Analog signal processing device and test system

Abstract

The invention relates to the technical field of vehicle-mounted signal testing, in particular to analog signal processing equipment and a testing system. The device comprises a carrier plate, a gain module, an impedance matching module and a reference ground switching module, and the impedance matching module is connected to the positive input end and the negative input end of the gain module; the impedance matching module is used for switching the differential positive signal and the differential negative signal to a target input path with the same impedance in response to the control signal and inputting the differential positive signal and the differential negative signal to the gain module; the gain module is used for gaining the input differential positive signal and the differential negative signal and then outputting the gained signal; the reference ground switching module is connected to the gain module and the impedance matching module; the reference ground switching module is used for carrying out connection switching between the in-board reference ground and the datum reference ground; the reference ground in the board is the reference ground of the analog signal carrier board; the gain module, the impedance matching module and the reference ground switching module are connected on the carrier plate. By adopting the scheme of the invention, the error of the processed analog signal can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle-mounted signal testing, and in particular to an analog signal processing device and a testing system. Background Art

[0002] HIL (Hardware-in-the-loop) testing, a testing method that combines real hardware with real-time simulation models, is currently widely used in in-vehicle testing scenarios. HIL testing typically uses an NI chassis and test board set; the NI chassis simulates in-vehicle devices or electrical systems and outputs corresponding status signals, while the test board set transmits signals between the NI chassis and the vehicle's ECU (Hardware-in-the-loop).

[0003] The interaction between the NI chassis and the ECU involves both digital and analog signal interactions. The analog processing board, which processes analog signals, is primarily used to adjust the voltage signal input from the NI chassis to the ECU's applicable input voltage range. However, analog signals are inherently susceptible to interference, and the complex scenarios and operating conditions of in-vehicle testing make interference more likely. A significant interference issue is the reference ground during analog signal processing. Due to certain interference, the reference ground provided on the analog processing board may not maintain zero potential, resulting in significant errors in the analog signal processing process and unreliable test results.

[0004] Therefore, how to reduce the error of analog signals and thus improve the reliability of test results is an urgent problem to be solved. Summary of the Invention

[0005] Based on this, it is necessary to provide an analog signal processing device and a test system that can reduce the error of the analog signal.

[0006] In a first aspect, the present application provides an analog signal processing device, the device comprising a carrier board, a gain module, an impedance matching module, and a reference ground switching module, wherein:

[0007] The impedance matching module is connected to the positive input terminal and the negative input terminal of the gain module;

[0008] The impedance matching module is configured to switch the differential positive signal and the differential negative signal to target input paths of the same impedance in response to a control signal, and input the signals to the gain module;

[0009] The gain module is used to output the input differential positive signal and the input differential negative signal after gaining the gain;

[0010] The reference ground switching module is connected to the gain module and the impedance matching module, and is used to switch between the internal reference ground and the reference ground; the internal reference ground is the reference ground of the carrier board;

[0011] The gain module, the impedance matching module, and the reference ground switching module are all connected to the carrier board.

[0012] In one embodiment, the reference ground switching module includes a switch and a first reference point and a second reference point arranged on the carrier board, wherein:

[0013] The first reference point is connected to the ground layer of the carrier board; the second reference point is used to connect to an external zero potential point;

[0014] A first end of the switch is connected to the impedance matching module and the gain module, and a second end of the switch is used to switch between the first reference point and the second reference point.

[0015] In one embodiment, the gain module includes a differential amplifier, a filtering module, and a reference resistor, wherein:

[0016] The positive input terminal and the negative input terminal of the differential amplifier are both connected to the impedance matching module, and the output terminal of the differential amplifier is connected to the filtering module;

[0017] One end of the reference resistor is connected to the positive input end of the differential amplifier, and the other end is connected to the reference ground switching module.

