Secondary audio differential signal acquisition circuit

Abstract

The utility model relates to the technical field of audio signal acquisition, and provides a secondary audio differential signal acquisition circuit, the acquisition circuit comprises a primary circuit and a secondary circuit, the primary circuit comprises a primary input circuit, a primary DC bias circuit, a primary amplification circuit and a primary output circuit, and the primary DC bias circuit is connected with the primary input circuit; the first-stage amplification circuit is connected with the first-stage input circuit and the first-stage direct current bias circuit; the primary output circuit is connected with the output end of the primary amplification circuit; the second-stage circuit comprises a second-stage input circuit, a second-stage direct current bias circuit, a second-stage amplification circuit and a second-stage output circuit, and the second-stage input circuit is connected with the output end of the first-stage amplification circuit; the second-stage direct current bias circuit is connected with the second-stage input circuit; the second-stage amplification circuit is connected with the second-stage input circuit and the second-stage direct current bias circuit; and the secondary output circuit is connected with the output end of the secondary amplification circuit. Through cooperative work of two stages of circuit structures, high-precision and high-stability acquisition of audio signals is realized.

Description

Technical Field

[0001] The present application relates to the technical field of audio signal acquisition, and in particular to a two-level audio differential signal acquisition circuit. Background Art

[0002] Single-stage op amp acquisition circuits are widely used in traditional audio signal acquisition technology. However, these circuits have significant limitations, primarily in their narrow acquisition range. Single-stage op amp acquisition circuits can typically only capture audio signals within a specific range. When the audio signal amplitude range is too large or too small, single-stage op amp acquisition circuits often cannot meet the acquisition requirements, resulting in signal distortion or loss, which in turn affects the quality and effectiveness of audio processing. Utility Model Content

[0003] In order to help solve the problem that an audio signal acquisition circuit cannot accurately acquire audio signals with a large amplitude range, the present application provides a two-level audio differential signal acquisition circuit.

[0004] The present application provides a two-stage audio differential signal acquisition circuit, which adopts the following technical solution;

[0005] A two-stage audio differential signal acquisition circuit, wherein the acquisition circuit includes a primary circuit and a secondary circuit.

[0006] The primary circuit includes a primary input circuit, a primary DC bias circuit, a primary amplifier circuit and a primary output circuit.

[0007] The primary input circuit is used to receive the audio differential signal;

[0008] The first-level DC bias circuit is connected to the first-level input circuit and is used to adjust the level of the audio differential signal to the linear amplification region of the first-level amplification circuit;

[0009] The first-level amplification circuit is connected to the first-level input circuit and the first-level DC bias circuit, and is configured to generate a first-level audio differential amplification signal according to the audio differential signal;

[0010] The first-level output circuit is connected to the output end of the first-level amplification circuit, and is used to output the first-level audio differential amplification signal;

[0011] The secondary circuit includes a secondary input circuit, a secondary DC bias circuit, a secondary amplifier circuit and a secondary output circuit.

[0012] The secondary input circuit is connected to the output end of the primary amplifying circuit and is used to receive the primary audio differential amplified signal;

[0013] The secondary DC bias circuit is connected to the secondary input circuit and is used to adjust the level of the audio differential signal to the linear amplification region of the secondary amplification circuit;

[0014] The secondary amplification circuit is connected to the secondary input circuit and the secondary DC bias circuit, and is used to generate a secondary audio differential amplification signal according to the primary audio differential amplification signal;

[0015] The secondary output circuit is connected to the output end of the secondary amplifying circuit and is used to output the secondary audio differential amplified signal.

