CN208862805U - A kind of signal processing circuit and equipment - Google Patents

A kind of signal processing circuit and equipment Download PDF

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Publication number
CN208862805U
CN208862805U CN201821530488.9U CN201821530488U CN208862805U CN 208862805 U CN208862805 U CN 208862805U CN 201821530488 U CN201821530488 U CN 201821530488U CN 208862805 U CN208862805 U CN 208862805U
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signal
low
pass filter
pwm
pwm signal
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CN201821530488.9U
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李璞
张佳宁
张道宁
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Lingyu Technology (beijing) Co Ltd
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Lingyu Technology (beijing) Co Ltd
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Abstract

This application discloses a kind of signal processing circuit and equipment, the signal processing circuit includes pulse width modulation (PWM) signal generator, low-pass filter and voltage comparator, in which: voltage comparator includes the second input terminal for receiving the first input end of voltage to be compared, for receiving Dynamic comparison threshold value and for the signal output end of output digit signals;Second input terminal is connected with the output end of low-pass filter, and the input terminal of low-pass filter is connected with PWM signal generator, and PWM signal generator is set as the adjustable pwm signal of output waveform duty ratio.The application passes through the adjustable pwm signal of PWM signal generator output waveform duty ratio to low-pass filter, low-pass filter filters out the Dynamic comparison threshold value of output amplitude changes after AC compounent analog signal as voltage comparator, improve the load capacity and output resolution ratio of circuit, the I2C peripheral resources for having saved MCU reduce the electronics Material Cost of ultrasound signal receipt device.

Description

A kind of signal processing circuit and equipment
Technical field
The utility model relates to signal processing technology field, in particular to a kind of signal processing circuit and equipment.
Background technique
Ultrasonic wave is a kind of sound wave of the frequency higher than 20000 hertz, is obtained because its lower-frequency limit is greater than the upper limit of hearing of people Name, its good directionality are easily obtained the sound energy relatively concentrated.Space orientation equipment, such as helmet locator and handle are determined Position device, can resolve current location information by way of supersonic sounding.Supersonic sounding principle is the space using ultrasonic wave Propagation characteristic, to determine by the specific location of positioning target.For example, ultrasonic transmission device can be placed in by positioning target Face, ultrasonic transmission device emits ultrasonic pulse according to certain time interval to surrounding, around on three fixed positions The pulse signal that emits of ultrasonic transmission device is received respectively, and the time of signal is received by comparing three positions, it can be with It is finally inversed by the specific location of ultrasonic transmission device, that is, by the position of positioning target.Alternatively, ultrasonic wave can also be received Device is placed in by above positioning target, and the ultrasonic transmission device around on fixed position is to surrounding according between the regular hour Every transmitting ultrasonic pulse, the time of ultrasonic signal is received by ultrasonic probe, ultrasonic receiver, can be finally inversed by by positioning mesh Target specific location.
Signal amplification (Signal Amplifier, SA) electricity is usually provided in existing ultrasound signal receipt device Road, detecting circuit (Circuito Detector) and envelope are sliced circuit.Energy can not when being propagated in air due to ultrasonic wave Disconnected decaying, SA is for amplifying the ultrasonic signal received.Detecting circuit is used to obtain amplified reception signal Waveform envelope line.Envelope, which is sliced circuit, believes the digital square-wave that the amplified ultrasonic wave analog signal of detection is converted into same frequency Number, single-chip microcontroller (Microcontroller Unit, MCU) obtains square wave by the input and output port (Input Output, IO) The width of signal obtains the more specific location information of handle locator and/or helmet locator.
Existing ultrasound signal receipt device is needed according to currently received ultrasonic signal, and dynamic adjusts the amplification of SA The comparison threshold value of multiple and envelope slice circuit carries out dynamic tune so as to the pulse width of the digital square-wave to output It is whole, guarantee output digital square-wave in only include ultrasonic transmission device transmitting ultrasonic signal, do not include wall or The reflection wave signal of surrounding objects reflection, to improve positioning accuracy and positional accuracy.
