Front-end amplification circuit, circuit board and data acquisition equipment

Abstract

The invention provides a front-end amplification circuit, a circuit board and data acquisition equipment, relates to the technical field of electronic circuits, and solves the problem that the working frequency of the data acquisition equipment is limited and an accurate signal measurement function is difficult to provide in the prior art. Therefore, different components in the to-be-measured signal are amplified, the working frequency range of the circuit is expanded, signal voltage can be amplified, a better signal-to-noise ratio and a better voltage standing wave ratio are achieved, the measurement accuracy of the signal is improved, and a more accurate signal measurement function is provided.

Description

Technical Field

[0001] The present application relates to the technical field of electronic circuits, and in particular to a front-end amplifier circuit, a circuit board and a data acquisition device. Background Art

[0002] In data acquisition equipment such as oscilloscopes, the front-end amplifier circuit plays a very important role. Its main function is to amplify the measured signal to an appropriate range so that it can be processed by the subsequent circuit, so that the weaker measured signal can also be detected. To this end, it needs to have a small reflection coefficient, and it also needs to enhance the current or voltage of the signal, and can superimpose or eliminate the DC component for subsequent circuit processing.

[0003] However, in the related art, the corresponding driving circuit is constructed by MOS tubes and triodes to form a front-end amplifier circuit, which can only enhance the driving current but cannot increase the signal voltage. Moreover, the circuit structure constructed by discrete components limits the operating frequency of the circuit, and it cannot work at a higher frequency, and it is even more difficult to achieve a lower voltage standing wave ratio. Therefore, the operating frequency of the data acquisition equipment is limited, resulting in poor accuracy in detecting low-frequency signals, difficulty in adapting to high-frequency signals, and difficulty in providing accurate signal measurement functions. Summary of the invention

[0004] The present application provides a front-end amplifier circuit, a circuit board and a data acquisition device, which solves the problem in the related art that the operating frequency of the data acquisition device is limited and it is difficult to provide accurate signal measurement function. The present application scheme can separate and amplify DC, low-frequency signals and high-frequency signals to achieve accurate measurement of different signals.

[0005] In a first aspect, the present application provides a front-end amplifier circuit, which includes a signal access module, a low-frequency amplifier module, a DC bias module, a radio frequency amplifier module and a signal output module.

[0006] The input end of the signal access module is connected to the signal receiving terminal to access the signal to be measured. The signal access module is used to provide input impedance for the front-end amplifier circuit, and the signal access module is also used to separate the DC and low-frequency signals and high-frequency signals in the signal to be measured;

[0007] The first input end of the low-frequency amplification module is connected to the input end of the signal access module, the second input end of the low-frequency amplification module is connected to the impedance output end of the signal access module, and the low-frequency amplification module is used to amplify direct current and low-frequency signals;

[0008] The output end of the DC bias module is connected to the bias access end of the low-frequency amplifier module. The DC bias module is used to access a DC bias voltage for the low-frequency amplifier module to offset the external bias voltage superimposed on the signal to be measured.

[0009] The input end of the radio frequency amplification module is connected to the impedance output end of the signal access module. The radio frequency amplification module is used to amplify the high frequency signal, and the amplification factor of the radio frequency amplification module matches the amplification factor of the low frequency amplification module.

[0010] The first input end of the signal output module is connected to the output end of the low-frequency amplification module, the second input end of the signal output module is connected to the output end of the radio frequency amplification module, and the output end of the signal output module is connected to the output signal terminal, which is used to provide the amplified measured signal to the subsequent circuit.

[0011] In a second aspect, the present application also provides a circuit board, which includes the front-end amplifier circuit as described in the first aspect above.

[0012] In a third aspect, the present application also provides a data acquisition device, which includes the circuit board as described in the second aspect above.