[0016] By adopting the above technical solution, the core of the two-stage audio differential signal acquisition circuit lies in achieving refined audio signal processing through a two-stage circuit structure. The first stage circuit, serving as the front-end signal processing unit, first receives the external audio differential signal. This design fully utilizes the anti-interference properties of differential signals, effectively reducing the impact of external environmental factors on signal quality. Subsequently, the first stage DC bias circuit adjusts the signal level to the linear amplification range of the first stage amplifier circuit, ensuring that the signal is not distorted during the amplification process. The first stage amplifier circuit then generates the first stage audio differential amplified signal based on this adjusted signal, which is output through the first stage output circuit. This processing stage provides a stable and clear signal source for the subsequent second stage amplification.

[0017] The secondary circuit, serving as further signal processing, receives the initially amplified audio signal via its input connected to the output of the primary amplifier circuit. A secondary DC bias circuit further adjusts the signal level to fit within the linear amplification range of the secondary amplifier circuit. The secondary amplifier circuit then generates a secondary audio differential amplification signal based on the adjusted signal, which is then output through the secondary output circuit. This processing stage not only further amplifies the signal but also increases the overall gain, enabling the acquisition circuit to process weaker audio signals.

[0018] Preferably, the acquisition circuit further includes an ESD protection circuit, which is connected to the input end of the acquisition circuit and is used to guide the electrostatic charge in the acquisition circuit to a safe area.

[0019] By adopting the above technical solution and adding an ESD protection circuit, this design fully considers the potential threat of static electricity to circuit components. The ESD protection circuit quickly directs static electricity charges in the acquisition circuit to the ground, effectively preventing damage to the circuit. This design not only improves the acquisition circuit's ability to resist static interference, but also protects circuit components from static shock, extending the circuit's service life.

[0020] Preferably, the ESD protection circuit includes a diode group, a first capacitor and a second capacitor, one end of the diode group is connected to the input end of the acquisition circuit, and the other end is grounded, for guiding the electrostatic charge to the ground, one end of the first capacitor is connected to the P pole of the input end of the acquisition circuit, and the other end is grounded, one end of the second capacitor is connected to the N pole of the input end of the acquisition circuit, and the other end is grounded, the first capacitor and the second capacitor are used to filter the audio differential signal.

[0021] By adopting the above technical solution, the specific implementation method of the ESD protection circuit is described in detail, and its working principle and effect are further revealed. The diode group serves as the main channel for electrostatic discharge, with its two ends connected to the input end of the acquisition circuit and the ground respectively, forming an effective electrostatic discharge path. When the electrostatic charge accumulates to a certain level, the diode group will quickly turn on and guide the electrostatic charge to the ground. At the same time, the first capacitor and the second capacitor are connected in parallel at the input end of the acquisition circuit to filter the audio differential signal. These two capacitors can filter out high-frequency noise and interference signals in the signal, making the output signal purer and more stable. This design not only improves the signal's anti-interference ability, but also ensures the accuracy and reliability of signal acquisition.

[0022] Preferably, the acquisition circuit further includes a DC isolation circuit, the input end of the DC isolation circuit is connected to the input end of the acquisition circuit, and the output end of the DC isolation circuit is connected to the input end of the first-level input circuit, for filtering out the DC component in the audio differential signal.

[0023] The above technical solution incorporates a DC blocking circuit, designed to filter out the DC component in the audio differential signal. This circuit acts as a high-pass filter for the DC component in the signal, allowing AC signals to pass while blocking them. Therefore, when the audio differential signal passes through the DC blocking circuit, the DC component is filtered out while the AC component remains unchanged. This design prevents the DC component from affecting the subsequent amplification circuitry, improving signal processing accuracy and stability. Furthermore, the DC blocking circuit enables the acquisition circuit to more accurately process the AC component in the audio signal, reducing signal distortion and noise interference.

[0024] Preferably, the DC blocking circuit includes a third capacitor and a fourth capacitor connected in parallel, and the third capacitor and the fourth capacitor are used to filter out the DC component in the audio differential signal.