[0018] In one embodiment, the impedance matching module includes a first matching resistor, a second matching resistor, an electromagnetic relay, and a switching transistor, wherein:

[0019] The first end of the first normally open contact of the electromagnetic relay is used to input a differential negative signal, and the first matching resistor is connected in series between the second end and the negative input terminal of the differential amplifier; the first end of the second normally open contact of the electromagnetic relay is used to input a differential positive signal, and the first matching resistor is connected in series between the second end and the positive input terminal of the differential amplifier;

[0020] The first end of the first normally closed contact of the electromagnetic relay is used to input a differential positive signal, and a second matching resistor is connected in series between the second end and the negative input terminal of the differential amplifier; the first end of the second normally closed contact of the electromagnetic relay is used to input a differential negative signal, and a second matching resistor is connected in series between the second end and the positive input terminal of the differential amplifier;

[0021] The base of the switching transistor is used to input the control signal of high level or low level, the collector of the switching transistor is connected to the first end of the coil of the electromagnetic relay, the second end of the coil of the electromagnetic relay is connected to the first power supply end, and the emitter of the switching transistor is connected to the first end of the switching switch.

[0022] In one embodiment, a first filter capacitor is connected in parallel across both ends of each first matching resistor and each second matching resistor.

[0023] In one embodiment, a second filter capacitor is connected in series between the positive power supply terminal and the negative power supply terminal of the differential amplifier and the first terminal of the switch.

[0024] In one embodiment, the device further includes a negative feedback resistor connected in series between the output terminal and the negative input terminal of the differential amplifier.

[0025] In one embodiment, both the positive input terminal and the negative input terminal of the differential amplifier are connected to a balancing potential module, and the balancing potential module is used to provide a balancing potential.

[0026] In one embodiment, the potential balancing module includes a first diode and a second diode;

[0027] The cathode of the first diode is connected to the anode of the second diode, the anode of the first diode is connected to a negative voltage, and the cathode of the second diode is connected to a positive voltage;

[0028] The cathode of the first diode is connected to the positive input terminal or the negative input terminal of the differential amplifier.

[0029] In a second aspect, the present application provides a test system, comprising an NI chassis, a backplane, a power supply card, and an analog signal processing device as described in any one of the first aspects, wherein:

[0030] The analog signal processing device and the power supply card are both connected via a backplane, and the power supply card is used to supply power to the analog signal processing device;

[0031] The NI chassis is used to provide an analog differential signal to the input end of the analog signal processing device, and the output end of the analog signal processing device is connected to the ECU to be tested.

[0032] In the analog signal processing device and test system described above, the impedance matching module, in response to a control signal, switches the differential positive and negative signals to target input paths with the same impedance and inputs them to the gain module. This ensures that the impedances of the differential positive and negative signals are the same upon input, thereby reducing interference and error between the two signals. The differential gain module can then perform a gain calculation on the difference between the input differential positive and negative signals to produce the final analog output signal.

[0033] The reference ground switching module can provide two reference grounds for the impedance matching module and the gain module, namely the internal reference ground provided by the carrier board, and the reference reference ground connected from the outside. When there is a lot of interference in the environment, the user can connect the impedance matching module and the gain module to the reference reference ground through the reference ground switching module. The user can connect the target potential of their needs to the reference reference ground, thereby meeting the actual needs of the user, and at the same time, it can also reduce the error and interference of the analog signal doping caused by the instability of the internal reference ground. When the environment is relatively stable and the interference is small, the user does not need to connect the potential to the reference reference ground, and can connect the impedance matching module and the gain module to the internal reference ground through the reference ground switching module, that is, directly use the reference ground layer of the carrier board to provide zero potential, which is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 is a simplified structural diagram of an analog signal processing device in one embodiment;

[0036] Figure 2 Schematic diagram of the structure of a gain module in one embodiment;

[0037] Figure 3 FIG. 4 is a schematic structural diagram of an impedance matching module in an embodiment. DETAILED DESCRIPTION

[0038] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0040] It will be understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor without departing from the scope of this application. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0041] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if there is transmission of electrical signals or data between the connected circuits, modules, units, etc.

[0042] It is understood that “at least one” refers to one or more, “a plurality” refers to two or more, and “at least a portion of an element” refers to a portion or all of an element.