[0013] The front-end amplifier circuit of the present application can separate DC and low-frequency signals and high-frequency signals, thereby amplifying different components in the measured signal separately, expanding the operating frequency range of the circuit, and can also amplify the signal voltage, thereby achieving a better signal-to-noise ratio and voltage standing wave ratio, which is beneficial to improving the measurement accuracy of the signal to provide a more accurate signal measurement function. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A principle block diagram of a front-end amplifier circuit provided in an embodiment of the present application;

[0015] Figure 2 An equivalent circuit diagram of a signal access module in an embodiment of the present application;

[0016] Figure 3 A schematic diagram of the circuit structure of a front-end amplifier circuit provided in one embodiment of the present application. DETAILED DESCRIPTION

[0017] The following is a further detailed description of the embodiments of the present application in conjunction with the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are only used to explain the embodiments of the present application, rather than to limit the embodiments of the present application. It should also be noted that, for ease of description, only the parts related to the embodiments of the present application rather than all structures are shown in the accompanying drawings, and those skilled in the art should be able to think of it after reading the specification of this application that as long as the technical features do not contradict each other, any combination of the technical features can constitute an optional implementation method.

[0018] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable when appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally a class, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally represents that the objects associated before and after are in an "or" relationship. In the description of the present application, "multiple" means two or more, and "several" means one or more.

[0019] As a component of data acquisition equipment such as oscilloscopes and data acquisition instruments, the front-end amplifier circuit plays an important role in the detection of weak signals by the data acquisition equipment. In the related art, the front-end amplifier circuit provided by the related art constructs a corresponding driving circuit through MOS tubes and triodes to perform front-end amplification.

[0020] However, this circuit can only enhance the driving current but cannot increase the signal voltage. Moreover, the circuit structure built with discrete components limits the operating frequency of the circuit and cannot operate at a higher frequency, and it is even more difficult to achieve a lower voltage standing wave ratio. Therefore, the operating frequency of the data acquisition device is limited, resulting in poor accuracy in detecting low-frequency signals, difficulty in adapting to high-frequency signals, and difficulty in providing accurate signal measurement functions.

[0021] In this regard, the embodiment of the present application provides a front-end amplifier circuit, which can separate and amplify DC, low-frequency signals and high-frequency signals to achieve accurate measurement of different signals. Figure 1 As shown, Figure 1 This is a principle block diagram of a front-end amplifier circuit provided in one embodiment of the present application, wherein the front-end amplifier circuit includes a signal access module 101, a low-frequency amplifier module 102, a DC bias module 103, a radio frequency amplifier module 104 and a signal output module 105.

[0022] Specifically, the input end of the signal access module 101 is connected to the signal receiving terminal, which is an interface connected to the outside in the front-end amplifier circuit, and can access the corresponding signal to be measured to connect the signal to be measured to the front-end amplifier circuit. The first input end of the low-frequency amplifier module 102 is connected to the input end of the signal access module 101, the second input end of the low-frequency amplifier module 102 is connected to the impedance output end of the signal access module 101, and the output end of the DC bias module 103 is connected to the bias access end of the low-frequency amplifier module 102. In addition, the input end of the RF amplifier module 104 is also connected to the impedance output end of the signal access module 101.

[0023] The first input end of the signal output module 105 is connected to the output end of the low frequency amplification module 102 , the second input end of the signal output module 105 is connected to the output end of the radio frequency amplification module 104 , and the output end of the signal output module 105 is connected to the output signal terminal.

[0024] It can be understood that after the signal to be measured enters the front-end amplifier circuit, the signal access module 101 separates the DC and low-frequency signals and high-frequency signals in the signal to be measured. In addition, the signal access module 101 also provides input impedance for the front-end amplifier circuit to perform impedance matching, thereby improving the transmission quality of the signal and reducing signal distortion and interference. Correspondingly, the DC and low-frequency signals enter the low-frequency amplifier module 102, and then the DC and low-frequency signals are amplified by the low-frequency amplifier module 102. Moreover, the DC bias module 103 connects a DC bias voltage to the low-frequency amplifier module 102 to offset the external bias voltage superimposed on the signal to be measured, thereby enabling the measurement of smaller signals.

[0025] The high-frequency signal enters the RF amplification module 104, and then is amplified by the RF amplification module 104. It is worth noting that the amplification factor of the RF amplification module 104 matches the amplification factor of the low-frequency amplification module 102, that is, the amplification factors of the two are equal, so that the front-end amplifier circuit provides the measured signal to the subsequent circuit at a corresponding amplification factor.

[0026] It can be seen from the above scheme that the front-end amplifier circuit of the present application can separate DC and low-frequency signals and high-frequency signals, so as to amplify different components in the measured signal respectively, expand the operating frequency range of the circuit, and can also amplify the signal voltage, thereby achieving a better signal-to-noise ratio and voltage standing wave ratio, which is beneficial to improving the measurement accuracy of the signal to provide a more accurate signal measurement function.