[0025] The above technical solution specifically illustrates the implementation of a DC blocking circuit, employing a third and fourth capacitor connected in parallel. These two capacitors, acting as high-pass filter elements, play a key role in the circuit. They not only filter out the DC component of the signal but also preserve the AC component. This simple and effective design reduces circuit complexity and improves signal processing accuracy. Furthermore, the parallel connection of the capacitors minimizes signal attenuation, thereby ensuring signal integrity during transmission.

[0026] Preferably, the acquisition circuit includes an amplifier circuit, an output circuit, and a DC bias circuit. The amplifier circuit includes the first-level amplifier circuit and the second-level amplifier circuit. The output circuit includes the first-level output circuit and the second-level output circuit. The DC bias circuit includes the first-level DC bias circuit and the second-level DC bias circuit. The amplifier circuit includes a first resistor, a second resistor, a fifth capacitor, and an operational amplifier chip.

[0027] The first resistor is connected to the inverting input terminal of the operational amplifier chip.

[0028] One end of the second resistor is connected to the inverting input terminal, and the other end is connected to the output terminal of the operational amplifier chip. The first resistor and the second resistor are used to set the gain and amplification factor of the amplifier circuit.

[0029] The fifth capacitor is connected in parallel to the second resistor and is used to isolate the DC component in the audio differential signal.

[0030] By adopting the above technical solution, the specific structure and functions of the amplifier circuit, output circuit, and DC bias circuit are described in detail. The amplifier circuit, as the core signal processing component, amplifies the audio signal through a combination of a first resistor, a second resistor, a fifth capacitor, and an op amp chip. This design fully utilizes the high gain and low noise characteristics of the op amp chip, resulting in a higher signal-to-noise ratio and lower distortion for the amplified signal. Furthermore, the first and second resistors act as feedback elements, controlling the signal amplification by setting the amplifier circuit's gain and amplification factor. The fifth capacitor acts as a coupling capacitor, isolating the DC component and transmitting the AC signal. The output circuit converts the amplified audio signal into a digital signal for output through a combination of a third resistor, a fourth resistor, a sixth capacitor, and an analog-to-digital converter. This design facilitates signal interfacing and transmission with other digital systems. The third and fourth resistors act as voltage dividers, setting the output circuit's voltage divider ratio to match the input requirements of subsequent circuits. The sixth capacitor acts as a filter.

[0031] Preferably, the output circuit is used to output an audio differential amplification signal, the audio differential amplification signal includes the first-level audio differential amplification signal and the second-level audio differential amplification signal, and the output circuit includes a third resistor, a fourth resistor, a sixth capacitor and an analog-to-digital converter.

[0032] The input end of the third resistor is connected to the output end of the amplifier circuit, and the output end of the third resistor is connected to the input end of the analog-to-digital converter.

[0033] The input ends of the fourth resistor and the sixth capacitor are connected to the output end of the third resistor, and the output ends of the fourth resistor and the sixth capacitor are grounded.

[0034] The third resistor and the fourth resistor are used to set the voltage division ratio of the output circuit, the sixth capacitor is used to filter the audio differential amplification signal, and the analog-to-digital converter is used to convert the audio differential amplification signal into a digital audio signal.

[0035] By adopting the above technical solution, the specific implementation and functionality of the output circuit have been further refined. The output circuit not only outputs the amplified audio signal but also ensures the stability and purity of the output signal through specific circuit design and optimization. Specifically, through carefully designed voltage divider ratios and filtering, the output circuit effectively removes high-frequency noise and unnecessary interference from the signal, thereby outputting a purer and more stable audio differential amplification signal. Furthermore, the inclusion of an analog-to-digital converter provides a digital output for the entire circuit system, allowing the collected audio signal to be easily connected to various digital processing systems for further analysis and processing. This digital output method not only improves signal transmission efficiency but also enhances the flexibility and scalability of signal processing.

[0036] Preferably, the DC bias circuit includes a fifth resistor, a sixth resistor, a seventh capacitor and a filter.