A kind of existing method for generating Dynamic comparison threshold value is the I2C (Inter-Integrated by MCU Circuit) the voltage signal of bus marco digital regulation resistance output variation.But the method has the following shortcomings:
1, digital regulation resistance output impedance is high, and load capacity is poor, and the road N ultrasonic signal conditioning circuit is needed using N piece number word Potentiometer, wherein N is natural number;
2, digital regulation resistance price is high, and quiescent dissipation is big;
3, digital regulation resistance has 128 voltage output grades, and output resolution ratio is low;
4, need to consume 1 road I2C peripheral resources of MCU.
Utility model content
In order to solve the above-mentioned technical problem, the utility model provides a kind of signal processing circuit and equipment, can be improved The load capacity and output resolution ratio of circuit save the I2C peripheral resources of MCU and reduce the electricity of ultrasound signal receipt device Sub- Material Cost.
In order to reach the utility model aim, the technical solution of the utility model embodiment is achieved in that
The utility model embodiment provides a kind of signal processing circuit, including pulse width modulates (Pulse Width Modulation, PWM) signal generator, low-pass filter and voltage comparator, in which:
Voltage comparator includes for receiving the first input end of voltage to be compared, for receiving Dynamic comparison threshold value Two input terminals and signal output end for output digit signals;
Second input terminal is connected with the output end of the low-pass filter, the input terminal of the low-pass filter and institute It states PWM signal generator to be connected, the PWM signal generator is set as the adjustable pwm signal of output waveform duty ratio.
In one embodiment, the PWM signal generator is that circuit occurs for pwm signal.
In one embodiment, the PWM generator is the pwm signal output interface of single-chip microcontroller.
In one embodiment, the low-pass filter is active n rank low-pass filter, wherein n is the low-pass filter Order.
In one embodiment, the order n of the low-pass filter is 2 or 4.
In one embodiment, the low-pass filter is the salung with gain adjustment-base Sallen-Key low-pass filter.
In one embodiment, the digital signal that the PWM signal generator is currently exported according to the signal output end The size of pulse width adjusts the waveform duty cycle of the pwm signal in next period of preset length.
In one embodiment, the pulse width of the digital signal currently exported according to the signal output end is big It is small, adjust the waveform duty cycle of the pwm signal in next period of preset length, comprising:
If the pulse width of the digital signal currently exported is less than preset first pulse width threshold, reduce next The waveform duty cycle of the pwm signal in period, to reduce the Dynamic comparison threshold value;
If the pulse width of the digital signal currently exported is in preset first pulse width threshold to preset second Between pulse width threshold, then keep the waveform duty cycle of the pwm signal in next period constant, to keep the Dynamic comparison Threshold value is constant;
If the pulse width of the digital signal currently exported is greater than preset second pulse width threshold, increase next The waveform duty cycle of the pwm signal in period, to increase the Dynamic comparison threshold value.
In one embodiment, the quantity of the PWM signal generator and the low-pass filter is respectively 1, the electricity The quantity for pressing comparator is at least two.
The utility model embodiment additionally provides a kind of equipment, including the signal processing circuit as described in any of the above item.
The technical solution of the utility model has the following beneficial effects:
Signal processing circuit and equipment provided by the utility model, can by PWM signal generator output waveform duty ratio For the pwm signal of tune to low-pass filter, low-pass filter filters out the analog signal conduct electricity of output amplitude variation after AC compounent The Dynamic comparison threshold value for pressing comparator, improves the load capacity and output resolution ratio of circuit, has saved the I2C peripheral hardware money of MCU Source reduces the electronics Material Cost of ultrasound signal receipt device.
Detailed description of the invention
Attached drawing described herein is used to provide a further understanding of the present invention, and is constituted part of this application, The exemplary embodiment of the utility model and the description thereof are used to explain the utility model, does not constitute to the improper of the utility model It limits.In the accompanying drawings:
Fig. 1 is a kind of structural schematic diagram of signal processing circuit of the utility model embodiment;
Fig. 2 is the waveform decomposition diagram of pwm signal in the related technology;
Fig. 3 is waveform variation schematic diagram of the pwm signal after low-pass filter;
Fig. 4 is a kind of circuit theory schematic diagram of signal processing circuit of the utility model embodiment.