[0043] As used herein, the singular forms "a," "an," and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include," "comprising," "having," and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof. Furthermore, the term "and / or" as used in this specification includes any and all combinations of the relevant listed items.

[0044] In an exemplary embodiment, the present application provides an analog signal processing device that can amplify or reduce an input analog signal so that the amplified analog signal outputted can meet the voltage range requirements of the signal receiving end (such as a host computer).

[0045] Furthermore, the analog signal processing device in the present application can be applied in actual detection scenarios; for example, it can be configured on a car, and the input end of the analog signal processing device is connected to the output end of the analog signal sensor, and receives the analog signal output by the analog signal sensor; the analog signal processing device performs gain processing on the analog signal and outputs it to the on-board ECU (Electronic Control Unit), wherein the analog signal sensors on the car include but are not limited to wheel speed sensors, acceleration sensors, current sensors, voltage sensors, and pressure sensors, etc.

[0046] The analog signal processing device in this application can also be used in the scenario of HIL (Hardware-in-the-Loop) testing of automobiles; for example, the input end of the analog signal processing device is connected to the output end of the NI chassis, and the NI chassis is used to output analog signals simulating the status of various parts / devices of the automobile. The analog signal processing device receives the analog signal output by the analog signal sensor, and outputs the analog signal to the on-board ECU (Electronic Control Unit) after gain processing.

[0047] Reference Figure 1 The analog signal processing device provided in the present application may specifically include a carrier board, a gain module, an impedance matching module and a reference ground switching module, wherein: the impedance matching module is connected to the positive input terminal and the negative input terminal of the gain module; the impedance matching module is used to switch the differential positive signal and the differential negative signal to the target input path of the same impedance in response to a control signal, and input them to the gain module; the gain module is used to output the input differential positive signal and the differential negative signal after gaining; the reference ground switching module is connected to the gain module and the impedance matching module, and the reference ground switching module is used to switch the connection between the on-board reference ground and the reference reference ground; the on-board reference ground is the reference ground of the carrier board; the gain module, the impedance matching module and the reference ground switching module are all connected on the carrier board.

[0048] In an embodiment of the present application, the analog signal input to the differential gain module is a differential signal, which includes a differential positive signal and a differential negative signal. The differential positive signal and the differential negative signal are input to the input end of the differential gain module through an impedance matching module. The impedance matching module provides at least two positive paths for the differential positive signal to be input to the positive input end of the differential gain module, and the impedance matching module provides at least two negative paths for the differential negative signal to be input to the negative input end of the differential gain module. The positive paths and the negative paths are symmetrically arranged so that each positive path corresponds to a negative path with the same impedance. In response to a control signal, the impedance matching module switches the differential positive signal and the differential negative signal to a target input path with the same impedance and inputs them to the gain module, so that the impedance of the differential positive signal and the differential negative signal is the same when input, thereby reducing the introduction of interference and errors between the two signals. The differential gain module can perform a gain after subtracting the input differential positive signal and the differential negative signal to obtain the final output analog signal.

[0049] The reference ground switching module can provide two reference grounds for the impedance matching module and the gain module, namely the internal reference ground provided by the carrier board, and the reference reference ground connected from the outside. When there is a lot of interference in the environment, the user can connect the impedance matching module and the gain module to the reference reference ground through the reference ground switching module. The user can connect the target potential of their needs to the reference reference ground, thereby meeting the actual needs of the user, and at the same time, it can also reduce the error and interference of the analog signal doped by the instability of the internal reference ground. When the environment is relatively stable and the interference is small, the user does not need to connect the potential to the reference reference ground, and can connect the impedance matching module and the gain module to the internal reference ground through the reference ground switching module, that is, directly use the ground layer of the carrier board to provide zero potential, which is more convenient.

[0050] In an exemplary embodiment, Figure 1 As shown, the reference ground switching module includes a switching switch K1 and a first reference point CK1 and a second reference point CK2 set on the carrier board, wherein: the first reference point CK1 is connected to the ground layer of the carrier board; the second reference point CK2 is used to connect to an external zero potential point; the first end of the switching switch is connected to the impedance matching module and the gain module, and the second end of the switching switch is used to switch between the first reference point and the second reference point.