[0037] One end of the fifth resistor is connected to the amplifier circuit, and the other end is connected to the filter.

[0038] One end of the sixth resistor is connected to the amplifier circuit, and the other end is grounded. The fifth resistor and the sixth resistor are used to provide a DC bias voltage for the amplifier circuit.

[0039] One end of the seventh capacitor is connected to the amplifier circuit, and the other end is grounded, and is used to remove high-frequency noise in the DC bias circuit.

[0040] By adopting the above technical solution, the paper focuses on the specific implementation and function of the DC bias circuit, detailing how the combination of circuit components provides a stable DC bias voltage and removes high-frequency noise in the DC bias circuit. The fifth resistor, sixth resistor, seventh capacitor, and filter together form the core of the DC bias circuit. The fifth and sixth resistors act as voltage dividers, precisely setting the voltage divider ratio to provide a stable and adjustable DC bias voltage for the amplifier circuit. This DC bias voltage is critical for ensuring the proper operation of the amplifier circuit and reducing signal distortion. Furthermore, the seventh capacitor, acting as a filter, effectively removes high-frequency noise from the DC bias circuit, further improving the accuracy and stability of signal processing. The addition of the filter further suppresses and filters noise in the DC bias circuit, ensuring the purity and reliability of the output signal. This refined DC bias circuit design not only improves signal acquisition quality but also enhances the stability and reliability of the entire circuit system.

[0041] In summary, the two-stage audio differential signal acquisition circuit of this application achieves high-precision, high-stability, and high-reliability audio signal acquisition through the coordinated operation of the two-stage circuit structure. This hierarchical processing approach not only improves the breadth and accuracy of signal acquisition, but also enhances the circuit's anti-interference ability and adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is a structural diagram of an embodiment of a two-stage audio differential signal acquisition circuit of the present application.

[0043] Figure numerals: 1. ESD protection circuit; 2. DC blocking circuit; 3. Primary input circuit; 4. Primary amplifier circuit; 5. Primary DC bias circuit; 6. Primary output circuit; 7. Secondary DC bias circuit; 8. Secondary amplifier circuit; 9. Secondary output circuit. DETAILED DESCRIPTION

[0044] With reference to the accompanying drawings and specific embodiments, the structure, composition, characteristics and advantages of the secondary audio differential signal acquisition circuit according to the present application will be described below in an exemplary manner. However, all descriptions should not be used to form any limitations on the present application.

[0045] In addition, for any single technical feature described or implied in the embodiments mentioned in this document, or any single technical feature shown or implied in the drawings, this application still allows for continued arbitrary combination or deletion between these technical features (or their equivalents) without any technical obstacles, and thus it should be considered that these more embodiments according to this application are also within the scope of the description in this document.

[0046] It should also be noted that terms such as "disposed" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integration; they can refer to direct connections or indirect connections through an intermediary. Unless otherwise specified, those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0047] Figure 1 This is a schematic structural diagram of an embodiment of a two-stage audio differential signal acquisition circuit of the present application. In this embodiment, the acquisition circuit may include a primary circuit and a secondary circuit. The primary circuit may include a primary input circuit, a primary DC bias circuit, a primary amplifier circuit, and a primary output circuit. The primary input circuit is used to receive the audio differential signal. The primary DC bias circuit is connected to the primary input circuit and is used to adjust the level of the audio differential signal to the linear amplification region of the primary amplifier circuit. The primary amplifier circuit is connected to the primary input circuit and the primary DC bias circuit and is used to generate a primary audio differential amplified signal based on the audio differential signal. The primary output circuit is connected to the output end of the primary amplifier circuit and is used to output the primary audio differential amplified signal. The secondary circuit includes a secondary input circuit, a secondary DC bias circuit, a secondary amplifier circuit and a secondary output circuit. The secondary input circuit is connected to the output end of the primary amplifier circuit and is used to receive the primary audio differential amplification signal. The secondary DC bias circuit is connected to the secondary input circuit and is used to adjust the level of the audio differential signal to the linear amplification region of the secondary amplifier circuit. The secondary amplifier circuit is connected to the secondary input circuit and the secondary DC bias circuit and is used to generate a secondary audio differential amplification signal based on the primary audio differential amplification signal. The secondary output circuit is connected to the output end of the secondary amplifier circuit and is used to output the secondary audio differential amplification signal.

