there is noise or think that noise changes in noise rough detection, noise examining will be triggered survey, utilize analysis noise spectrum and energy distribution situation to carry out noise examining survey, and for selecting the frequency of applicable work to prepare in the process of early noise examining survey.In the process that noise examining is surveyed, only do walkaway, and do not do touch information and report, application software can not report or repeat the point reporting previous frame.The time of surveying due to noise examining is very short, and under the frame per second of 60 frames/second, only need the time of 1-2 frame, therefore this process can not affect the use of user.Analysis noise spectrum and energy distribution situation can be carry out simultaneously or sequentially carry out successively in no particular order in the detection.
It is adopt to carry out analysis noise spectrum and energy distribution to received signal that examining is surveyed, and for selecting suitable working frequency points.
In step s 701, terminate to extract examining survey noise characteristic value when noise examining is surveyed, and be updated to together with the eigenwert of noise rough detection in noise characteristic value data base that noise rough detection and noise examining survey.The use of walkaway contrast is done after waiting until.
In step S801, a walkaway is complete.
Figure 14 shows the capacitance plate noise detection apparatus that the embodiment of the present invention provides, and this pick-up unit comprises noise rough detection module, noise judges logging modle, noise examining is surveyed and judged contrast module, the thin detection module of noise and noise characteristic value memory module.
Noise rough detection module, the signal received by receiving end adopts sweep frequency mode and data characteristics analysis mode to carry out noise rough detection, exports the signal of a noise rough detection.
Noise judges logging modle, makes a decision, check whether there is noise in this noise rough detection signal to the signal that noise rough detection module exports, if there is noise, then records the noise characteristic value of current noise rough detection, and exports the signal that exists noise.If there is no noise, then export the signal that does not exist noise, and this walkaway terminates.
Noise examining is surveyed and is judged contrast module, noise is judged that the working frequency range that there is the noise characteristic value of noise signal that logging modle exports judges whether to be surveyed by examining, if surveyed by examining, then current noise eigenwert compares difference with the noise characteristic value of noise rough detection in data base, as difference is greater than preset value, then noise changes, and sends the signal triggering noise examining and survey.As difference is less than preset value, then current noise is negligible, thinks and is surveyed by examining, and this walkaway terminates to send walkaway end signal.
The thin detection module of noise, noise rough detection is thought there is noise detecting signal that noise or noise change triggers noise examining and survey, the noise examining then carrying out analyzing noise spectrum and energy distribution is to received signal surveyed, the noise characteristic value signal that output noise examining is surveyed.
The noise characteristic value signal data that noise rough detection, examining are surveyed are updated in the noise characteristic value data base of noise rough detection, examining survey by noise characteristic value memory module respectively.
Noise judges that logging modle comprises noise judge module and noise recording module.
Whether noise judge module, exist noise in the signal judging noise rough detection and send the signal of a judged result.
Noise recording module, if judging result signal there is noise, then records current noise eigenwert, and after exporting a noise characteristic value letter.
Noise examining is surveyed and is judged that contrast module comprises noise examining and surveys judge module and noise vs's module.
Judge module is surveyed in noise examining, judges whether to be surveyed by examining, if can be sent by thin detection signal by examining survey, if do not surveyed by examining, will send and carry out thin detection signal the working frequency range of current noise eigenwert.
Noise vs's module, to send by examining survey altogether the noise characteristic value in signal compares difference with the noise characteristic value of noise rough detection in data base, as difference is greater than preset value, then noise changes, send the signal that current noise needs to carry out examining survey, as difference is less than preset value, then noise does not send out change upper, sends this walkaway end signal.
Problem for convenience of explanation, illustrates as follows:
In order to quick detection noise, this method surveys two parts through noise rough detection and examining.Rough detection is completed by software-hardware synergism, and examining is surveyed and completed by hardware.In rough detection process, just simply judge whether to there is noise, now judge that precision is low, but detection only consumes little time and bandwidth detects.Only have rough detection to find to there is noise, just trigger examining and survey.Thin testing process, the frequency spectrum of analysis noise that can be meticulous and energy distribution situation, for selecting suitable working frequency points ready, the relative rough detection of hardware spending now increases to some extent.