[0051] Specifically, the switch K1 can be a single-pole double-throw switch, a push-button switch, or any other type of switch or component, as long as it can achieve switching between the first reference point CK1 and the second reference point CK2. The carrier board typically employs a 6-layer or 4-layer PCB structure, with at least one pre-set ground layer within the carrier board's layer structure to provide a zero potential GND-1 for the chips or components mounted thereon. The first reference point CK1 is connected to the carrier board's ground layer.

[0052] The second reference point CK2 is left floating. It can be configured as a terminal interface fixed to the carrier board or a floating pin. Users can connect their customized target potential GND-2 through the second reference point CK2. It should be noted that the target potential can be zero or a non-zero potential, and users can choose this based on their actual needs.

[0053] In one embodiment, Figure 2 As shown, the gain module can specifically include a differential amplifier U1, a filtering module and a reference resistor RO, wherein: the positive input and negative input terminals of the differential amplifier U1 are both connected to the impedance matching module, and the output terminal of the differential amplifier U1 is connected to the filtering module; one end of the reference resistor R0 is connected to the positive input terminal of the differential amplifier U1, and the other end is connected to the reference ground switching module.

[0054] Specifically, the positive input terminal of the differential amplifier U1 is used to input a differential positive signal, and the negative input terminal of the differential amplifier U1 is used to input a differential negative signal; the positive power supply terminal of the differential amplifier U1 is connected to an external positive input voltage, and the negative power supply terminal of the differential amplifier U1 is connected to an external negative input voltage. Furthermore, in order to maintain the stability of the power supply of the differential amplifier U1, a filter capacitor C1 is connected in series to both the positive power supply terminal and the negative power supply terminal of the differential amplifier U1. One end of one filter capacitor C1 is connected to the positive power supply terminal of the differential amplifier U1, and the other end is grounded; one end of another filter capacitor C1 is connected to the negative power supply terminal of the differential amplifier U1, and the other end is grounded. The grounding of the filter capacitor C1 is connected to the first end of the switching switch in the reference ground switching module. When the power supply voltage of the differential amplifier U1 decreases, the filter capacitor C1 can discharge, thereby keeping the power supply voltage of the differential amplifier U1 stable, and reducing the interference caused by power supply voltage fluctuations on signal processing.

[0055] Further, refer to Figure 2 Differential amplifier U1 outputs a gain signal after differential gain and feeds this gain signal back to the ECU. The filter module is used to filter the gain signal output by differential amplifier U1 to obtain a more stable gain signal. In other words, the filter module configuration ensures that the gain signal fed back to the ECU from differential amplifier U1 is more stable and less susceptible to interference. The filter module specifically includes resistor R3 and capacitor C4. The first end of resistor R3 is connected to the output end of differential amplifier U1, and the second end of resistor R3 is used to output an analog signal. The first end of capacitor C4 is connected to the second end of resistor R3, and the second end of capacitor C4 is connected to the first end of switch K1 and grounded.

[0056] Further, refer to Figure 2A capacitor C2 is connected in parallel across reference resistor R0. Reference resistor R0 and capacitor C2 form an RC oscillator circuit, thereby filtering the signal input to the positive input of differential amplifier U1. The ratio of the resistance of reference capacitor R0 to the equivalent resistance of the input impedance connected to the positive input of differential amplifier U1 represents the gain of gain amplifier U1. This means that, while the input impedance connected to the positive input of differential amplifier U1 is fixed, the gain of differential amplifier U1 can be adjusted by changing the resistance of reference capacitor R0. Therefore, in one possible implementation, reference resistor R0 can be replaced with a digital potentiometer. A digital potentiometer can be controlled by a digital signal, thereby changing its equivalent resistance. If reference resistor R0 is a digital potentiometer, the user can output a corresponding digital signal to the digital potentiometer through the NI chassis or ECU, thereby changing the equivalent resistance of the digital potentiometer. This allows for convenient adjustment of the gain of differential amplifier U1.

