Signal measuring circuit and device for wheel speed sensor

Abstract

The utility model provides a signal measuring circuit and device for a wheel speed sensor, which relates to the technical field of wheel speed detection, and is characterized in that an input end of a proportional mirror current source circuit is connected with a signal input end so as to convert a current signal output by the signal input end into a voltage signal and amplify the voltage signal; the output end of the proportional mirror current source circuit is connected with the input end of the signal identification circuit; the signal identification circuit is provided with a first signal output port and a second signal output port, and the first signal output port and the second signal output port are both configured to decide to output a high level or a low level according to the amplitude of an input signal. The control module is connected with the first signal output port and the second signal output port so as to obtain target information through measurement according to the transmitted high level or low level. According to the utility model, the problem of low noise margin of the existing wheel speed sensor signal measuring circuit is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of wheel speed detection, in particular to a wheel speed sensor signal measurement circuit and device. Background Art

[0002] The AK protocol wheel speed sensor is a wheel speed sensor that transmits signals via the AK protocol. Compared with traditional wheel speed sensors, it is an active sensor and is widely used in the automotive field.

[0003] The AK protocol wheel speed sensor outputs a frame signal containing speed pulses and data protocol bits, corresponding to speed signals and data signals. The speed pulse represents the vehicle speed signal, and the wheel speed can be calculated based on the time interval between two adjacent speed pulses and the number of teeth on the gear. The data protocol bits represent other additional information, such as the direction of rotation of the wheel, the amplitude of the magnetic field, and other information. The AK signal characterizes the signal characteristics by the magnitude of the current, and the current is divided into three levels. High-level current (I H , HIGH-level supply current), generally 28mA, used for speed pulses; medium-level current (I M , MID-level supply current), generally 14mA, for data protocol bits; low-level current (I L , LOW-level supply current), generally 7mA, is used to indicate the low level of the signal.

[0004] The AK wheel speed sensor uses current to transmit signals, but its load capacity is not strong. Its load resistance is relatively small, and the maximum load resistance is between 50Ω and 100Ω. At the same time, the output current signal error of the wheel speed sensor is large, and the maximum error can reach ±20%.

[0005] In the known Figure 1 In the measurement system of the AK wheel speed signal, the sampling resistor RS (i.e., the load resistor of the wheel speed sensor) converts the current signal Is into a voltage signal WSI, whose voltage is compared with the reference voltage V by means of the comparator U1. REFH Compare the output characteristic signal WSO1 with the reference voltage V REFM Compare and output characteristic signal WSO2.

[0006] Since the value of the sampling resistor is limited, in the known solution, the noise tolerance of the WSO1 and WSO2 signal outputs is limited to several hundred millivolts. REFH Error, V REFMThe error and RS error will be reduced, even down to tens of millivolts. As the system working environment changes and the product ages, the sampling resistor RS, the reference voltage V REFH 、V REFM There are also temperature drift and aging drift errors. The noise tolerance of the system will further decrease, that is, the tolerance capability will weaken and the anti-interference ability will deteriorate, resulting in the output of abnormal signals, causing wheel speed measurement failures, affecting the vehicle's ABS, TCS and other active safety control calculations, and posing a hidden danger to the vehicle's travel safety. Utility Model Content

[0007] In view of the deficiencies in the prior art, the utility model provides a wheel speed sensor signal measurement circuit and device, which solves the problem of low noise tolerance of the existing wheel speed sensor signal measurement circuit.

[0008] At least one embodiment of the present utility model provides a wheel speed sensor signal measurement circuit, comprising: a signal input terminal, a proportional mirror current source circuit, a signal identification circuit and a control module, wherein:

[0009] The input end of the proportional mirror current source circuit is connected to the signal input end to convert the current signal output from the signal input end into a voltage signal and amplify the voltage signal;

[0010] The output end of the proportional mirror current source circuit is connected to the input end of the signal recognition circuit;

[0011] The signal identification circuit has a first signal output port and a second signal output port, and the first signal output port and the second signal output port are both configured to output a high level or a low level according to the amplitude of the input signal. The control module is respectively connected to the first signal output port and the second signal output port to obtain target information based on the transmitted high level or low level measurement.

[0012] The technical solution disclosed by the utility model has at least the following beneficial effects:

[0013] By adjusting the ratio K of the proportional mirror current source, a pulse signal with a larger amplitude can be provided for the subsequent circuit, and a larger noise margin space can be provided for the signal recognition circuit.

