Pre-amplification circuit, signal measuring device and computer fault diagnosis system

Abstract

The utility model relates to the technical field of signal processing, and particularly discloses a pre-amplification circuit, a signal measuring device and a computer fault diagnosis system, the pre-amplification circuit comprises an input filtering module, an amplification processing module and an output filtering module, the input filtering module and the output filtering module are both electrically connected with the amplification processing module; the input filtering module is used for carrying out filtering and noise reduction processing on the input bias voltage to obtain the bias voltage after filtering and noise reduction; the amplification processing module is used for performing amplification and negative feedback processing on the fault signal to be diagnosed under the bias voltage after filtering and noise reduction so as to form an amplification processing signal capable of meeting a preset signal-to-noise ratio; and the output filtering module is used for performing output filtering processing on the amplification processing signal to obtain a pre-amplification output signal, and the pre-amplification output signal is used for being input to the main amplification circuit for amplification processing to obtain a measurement result of the fault signal to be diagnosed. The pre-amplification circuit provided by the utility model has the advantages of high sensitivity and low noise.

Description

Technical Field

[0001] The utility model relates to the technical field of signal processing, in particular to a preamplifier circuit, a signal measuring device and a computer fault diagnosis system. Background Art

[0002] Currently, signal measurement devices are often used to improve the accuracy of computer fault diagnosis. These devices typically include a preamplifier circuit, which pre-processes and amplifies the input signal before further amplification for signal identification and measurement. Therefore, the preamplifier's signal amplification performance can determine the accuracy of subsequent signal identification.

[0003] In the commonly used preamplifier circuits of the prior art, the feedback terminal, which plays the primary role in amplification and feedback, is typically composed of a feedback resistor and a capacitor. To improve the sensitivity of the preamplifier circuit, the feedback resistor is typically set to a value in the hundreds of megohms. This resistance, however, introduces significant noise into the preamplifier circuit, making it a major source of noise in current preamplifier circuits. Furthermore, when the preamplifier circuit operates at high frequencies, the attenuation of the large resistor in the feedback circuit is significant, causing the actual resistance of the feedback resistor in the feedback circuit to be affected by the frequency. This, in turn, prevents the preamplifier circuit's electrical signal from performing pole-to-zero cancellation after passing through the shaping amplifier. Furthermore, the high resistance of the feedback resistor increases the parasitic capacitance in the preamplifier circuit, ultimately affecting the sensitivity of the preamplifier circuit.

[0004] Therefore, how to provide a high-sensitivity and low-noise preamplifier circuit has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0005] The utility model provides a preamplifier circuit, a signal measuring device and a computer fault diagnosis system, which solve the problems of low sensitivity and high noise existing in the related technology.

[0006] As a first aspect of the present invention, a preamplifier circuit is provided, comprising: an input filter module, an amplification processing module, and an output filter module, wherein the input filter module and the output filter module are both electrically connected to the amplification processing module;

[0007] The input filtering module is used to perform filtering and noise reduction processing on the input bias voltage to obtain the bias voltage after filtering and noise reduction;

[0008] The amplification processing module is used to amplify and perform negative feedback processing on the fault signal to be diagnosed under the bias voltage after filtering and noise reduction, so as to form an amplified processing signal that can meet the preset signal-to-noise ratio;

[0009] The output filtering module is used to perform output filtering processing on the amplified processing signal to obtain a pre-amplified output signal, and the pre-amplified output signal is used to be input into the main amplifier circuit for amplification processing to obtain a measurement result of the fault signal to be diagnosed.

[0010] Furthermore, the amplification processing module includes an amplification unit and a feedback unit, and the feedback unit is electrically connected to the amplification unit.

[0011] The amplifying unit is used to amplify the fault signal to be diagnosed under the bias voltage after filtering and noise reduction to obtain an amplified signal;

[0012] The feedback unit is used to form a negative feedback loop in the process of the amplifying unit obtaining the amplified signal to obtain an amplified processed signal that can meet a preset signal-to-noise ratio.

