Audio signal gain circuit, audio system and recorder

Abstract

This invention provides an audio signal gain circuit, an audio system, and a recorder. The audio signal gain circuit includes a switching module, an input resistor module, and a differential amplifier module, each with a high-gain channel and a low-gain channel. The input terminal of the input resistor module is used to receive the original audio signal to be gained, and the output terminal of the input resistor module is electrically connected to the input terminal of the differential amplifier module. The output terminal of the differential amplifier module is used to output the gained target audio signal. The switching module is connected in series with the input resistor module and the differential amplifier module and is used to adjust the actual input resistance of the input resistor module connected to the differential amplifier module. This invention achieves adjustable input resistance, thereby enabling the use of corresponding gain channels in the differential amplifier module to achieve gain processing of audio signals of different formats in different gain channels. While achieving high dynamic range gain processing, it saves hardware consumption, has low cost, and good consistency.

Description

Technical Field

[0001] This invention relates to the field of audio processing technology, specifically to an audio signal gain circuit, an audio system, and a recorder. Background Technology

[0002] Audio signal gain refers to amplifying or attenuating the amplitude of an audio signal by a certain factor, thereby controlling the signal strength and thus the volume. Audio signal gain circuits may handle audio signals of different formats, such as microphone input and line input. Since different audio signal formats have significantly different amplitudes, different gain methods must be used to process them to ensure that subsequent circuits achieve the appropriate operating level.

[0003] Existing technologies typically employ multiple independent gain circuits, each achieving different gain effects. This allows multiple independent gain circuits to be used to process audio signals of different formats. However, this approach is costly and has poor consistency. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides an audio signal gain circuit, an audio system and a recorder.

[0005] In a first aspect, in one embodiment, the present invention provides an audio signal gain circuit, the audio signal gain circuit comprising a switching module composed of a high-gain switching unit and a low-gain switching unit, an input resistor module composed of a high-gain input resistor unit and a low-gain input resistor unit, and a differential amplifier module composed of a high-gain differential amplifier unit and a low-gain differential amplifier unit. The input terminals of the high-gain input resistor unit and the low-gain input resistor unit are used to input the original audio signal. The output terminal of the high-gain input resistor unit is electrically connected to the input terminal of the high-gain differential amplifier unit, and the output terminal of the low-gain input resistor unit is electrically connected to the input terminal of the low-gain differential amplifier unit. The output terminal of the high-gain differential amplifier unit is used to output the first audio signal after high gain, and the output terminal of the low-gain differential amplifier unit is used to output the second audio signal after low gain. The high-gain switching unit is connected in series with the high-gain input resistor unit and the high-gain differential amplifier unit to adjust the actual input resistance of the high-gain input resistor unit connected to the high-gain differential amplifier unit; the low-gain switching unit is connected in series with the low-gain input resistor unit and the low-gain differential amplifier unit to adjust the actual input resistance of the low-gain input resistor unit connected to the low-gain differential amplifier unit.

[0006] In one embodiment, the high-gain switching unit includes a first high-gain analog switch, the high-gain input resistor unit includes a first high-gain resistor and a second high-gain resistor, and the high-gain differential amplifier unit includes a first-stage differential amplifier and a second-stage differential amplifier. The first terminal of the first high-gain resistor and the first terminal of the second high-gain resistor are respectively used to input the original audio signal. The second terminal of the first high-gain resistor is electrically connected to the input terminal of the first-stage differential amplifier. The output terminal of the first-stage differential amplifier is electrically connected to the first input terminal of the first high-gain analog switch. The second terminal of the second high-gain resistor is electrically connected to the second input terminal of the first high-gain analog switch. The common terminal of the first high-gain analog switch is electrically connected to the input terminal of the second-stage differential amplifier. The output terminal of the second-stage differential amplifier is used to output the first audio signal.

[0007] In one embodiment, the high-gain switching unit further includes a second high-gain analog switch; The common terminal of the second high-gain analog switch is used to input the original audio signal. The first input terminal of the second high-gain analog switch is electrically connected to the first terminal of the first high-gain resistor, and the second input terminal of the second high-gain analog switch is electrically connected to the first terminal of the second high-gain resistor.