[0014] In one embodiment of the present invention, the proportional mirror current source circuit includes a resistor RS, a resistor R201, a resistor R202, a switch tube Q201, a switch tube Q202 and a power supply VCC, wherein:

[0015] The signal input end is connected to the common end through the input end of the switch tube Q201, the output end of the switch tube Q201 and the resistor RS in sequence. The input end of the switch tube Q201 is also connected to the control end of the switch tube Q201 and the control end of the switch tube Q202 respectively. The power supply VCC is connected to the common end through the resistor R201, the input end of the switch tube Q202, the output end of the switch tube Q202 and the resistor R202 in sequence. The input end of the switch tube Q202 is the output end of the proportional mirror current source circuit.

[0016] The technical solution disclosed by the utility model has at least the following beneficial effects:

[0017] Through the above settings, the signal input terminal receives I L ,I M ,I H The voltage generated in WSI between the three levels of current is amplified by R201 / R202 times compared to the signal collected directly through resistor RS without a proportional mirror current source. The tolerance capability of the signal recognition circuit is also increased by R201 / R202 times, and the anti-interference level of the system is improved.

[0018] In one embodiment of the present invention, the signal recognition circuit includes a voltage comparator U2 and a voltage comparator U3, wherein:

[0019] The output end of the proportional mirror current source circuit is connected to the same-direction input end of the voltage comparator U2 and the voltage comparator U3 respectively, and the reverse input end of the voltage comparator U2 is connected to the reference voltage V REFH The reverse input terminal of the voltage comparator U3 is connected to a reference voltage V REFM ;

[0020] The output end of the voltage comparator U2 is connected to the control module as a first signal output port, and the output end of the voltage comparator U3 is connected to the control module as a second signal output port.

[0021] The technical solution disclosed by the utility model has at least the following beneficial effects:

[0022] Through the reference voltage V REFH With reference voltage V REFM The configuration can compare the input voltage signal with the above-mentioned reference voltage to obtain a high level or a low level that can reflect the wheel speed information.

[0023] In one embodiment of the present invention, the signal input terminal is used to output signals I that increase in sequence to represent three current pulse levels. H , signal I M and signal IL，

[0024] Reference voltage V REFH =0.5×(WSI M +WSI H )

[0025] Among them, WSI M Indicates signal I M The voltage signal after passing through the proportional mirror current source circuit, WSI H Indicates signal I H The voltage signal after passing through the proportional mirror current source circuit.

[0026] In one embodiment provided by the present utility model;

[0027] Reference voltage V REFM =0.5×(WSI L +WSI M )

[0028] Among them, WSI L Indicates signal I L The voltage signal after passing through the proportional mirror current source circuit.

[0029] The technical solution disclosed by the utility model has at least the following beneficial effects:

[0030] Through this reference voltage V REFH and reference voltage V REFM The selection of voltage comparator can maximize the tolerance or noise tolerance of the voltage comparator.

[0031] In one embodiment provided by the present utility model, an ADC converter and a programmable voltage source are also included, wherein:

[0032] The input end of the signal recognition circuit is connected to the control module through the ADC converter, and the reverse input end of the voltage comparator U2 and the reverse input end of the voltage comparator U3 are both connected to the control module through the programmable voltage source. The ADC converter is used to collect the signal of the input end of the signal recognition circuit to configure the reference voltage V through the control module and the programmable voltage source. REFH and reference voltage V REFM .

[0033] The technical solution disclosed by the utility model has at least the following beneficial effects:

[0034] The reference voltage V can be programmed using an ADC converter and a programmable voltage source. REFH and reference voltage V REFMDynamically adjust the reference voltage to always keep the noise margin at the system maximum value.

[0035] In one embodiment of the present invention, the switch tube Q201 and the switch tube Q202 are both triodes.

[0036] In one embodiment of the present invention, the transistor is an NPN transistor, and the input end of the switch tube Q201, the output end of the switch tube Q201 and the control end of the switch tube Q201 are the collector, emitter and base of the corresponding transistor respectively;

[0037] The input end of the switch tube Q202, the output end of the switch tube Q202 and the control end of the switch tube Q202 are the collector, emitter and base of the corresponding triode respectively.