[0013] Furthermore, the amplifying unit includes: an operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor and a second capacitor.

[0014] The non-inverting input terminal of the operational amplifier is connected to one end of the first resistor, and the other end of the first resistor is connected to a power supply;

[0015] The inverting input terminal of the operational amplifier is connected to one end of the third resistor, the other end of the third resistor is connected to the power supply, and the inverting input terminal of the operational amplifier is also used to connect to the feedback unit;

[0016] The positive power supply terminal of the operational amplifier is connected to the power supply via a fourth resistor, and the positive power supply terminal and the negative power supply terminal of the operational amplifier are both connected to the signal ground;

[0017] The output end of the operational amplifier is used to connect to the feedback unit and the output filter module respectively;

[0018] The second resistor is connected in parallel with the first capacitor, one end of the parallel connection is connected to the non-inverting input terminal of the operational amplifier, and the other end of the parallel connection is connected to the signal ground;

[0019] One end of the second capacitor is connected to the other end of the third resistor, and the other end of the second capacitor is connected to the signal ground.

[0020] Furthermore, the feedback unit includes: a switch tube, a third capacitor, a fourth capacitor and a fifth resistor.

[0021] The control end of the switch tube is respectively connected to one end of the fifth resistor and one end of the third capacitor, the other end of the fifth resistor is connected to the output end of the operational amplifier, the other end of the third capacitor is connected to one end of the fourth capacitor, and the other end of the fourth capacitor is connected to the output end of the operational amplifier;

[0022] The first end of the switch tube is connected to the inverting input end of the operational amplifier, and the second end of the switch tube is connected to the signal ground.

[0023] Furthermore, the operational amplifier includes an operational amplifier of model ADA4898, and the switch tube includes a field effect tube of model 2N4416.

[0024] Furthermore, the input filter module includes: a sixth resistor, a seventh resistor, a fifth capacitor and a sixth capacitor,

[0025] One end of the fifth capacitor is connected to the signal ground, and the other end of the fifth capacitor is connected to one end of the sixth resistor;

[0026] The other end of the sixth resistor is connected to one end of the sixth capacitor, and the other end of the sixth capacitor is connected to the amplification processing module;

[0027] One end of the seventh resistor is connected to one end of the sixth resistor, and the other end of the seventh resistor is connected to a power supply.

[0028] Furthermore, the output filter module includes: an eighth resistor and a seventh capacitor,

[0029] One end of the seventh capacitor is connected to the output end of the amplification processing module, and the other end of the seventh capacitor is the output end of the preamplifier circuit;

[0030] One end of the eighth resistor is connected to the other end of the seventh capacitor, and the other end of the eighth resistor is connected to the signal ground.

[0031] As another aspect of the present invention, a signal measuring device is provided, comprising: a bias voltage circuit, a main amplifier circuit, and the preamplifier circuit described above, wherein the bias voltage circuit is electrically connected to the preamplifier circuit, and the preamplifier circuit is electrically connected to the main amplifier circuit;

[0032] The bias voltage circuit is used to provide a bias voltage for the preamplifier circuit;

[0033] The preamplifier circuit is used to perform preamplification processing on the fault signal to be diagnosed collected by the signal acquisition device to obtain a preamplified output signal;

[0034] The main amplifier circuit is used to perform secondary amplification processing on the pre-amplifier output signal to obtain a measurement result of the fault signal to be diagnosed.

[0035] Furthermore, the bias voltage circuit includes a bias voltage source.

[0036] As another aspect of the present invention, a computer fault diagnosis system is provided, which includes: a signal acquisition device and the signal measurement device described above, wherein the signal acquisition device is communicatively connected to the signal measurement device;

[0037] The signal acquisition device is used to collect the fault signal to be diagnosed;

[0038] The signal measuring device is used to perform pre-amplification processing and secondary amplification processing on the fault signal to be diagnosed in sequence to obtain a measurement result of the fault signal to be diagnosed.