[0027] In one embodiment, the signal access module includes a first resistor, a first capacitor and a first inductor. Specifically, the first end of the first resistor is connected to the first end of the first capacitor, the second end of the first resistor is connected to the second end of the first capacitor, the first end of the first inductor is connected to the second end of the first capacitor, and the second end of the first inductor is grounded. Among them, the first end of the first resistor serves as the input end of the signal access module, the second end of the first resistor serves as the impedance output end of the signal access module, and the resistance value of the first resistor matches the equivalent input resistance of the RF amplification module, and the inductance value of the first inductor is equal to the product of the capacitance value of the first capacitor and the square of the resistance value of the first resistor; the first capacitor is used to isolate DC and low-frequency signals and conduct high-frequency signals, and the first inductor is used to isolate high-frequency signals and conduct DC and low-frequency signals.

[0028] like Figure 2 As shown, Figure 2: is an equivalent circuit diagram of a signal access module in an embodiment of the present application, wherein the first resistor R1 is connected in parallel with the first capacitor C1, and the first inductor L1 is connected in series with the first capacitor C1. The resistor R8 is the equivalent input resistor of the RF amplification module. In the RF amplification module, the resistor R8 is equivalent to the resistor grounded at the input end of the RF amplification module. Figure 2 In the embodiment, the resistor R8 is connected in parallel to the first inductor L1. The first resistor R1 matches the resistor R8, so that the input impedance of the circuit is equivalent to the resistance value of the first resistor, thereby better matching the system and facilitating more accurate measurement of the signal.

[0029] And when the inductance of the first inductor is equal to the product of the capacitance of the first capacitor and the square of the resistance of the first resistor, the signal access module is equivalent to a resistor with a fixed resistance relative to the signal to be measured. It can be understood that after the measured signal enters the signal access module, under the action of the first capacitor C1, the high-frequency signal will pass through the first capacitor C1, while the DC and low-frequency signals will pass through the first resistor R1. In addition, under the action of the first inductor L1, the DC and low-frequency signals will pass through the first inductor L1, while the high-frequency signal will pass through the resistor R8. In this regard, due to the existence of the first capacitor C1, the DC and low-frequency signals can enter the low-frequency amplification module after passing through the first resistor R1; due to the existence of the first inductor L1, the high-frequency signal can be connected to the RF amplification module through the resistor R8.

[0030] Therefore, the signal access module can use the first capacitor to isolate the high-frequency signal outside the low-frequency amplification module, and use the inductor in parallel with the RF amplification module to isolate the DC and low-frequency signals outside the RF amplification module, thereby realizing the measurement of DC, low-frequency signals and high-frequency signals, which helps to expand the operating frequency range of the circuit.

[0031] In one embodiment, the low-frequency amplification module includes a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and an operational amplifier, thereby forming a differential amplification circuit to process the low-frequency component in the measured signal, making the measurement of the low-frequency component more accurate.

[0032] Specifically, the first end of the second resistor is connected to the impedance providing end of the signal access module, the second end of the second resistor is connected to the first end of the third resistor, the second end of the second resistor is connected to the non-inverting input end of the operational amplifier, and the second end of the third resistor is grounded. The first end of the fourth resistor is connected to the input end of the signal access module, the second end of the fourth resistor is connected to the inverting input end of the operational amplifier, the first end of the fifth resistor is connected to the second end of the fourth resistor, the second end of the fifth resistor is connected to the output end of the operational amplifier, and the first end of the sixth resistor is connected to the output end of the operational amplifier.

[0033] Among them, the first end of the fourth resistor serves as the first input end of the low-frequency amplification module, the first end of the second resistor serves as the second input end of the low-frequency amplification module, the second end of the fourth resistor serves as the bias access end of the low-frequency amplification module, the second end of the sixth resistor serves as the output end of the low-frequency amplification module, and the resistance value of the sixth resistor matches the equivalent output resistance of the RF amplification module.