[0048] The first-stage circuit, serving as the front-end signal processing unit, first receives the external audio differential signal. This design leverages the differential signal's anti-interference properties, effectively minimizing the impact of external environmental factors on signal quality. Subsequently, the first-stage DC bias circuit adjusts the signal level to the linear amplification range of the first-stage amplifier circuit, ensuring distortion-free amplification. The first-stage amplifier circuit then generates the first-stage audio differential amplified signal based on this adjusted signal, which is then output through the first-stage output circuit. This processing stage provides a stable and clear signal source for the subsequent second-stage amplification.

[0049] The secondary circuit, serving as further signal processing, receives the initially amplified audio signal via its input connected to the output of the primary amplifier circuit. A secondary DC bias circuit further adjusts the signal level to fit within the linear amplification range of the secondary amplifier circuit. The secondary amplifier circuit then generates a secondary audio differential amplification signal based on the adjusted signal, which is then output through the secondary output circuit. This processing stage not only further amplifies the signal but also increases the overall gain, enabling the acquisition circuit to process weaker audio signals.

[0050] from Figure 1 It can also be seen that the acquisition circuit may also include an ESD protection circuit. The ESD protection circuit is connected to the input end of the acquisition circuit and is used to guide the electrostatic charge in the acquisition circuit to a safe area, that is, to guide the electrostatic charge to the ground. Specifically, the ESD protection circuit may include a diode group, a first capacitor and a second capacitor. Figure 1 In the illustrated embodiment, the diode group may be D21, the first capacitor may be C71, and the second capacitor may be C86. One end of D21 is connected to the input of the acquisition circuit and the other end is grounded, used to guide electrostatic charge to the ground. One end of C71 is connected to the P-pole of the input of the acquisition circuit and the other end is grounded. One end of C86 is connected to the N-pole of the input of the acquisition circuit and the other end is grounded. C71 and C86 are used to filter the audio differential signal.

[0051] The ESD protection circuit uses the synergistic effect of the diode group, the first capacitor, and the second capacitor to quickly direct static electricity charges in the acquisition circuit to the ground, effectively preventing static electricity from damaging the circuit. The diode group serves as the primary electrostatic discharge channel, and its fast response ensures that static electricity charges are quickly channeled away. The first and second capacitors act as filtering elements, filtering the audio differential signal, further improving signal purity and acquisition quality. This design not only improves the acquisition circuit's ability to resist electrostatic interference, but also protects circuit components from electrostatic shock, extending the circuit's service life.

[0052] from Figure 1 It can also be seen that the acquisition circuit can also include a DC isolation circuit. The input end of the DC isolation circuit is connected to the input end of the acquisition circuit, and the output end of the DC isolation circuit is connected to the input end of the primary input circuit, which is used to filter out the DC component in the audio differential signal. Specifically, the DC isolation circuit can include a third capacitor and a fourth capacitor connected in parallel, and the third capacitor and the fourth capacitor are used to filter out the DC component in the audio differential signal. Figure 1 In the illustrated embodiment, the third capacitor may be C87 and the fourth capacitor may be C88.

[0053] The third and fourth capacitors not only filter out the DC component in the signal, but also maintain the AC component. This simple and effective design reduces circuit complexity and improves signal processing accuracy. Furthermore, the parallel connection of the capacitors minimizes signal attenuation caused by the DC blocking circuit, thus ensuring signal integrity during transmission.