[0039] The preamplifier circuit provided by the present invention performs noise reduction filtering on the input bias voltage through an input filtering module, and amplifies and negatively feedback-processes the fault signal to be diagnosed at the bias voltage after filtering and noise reduction through an amplification processing module, thereby generating an amplified processed signal that meets a preset signal-to-noise ratio. Finally, the amplified processed signal is output filtered through an output filtering module to obtain a preamplified output signal. This preamplifier circuit of the present invention utilizes the low-noise characteristics of the feedback circuit portion of the amplification processing module to replace the high-resistance feedback circuit in the prior art, thereby obtaining an amplified processed signal that meets the preset signal-to-noise ratio, thereby improving the sensitivity and noise resistance of the preamplifier circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation to the present invention.

[0041] Figure 1 This is a circuit schematic diagram of the preamplifier circuit provided by the utility model.

[0042] Figure 2 This is a schematic diagram of the simulation software parameter settings provided by the utility model.

[0043] Figure 3 This is a schematic diagram of the simulation results of the simulation software provided by the utility model.

[0044] Figure 4 This is a structural block diagram of the signal measurement device provided by the utility model.

[0045] Figure 5 This is a structural block diagram of the computer fault diagnosis system provided by the utility model. DETAILED DESCRIPTION

[0046] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0048] It should be noted that the terms "first," "second," and the like in the specification and claims of the present invention and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present invention described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products, or apparatuses.

[0049] In current computer fault diagnosis, the accuracy of subsequent fault diagnosis is determined by early signal acquisition and measurement, while signal amplification affects the precision of signal measurement. Existing preamplifier circuits suffer from low sensitivity and high noise levels due to factors such as the high resistance of their feedback circuits.

[0050] Based on this, a preamplifier circuit is provided in this embodiment. Figure 1 1 is a circuit diagram of a preamplifier circuit 100 according to an embodiment of the present invention, as shown in FIG. Figure 1 As shown, it includes: an input filtering module 110, an amplifying processing module 120 and an output filtering module 130, and the input filtering module 110 and the output filtering module 130 are both electrically connected to the amplifying processing module 120;

[0051] The input filtering module 110 is used to perform filtering and noise reduction processing on the input bias voltage to obtain the bias voltage after filtering and noise reduction;

[0052] The amplification processing module 120 is used to amplify and perform negative feedback processing on the fault signal to be diagnosed under the bias voltage after filtering and noise reduction, so as to form an amplified processing signal that can meet the preset signal-to-noise ratio;

[0053] The output filtering module 130 is used to perform output filtering processing on the amplified processed signal to obtain a pre-amplified output signal, and the pre-amplified output signal is used to input into the main amplifier circuit for amplification processing to obtain a measurement result of the fault signal to be diagnosed.

[0054] In an embodiment of the present invention, the input filtering module 110 can filter and reduce the noise of the input bias voltage, and the amplification processing module 120 can amplify and perform negative feedback processing on the fault signal to be diagnosed under the bias voltage after filtering and reducing the noise. Specifically, during the amplification and negative feedback processing, the fault signal to be diagnosed can be negatively feedback-regulated to obtain an amplified processing signal that meets the preset signal-to-noise ratio. It should be understood here that the feedback circuit portion of the amplification processing module 120 in the embodiment of the present invention can replace the high-resistance feedback circuit in the prior art with a low-noise characteristic to obtain an amplified processing signal that meets the preset signal-to-noise ratio. Finally, the amplified processing signal that meets the preset signal-to-noise ratio is output and filtered by the output filtering module 130 to obtain a pre-amplified output signal. After being output by the pre-amplifier circuit, the pre-amplified output signal can enter the main amplifier circuit for further amplification processing, and finally obtain the measurement result of the fault signal to be diagnosed.