[0008] In one embodiment, the low-gain switching unit includes a first low-gain analog switch, the low-gain input resistor unit includes a first low-gain resistor and a second low-gain resistor, and the low-gain differential amplifier unit includes a single-stage differential amplifier. The first terminal of the first low-gain resistor and the first terminal of the second low-gain resistor are respectively used to input the original audio signal. The second terminal of the first low-gain resistor is electrically connected to the first input terminal of the first low-gain analog switch. The second terminal of the second low-gain resistor is electrically connected to the second input terminal of the first low-gain analog switch. The common terminal of the first low-gain analog switch is electrically connected to the input terminal of the single-stage differential amplifier. The output terminal of the single-stage differential amplifier is used to output the second audio signal.

[0009] In one embodiment, the low-gain switching unit further includes a second low-gain analog switch; The common terminal of the second low-gain analog switch is used to input the original audio signal. The first input terminal of the second low-gain analog switch is electrically connected to the first terminal of the first low-gain resistor, and the second input terminal of the second low-gain analog switch is electrically connected to the first terminal of the second low-gain resistor.

[0010] In one embodiment, the raw audio signal includes audio signals from time-division multiplexed microphone inputs and audio signals from line inputs.

[0011] In a second aspect, in one embodiment, the present invention provides an audio system, the audio system including a signal input interface, a signal conditioning circuit, an analog-to-digital conversion circuit, a digital processing circuit, and an audio signal gain circuit in any of the above embodiments; The signal input interface, signal conditioning circuit, audio signal gain circuit, analog-to-digital conversion circuit and digital processing circuit are electrically connected in sequence. The audio signal gain circuit is used to receive the original audio signal to be gained from the signal conditioning circuit and output the first audio signal and the second audio signal after gain to the analog-to-digital conversion circuit.

[0012] In one embodiment, the audio system further includes a phantom power control circuit; The phantom power control circuit is electrically connected to the signal conditioning circuit and the audio signal gain circuit, respectively, to provide phantom power.

[0013] In one embodiment, the audio system also includes an interactive interface; The interactive interface is electrically connected to the digital processing circuitry and is used to interact with external devices to enable program upgrades, audio output, and / or system power supply.

[0014] Thirdly, in one embodiment, the present invention provides a recorder, the recorder including a recorder body and an audio signal gain circuit as described in any of the above embodiments or an audio system as described in any of the above embodiments disposed on the recorder body.

[0015] The audio signal gain circuit, audio system, and recorder described above are configured with a switching module and an input resistor module, each with a high-gain channel and a low-gain channel. The switching module connects the corresponding resistor channel in the input resistor module to the differential amplifier module, thereby adjusting the actual input resistance of the input resistor module connected to the differential amplifier module. This achieves adjustable input resistance, allowing the corresponding gain channel in the differential amplifier module to be multiplexed in different gain channels to achieve gain processing for audio signals of different formats. While achieving high dynamic range gain processing, this approach saves hardware consumption, reduces cost, and provides good consistency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the audio signal gain circuit in one embodiment of the present invention; Figure 2This is a schematic diagram of a dual-path audio signal gain circuit in one embodiment of the present invention; Figure 3 This is a schematic diagram of the audio signal gain circuit in a first-mode state in one embodiment of the present invention; Figure 4 This is a schematic diagram of the audio signal gain circuit in a second-mode state in one embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of an audio system in one embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the audio system, which further includes a phantom power control circuit and an interactive interface, in one embodiment of the present invention. Figure 7 This is a schematic diagram of the signal input interface, signal conditioning circuit, and phantom power control circuit in one embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified. In this application, the term "exemplary" is used to mean "used as an example, illustration, or description." Any embodiment described as "exemplary" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to implement and use the invention. In the following description, details are set forth for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be implemented without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed herein.

[0020] Firstly, such as Figure 1 As shown, in one embodiment, the present invention provides an audio signal gain circuit 100, which includes a switching module 110, an input resistor module 120, and a differential amplifier module 130.

[0021] The input terminal of the input resistor module 120 is used to input the original audio signal VIN to be gained. The output terminal of the input resistor module 120 is electrically connected to the input terminal of the differential amplifier module 130. The output terminal of the differential amplifier module 130 is used to output the target audio signal VOUT after gain.

[0022] The switch module 110 is connected in series with the input resistor module 120 and the differential amplifier module 130, and is used to adjust the actual input resistance of the input resistor module 120 connected to the differential amplifier module 130.