[0054] The acquisition circuit may include an amplifier circuit, an output circuit and a DC bias circuit. The amplifier circuit may include the aforementioned first-level amplifier circuit and second-level amplifier circuit. The output circuit may include the aforementioned first-level output circuit and second-level output circuit. The DC bias circuit may include the aforementioned first-level DC bias circuit and second-level DC bias circuit.

[0055] Specifically, the amplifier circuit may include a first resistor, a second resistor, a fifth capacitor and an operational amplifier chip. Figure 1 In the embodiment shown, in the first-stage amplifier circuit, the first resistor may be R87, the second resistor may be R92, the fifth capacitor may be C93, and the operational amplifier chip may be U15A. Figure 1 As can be seen in the figure, R87 is connected to the inverting input of U15A. One end of R92 is connected to the inverting input of R92, and the other end is connected to the output of U15A. R87 and R92 are used to set the gain and amplification factor of the first-stage amplifier circuit. C93 is connected in parallel with R92 to isolate the DC component of the audio differential signal.

[0056] Similarly, in the secondary amplifier circuit, the first resistor can be R93, the second resistor can be R94, the fifth capacitor can be C95, and the operational amplifier chip can be U15B. Figure 1 As can be seen in the figure, R93 is connected to the inverting input of U15A. One end of R94 is connected to the inverting input of U15B, and the other end is connected to the output of U15B. R93 and R94 are used to set the gain and amplification factor of the first-stage amplifier circuit. C95 is connected in parallel with R92 to isolate the DC component of the audio differential signal.

[0057] The amplifier circuit, as the core signal processing component, amplifies the audio signal through a combination of a first resistor, a second resistor, a fifth capacitor, and an op amp chip. This design leverages the high gain and low noise characteristics of the op amp chip, resulting in a higher signal-to-noise ratio and lower distortion for the amplified signal. Furthermore, the first and second resistors act as feedback elements, controlling the signal amplification by setting the amplifier circuit's gain and amplification factor. The fifth capacitor acts as a coupling capacitor, isolating the DC component and transmitting the AC signal. The output circuit converts the amplified audio signal into a digital signal for output through a combination of a third resistor, a fourth resistor, a sixth capacitor, and an analog-to-digital converter. This design facilitates signal interfacing and transmission with other digital systems. The third and fourth resistors act as voltage dividers, setting the output circuit's voltage divider ratio to match the input requirements of subsequent circuits. The sixth capacitor acts as a filter.

[0058] The output circuit is used to output the audio differential amplification signal, which may include a first-level audio differential amplification signal and a second-level audio differential amplification signal. The output circuit may include a third resistor, a fourth resistor, a sixth capacitor, and an analog-to-digital converter. Figure 1 In the illustrated embodiment, in the first-stage output circuit, the third resistor may be R97, the fourth resistor may be R98, the sixth capacitor may be C97, the analog-to-digital converter may be AUDIO AD 1, the input end of R97 is connected to the output end of the first-stage amplifier circuit, the output end of R97 is connected to the input end of AUDIO AD 1, the input ends of R98 and C97 are connected to the output end of R97, the output ends of R98 and C97 are grounded, R97 and R98 are used to set the voltage division ratio of the first-stage output circuit, C97 is used to filter the audio differential amplification signal, and AUDIO AD 1 is used to convert the audio differential amplification signal into a digital audio signal.

[0059] Similarly, in the secondary output circuit, the third resistor can be R99, the fourth resistor can be R100, the sixth capacitor can be C98, the analog-to-digital converter can be AUDIO AD 2, the input end of R99 is connected to the output end of the secondary amplifier circuit, the output end of R99 is connected to the input end of AUDIO AD 2, the input ends of R100 and C98 are connected to the output end of R99, the output ends of R100 and C98 are grounded, R99 and R100 are used to set the voltage division ratio of the secondary output circuit, C98 is used to filter the audio differential amplification signal, and AUDIO AD 1 is used to convert the audio differential amplification signal into a digital audio signal.