Specific embodiment
For the purpose of this utility model, technical solution and advantage is more clearly understood, below in conjunction with attached drawing to this The embodiment of utility model is described in detail.It should be noted that in the absence of conflict, embodiment in the application and Feature in embodiment can mutual any combination.
Referring to Fig.1, the utility model embodiment provides a kind of signal processing circuit, including PWM signal generator, low pass Filter and voltage comparator, in which:
Voltage comparator includes for receiving the first input end of voltage to be compared, for receiving Dynamic comparison threshold value Two input terminals and signal output end for output digit signals;
Second input terminal is connected with the output end of the low-pass filter, the input terminal of the low-pass filter and institute It states PWM signal generator to be connected, the PWM signal generator is set as the adjustable pwm signal of output waveform duty ratio.
Fig. 2 is the waveform decomposition diagram of pwm signal.Pwm signal be fix in a kind of period, the impulse wave that pulsewidth is controllable Shape, pwm signal waveform can be broken down into a DC component, and a same duty cycle but average amplitude be zero it is new Square wave, the amplitude proportional of this DC component is in the duty ratio of PWM waveform.Duty ratio just refers in one cycle, at signal The percentage of entire signal period is occupied in the time of high level, such as: 1 μ s of pulse width, the pulse train of 4 μ s of signal period Duty ratio is 0.25.If the pulsewidth in pwm signal each period is identical, i.e. the duty ratio of pwm signal is constant, then Pwm signal can only obtain DC waveform after low-pass filter filters out AC compounent;If making the duty ratio of pwm signal at any time Between change, for example, the pulsewidth in pwm signal each period changes according to the rule of sine wave, then its DC component changes correspondingly, The analog signal of amplitude variation as shown in Figure 3 will be exported after low-pass filter filters out AC compounent.By changing PWM letter Number duty ratio, can produce different analog signals.
In an embodiment of the utility model, the PWM signal generator is that circuit occurs for pwm signal.
Specifically, it includes triangular wave or saw-toothed wave generator and comparator, the triangular wave that circuit, which occurs, for the pwm signal Or saw-toothed wave generator generates high frequency modulated wave, generates pwm signal through comparator.Triangular wave or sawtooth wave and adjustable dc voltage Compare, generates the pwm signal of adjustable duty cycle.Circuit evolving pwm signal occurs by pwm signal, advantage is at low cost, each ring Waveform and voltage value Observable are saved, is easy to expanded application circuit, the disadvantage is that circuit level is low, is unfavorable for commercialization.
In another embodiment of the utility model, the PWM generator is the pwm signal output interface of single-chip microcontroller.
It should be noted that PWM generator module would generally be integrated inside existing single-chip microcontroller, the PWM generator mould Block generates pwm signal under SCM program control.This method advantage is that circuit is simple, is convenient for process control, the disadvantage is that unfavorable It is restricted when observing PWM and generating process, use by single-chip microcontroller performance.
The PWM generator of the utility model may be the programmable logic device with pwm signal generating routine or dedicated Chip, the programmable logic device include Complex Programmable Logic Devices (Complex Programmable Logic Device, CPLD) or Field Programmable Gate Array Devices (Field-Programmable Gate Array, FPGA).Pass through Pwm signal is generated using the programmable logic device with pwm signal generating routine or special chip, it is easy to use, safe, it is convenient for It is applied in product design, disadvantage is detrimental to adjust parameters.
In an embodiment of the utility model, the low-pass filter is active n rank low-pass filter, wherein n is institute State the order of low-pass filter.
Specifically, the order n of the low-pass filter is 2 or 4.
In an embodiment of the utility model, the low-pass filter is the salung with gain adjustment-base Sallen- Key low-pass filter.
In an embodiment of the utility model, the PWM signal generator is currently exported according to the signal output end Digital signal pulse width size, adjust the waveform duty cycle of the pwm signal in next period of preset length.