[0023] In this embodiment, the switch module 110 is connected in series between the input resistor module 120 and the differential amplifier module 130; in other embodiments, the switch module 110 may also be connected in series between the original audio signal VIN and the input resistor module 120.

[0024] The switch module 110 adjusts the input resistance by changing its own switching state. Specifically, when the switch module 110 is in the first switch state, the first resistor channel in the input resistor module 120 is connected to the input terminal of the differential amplifier module 130. At this time, the original audio signal VIN is transmitted to the input terminal of the differential amplifier module 130 after passing through the first resistor channel in the input resistor module 120. The differential amplifier module 130 performs the corresponding first gain processing based on the first input resistance provided by the first resistor channel in the input resistor module 120 and outputs the target audio signal VOUT after the first gain processing. Similarly, when the switch module 110 is in the second switch state, the second resistor channel in the input resistor module 120 is connected to the input terminal of the differential amplifier module 130. At this time, the original audio signal VIN is transmitted to the input terminal of the differential amplifier module 130 after passing through the second resistor channel in the input resistor module 120. The differential amplifier module 130 performs the corresponding second gain processing based on the second input resistance provided by the second resistor channel in the input resistor module 120 and outputs the target audio signal VOUT after the second gain processing. The first input resistance provided by the first resistor channel and the second input resistance provided by the second resistor channel are different, so the gain effects of the first gain processing and the second gain processing are also different.

[0025] Understandably, the switch module 110 can also have more switch states, and the input resistor module 120 can also have more resistor channels, thereby achieving gain processing with more gain effects.

[0026] As a supplement, the original audio signal VIN corresponds to different formats, such as audio signals input from a microphone or line input. The output impedance of a microphone and the output impedance of a line differ significantly. To ensure reliable signal transmission, a corresponding input impedance needs to be configured to match the output impedance of the preceding stage. In this embodiment, the actual input resistance of the input resistance module 120 connected to the differential amplifier module 130 is adjusted via the switch module 110. This not only enables the differential amplifier module 130 to achieve gain processing with different gain effects but also provides different input impedances simultaneously for impedance matching.

[0027] In other words, the raw audio signal includes the audio signal from the time-division multiplexing microphone input and the audio signal from the line input.

[0028] Furthermore, in this embodiment, the input resistor module 120 is directly connected to the original audio signal VIN, eliminating the need for a pre-amplification module. This avoids the signal-to-noise ratio degradation caused by "attenuation-re-amplification," thereby significantly improving the dynamic range and weak signal acquisition capability.

[0029] The audio signal gain circuit 100 described above is configured with a switch module 110 and an input resistor module 120. The switch module 110 is used to connect the corresponding resistor channel in the input resistor module 120 to the differential amplifier module 130, thereby adjusting the actual input resistance of the input resistor module 120 connected to the differential amplifier module 130. This achieves adjustable input resistance, enabling the differential amplifier module 130 to be reused to achieve gain processing for audio signals of different formats. While achieving high dynamic range gain processing, it saves hardware consumption, has low cost, and good consistency.

[0030] like Figure 2 As shown, in one embodiment, the switching module 110 includes a high-gain switching unit 111 and a low-gain switching unit 112, the input resistor module 120 includes a high-gain input resistor unit 121 and a low-gain input resistor unit 122, and the differential amplifier module 130 includes a high-gain differential amplifier unit 131 and a low-gain differential amplifier unit 132.

[0031] The input terminals of the high-gain input resistor unit 121 and the low-gain input resistor unit 122 are respectively used to input the original audio signal VIN. The output terminal of the high-gain input resistor unit 121 is electrically connected to the input terminal of the high-gain differential amplifier unit 131, and the output terminal of the low-gain input resistor unit 122 is electrically connected to the input terminal of the low-gain differential amplifier unit 132. The output terminal of the high-gain differential amplifier unit 131 is used to output the first audio signal VOUT1 after high gain, and the output terminal of the low-gain differential amplifier unit 132 is used to output the second audio signal VOUT2 after low gain. In the above embodiment, the target audio signal VOUT includes the first audio signal VOUT1 and the second audio signal VOUT2.