[0060] The output circuit not only outputs the amplified audio signal but also ensures its stability and purity through specialized circuit design and optimization. Specifically, through carefully designed voltage divider ratios and filtering, the output circuit effectively removes high-frequency noise and unwanted interference from the signal, resulting in a purer and more stable audio differential amplification signal. Furthermore, the inclusion of an analog-to-digital converter provides a digital output for the entire circuit system, enabling the collected audio signal to be easily connected to various digital processing systems for further analysis and processing. This digital output method not only improves signal transmission efficiency but also enhances the flexibility and scalability of signal processing.

[0061] from Figure 1 It can also be seen that the acquisition circuit can also include a DC bias circuit, which includes a fifth resistor, a sixth resistor, a seventh capacitor and a filter. Figure 1In the illustrated embodiment, in the primary DC bias circuit, the fifth resistor may be R90, the sixth resistor may be R91, the seventh capacitor may be C92, and the filter may be 12V CTRL FILTER 1. One end of R90 is connected to the primary amplifier circuit, and the other end is connected to the filter 12V CTRL FILTER 1. One end of R91 is connected to the primary amplifier circuit, and the other end is grounded. R90 and R91 are used to provide a DC bias voltage for the primary amplifier circuit. One end of C92 is connected to the primary amplifier circuit, and the other end is grounded, and is used to remove high-frequency noise in the primary DC bias circuit.

[0062] Similarly, in the secondary DC bias circuit, the fifth resistor can be R95, the sixth resistor can be R96, the seventh capacitor can be C96, and the filter can be 12V CTRL FILTER 2. One end of R95 is connected to the secondary amplifier circuit and the other end is connected to the filter. One end of R96 is connected to the secondary amplifier circuit and the other end is grounded. R95 and R96 are used to provide a DC bias voltage for the secondary amplifier circuit. One end of C96 is connected to the amplifier circuit and the other end is grounded to remove high-frequency noise in the DC bias circuit.

[0063] The fifth resistor, sixth resistor, seventh capacitor, and filter together constitute the core of the DC bias circuit. The fifth and sixth resistors act as voltage dividers, providing a stable and adjustable DC bias voltage for the amplifier circuit by precisely setting the voltage divider ratio. This DC bias voltage is a key factor in ensuring the normal operation of the amplifier circuit and reducing signal distortion. At the same time, the seventh capacitor, as a filtering element, can effectively remove high-frequency noise from the DC bias circuit, further improving the accuracy and stability of signal processing. The addition of the filter further suppresses and filters the noise in the DC bias circuit, ensuring the purity and reliability of the output signal. This refined DC bias circuit design not only improves the quality of signal acquisition, but also enhances the stability and reliability of the entire circuit system.

[0064] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A secondary audio differential signal acquisition circuit, characterized in that: The acquisition circuit includes a primary circuit and a secondary circuit. The primary circuit includes a primary input circuit, a primary DC bias circuit, a primary amplifier circuit and a primary output circuit. The primary input circuit is used to receive the audio differential signal; The first-level DC bias circuit is connected to the first-level input circuit and is used to adjust the level of the audio differential signal to the linear amplification region of the first-level amplification circuit; The first-level amplification circuit is connected to the first-level input circuit and the first-level DC bias circuit, and is configured to generate a first-level audio differential amplification signal according to the audio differential signal; The first-level output circuit is connected to the output end of the first-level amplification circuit, and is used to output the first-level audio differential amplification signal; The secondary circuit includes a secondary input circuit, a secondary DC bias circuit, a secondary amplifier circuit and a secondary output circuit. The secondary input circuit is connected to the output end of the primary amplifying circuit and is used to receive the primary audio differential amplified signal; The secondary DC bias circuit is connected to the secondary input circuit and is used to adjust the level of the audio differential signal to the linear amplification region of the secondary amplification circuit; The secondary amplification circuit is connected to the secondary input circuit and the secondary DC bias circuit, and is used to generate a secondary audio differential amplification signal according to the primary audio differential amplification signal; The secondary output circuit is connected to the output end of the secondary amplifying circuit and is used to output the secondary audio differential amplified signal.