First set forth rough detection process below, due to the phase relation that noise and sweep signal are not fixed, in order to obtain noise information accurately, detuner 70 in hardware adopts quadrature demodulation pattern, as shown in Figure 7, the content great majority that this programme is set forth realize at numerical portion, but because detuner can before A-D converter 60, therefore some thoughts of scheme also can realize in simulation part, do not affect result.Comparison diagram 3, analogue low pass filtering 30 is configured to digital low-pass filtering 702, the signal that both export through square after be added and can obtain the energy of input signal.This input signal can be useful signal, noise signal or both mixed signals.Simple in order to realize, digital low-pass filtering 702 is usually designed to tired and device 80.Tired and device 80 has certain bandwidth, and this bandwidth limits its selecting frequency characteristic, and bandwidth and tired and time span are inversely proportional to, tired and the time is longer, and bandwidth is narrower, and selecting frequency characteristic is better.
In this example, empty scanning is utilized to carry out detection noise.In the normal scan of every frame, insert an empty scanning, sky scans the beginning or end position or other any positions that can be inserted in every frame.As shown in Figure 6, suppose the beginning location of empty scanning at every frame, the time of empty scanning can be greater than or less than the normal scan of transmitting terminal.Simple in order to realize, sky is set in this example and equals normal single transmitting terminal sweep time sweep time.Empty scan period, complete hardware rough detection.The way that hardware rough detection can adopt Fig. 7 to describe, detects current demand signal energy, if energy exceedes certain threshold value, thinks to there is interference.The energy now detected be by the energy of all frequency components of digital low-pass filtering 702 frequency selection network and.Because the time of sky scanning is shorter, known by analysis above, now the selecting frequency characteristic of wave digital lowpass filter 702 is also not bery accurate, therefore, probably can only judge whether there is interference near ongoing frequency, but accordingly, the hardware spending at this time consumed is also very little.
Another kind method also can detect the signal that digital low-pass filtering 702 exports simultaneously, the variable quantity of observation signal within this period, and detects digital low-pass filtering 702 change amount signal sum and whether exceed certain threshold value, if so, then thinks to there is interference.Because the signal in detuner 70 after multiplier 701 and digital low-pass filtering 702, if not interference, will be a DC component, if there is AC compounent, certainly exist interference.AC signal certainly exists changes in amplitude within a certain period of time, therefore can be detected.Because empty sweep time is not long, Dan Kan mono-tunnel exports, and may not have too significant change, but the component that observation two is orthogonal simultaneously, detect their variable quantity sum, just can improve accuracy in detection greatly.The energy of signal and the variable quantity of signal as the eigenwert of hardware rough detection, can preserve, and when the eigenwert that rough detection next time arrives is from time different before, then likely noise signal there occurs change, needs again to do noise analysis.
On the other hand, hardware when normal scan, the demodulation all separately of every road receiving end data, to obtain normal touch information, as shown in Figure 8.And in empty scan period, can every road receiving end independent detection, also whole frame data can be detected, make detection more accurate.As shown in Figure 9, utilize totalizer 703 tired for all signals with afterwards, then detect.Totalizer 703 is tired and also can carry out before digital-to-analog converter 60.
Another kind method is, also only can carry out walkaway, this time to the receiving end signal with peak-peak, totalizer 703 is replaced by a maximal value finder.
When after the complete frame data of hardware scanning, data can be reported controller, controller can analyze data, and draws touch information.This means that the software in controller can utilize frame data to carry out detection noise.According to the design feature of mutual capacitance screen, when noise is incorporated into after in system by people's touching, the permutation at touch points place all can by noise.So we can carry out holistic approach to judge whether to there is interference to data.Such as, after signal is mixed into noise, noise can reduce the signal to noise ratio (S/N ratio) of system.Signal to noise ratio (S/N ratio) can calculate like this: signal to noise ratio (S/N ratio)=(Up-Uu)/Q, wherein, and the mean value that Up representative touches, the mean value that Uu representative touches, the standard deviation of Q representative touch data shake.
As shown in Figure 10,11, for a clean signal, can there is shake in its data, but the standard deviation Q of thing touch data shake only swings in a smaller scope, and when noise adds after, the standard deviation Q that thing touch data is shaken can be strengthened significantly.If the standard deviation Q value change of thing touch data shake is very little, then illustrate that noise is minimum to effect of signals, can not consider.Therefore, we can utilize this point, judge in row, and the point that the standard deviation Q value of thing touch data shake is excessive accounts for the total ratio of counting of a row receiving end whether to judge in current signal containing interference.Such as, this ratio can be 1/2.The ratio that the standard deviation Q value of thing touch data shake is not normal as one of eigenwert of software rough detection noise, can merge with the noise characteristic of hardware detection and uses.Also have some other data characteristics can be used to the walkaway doing software aspect, the data difference that such as can compare identical point between different frame judges, or detects in data whether occur hop situation.Because software has more data volume relative to hardware, data between frame even can be utilized to make a decision, therefore, when noise is discontinuous, the Detection Information faster more complete than hardware can be obtained by the mode of software, and strict to time requirement at some, hardware can not carry out in the system of walkaway, has more advantage.