[0038] The utility model also provides a wheel speed sensor signal measuring device, comprising the wheel speed sensor signal measuring circuit as mentioned above. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a measurement circuit diagram of a wheel speed sensor in the prior art;

[0040] Figure 2 The schematic diagram of the wheel speed sensor signal measurement circuit provided by the utility model;

[0041] Figure 3 A schematic diagram of the circuit connection relationship of one embodiment of the utility model;

[0042] Figure 4 The schematic diagram of the input and output relationship of the signal recognition circuit;

[0043] Figure 5 It is a schematic diagram of the connection relationship of the ADC converter;

[0044] Figure 6 The waveform diagram shows the dynamic adjustment of the reference voltage using the ADC converter.

[0045] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0046] 100, signal input terminal; 200, proportional mirror current source circuit; 500, signal recognition circuit; 600, control module; 700, ADC converter; 800, programmable voltage source. DETAILED DESCRIPTION

[0047] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0048] Furthermore, those skilled in the art may combine and associate different embodiments or examples and features of different embodiments or examples described in this specification without mutual contradiction.

[0049] In the known Figure 1 In the measurement system of the AK wheel speed signal, the sampling resistor RS (i.e., the load resistor of the wheel speed sensor) converts the current signal Is into a voltage signal WSI, whose voltage is compared with the reference voltage V by means of the comparator U1. REFH Compare the output characteristic signal WSO1 with the reference voltage V REFM Compare and output characteristic signal WSO2.

[0050] Reference voltage V REFH 、V REFM The voltage between the high-level current and the medium-level current, and the voltage between the medium-level current and the low-level current are preset respectively, so that the system has the maximum noise tolerance. According to the definition of digital circuit noise tolerance = min{high-level noise tolerance, low-level noise tolerance}, the noise tolerance of WSO1 is min{WSI H -V REFH , V REFH -WSI M}, the noise tolerance of WSO2 is min{WSI M -V REFM , V REFM -WSI L},WSI H For high level current I H The voltage generated at WSI, WSI M For medium current I M The voltage generated at WSI, WSI L The low level current I L The voltage generated at the WSI.

[0051] Since the value of the sampling resistor is limited, in the known solution, the noise tolerance of the WSO1 and WSO2 signal outputs is limited to several hundred millivolts, especially when considering the wheel speed sensor error, V REFH Error, V REFM The error and resistance RS error will be reduced, even down to tens of millivolts. As the system working environment changes and the product ages, the sampling resistor RS, the reference voltage V REFH 、V REFM There are also temperature drift and aging drift errors. The noise tolerance of the system will further decrease, that is, the tolerance capability will weaken and the anti-interference ability will deteriorate, resulting in the output of abnormal signals and wheel speed measurement failures, affecting the vehicle's ABS, TCS and other active safety control calculations, posing a hidden danger to the vehicle's travel safety.

[0052] In order to solve the above problems, the utility model provides a wheel speed sensor signal measurement circuit, please refer to Figure 2 As shown, it includes: a signal input terminal 100, a proportional mirror current source circuit 200, a signal identification circuit 500 and a control module 600, wherein:

[0053] The input end of the proportional mirror current source circuit 200 is connected to the signal input end 100 to convert the current signal output by the signal input end 100 into a voltage signal and amplify it;

[0054] The output end of the proportional mirror current source circuit 200 is connected to the input end of the signal recognition circuit 500;

[0055] The signal identification circuit 500 has a first signal output port and a second signal output port, and the first signal output port and the second signal output port are both configured to output a high level or a low level according to the amplitude of the input signal. The control module 600 is respectively connected to the first signal output port and the second signal output port to obtain target information based on the transmitted high level or low level measurement.

[0056] By adjusting the ratio K of the proportional mirror current source, a pulse signal with a larger amplitude can be provided for subsequent circuits, and a larger noise margin space can be provided for the signal recognition circuit 500 .

[0057] Next, combine Figure 3 right Figure 2 For further explanation:

[0058] In this example, the switch tubes are all connected using NPN transistors, the control end of each transistor is the base, the input end of each transistor is the collector, and the output end of each transistor is the emitter;

[0059] Specifically, the proportional mirror current source circuit 200 includes a resistor RS, a resistor R201, a resistor R202, a transistor Q201, a transistor Q202 and a power supply VCC, wherein:

[0060] The signal input terminal 100 is connected to the common terminal through the collector of the transistor Q201, the emitter of the transistor Q201 and the resistor RS in sequence. It should be understood that the common terminal mentioned in the present disclosure is grounded, and the collector of the transistor Q201 is also connected to the base of the transistor Q201 and the base of the transistor Q202 respectively. The power supply VCC is connected to the common terminal through the resistor R201, the collector of the transistor Q202, the emitter of the transistor Q202 and the resistor R202 in sequence. The collector of the transistor Q202 is the output terminal of the proportional mirror current source circuit 200.