[0034] It should be noted that, in one embodiment, the input impedance provided by the signal access module includes a first resistor, and accordingly, the second resistor and the fourth resistor in the low-frequency amplification module are much larger than the first resistor, such as the ratio of the resistance value of the second resistor to the first resistor and the ratio of the resistance value of the fourth resistor to the first resistor are both greater than or equal to 100, that is, the resistance value of the second resistor and the resistance value of the fourth resistor are both 100 times or more of the resistance value of the first resistor.

[0035] Optionally, in one embodiment, the DC bias module includes a seventh resistor, the first end of the seventh resistor is connected to a DC bias voltage, the second end of the seventh resistor is connected to the bias access terminal of the low-frequency amplifier module, and the DC bias voltage matches the external bias voltage, that is, the DC bias voltage is equal to the external bias voltage. In this regard, the external bias voltage superimposed on the signal to be measured can be offset by the DC bias voltage, which is helpful for measuring small signals. Optionally, in another embodiment, the seventh resistor can also be replaced by other devices, such as using a voltage regulator diode to replace the seventh resistor to access the corresponding DC bias voltage.

[0036] In one embodiment, the signal output module includes a second inductor and a second capacitor. Specifically, a first end of the second inductor is connected to an output end of the low-frequency amplification module, a first end of the second capacitor is connected to an output end of the radio frequency amplification module, and a second end of the second inductor is connected to a second end of the second capacitor.

[0037] The second inductor is used to conduct the amplified DC and low-frequency signals, the second capacitor is used to conduct the amplified high-frequency signals, and the reactance ratio corresponding to the second inductor and the second capacitor matches the reactance ratio corresponding to the signal access module.

[0038] It can be understood that, by utilizing the characteristics of the second capacitor and the second inductor, the signal output module can separate the connected signal again, wherein the signal passing through the second inductor retains the DC and low-frequency signal, while the signal passing through the second capacitor retains the high-frequency signal. For this, the second inductor is connected to the output end of the low-frequency amplification module, and the second capacitor is connected to the output end of the radio frequency amplification module, thereby realizing the access and output of the amplified signal. Therefore, through the signal output module, the front-end amplifier circuit can access the amplified DC and low-frequency signals and high-frequency signals, thereby providing the amplified signal to be measured for the subsequent circuit, achieving a better signal-to-noise ratio and voltage standing wave ratio.

[0039] Figure 3A circuit structure diagram of a front-end amplifier circuit provided for an embodiment of the present application. In one embodiment, a signal access module in the front-end amplifier circuit includes a first resistor R1, a first capacitor C1 and a first inductor L1. The first end of the first resistor R1 is connected to the first end of the first capacitor C1, the second end of the first resistor R1 is connected to the second end of the first capacitor C1, the first end of the first inductor L1 is connected to the second end of the first capacitor C1, and the second end of the first inductor L1 is grounded.

[0040] The low-frequency amplification module includes a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and an operational amplifier U1. The first end of the second resistor R2 is connected to the second end of the first resistor, the second end of the second resistor R2 is connected to the first end of the third resistor R3, the second end of the second resistor R2 is connected to the in-phase input terminal of the operational amplifier U1, and the second end of the third resistor R3 is grounded; the first end of the fourth resistor R4 is connected to the first end of the first resistor, the second end of the fourth resistor R4 is connected to the inverting input terminal of the operational amplifier U1, the first end of the fifth resistor R5 is connected to the second end of the fourth resistor R4, the second end of the fifth resistor R5 is connected to the output terminal of the operational amplifier U1, and the first end of the sixth resistor R6 is connected to the output terminal of the operational amplifier U1. In addition, one end of the seventh resistor R7 is connected to the inverting input terminal of the operational amplifier U1, and the other end of the seventh resistor R7 is connected to the DC bias voltage.

[0041] The dotted-line frame portion in the figure identifies the radio frequency amplification module, which equivalently represents the equivalent input resistance (ie, resistance R8) and the equivalent output resistance (ie, resistance R9) of the radio frequency amplification module.

[0042] In addition, the signal output module includes a second inductor L2 and a second capacitor C2, the first end of the second inductor L2 is connected to the output end of the low-frequency amplification module, the first end of the second capacitor C2 is connected to the output end of the radio frequency amplification module, and the second end of the second inductor L2 is connected to the second end of the second capacitor C2.