Using wherein a kind of, the result that software and hardware detects, according to the situation of practical application, can be judged as that main, two judgements as combining the weighted sums of criterion or two judgements as criterion, thus trigger the thin testing process of noise below.
When noise examining is surveyed, transmitting terminal scanning is closed completely, in this time, only does walkaway, and not touch information reporting, upper application software can repeat report the point of previous frame or do not report a little.Because thin detection time is very short, under the frame per second of 60 frames/second, only need 1-2 frame time, depend on that whether noise is continuous, therefore, this process can not have influence on user and use.
Shown in Fig. 7, utilize the feature that totalizer 703 outputs signal, as energy, rate of change etc., can judge in current demand signal, whether to there is the signal identical or close with restituted signal frequency, and the selecting frequency characteristic of digital low-pass filtering 702, determine the accuracy that this judges, selecting frequency characteristic is better, more can judge whether the interference that there is restituted signal frequency accurately.Examining is surveyed needs digital low-pass filtering 702 to have good selecting frequency characteristic.In many systems, digital low-pass filtering 702 is generally designed to tired and device, and shown in Figure 12,13, tired and device only needs adder unit, realizes very convenient.But this performance that is tired and device depend on tired and time span.Suppose that the tired and time is R sampled point, 1102 represent now tired and spectral characteristic, see on the whole, frequency spectrum presents low-pass characteristic, but high frequency attenuation and cutoff frequency width are all limited to R, if tired and time are doubled, become 2R, then 1103 represent new tired and corresponding frequency spectrum, can find out, along with tired and time become one times, cutoff frequency and high frequency attenuation are all in scale compression.That is, along with tired and time lengthen, the performance of filter that tired and device 80 is formed will get a promotion.In noise rough detection, tired shorter with the time, cutoff frequency that is tired and device 80 is wider, be generally a few KHz, therefore probably can only know whether there is interference near current restituted signal frequency, but in examining is surveyed, the bandwidth requirement of tired and device 80 is usually between hundreds of-1KHz, and now adopt whole frame to detect, therefore can meet this requirement.
Consistent when the sequential chart during examining survey and normal use, shown in Fig. 8, just transmitting terminal 1-transmitting terminal n Close All, now, similar to rough detection, whole frame data can be used to do walkaway, the structure detected still adopts Fig. 9 structure, but note, the frequency, demodulation frequency of now each detuner use is no longer consistent, such as, the frequency, demodulation frequency of detuner 70 can be current transmitting terminal sweep frequency side-play amount, the frequency, demodulation frequency of detuner 70 and current transmitting terminal sweep frequency offset any the first side-play amount a little, detuner 70 can be the second side-play amount of another and transmitting terminal sweep frequency different frequency.Like this, we just within the time of a frame, can carry out the detection of multiple frequency.The energy information of these frequencies is also saved down and is used as examining survey eigenwert.If noiseless under present operating frequency, then continue to select ongoing frequency work.If there is noise, then the frequency selecting noise energy minimum is by the working frequency points as next candidate.
Certainly, in order to obtain better selecting frequency characteristic, can do further lifting to design that is tired and device 80, tired and device 80 also can be designed to the wave filter of other kinds, such as, and various FIR filter, or iir filter.The filtering characteristic of these wave filters can be accomplished to be better than tired and wave filter 80, so, we can design many one-levels pre-filtering 90 before tired and device 80, as shown in figure 14, and one-level pre-filtering 90, when tired and device 80 with and after one-level pre-filtering 90 connect, frequency-selecting performance will be much higher than tires out and device 80.One-level pre-filtering 90 can be designed to tired and device, or better FIR or iir filter.
The foregoing is only preferred embodiment of the present invention, not in order to limit the present invention, all any amendments done within the spirit and principles in the present invention, equivalent replacement and improvement etc., all should be included within protection scope of the present invention.