[0061] In this circuit, the signal sampling resistor is resistor R201. The amplitude of the signal sampling does not directly depend on the load resistance value RS of the sensor, but depends on the ratio K of the proportional mirror current source circuit 200 (K=RS / R202) and the resistance value of the sampling resistor R201. Therefore, the sampling resistor RS can be selected to have a resistance value suitable for the wheel speed sensor. By adjusting the ratio K of the proportional mirror current source and the resistance value of the resistor R202, a larger pulse signal can be provided for the subsequent circuit, thereby providing a larger noise tolerance space for the signal recognition circuit 500.

[0062] The characteristics of the proportional mirror current source circuit 200 are: the left side uses the wheel speed sensor as the signal input terminal 100 and is connected to the battery VBAT, the output voltage of the battery is V1, and the right side is connected to VCC through the resistor R201. VCC is a DC regulated power supply and can use the same power supply as the subsequent circuit, which is generally 5V. If the system requires a larger noise tolerance, a higher noise tolerance value can be obtained by increasing the VCC voltage.

[0063] The working principle of the whole circuit is:

[0064] The current Id≈Is×K, and the output voltage signal WSI of the proportional mirror current source circuit 200 is: VCC-R201×Id=VCC-R201×K×Is, wherein the current Is refers to the output current of the wheel speed sensor received by the signal input terminal 100, and the current Id refers to the output current of the power supply VCC.

[0065] The signal input terminal 100 receives the output current I of the wheel speed sensor L ,I M ,I H The voltage signals WSI of the three levels of current after passing through the proportional mirror current source circuit 200 are:

[0066] WSI L =VCC-R201×K×I L ;

[0067] WSI M=VCC-R201×K×I M ;

[0068] WSI H =VCC-R201×K×I H ;

[0069] Output current I L With the output current I M The voltage difference generated by the level current at WSI is R201×K×(I M -I L )=R201×K×(I M -I L );

[0070] I M with I H The voltage difference generated by the level current at WSI is R201×K×(I M -I L )=R201×K×(I H -I M );

[0071] This voltage difference is the sampling signal of the circuit. In this example, the output current I L ,I M ,I H The voltage generated in WSI between the three levels of current is amplified by R201 / R202 times compared to the signal collected directly through the resistor RS without a proportional mirror current source. The tolerance capability of the signal recognition circuit 500 is also improved by R201 / R202 times, and the anti-interference level of the system is improved.

[0072] Specifically, the signal recognition circuit 500 includes a voltage comparator U2 and a voltage comparator U3, wherein:

[0073] The output end of the proportional mirror current source circuit 200 is connected to the same-direction input end of the voltage comparator U2 and the voltage comparator U3 respectively, and the reverse input end of the voltage comparator U2 is connected to the reference voltage V REFH The reverse input terminal of the voltage comparator U3 is connected to a reference voltage V REFM ;

[0074] The output end of the voltage comparator U2 is connected to the control module 600 as a first signal output port, and the output end of the voltage comparator U3 is connected to the control module 600 as a second signal output port.

[0075] Through the reference voltage V REFH With reference voltage V REFMThe configuration can compare the input voltage signal with the reference voltage to obtain a high level or low level that can more accurately reflect the corresponding information.

[0076] Specifically, the signal input terminal 100 is used to receive signals I1 from the wheel speed sensor that increase in sequence to represent three current pulse levels. H , signal I M and signal I L signal and output it;

[0077] Reference voltage V REFH =0.5×(WSI M +WSI H )

[0078] Among them, WSI M Indicates signal I M The voltage signal after passing through the proportional mirror current source circuit 200, WSI H Indicates signal I H The voltage signal after passing through the proportional mirror current source circuit 200.

[0079] Reference voltage V REFM =0.5×(WSI L +WSI M )

[0080] Among them, WSI L Indicates signal I L The voltage signal after passing through the proportional mirror current source circuit 200.