[0043] Among them, the second resistor R2 and the fourth resistor R4 are both much larger than the first resistor R1, and the first resistor R1 matches the resistor R8, and the sixth resistor R6 matches the resistor R9. In addition, the reactance ratio corresponding to the first inductor L1 and the first capacitor C1 is a first reactance ratio, and the reactance ratio corresponding to the second inductor L2 and the second capacitor C2 is a second reactance ratio, and the first reactance ratio is equal to the second reactance ratio. Specifically, the values ​​of the first reactance ratio and the second reactance ratio are both the square of the resistance value of the first resistor.

[0044] It is understandable that, under the action of the first capacitor C1, high frequency signals pass through the first capacitor C1, while DC and low frequency signals pass through the first resistor R1. In addition, under the action of the first inductor L1, DC and low frequency signals pass through the first inductor L1, while high frequency signals pass through the resistor R8.

[0045] In this regard, due to the presence of the first capacitor C1, the DC and low-frequency signals can enter the low-frequency amplification module through the first resistor R1, and further amplify through the differential amplifier circuit formed by the operational amplifier U1 and the corresponding resistors. In addition, due to the presence of the first inductor L1, the high-frequency signal can be connected to the RF amplification module through the resistor R8, thereby amplifying the high-frequency signal.

[0046] Similarly, based on the characteristics of the second inductor L2 and the second capacitor C2, the second inductor L2 is connected to the output end of the low-frequency amplification module (i.e., the second end of the sixth resistor R6), and the second capacitor C2 is connected to the output end of the radio frequency amplification module (such as one end of the resistor R9 in the figure), thereby realizing the access and output of the amplified signal.

[0047] Therefore, the front-end amplifier circuit of the present application can separate DC and low-frequency signals and high-frequency signals, thereby amplifying different components in the measured signal separately, expanding the operating frequency range of the circuit, and can also amplify the signal voltage, thereby achieving a better signal-to-noise ratio and voltage standing wave ratio, which is beneficial to improving the measurement accuracy of the signal to provide a more accurate signal measurement function.

[0048] It should be noted that in some embodiments, the RF amplification module can use a RF amplification circuit, such as an operational amplifier in-phase RF amplification circuit, a low-noise amplification circuit, etc. to amplify the high-frequency signal; in addition, the RF amplification module can also use a RF amplifier to amplify the high-frequency signal.

[0049] An embodiment of the present application also provides a circuit board, which includes the front-end amplifier circuit of the above embodiment. Similarly, the circuit board can also separate DC and low-frequency signals and high-frequency signals, so as to amplify different components in the measured signal respectively, thereby expanding the operating frequency range, and can also amplify the signal voltage, thereby achieving a better signal-to-noise ratio and voltage standing wave ratio, which is beneficial to improving the measurement accuracy of the signal to provide a more accurate signal measurement function.

[0050] The embodiment of the present application also provides a data acquisition device, which can be an oscilloscope device or a data acquisition instrument. The data acquisition device includes the above-mentioned circuit board, so the data acquisition device can adapt to a larger operating frequency range, and amplify different components in the measured signal respectively, thereby amplifying the signal voltage, thereby achieving a better signal-to-noise ratio and voltage standing wave ratio, which is conducive to improving the measurement accuracy of the signal, so as to provide a more accurate signal measurement function.

[0051] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0052] Note that the above are only preferred embodiments of the present application and the technical principles used. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present application. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A front-end amplifier circuit, characterized in that: include: A signal access module, wherein the input end of the signal access module is connected to the signal receiving terminal to access the signal to be measured, the signal access module is used to provide input impedance for the front-end amplifier circuit, and the signal access module is also used to separate the DC and low-frequency signals and high-frequency signals in the signal to be measured; A low-frequency amplification module, wherein a first input end of the low-frequency amplification module is connected to an input end of the signal access module, a second input end of the low-frequency amplification module is connected to an impedance output end of the signal access module, and the low-frequency amplification module is used to amplify the DC and low-frequency signals; A DC bias module, wherein the output end of the DC bias module is connected to the bias access end of the low-frequency amplification module, and the DC bias module is used to access a DC bias voltage for the low-frequency amplification module to offset the external bias voltage superimposed on the signal to be measured; A radio frequency amplification module, wherein the input end of the radio frequency amplification module is connected to the impedance output end of the signal access module, the radio frequency amplification module is used to amplify the high frequency signal, and the amplification factor of the radio frequency amplification module matches the amplification factor of the low frequency amplification module; A signal output module, wherein the first input end of the signal output module is connected to the output end of the low-frequency amplification module, the second input end of the signal output module is connected to the output end of the radio frequency amplification module, and the output end of the signal output module is connected to the output signal terminal, for providing the amplified signal to be measured to the subsequent circuit.