[0057] In one embodiment, referring to Figure 2 The device also includes a negative feedback resistor RF, connected in series between the output and negative input of differential amplifier U1, achieving closed-loop feedback. Furthermore, a capacitor C5 is connected in parallel across negative feedback resistor RF. On the one hand, negative feedback resistor RF further filters out common-mode noise in the circuit through its high common-mode rejection ratio, thereby eliminating common-mode interference. On the other hand, the closed-loop negative feedback mechanism effectively reduces the output impedance of differential amplifier U1, thereby preventing output signal attenuation caused by loading effects in subsequent circuits (such as ADCs or long cables).

[0058] In one embodiment, referring to Figure 3 The impedance matching module includes a first matching resistor R1, a second matching resistor R2, an electromagnetic relay KM and a switching transistor Q1; wherein, the first end of the first normally open contact KM-1 of the electromagnetic relay KM is used to input a differential negative signal, and a first matching resistor R1 is connected in series between the second end and the negative input end of the differential amplifier U1; the first end of the second normally open contact KM-2 of the electromagnetic relay KM is used to input a differential positive signal, and a first matching resistor R1 is connected in series between the second end and the positive input end of the differential amplifier U1; the first end of the first normally closed contact KM-3 of the electromagnetic relay KM is used to input a differential positive signal, and a second matching resistor R2 is connected in series between the second end and the negative input end of the differential amplifier U1; the first end of the second normally closed contact KM-4 of the electromagnetic relay KM is used to input a differential negative signal, and a second matching resistor R2 is connected in series between the positive input end of the differential amplifier U1.

[0059] The base of the switching transistor Q1 is used to input a high-level or low-level control signal, the collector of the switching transistor Q1 is connected to the first end of the coil of the electromagnetic relay KM, the second end of the coil of the electromagnetic relay KM is used to input the power supply voltage, and the emitter of the switching transistor Q1 is connected to the first end of the switching switch K1.

[0060] Specifically, when the control signal externally input to the base of the switching transistor Q1 is at a low level, the collector to emitter of the switching transistor Q1 is not conductive, and therefore, the power supply circuit of the coil of the electromagnetic relay KM cannot be conductive, and the coil of the electromagnetic relay KM cannot be energized; thus, the first normally open contact KM-1 and the second normally open contact KM-2 of the electromagnetic relay KM are both in the disconnected state, while the first field closed contact KM-3 and the second normally closed contact KM-4 of the electromagnetic relay KM are both in the closed state, so that the differential positive signal can be input to the positive input terminal of the differential amplifier U1 through the second matching resistor R2, and the differential negative signal can be input to the negative input terminal of the differential amplifier U1 through another second matching resistor R2.

[0061] Specifically, refer to Figure 2 and Figure 3 The base of the switching transistor Q1 is connected to a protective resistor R5. The external control signal is input to the base of the switching transistor Q1 through the protective resistor R5. The protective resistor limits the current input to the base of the switching transistor Q1, thereby protecting the components. A pull-down resistor R6 is connected in series between the base and emitter of the switching transistor Q1. Because the base of the switching transistor Q1 only conducts from the collector to the emitter when it receives a high-level control signal, a default low level needs to be set for the base of the switching transistor Q1 when the switching transistor Q1 is not conducting. This default low level is provided by the pull-down resistor R6.

[0062] Further, refer to Figure 2 and Figure 3 Electromagnetic relay KM also has a bleeder diode D0 connected in parallel across both ends. A resistor R7 is connected to the second end of electromagnetic relay KM. Resistor R7 limits the current within the coil of electromagnetic relay KM, protecting it from overcurrent. The anode of bleeder diode D0 is connected to the first end of the coil of electromagnetic relay KM, and the cathode is connected to the second end of the coil. When the coil of electromagnetic relay KM is energized, bleeder diode D0 is inoperative. When the coil of electromagnetic relay KM is de-energized, bleeder diode D0 and the coil of electromagnetic relay KM form a closed circuit, dissipating any residual energy in the coil.