[0081] The voltage comparator U2 is used to identify the speed pulse signal of the AK signal. The positive input terminal of the voltage comparator U2 receives the voltage signal WSI output by the operational amplifier U1 and compares it with the reference voltage V REFH By comparison, the voltage signal WSI voltage is greater than or equal to V REFH When the output is high level, the voltage signal WSI voltage is less than V REFH When the voltage comparator U2 outputs a low level signal, the first characteristic signal WSO1 is output. The reference voltage V REFH Select Comply with: WSI M <V REFH <WSI H , preferably 0.5×(WSI M +WSI H ), that is, VCC-0.5×R201×K×(I M +I H ).

[0082] The voltage comparator U3 is used to identify the data protocol bit signal of the AK signal. The positive input terminal of the voltage comparator U3 receives the voltage signal WSI output by the operational amplifier U1 and compares it with the reference voltage V REFM By comparison, the voltage signal WSI voltage is greater than or equal to V REFM When the output is high level, the voltage signal WSI voltage is less than V REFM When the reference voltage V REFM Select Comply with: WSI L <V REFM <WSI M , preferably 0.5×(WSI L +WSI M ), that is, VCC-0.5×R201×K×(I M +I L ).

[0083] Figure 4 The waveform diagram at the top is the voltage signal WSI, and the highest level represents the voltage signal WSI. H , the middle level signal represents the voltage signal WSI M and the lowest level indicates the voltage signal WSI L ;

[0084] WSO1 is the first characteristic signal output by the voltage comparator U2; WSO2 is the second characteristic signal output by the voltage comparator U3.

[0085] The control module 600 collects two characteristic signals WSO1 and WSO2, and performs operations and processing through built-in software to calculate the rotation speed of the wheels and identify information such as the vehicle's rotation direction.

[0086] Specifically, please refer to Figure 5 As shown, it also includes an ADC converter 700 and a programmable voltage source 800, wherein:

[0087] The input end of the signal recognition circuit 500 is connected to the control module 600 through the ADC converter 700, and the reverse input end of the voltage comparator U2 and the reverse input end of the voltage comparator U3 are connected to the control module 600 through the programmable voltage source 800. The ADC converter 700 is used to collect the signal of the input end of the signal recognition circuit 500 to configure the reference voltage V through the control module 600 and the programmable voltage source 800. REFH and reference voltage V REFM .

[0088] It should be understood that the programmable voltage source 800 may be a built-in unit of the control module 600 . Generally, the ADC converter 700 may also be a built-in unit of the control module 600 .

[0089] The implementation process is as follows: the high-level pulse voltage, the medium-level pulse voltage, and the low-level voltage of the voltage signal WSI are collected through the ADC converter 700, and then the reference voltage V is configured by configuring the built-in programmable voltage source 800 through the internal register according to the collected voltage signal. REFH and reference voltage V REFM , the configuration principle is V REFH The voltage is configured as 0.5 times the sum of the high-level pulse voltage and the medium-level pulse voltage, V REFM It is configured as 0.5 times the sum of the medium level pulse voltage and the low level pulse voltage. Since the error of the wheel speed sensor is a slow changing process, it is only necessary to power on or regularly update the reference voltage V REFH and reference voltage V REFM That's it.

[0090] Figure 6 It is a waveform diagram of dynamically adjusting the reference voltage. Due to the sensor or system error, the second wheel speed pulse signal input to the signal recognition circuit 500 has an overall increase in amplitude compared to the first wheel speed pulse signal. Under the function of dynamically adjusting the wheel speed pulse, the reference voltage of the comparator increases in amplitude synchronously with the signal, always ensuring that the reference voltage is located at the center of the signal, eliminating the sensor or system error. Obviously, if the reference voltage is not adjusted for the second pulse signal, the medium pulse signal voltage will be recognized abnormally.

[0091] That is, the reference voltage V that can be programmed by using the ADC converter 700 and the programmable voltage source 800 REFH and reference voltage V REFM Dynamically adjust the reference voltage to always keep the noise margin at the system maximum value.

[0092] The utility model also provides a wheel speed sensor signal measuring device, comprising the wheel speed sensor signal measuring circuit as mentioned above.

[0093] The above examples all use AK wheel speed sensor as a demonstration solution, which is also applicable to the standard PWM type and intelligent PWM type currently on the market.