[0032] The high-gain switching unit 111 is connected in series with the high-gain input resistor unit 121 and the high-gain differential amplifier unit 131, and is used to adjust the actual input resistance of the high-gain input resistor unit 121 connected to the high-gain differential amplifier unit 131; the low-gain switching unit 112 is connected in series with the low-gain input resistor unit 122 and the low-gain differential amplifier unit 132, and is used to adjust the actual input resistance of the low-gain input resistor unit 122 connected to the low-gain differential amplifier unit 132.

[0033] In this embodiment, the high-gain switching unit 111 is connected in series between the high-gain input resistor unit 121 and the high-gain differential amplifier unit 131, and the low-gain switching unit 112 is connected in series between the low-gain input resistor unit 122 and the low-gain differential amplifier unit 132. In other embodiments, the high-gain switching unit 111 may also be connected in series between the original audio signal VIN and the high-gain input resistor unit 121, and the low-gain switching unit 112 may also be connected in series between the original audio signal VIN and the low-gain input resistor unit 122.

[0034] Even audio signals of the same format can vary in strength, thus requiring different gain processing. This embodiment sets up two gain channels with different gain effects for each audio signal, enabling reliable gain processing for audio signals of the same format but different intensities, further improving the dynamic range of audio signal gain processing. Combined with adjustments to the input resistor, this ultimately achieves high dynamic range gain processing for audio signals of different formats and intensities.

[0035] like Figure 2 , Figure 3 and Figure 4 As shown, in one embodiment, the high-gain switching unit 111 includes a first high-gain analog switch K11 and a second high-gain analog switch K12, the high-gain input resistor unit 121 includes a first high-gain resistor R11 and a second high-gain resistor R12, and the high-gain differential amplifier unit 131 includes a first-stage differential amplifier U11 and a second-stage differential amplifier U12.

[0036] The common terminals (D1, D2) of the second high-gain analog switch K12 are used to input the original audio signal VIN through the filter capacitor C. The first input terminals (S1A, S2A) of the second high-gain analog switch K12 are electrically connected to the first terminal of the first high-gain resistor R11. The second input terminals (S1B, S2B) of the second high-gain analog switch K12 are electrically connected to the first terminal of the second high-gain resistor R12. The second terminal of the first high-gain resistor R11 is electrically connected to the input terminal of the first stage differential amplifier U11. The output terminal of the first stage differential amplifier U11 is electrically connected to the first input terminals (S1A, S2A) of the first high-gain analog switch K11. The second terminal of the second high-gain resistor R12 is electrically connected to the second input terminals (S1B, S2B) of the first high-gain analog switch K11. The common terminals (D1, D2) of the first high-gain analog switch K11 are electrically connected to the input terminal of the second stage differential amplifier U12. The output terminal of the second stage differential amplifier U12 is used to output the first audio signal VOUT1.

[0037] Among them, such as Figure 3As shown, when the first high-gain analog switch K11 connects its first input terminal (S1A, S2A) and common terminal (D1, D2) and the second high-gain analog switch K12 connects its first input terminal (S1A, S2A) and common terminal (D1, D2), the input original audio signal VIN is transmitted to the first-stage differential amplifier U11 through the first high-gain resistor R11. After passing through the gain processing of the first-stage differential amplifier U11 and the second-stage differential amplifier U12, the first audio signal VOUT1 is finally output. In this state, the input original audio signal VIN has undergone two-stage gain processing based on the first high-gain resistor R11, and the signal amplification factor is relatively high, which is suitable for weak signal components in the audio signal input by the microphone.

[0038] Similarly, such as Figure 4 As shown, when the first high-gain analog switch K11 connects its second input terminals (S1B, S2B) and common terminals (D1, D2), and the second high-gain analog switch K12 connects its second input terminals (S1B, S2B) and common terminals (D1, D2), the input original audio signal VIN passes through the second high-gain resistor R12 and directly skips the first-stage differential amplifier U11 and is transmitted to the second-stage differential amplifier U12. After the gain processing of the second-stage differential amplifier U12, the first audio signal VOUT1 is finally output. In this state, the input original audio signal VIN only undergoes the second-stage gain processing based on the second high-gain resistor R12, and the signal amplification factor is relatively low, which is suitable for weak signal components in the audio signal input by the line.