Claims (7)
1. a capacitance plate noise detecting method, is characterized in that, this detection method comprises the following steps:
A, Received signal strength data characteristics is utilized to carry out noise rough detection;
B, noise rough detection is judged whether to there is noise, if there is noise, record the noise characteristic value of current noise rough detection;
The detection of D, noise rough detection there is noise or noise changes, then utilize analysis noise spectrum and energy distribution to carry out noise examining survey to received signal;
Described noise rough detection analyzes Received signal strength part or the overall situation, and signal amplitude to received signal, frequency and signal intensity deviation judge whether to there is noise or noise changes, and judge whether that needing to do noise examining surveys accordingly;
It is noise spectrum and the energy distribution of analyzing Received signal strength that described noise examining is surveyed, and is the working frequency points that Systematic selection is suitable;
Described data characteristics, when touching generation, reacts the signal intensity on capacitance plate;
Further comprising the steps of after described step B, before step D:
C, judge whether the working frequency range of current noise rough detection is surveyed by noise examining, if surveyed by noise examining, the noise characteristic of current noise rough detection compares difference with the noise characteristic value of noise rough detection in data base, as difference is greater than preset value, then noise changes;
Also step e is comprised after described step D:
E, by noise rough detection, noise examining survey noise characteristic value be updated to respectively noise rough detection, noise examining survey noise characteristic value data base in.
2. capacitance plate noise detecting method according to claim 1, it is characterized in that, described noise rough detection comprises the Data Detection of local and the overall situation, final detection result using one be judged as main or two judge as combine criterion or two judge that weighted sum is as criterion.
3. capacitance plate noise detecting method according to claim 1, is characterized in that, described step B is divided into following steps:
B1, noise rough detection is judged whether to there is noise;
If B2 exists noise, record the noise characteristic value of current noise rough detection.
4. capacitance plate noise detecting method according to claim 2, is characterized in that, described step C is divided into following steps:
C1, judge whether the working frequency range of current noise rough detection is surveyed by noise examining;
If C2 is surveyed by noise examining, the noise characteristic of current noise rough detection compares difference with the noise characteristic value of noise rough detection in data base, and as difference is greater than preset value, then noise changes.
5. a capacitance plate noise detection apparatus, is characterized in that, this pick-up unit comprises:
Noise rough detection module, the signature analysis of the data characteristics and whole frame data to received signal that detect Received signal strength waveform for utilizing detuner carries out noise rough detection;
Noise judges logging modle, for judging whether to there is noise to noise rough detection, if there is noise, records the noise characteristic value of current noise rough detection;
Noise examining is surveyed and is judged contrast module, for judging whether the working frequency range of current noise rough detection is surveyed by noise examining, if surveyed by noise examining, judge that the noise characteristic of current noise rough detection compares difference with the noise characteristic value of noise rough detection in data base, as difference is greater than preset value, then noise changes;
, there is noise for the detection of noise rough detection in the thin detection module of noise or noise changes, then utilize analysis noise spectrum and energy distribution to carry out noise examining survey to received signal;
Noise characteristic value memory module, in the noise characteristic value data base that the noise characteristic value for noise rough detection, noise examining being surveyed is updated to noise rough detection respectively, noise examining is surveyed.
6. capacitance plate noise detection apparatus according to claim 5, is characterized in that, described noise judges that logging modle comprises with lower module:
Noise judge module, for judging whether to there is noise to noise rough detection;
Noise recording module, if for there is noise, records the noise characteristic value of current noise rough detection.
7. capacitance plate noise detection apparatus according to claim 6, is characterized in that, described noise examining is surveyed and judged that contrast module comprises with lower module:
Judge module is surveyed in noise examining, for judging whether the working frequency range of current noise rough detection is surveyed by noise examining;
Noise vs's module, if for being surveyed by noise examining, judge that the noise characteristic of current noise rough detection compares difference with the noise characteristic value of noise rough detection in data base, as difference is greater than preset value, then noise changes.
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| CN106575177B (en) * | 2015-09-14 | 2019-09-13 | 华为技术有限公司 | The control method and terminal of touch screen report point quantity |
| CN105389225A (en) * | 2015-11-25 | 2016-03-09 | 小米科技有限责任公司 | Touch screen reporting point processing method and apparatus |
| CN105548733B (en) * | 2015-12-03 | 2018-05-29 | 广东欧珀移动通信有限公司 | The test method and device of noise |
| CN110110628B (en) * | 2019-04-24 | 2023-08-04 | 华为技术有限公司 | Method and equipment for detecting degradation of frequency synthesizer |
| TWI759017B (en) * | 2020-12-17 | 2022-03-21 | 大陸商北京集創北方科技股份有限公司 | Noise detection method and touch chip and touch display using the same |
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