It should be noted that for ultrasonic signal, pulsewidth is too wide to be made because being likely to be received reflection wave signal etc. It is not high at positioning accuracy and positional accuracy;Pulsewidth is too narrow, then the ultrasonic signal being easily lost in the locating periodically.This Shen The size of the pulse width of the digital signal please currently exported by basis, adjusts the comparison threshold value in next period, can be to defeated The pulse width of digital signal out is adaptively adjusted, and positioning accuracy and positional accuracy are improved.
In the present embodiment, the size of the pulse width of the digital signal currently exported according to the signal output end, Adjust the waveform duty cycle of the pwm signal in next period of preset length, comprising:
If the pulse width of the digital signal currently exported is less than preset first pulse width threshold, reduce next period The pwm signal waveform duty cycle, to reduce the Dynamic comparison threshold value;
If the pulse width of the digital signal currently exported is in preset first pulse width threshold to preset second pulsewidth Between threshold value, then keep the waveform duty cycle of the pwm signal in next period constant, to keep the Dynamic comparison threshold value It is constant;
If the pulse width of the digital signal currently exported is greater than preset second pulse width threshold, increase next period The pwm signal waveform duty cycle, to increase the Dynamic comparison threshold value.
In an embodiment of the utility model, the quantity of the PWM signal generator and the low-pass filter is distinguished It is 1, the quantity of the voltage comparator is at least two.
By the low-pass filter for selecting output impedance low, plurality of voltages comparator can be driven simultaneously, to reduce electricity The electronics Material Cost on road.
A kind of signal processing circuit as shown in Figure 4, wherein first resistor R1, second resistance R2,3rd resistor R3, Four resistance R4, first capacitor C1, the second capacitor C2 and operational amplifier U1A constitute Sallen-Key second-order low-pass filter;A1 For comparator, the 6th resistance R6 is pull-up resistor, and the 5th resistance R5 is positive feedback resistor, can also not use the 5th in this circuit NC in resistance R5 and 3rd resistor R3, Fig. 4 indicates not connected (No Connection).A termination power of third capacitor C3 (3.3V), other end ground connection, for eliminating the ripple of power supply.AGND in Fig. 4 indicates simulation ground, i.e. analog circuit zero potential Common reference.
Sallen-Key second-order low-pass filter is input to using the pwm signal that the duty ratio that MCU is exported changes over time Input terminal, pwm signal become after the low-pass filter amplitude variation analog signal, as voltage comparator A1's Dynamic comparison threshold signal.The resolution ratio of digital analog converter (Digital to Analog Converter, DAC) is to measure DAC An important parameter, in the case where PWM timer clock is fixed, the resolution ratio of DAC is determined by the carrier frequency of pwm signal It is fixed.The pwm signal of 10KHZ is exported under the driving of 108MHZ clock using MCU on-chip timer, it is possible to provide 10800 counter values (i.e. resolution ratio), and existing digital regulation resistance only has 128 voltage output grades, output resolution ratio is significantly lower than the application's The output resolution ratio of signal processing circuit.Sallen-Key second-order low-pass filter in Fig. 4 includes operational amplifier U1A and outer The resistance capacitance enclosed, the General operational amplifier that the operational amplifier U1A is 1MHz using the gain bandwidth product that 3PEAK company produces TP321, the low-pass filter output impedance is low, multichannel (for example, 7 tunnels) voltage comparator can be driven simultaneously, to reduce electricity The electronics Material Cost on road.
The utility model embodiment additionally provides a kind of equipment, including the signal processing circuit as described in any of the above item.
In an embodiment of the utility model, the equipment is ultrasound signal receipt device.
In an embodiment of the utility model, the equipment further includes signal amplification circuit, detecting circuit, the signal Amplifying circuit, detecting circuit and the signal processing circuit are sequentially connected, in which:
The signal amplification circuit, for being amplified to reception signal;
The detecting circuit, for obtaining the amplified waveform envelope line for receiving signal;
The signal processing circuit, for according to obtained waveform envelope line (i.e. previously described voltage to be compared) and working as Preceding Dynamic comparison threshold value, output digit signals;And the size of the pulse width according to the digital signal currently exported, adjust institute State Dynamic comparison threshold value.
It should be noted that the specific structure of the signal processing circuit is as it was noted above, details are not described herein again.