[0055] Therefore, the preamplifier circuit provided by the present invention performs noise reduction filtering on the input bias voltage through the input filtering module, and amplifies and performs negative feedback processing on the fault signal to be diagnosed at the bias voltage after filtering and noise reduction through the amplification processing module, thereby forming an amplified processing signal that meets the preset signal-to-noise ratio. Finally, the amplified processing signal is output filtered by the output filtering module to obtain a preamplified output signal. This preamplifier circuit of the present invention replaces the high-resistance feedback circuit in the prior art with the low-noise characteristics of the feedback circuit portion of the amplification processing module to obtain an amplified processing signal that meets the preset signal-to-noise ratio, thereby improving the sensitivity and noise resistance of the preamplifier circuit.

[0056] In the embodiment of the present utility model, Figure 1 As shown, the amplification processing module 120 includes an amplification unit 121 and a feedback unit 122, and the feedback unit 122 is electrically connected to the amplification unit 121.

[0057] The amplifying unit 121 is used to amplify the fault signal to be diagnosed under the bias voltage after filtering and noise reduction to obtain an amplified signal;

[0058] The feedback unit 122 is configured to form a negative feedback loop when the amplifying unit obtains the amplified signal, so as to obtain an amplified signal that meets a preset signal-to-noise ratio.

[0059] Specifically, if Figure 1 As shown, the amplifying unit 121 includes: an operational amplifier U1, a first resistor R11, a second resistor R12, a third resistor R10, a fourth resistor R8, a first capacitor C7 and a second capacitor C6,

[0060] The non-inverting input terminal of the operational amplifier U1 is connected to one end of the first resistor R11, and the other end of the first resistor R11 is connected to the power supply VCC;

[0061] The inverting input terminal of the operational amplifier U1 is connected to one end of the third resistor R10, and the other end of the third resistor R10 is connected to the power supply VCC. The inverting input terminal of the operational amplifier U1 is also used to connect to the feedback unit 122;

[0062] The positive power supply terminal of the operational amplifier U1 is connected to the power supply VCC through the fourth resistor R8, and the positive power supply terminal and the negative power supply terminal of the operational amplifier U1 are both connected to the signal ground;

[0063] The output end of the operational amplifier U1 is used to connect to the feedback unit 122 and the output filter module 130 respectively;

[0064] The second resistor R12 is connected in parallel with the first capacitor C7, one end of the parallel connection is connected to the non-inverting input terminal of the operational amplifier U1, and the other end of the parallel connection is connected to the signal ground;

[0065] One end of the second capacitor C6 is connected to the other end of the third resistor R10 , and the other end of the second capacitor C6 is connected to the signal ground.

[0066] In the embodiment of the present invention, the operational amplifier U1 can be implemented using the ADA4898 operational amplifier from Analog Devices, Inc., USA. The bandwidth of the ADA4898 operational amplifier can be 65 MHz. Due to its wide power supply voltage and ultra-low bandwidth noise, it can reduce distortion, thereby improving the stability of unity gain. Therefore, by using an operational amplifier with a wide voltage range and the advantages of high gain and low noise, the amplification unit can effectively improve the sensitivity of the amplification processing module.

[0067] Specifically, if Figure 1 As shown, the feedback unit 122 includes: a switch tube Q1, a third capacitor C1, a fourth capacitor C3 and a fifth resistor R3.

[0068] The control end of the switch tube Q1 is respectively connected to one end of the fifth resistor R3 and one end of the third capacitor C1, the other end of the fifth resistor R3 is connected to the output end of the operational amplifier U1, the other end of the third capacitor C1 is connected to one end of the fourth capacitor C3, and the other end of the fourth capacitor C3 is connected to the output end of the operational amplifier U1;

[0069] A first end of the switch tube Q1 is connected to the inverting input end of the operational amplifier U1 , and a second end of the switch tube Q1 is connected to the signal ground.

[0070] The aforementioned low-noise feedback circuit portion includes at least a negative feedback loop. Specifically, in feedback unit 122, the amplified signal output from the output terminal of operational amplifier U1 passes through third capacitor C1 and fourth capacitor C3 to reach switch Q1, forming a negative feedback loop. Compared to high-resistance feedback loops in the prior art, this negative feedback loop has the advantages of low noise and high sensitivity. Therefore, the amplification processing module formed by the combination of the feedback unit and the amplification unit can amplify and negatively feedback the fault signal to be diagnosed, thereby obtaining an amplified processed signal that meets a preset signal-to-noise ratio.