2. The acquisition circuit according to claim 1, characterized in that: The acquisition circuit further includes an ESD protection circuit, which is connected to an input end of the acquisition circuit and is used to guide electrostatic charges in the acquisition circuit to a safe area.

3. The acquisition circuit according to claim 2, characterized in that: The ESD protection circuit includes a diode group, a first capacitor, and a second capacitor. One end of the diode group is connected to the input end of the acquisition circuit, and the other end is grounded, for guiding the electrostatic charge to the ground. One end of the first capacitor is connected to the P pole of the input end of the acquisition circuit, and the other end is grounded. One end of the second capacitor is connected to the N pole of the input end of the acquisition circuit, and the other end is grounded. The first capacitor and the second capacitor are used to filter the audio differential signal.

4. The acquisition circuit according to claim 1, characterized in that: The acquisition circuit further includes a DC isolation circuit, the input end of the DC isolation circuit is connected to the input end of the acquisition circuit, and the output end of the DC isolation circuit is connected to the input end of the primary input circuit, for filtering out the DC component in the audio differential signal.

5. The acquisition circuit according to claim 4, characterized in that: The DC blocking circuit includes a third capacitor and a fourth capacitor connected in parallel. The third capacitor and the fourth capacitor are used to filter out the DC component in the audio differential signal.

6. The acquisition circuit according to claim 4, characterized in that: The acquisition circuit includes an amplifier circuit, an output circuit, and a DC bias circuit. The amplifier circuit includes the first-level amplifier circuit and the second-level amplifier circuit. The output circuit includes the first-level output circuit and the second-level output circuit. The DC bias circuit includes the first-level DC bias circuit and the second-level DC bias circuit. The amplifier circuit includes a first resistor, a second resistor, a fifth capacitor, and an operational amplifier chip. The first resistor is connected to the inverting input terminal of the operational amplifier chip. One end of the second resistor is connected to the inverting input terminal, and the other end is connected to the output terminal of the operational amplifier chip. The first resistor and the second resistor are used to set the gain and amplification factor of the amplifier circuit. The fifth capacitor is connected in parallel to the second resistor and is used to isolate the DC component in the audio differential signal.

7. The acquisition circuit according to claim 6, characterized in that: The output circuit is used to output an audio differential amplification signal, wherein the audio differential amplification signal includes the first-level audio differential amplification signal and the second-level audio differential amplification signal. The output circuit includes a third resistor, a fourth resistor, a sixth capacitor, and an analog-to-digital converter. The input end of the third resistor is connected to the output end of the amplifier circuit, and the output end of the third resistor is connected to the input end of the analog-to-digital converter. The input ends of the fourth resistor and the sixth capacitor are connected to the output end of the third resistor, and the output ends of the fourth resistor and the sixth capacitor are grounded. The third resistor and the fourth resistor are used to set the voltage division ratio of the output circuit, the sixth capacitor is used to filter the audio differential amplification signal, and the analog-to-digital converter is used to convert the audio differential amplification signal into a digital audio signal.

8. The acquisition circuit according to claim 6, characterized in that: The DC bias circuit includes a fifth resistor, a sixth resistor, a seventh capacitor and a filter. One end of the fifth resistor is connected to the amplifier circuit, and the other end is connected to the filter. One end of the sixth resistor is connected to the amplifier circuit, and the other end is grounded. The fifth resistor and the sixth resistor are used to provide a DC bias voltage for the amplifier circuit. One end of the seventh capacitor is connected to the amplifier circuit, and the other end is grounded, and is used to remove high-frequency noise in the DC bias circuit.

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