Signal processing circuit and equipment provided by the utility model, can by PWM signal generator output waveform duty ratio For the pwm signal of tune to low-pass filter, low-pass filter filters out the analog signal conduct electricity of output amplitude variation after AC compounent The Dynamic comparison threshold value for pressing comparator, improves the load capacity and output resolution ratio of circuit, has saved the I2C peripheral hardware money of MCU Source reduces the electronics Material Cost of ultrasound signal receipt device.
The above descriptions are merely preferred embodiments of the present invention, is not intended to limit the utility model, for this For the technical staff in field, various modifications and changes may be made to the present invention.It is all in the spirit and principles of the utility model Within, any modification, equivalent replacement, improvement and so on should be included within the scope of protection of this utility model.

Claims (10)

1. a kind of signal processing circuit, which is characterized in that including pulse width modulation (PWM) signal generator, low-pass filter and Voltage comparator, in which:
Voltage comparator includes for receiving the first input end of voltage to be compared, second for receiving Dynamic comparison threshold value defeated Enter end and the signal output end for output digit signals;
Second input terminal is connected with the output end of the low-pass filter, the input terminal of the low-pass filter with it is described PWM signal generator is connected, and the PWM signal generator is set as the adjustable pwm signal of output waveform duty ratio.
2. signal processing circuit according to claim 1, which is characterized in that the PWM signal generator is pwm signal hair Raw circuit.
3. signal processing circuit according to claim 1, which is characterized in that the PWM generator is that the PWM of single-chip microcontroller believes Number output interface.
4. signal processing circuit according to claim 1, which is characterized in that the low-pass filter is active n rank low pass Filter, wherein n is the order of the low-pass filter.
5. signal processing circuit according to claim 4, which is characterized in that the order n of the low-pass filter is 2 or 4.
6. signal processing circuit according to claim 4, which is characterized in that the low-pass filter is with gain adjustment Salung-base Sallen-Key low-pass filter.
7. signal processing circuit according to claim 1, which is characterized in that the PWM signal generator is according to the letter The size of the pulse width for the digital signal that number output end currently exports adjusts the PWM letter in next period of preset length Number waveform duty cycle.
8. signal processing circuit according to claim 7, which is characterized in that described currently defeated according to the signal output end The size of the pulse width of digital signal out adjusts the waveform duty cycle of the pwm signal in next period of preset length, Include:
If the pulse width of the digital signal currently exported is less than preset first pulse width threshold, reduce next period The pwm signal waveform duty cycle, to reduce the Dynamic comparison threshold value;
If the pulse width of the digital signal currently exported is in preset first pulse width threshold to preset second pulsewidth Between threshold value, then keep the waveform duty cycle of the pwm signal in next period constant, to keep the Dynamic comparison threshold value It is constant;
If the pulse width of the digital signal currently exported is greater than preset second pulse width threshold, increase next period The pwm signal waveform duty cycle, to increase the Dynamic comparison threshold value.
9. signal processing circuit according to claim 1, which is characterized in that the PWM signal generator and the low pass The quantity of filter is respectively 1, and the quantity of the voltage comparator is at least two.
10. a kind of equipment, which is characterized in that including the described in any item signal processing circuits of the claim 1 to 9.
CN201821530488.9U 2018-09-18 2018-09-18 A kind of signal processing circuit and equipment Active CN208862805U (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111245404A (en) * 2020-01-15 2020-06-05 北京雪迪龙科技股份有限公司 Apparatus and method for generating waveforms
CN111565044A (en) * 2020-05-25 2020-08-21 明峰医疗系统股份有限公司 ADC device based on phase-splitting clock TDC and analog-to-digital conversion method thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111245404A (en) * 2020-01-15 2020-06-05 北京雪迪龙科技股份有限公司 Apparatus and method for generating waveforms
CN111565044A (en) * 2020-05-25 2020-08-21 明峰医疗系统股份有限公司 ADC device based on phase-splitting clock TDC and analog-to-digital conversion method thereof
CN111565044B (en) * 2020-05-25 2024-05-03 明峰医疗系统股份有限公司 ADC device based on split-phase clock TDC and analog-to-digital conversion method thereof

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