[0071] In the embodiment of the present invention, the switch tube Q1 includes a field effect tube of model 2N4416.

[0072] It should be understood that in the embodiment of the present invention, by selecting a 2N4416 field effect transistor to replace the high-resistance feedback circuit in the prior art to form a discharge circuit, the signal-to-noise ratio of the amplification processing module can be effectively improved.

[0073] It should be noted that when the specific model of the switch tube Q1 is a 2N4416 field effect tube, the switch tube Q1 is an N-type MOS tube. Therefore, the control end of the switch tube Q1 is specifically the gate, the first end of the switch tube Q1 is specifically the drain, and the second end of the switch tube Q1 is specifically the source; when a P-type MOS tube is selected, the control end of the switch tube is specifically the gate, the first end of the switch tube Q1 is specifically the source, and the second end of the switch tube Q1 is specifically the drain.

[0074] In the embodiment of the present utility model, Figure 1 As shown, the input filter module 110 includes: a sixth resistor R6, a seventh resistor R7, a fifth capacitor C2 and a sixth capacitor C5,

[0075] One end of the fifth capacitor C2 is connected to the signal ground, and the other end of the fifth capacitor C2 is connected to one end of the sixth resistor R6;

[0076] The other end of the sixth resistor R6 is connected to one end of the sixth capacitor C5, and the other end of the sixth capacitor C5 is connected to the amplification processing module 120;

[0077] One end of the seventh resistor R7 is connected to one end of the sixth resistor R6 , and the other end of the seventh resistor R7 is connected to the power supply VCC.

[0078] It should be noted that, in an embodiment of the present invention, the input filter module 110 can be connected to a bias voltage circuit, which can provide a bias voltage for the input filter module 110. Specifically, the other end of the sixth resistor R6 in the input filter module 110 can be connected to the bias voltage circuit.

[0079] Specifically, the bias voltage circuit may include a bias voltage source.

[0080] In the embodiment of the present utility model, Figure 1 As shown, the output filter module 130 includes: an eighth resistor R9 and a seventh capacitor C4,

[0081] One end of the seventh capacitor C4 is connected to the output end of the amplification processing module 120, and the other end of the seventh capacitor C4 is the output end of the preamplifier circuit 100;

[0082] One end of the eighth resistor R9 is connected to the other end of the seventh capacitor C4 , and the other end of the eighth resistor R9 is connected to the signal ground.

[0083] The preamplifier circuit of the embodiment of the present invention is simulated and analyzed by the simulation system. First, the device parameters in the preamplifier circuit are determined, and simulation is performed based on the determined device parameters. During the simulation process, the output electrical signal is simulated by the pulse voltage signal. The signal setting is as follows: Figure 2 As shown in the figure, the most suitable readout circuit is determined based on the simulation results and actual circuit test. The waveform of the output signal of the pulse voltage simulation is as follows Figure 3 As shown, based on the Figure 3 The waveform diagram of the output signal shown shows that the output ripple of the amplified output signal of the preamplifier circuit of the present invention is less than 10mV, the signal-to-noise ratio is greater than 4:1, and it has the characteristics of low noise.

[0084] In summary, the preamplifier circuit provided by the present invention reduces the noise impact caused by the high-resistance feedback introduced in traditional preamplifier circuits compared to the prior art. Furthermore, the reduced structure of the feedback terminal reduces the thermal noise introduced into the preamplifier circuit, thereby improving the noise immunity of the entire system. Therefore, the preamplifier circuit provided by the present invention has the advantages of low noise and high sensitivity.