[0063] Reference Figure 2When the control signal externally input to the base of the switching transistor Q1 is at a high level, the collector of the switching transistor Q1 is turned on to the emitter, so the power supply circuit of the coil of the electromagnetic relay KM is turned on, and the coil of the electromagnetic relay KM is energized; thereby, the first normally open contact KM-1 and the second normally open contact KM-2 of the electromagnetic relay KM are both switched to a closed state, and the first field closed contact KM-3 and the second normally closed contact KM-4 of the electromagnetic relay KM are both switched to an open state, so that the differential positive signal can be input to the positive input terminal of the differential amplifier U1 through the first matching resistor R1, and the differential negative signal can be input to the negative input terminal of the differential amplifier U1 through another first matching resistor R1.

[0064] By inputting a high-level or low-level control signal as described above, the differential signal can be input to differential amplifier U1 through first matching resistor R1 or second matching resistor R2, thereby enabling selection of the differential signal input impedance. Furthermore, since both normally open contacts KM-1 and KM-2 of electromagnetic relay KM are connected to first matching resistor R1, and both normally closed contacts KM-3 and KM-4 of electromagnetic relay KM are connected to second matching resistor R2, the two normally closed contacts can be opened or opened synchronously, and the two normally open contacts can also be opened or opened synchronously, thereby maintaining consistent input impedance for the differential positive and negative signals.

[0065] Furthermore, a first filter capacitor C3 is connected in parallel across both ends of each first matching resistor R1 and each second matching resistor R2; thereby, regardless of which matching resistor the differential positive signal and the differential negative signal pass through to be input into the differential amplifier U1, a single filter can be achieved, which enables the differential positive signal and the differential negative signal input into the differential amplifier U1 to remain stable.

[0066] In one embodiment, referring to Figure 3 The positive input and negative input of the differential amplifier are both connected to a balancing potential module, which is used to provide a balancing potential. The balancing potential module has at least four functions, which are described below.

[0067] The first function is: the virtual short effect of the differential amplifier U1 forces the potential of the two input terminals to be equal, ensuring that the common-mode signal (such as noise or interference) is canceled out at the input terminal and only the differential-mode signal is amplified; the setting of the balanced potential module can improve the circuit's ability to suppress common-mode interference and enhance the signal-to-noise ratio of the signal.

[0068] The second function is: under the virtual short condition, the voltage difference at the input end of the differential amplifier U1 is determined only by the differential mode signal. The existence of the balanced potential module can avoid the error introduced by the common mode voltage. At the same time, combined with negative feedback, the differential amplifier U1 can accurately amplify the useful signal.

[0069] The third function is: the virtual-off characteristic of the differential amplifier U1 makes the input current approach zero, and the impedance seen from the signal source is extremely high, which reduces the load effect on the high-impedance signal source and can ensure the accuracy of signal acquisition.

[0070] The fourth function is that the balanced potential module connected to the two input terminals of the differential amplifier U1 can be designed symmetrically in physical layout, reducing the differential impact of external electromagnetic interference and further improving the noise resistance performance.

[0071] Specifically, the balanced potential module includes a first diode D1 and a second diode D2; wherein, the cathode of the first diode D1 is connected to the anode of the second diode D2, the anode of the first diode D1 is connected to a negative voltage, and the cathode of the second diode D2 is connected to a positive voltage; the cathode of the first diode D1 is connected to the positive input terminal or the negative input terminal of the differential amplifier U1.

[0072] It is understandable that the above-mentioned balanced potential module and impedance matching module can also adopt other forms, and are not limited to the forms mentioned in the above embodiments, as long as they can achieve the functions of completing the corresponding reference potential reference and switching and matching the input impedance of the differential signal.