[0094] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. Wheel speed sensor signal measurement circuit, characterized in that: include: A signal input terminal (100), a proportional mirror current source circuit (200), a signal identification circuit (500) and a control module (600), wherein: The input end of the proportional mirror current source circuit (200) is connected to the signal input end (100) to convert the current signal output by the signal input end (100) into a voltage signal and amplify the voltage signal; The output end of the proportional mirror current source circuit (200) is connected to the input end of the signal recognition circuit (500); The signal identification circuit (500) has a first signal output port and a second signal output port, and the first signal output port and the second signal output port are both configured to output a high level or a low level according to the amplitude of an input signal, and the control module (600) is respectively connected to the first signal output port and the second signal output port to obtain target information according to the transmitted high level or low level measurement.

2. The wheel speed sensor signal measurement circuit according to claim 1, characterized in that: The proportional mirror current source circuit (200) comprises a resistor RS, a resistor R201, a resistor R202, a switch tube Q201, a switch tube Q202 and a power source VCC, wherein: The signal input end (100) is connected to the common end through the input end of the switch tube Q201, the output end of the switch tube Q201 and the resistor RS in sequence; the input end of the switch tube Q201 is also connected to the control end of the switch tube Q201 and the control end of the switch tube Q202 respectively; the power supply VCC is connected to the common end through the resistor R201, the input end of the switch tube Q202, the output end of the switch tube Q202 and the resistor R202 in sequence; the input end of the switch tube Q202 is the output end of the proportional mirror current source circuit (200).

3. The wheel speed sensor signal measurement circuit according to claim 2, characterized in that: The signal recognition circuit (500) comprises a voltage comparator U2 and a voltage comparator U3, wherein: The output end of the proportional mirror current source circuit (200) is connected to the same-direction input ends of the voltage comparator U2 and the voltage comparator U3 respectively, and the reverse input end of the voltage comparator U2 is connected to a reference voltage V REFH The reverse input terminal of the voltage comparator U3 is connected to a reference voltage V REFM ; The output end of the voltage comparator U2 is connected to the control module (600) as a first signal output port, and the output end of the voltage comparator U3 is connected to the control module (600) as a second signal output port.

4. The wheel speed sensor signal measurement circuit according to claim 3, characterized in that: The signal input terminal (100) is used to output signals I that increase in sequence to represent three current pulse levels. H , signal I M and signal I L ; Reference voltage V REFH =0.5×(WSI M +WSI H ) Among them, WSI M Indicates signal I M The voltage signal after passing through the proportional mirror current source circuit (200), WSI H Indicates signal I H A voltage signal after passing through the proportional mirror current source circuit (200).

5. The wheel speed sensor signal measurement circuit according to claim 4, characterized in that: Reference voltage V REFM =0.5×(WSI L +WSI M ) Among them, WSI L Indicates signal I L A voltage signal after passing through the proportional mirror current source circuit (200).

6. The wheel speed sensor signal measurement circuit according to claim 5, characterized in that: Also included is an ADC converter (700) and a programmable voltage source (800), wherein: The input end of the signal recognition circuit (500) is connected to the control module (600) through the ADC converter (700), and the reverse input end of the voltage comparator U2 and the reverse input end of the voltage comparator U3 are both connected to the control module (600) through the programmable voltage source (800). The ADC converter (700) is used to collect the signal at the input end of the signal recognition circuit (500) so as to configure the reference voltage V through the control module (600) and the programmable voltage source (800). REFH and reference voltage V REFM .

7. The wheel speed sensor signal measurement circuit according to claim 2, characterized in that: The switch tube Q201 and the switch tube Q202 are both triodes.

8. The wheel speed sensor signal measurement circuit according to claim 7, characterized in that: The transistor is an NPN transistor, and the input end of the switch tube Q201, the output end of the switch tube Q201 and the control end of the switch tube Q201 are the collector, emitter and base of the corresponding transistor respectively; The input end of the switch tube Q202, the output end of the switch tube Q202 and the control end of the switch tube Q202 are the collector, emitter and base of the corresponding triode respectively.

9. The wheel speed sensor signal measurement circuit according to claim 8, characterized in that: The common terminal is grounded.

10. A wheel speed sensor signal measuring device, characterized in that: The invention comprises a wheel speed sensor signal measuring circuit as claimed in any one of claims 1 to 9.

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