[0085] As another embodiment of the present invention, a signal measuring device 10 is provided, wherein Figure 4 As shown, it includes: a bias voltage circuit 200, a main amplifier circuit 300 and the preamplifier circuit 100 described in any one of the above, the bias voltage circuit 200 is electrically connected to the preamplifier circuit 100, and the preamplifier circuit 100 is electrically connected to the main amplifier circuit 300;

[0086] The bias voltage circuit 200 is used to provide a bias voltage for the preamplifier circuit;

[0087] The preamplifier circuit 100 is used to perform preamplification processing on the fault signal to be diagnosed collected by the signal acquisition device to obtain a preamplified output signal;

[0088] The main amplifier circuit 300 is used to perform secondary amplification processing on the pre-amplifier output signal to obtain a measurement result of the fault signal to be diagnosed.

[0089] Specifically, the bias voltage circuit includes a bias voltage source.

[0090] In the embodiment of the present utility model, the bias voltage circuit is specifically Figure 1 The diode D1 in the figure is taken as an example. It should be understood that the diode D1 can be replaced by a bias voltage source to provide the bias voltage function.

[0091] The signal measuring device provided by the present utility model utilizes the aforementioned preamplifier circuit to perform preamplification processing on the fault signal to be diagnosed before the main amplifier circuit, and then further amplifies the preamplified signal through the main amplifier circuit, thereby obtaining a measurement result of the fault signal to be diagnosed. Because the preamplifier circuit can replace the high-resistance feedback circuit in the prior art by utilizing the low-noise characteristics of the feedback circuit portion of the amplification processing module to obtain an amplified processed signal that meets a preset signal-to-noise ratio, and has the advantages of high sensitivity and low noise, the signal measuring device based on this preamplifier circuit can obtain more accurate measurement results when obtaining measurement results based on the advantages of the preamplifier circuit.

[0092] It should be understood that the main amplifying circuit in the embodiment of the present invention may specifically include an operational amplifier.

[0093] As another embodiment of the present invention, a computer fault diagnosis system 1 is provided, wherein, Figure 5 As shown, it includes: a signal acquisition device 20 and the signal measuring device 10 mentioned above, the signal acquisition device 20 is communicatively connected with the signal measuring device 10;

[0094] The signal acquisition device 20 is used to collect the fault signal to be diagnosed;

[0095] The signal measuring device 10 is used to perform pre-amplification processing and secondary amplification processing on the fault signal to be diagnosed in sequence to obtain a measurement result of the fault signal to be diagnosed.

[0096] In the embodiment of the present invention, the signal acquisition device 20 can specifically acquire the fault signal to be diagnosed in the form of voltage or current. Specifically, the fault signal to be diagnosed in the form of voltage can be acquired, for example, by a voltage data collector, and the fault signal to be diagnosed in the form of current can be acquired, for example, by a Hall effect sensor or the like. The specific selection can be made as needed and is not limited here.

[0097] The computer fault diagnosis system provided by the present invention adopts the aforementioned signal measurement device. Since the aforementioned signal measurement device has the advantage of obtaining more accurate measurement results, the computer fault diagnosis system provided by the present invention has the advantage of accurate diagnosis.

[0098] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A preamplifier circuit, characterized in that: include: An input filtering module, an amplifying processing module and an output filtering module, wherein the input filtering module and the output filtering module are both electrically connected to the amplifying processing module; The input filtering module is used to perform filtering and noise reduction processing on the input bias voltage to obtain the bias voltage after filtering and noise reduction; The amplification processing module is used to amplify and perform negative feedback processing on the fault signal to be diagnosed under the bias voltage after filtering and noise reduction, so as to form an amplified processing signal that can meet the preset signal-to-noise ratio; The output filtering module is used to perform output filtering processing on the amplified processing signal to obtain a pre-amplified output signal, and the pre-amplified output signal is used to input into the main amplifier circuit for amplification processing to obtain a measurement result of the fault signal to be diagnosed.

2. The preamplifier circuit according to claim 1, wherein: The amplification processing module includes an amplification unit and a feedback unit, and the feedback unit is electrically connected to the amplification unit. The amplifying unit is used to amplify the fault signal to be diagnosed under the bias voltage after filtering and noise reduction to obtain an amplified signal; The feedback unit is used to form a negative feedback loop in the process of the amplifying unit obtaining the amplified signal to obtain an amplified processed signal that can meet a preset signal-to-noise ratio.