[0073] In the description of this specification, reference to the terms "some embodiments" or "other embodiments" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0074] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0075] The above embodiments merely illustrate several embodiments of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. An analog signal processing device, characterized in that The device includes a carrier board, a gain module, an impedance matching module, and a reference ground switching module, wherein: The impedance matching module is connected to the positive input terminal and the negative input terminal of the gain module; The impedance matching module is configured to switch the differential positive signal and the differential negative signal to target input paths of the same impedance in response to a control signal, and input the signals to the gain module; The gain module is used to output the input differential positive signal and the input differential negative signal after gaining the gain; The reference ground switching module is connected to the gain module and the impedance matching module, and is used to switch between the internal reference ground and the reference ground; the internal reference ground is the reference ground of the carrier board; The gain module, the impedance matching module, and the reference ground switching module are all connected to the carrier board.

2. The analog signal processing device according to claim 1, wherein The reference ground switching module includes a switch and a first reference point and a second reference point arranged on the carrier board, wherein: The first reference point is connected to the ground layer of the carrier board; the second reference point is used to connect to an external zero potential point; A first end of the switch is connected to the impedance matching module and the gain module, and a second end of the switch is used to switch between the first reference point and the second reference point.

3. The analog signal processing device according to claim 2, characterized in that The gain module includes a differential amplifier, a filter module and a reference resistor, wherein: The positive input terminal and the negative input terminal of the differential amplifier are both connected to the impedance matching module, and the output terminal of the differential amplifier is connected to the filtering module; One end of the reference resistor is connected to the positive input end of the differential amplifier, and the other end is connected to the reference ground switching module.

4. The analog signal processing device according to claim 3, characterized in that The impedance matching module includes a first matching resistor, a second matching resistor, an electromagnetic relay and a switching transistor, wherein: The first end of the first normally open contact of the electromagnetic relay is used to input a differential negative signal, and the first matching resistor is connected in series between the second end and the negative input terminal of the differential amplifier; the first end of the second normally open contact of the electromagnetic relay is used to input a differential positive signal, and the first matching resistor is connected in series between the second end and the positive input terminal of the differential amplifier; The first end of the first normally closed contact of the electromagnetic relay is used to input a differential positive signal, and a second matching resistor is connected in series between the second end and the negative input terminal of the differential amplifier; the first end of the second normally closed contact of the electromagnetic relay is used to input a differential negative signal, and a second matching resistor is connected in series between the second end and the positive input terminal of the differential amplifier; The base of the switching transistor is used to input the control signal of high level or low level, the collector of the switching transistor is connected to the first end of the coil of the electromagnetic relay, the second end of the coil of the electromagnetic relay is connected to the first power supply end, and the emitter of the switching transistor is connected to the first end of the switching switch.

5. The analog signal processing device according to claim 4, characterized in that A first filtering capacitor is connected in parallel to both ends of each first matching resistor and each second matching resistor.

6. The analog signal processing device according to claim 4, characterized in that A second filtering capacitor is connected in series between the positive power supply terminal and the negative power supply terminal of the differential amplifier and the first end of the switch.

7. The analog signal processing device according to claim 5, characterized in that The device further includes a negative feedback resistor connected in series between the output terminal and the negative input terminal of the differential amplifier.

8. The analog signal processing device according to claim 7, characterized in that The positive input terminal and the negative input terminal of the differential amplifier are both connected to a balancing potential module, and the balancing potential module is used to provide a balancing potential.

9. The analog signal processing device according to claim 8, characterized in that The balanced potential module includes a first diode and a second diode; The cathode of the first diode is connected to the anode of the second diode, the anode of the first diode is connected to a negative voltage, and the cathode of the second diode is connected to a positive voltage; The cathode of the first diode is connected to the positive input terminal or the negative input terminal of the differential amplifier.

10. A testing system, characterized in that: The system comprises an NI chassis, a backplane, a power supply card, and an analog signal processing device according to any one of claims 1 to 9, wherein: The analog signal processing device and the power supply card are both connected via a backplane, and the power supply card is used to supply power to the analog signal processing device; The NI chassis is used to provide an analog differential signal to the input end of the analog signal processing device, and the output end of the analog signal processing device is connected to the ECU to be tested.

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