2. The front-end amplifier circuit according to claim 1, characterized in that: The signal access module includes a first resistor, a first capacitor and a first inductor; The first end of the first resistor is connected to the first end of the first capacitor, the second end of the first resistor is connected to the second end of the first capacitor, the first end of the first inductor is connected to the second end of the first capacitor, and the second end of the first inductor is grounded; Among them, the first end of the first resistor serves as the input end of the signal access module, the second end of the first resistor serves as the impedance output end of the signal access module, and the resistance value of the first resistor matches the equivalent input resistance of the RF amplification module, and the inductance value of the first inductor is equal to the product of the capacitance value of the first capacitor and the square of the resistance value of the first resistor; the first capacitor is used to isolate the DC and low-frequency signals and conduct the high-frequency signals, and the first inductor is used to isolate the high-frequency signals and conduct the DC and low-frequency signals.

3. The front-end amplifier circuit according to claim 1, characterized in that: The low-frequency amplification module includes a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and an operational amplifier; The first end of the second resistor is connected to the impedance providing end of the signal access module, the second end of the second resistor is connected to the first end of the third resistor, the second end of the second resistor is connected to the non-inverting input end of the operational amplifier, and the second end of the third resistor is grounded; The first end of the fourth resistor is connected to the input end of the signal access module, the second end of the fourth resistor is connected to the inverting input end of the operational amplifier, the first end of the fifth resistor is connected to the second end of the fourth resistor, the second end of the fifth resistor is connected to the output end of the operational amplifier, and the first end of the sixth resistor is connected to the output end of the operational amplifier; Among them, the first end of the fourth resistor serves as the first input end of the low-frequency amplification module, the first end of the second resistor serves as the second input end of the low-frequency amplification module, the second end of the fourth resistor serves as the bias access end of the low-frequency amplification module, the second end of the sixth resistor serves as the output end of the low-frequency amplification module, and the resistance value of the sixth resistor matches the equivalent output resistance of the RF amplification module.

4. The front-end amplifier circuit according to claim 3, characterized in that: When the input impedance provided by the signal access module includes a first resistor, a resistance ratio of the second resistor to the first resistor and a resistance ratio of the fourth resistor to the first resistor are both greater than or equal to 100.

5. The front-end amplifier circuit according to claim 1 or 3, characterized in that: The DC bias module includes a seventh resistor, a first end of the seventh resistor is connected to the DC bias voltage, a second end of the seventh resistor is connected to the bias access end of the low-frequency amplification module, and the DC bias voltage matches the external bias voltage.

6. The front-end amplifier circuit according to claim 1 or 2, characterized in that: The signal output module includes a second inductor and a second capacitor; A first end of the second inductor is connected to the output end of the low-frequency amplification module, a first end of the second capacitor is connected to the output end of the radio frequency amplification module, and a second end of the second inductor is connected to the second end of the second capacitor; The second inductor is used to conduct the amplified DC and low-frequency signals, the second capacitor is used to conduct the amplified high-frequency signals, and the reactance ratio corresponding to the second inductor and the second capacitor matches the reactance ratio corresponding to the signal access module.

7. The front-end amplifier circuit according to claim 6, characterized in that: When the signal access module includes a first inductor and a first capacitor connected in series, the reactance ratio corresponding to the first inductor and the first capacitor is a first reactance ratio, the reactance ratio corresponding to the second inductor and the second capacitor is a second reactance ratio, and the first reactance ratio is equal to the second reactance ratio.

8. The front-end amplifier circuit according to claim 7, characterized in that: The signal access module further includes a first resistor connected in parallel with the first inductor, and the first reactance ratio and the second reactance ratio are both equal to the square of the resistance of the first resistor.

9. A circuit board, characterized in that: The circuit board includes the front-end amplifier circuit as described in any one of claims 1-8.

10. A data acquisition device, characterized in that: The data acquisition device comprises the circuit board as claimed in claim 9.

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