3. The preamplifier circuit according to claim 2, wherein: The amplifying unit includes: an operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor and a second capacitor. The non-inverting input terminal of the operational amplifier is connected to one end of the first resistor, and the other end of the first resistor is connected to a power supply; The inverting input terminal of the operational amplifier is connected to one end of the third resistor, the other end of the third resistor is connected to the power supply, and the inverting input terminal of the operational amplifier is also used to connect to the feedback unit; The positive power supply terminal of the operational amplifier is connected to the power supply via a fourth resistor, and the positive power supply terminal and the negative power supply terminal of the operational amplifier are both connected to the signal ground; The output end of the operational amplifier is used to connect to the feedback unit and the output filter module respectively; The second resistor is connected in parallel with the first capacitor, one end of the parallel connection is connected to the non-inverting input terminal of the operational amplifier, and the other end of the parallel connection is connected to the signal ground; One end of the second capacitor is connected to the other end of the third resistor, and the other end of the second capacitor is connected to the signal ground.

4. The preamplifier circuit according to claim 3, wherein: The feedback unit includes: a switch tube, a third capacitor, a fourth capacitor and a fifth resistor. The control end of the switch tube is respectively connected to one end of the fifth resistor and one end of the third capacitor, the other end of the fifth resistor is connected to the output end of the operational amplifier, the other end of the third capacitor is connected to one end of the fourth capacitor, and the other end of the fourth capacitor is connected to the output end of the operational amplifier; The first end of the switch tube is connected to the inverting input end of the operational amplifier, and the second end of the switch tube is connected to the signal ground.

5. The preamplifier circuit according to claim 4, characterized in that: The operational amplifier includes an operational amplifier of model ADA4898, and the switch tube includes a field effect tube of model 2N4416.

6. The preamplifier circuit according to any one of claims 1 to 5, characterized in that: The input filter module includes: a sixth resistor, a seventh resistor, a fifth capacitor and a sixth capacitor, One end of the fifth capacitor is connected to the signal ground, and the other end of the fifth capacitor is connected to one end of the sixth resistor; The other end of the sixth resistor is connected to one end of the sixth capacitor, and the other end of the sixth capacitor is connected to the amplification processing module; One end of the seventh resistor is connected to one end of the sixth resistor, and the other end of the seventh resistor is connected to a power supply.

7. The preamplifier circuit according to any one of claims 1 to 5, characterized in that: The output filter module includes: an eighth resistor and a seventh capacitor, One end of the seventh capacitor is connected to the output end of the amplification processing module, and the other end of the seventh capacitor is the output end of the preamplifier circuit; One end of the eighth resistor is connected to the other end of the seventh capacitor, and the other end of the eighth resistor is connected to the signal ground.

8. A signal measuring device, characterized in that: include: A bias voltage circuit, a main amplifier circuit, and the preamplifier circuit according to any one of claims 1 to 7, wherein the bias voltage circuit is electrically connected to the preamplifier circuit, and the preamplifier circuit is electrically connected to the main amplifier circuit; The bias voltage circuit is used to provide a bias voltage for the preamplifier circuit; The preamplifier circuit is used to perform preamplification processing on the fault signal to be diagnosed collected by the signal acquisition device to obtain a preamplified output signal; The main amplifier circuit is used to perform secondary amplification processing on the pre-amplifier output signal to obtain a measurement result of the fault signal to be diagnosed.

9. The signal measuring device according to claim 8, characterized in that: The bias voltage circuit includes a bias voltage source.

10. A computer fault diagnosis system, characterized in that: include: A signal acquisition device and a signal measuring device according to claim 8 or 9, wherein the signal acquisition device is communicatively connected to the signal measuring device; The signal acquisition device is used to collect the fault signal to be diagnosed; The signal measuring device is used to perform pre-amplification processing and secondary amplification processing on the fault signal to be diagnosed in sequence to obtain a measurement result of the fault signal to be diagnosed.

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