[0039] It is understood that this embodiment simultaneously sets a first high-gain analog switch K11 and a second high-gain analog switch K12 to achieve adjustable input resistance, which can improve the reliability of adjustment. In other embodiments, only one high-gain analog switch can be used, such as only the first high-gain analog switch K11. In this case, the first terminal of the first high-gain resistor R11 and the first terminal of the second high-gain resistor R12 are directly connected to the original audio signal VIN through the filter capacitor C.

[0040] This embodiment uses a two-stage differential amplifier and a high-gain analog switch to control different numbers of differential amplifiers to work while adjusting the input resistance, thus achieving different gain processing more flexibly.

[0041] like Figure 2 , Figure 3 and Figure 4As shown, in one embodiment, the low-gain switching unit 112 includes a first low-gain analog switch K21 and a second low-gain analog switch K22, the low-gain input resistor unit 122 includes a first low-gain resistor R21 and a second low-gain resistor R22, and the low-gain differential amplifier unit 132 includes a single-stage differential amplifier U2.

[0042] The common terminals (D1, D2) of the second low-gain analog switch K22 are used to input the original audio signal VIN. The first input terminals (S1A, S2A) of the second low-gain analog switch K22 are electrically connected to the first terminal of the first low-gain resistor R21. The second input terminals (S1B, S2B) of the second low-gain analog switch K22 are electrically connected to the first terminal of the second low-gain resistor R22. The second terminal of the first low-gain resistor R21 is electrically connected to the first input terminals (S1A, S2A) of the first low-gain analog switch K21. The second terminal of the second low-gain resistor R22 is electrically connected to the second input terminals (S1B, S2B) of the first low-gain analog switch K21. The common terminals (D1, D2) of the first low-gain analog switch K21 are electrically connected to the input terminal of the single-stage differential amplifier U2. The output terminal of the single-stage differential amplifier U2 is used to output the second audio signal VOUT2.

[0043] Among them, such as Figure 3 As shown, when the first low-gain analog switch K21 connects its first input terminal (S1A, S2A) and common terminal (D1, D2) and the second low-gain analog switch K22 connects its first input terminal (S1A, S2A) and common terminal (D1, D2), the input original audio signal VIN is transmitted to the single-stage differential amplifier U2 through the first low-gain resistor R21. After gain processing by the single-stage differential amplifier U2, the second audio signal VOUT2 is finally output. In this state, the input original audio signal VIN has undergone single-stage gain processing based on the first low-gain resistor R21, and the signal attenuation factor is relatively low or no signal attenuation is performed, which is suitable for strong signal components in the audio signal input by the microphone.

[0044] Similarly, such as Figure 4 As shown, when the first low-gain analog switch K21 connects its second input terminals (S1B, S2B) and common terminals (D1, D2), and the second low-gain analog switch K22 connects its second input terminals (S1B, S2B) and common terminals (D1, D2), the input original audio signal VIN is sent to the single-stage differential amplifier U2 through the second low-gain resistor R22. After gain processing by the single-stage differential amplifier U2, the second audio signal VOUT2 is finally output. In this state, the input original audio signal VIN has undergone single-stage gain processing based on the second low-gain resistor R22, and the signal attenuation factor is relatively high, which is suitable for strong signal components in the line input audio signal.

[0045] It is understood that this embodiment simultaneously uses a first low-gain analog switch K21 and a second low-gain analog switch K22 to achieve adjustable input resistance, thereby improving the reliability of the adjustment. In other embodiments, only one low-gain analog switch may be used, such as only the first low-gain analog switch K21. In this case, the first terminal of the first low-gain resistor R21 and the first terminal of the second low-gain resistor R22 are directly connected to the original audio signal VIN through the filter capacitor C.

[0046] This embodiment achieves different gain processing by setting up a single-stage differential amplifier and adjusting the input resistance through a configured low-gain analog switch.

[0047] To make the above dual-path gain implementation clearer, a detailed description will now be given using both microphone input and line input audio signals: In microphone input mode (MIC IN), all analog switches are in the following states: Figure 3 As shown, the dual-channel system operates in the following configuration to adapt to the acquisition of audio signals from microphone input; High-gain path: Two-stage differential amplifiers are used in series to amplify weak signals in the -127dBu range; 1. Amplification stage configuration: Two-stage differential amplification; First-stage differential amplifier: ±5V dual power supply, fixed gain of 20dB, completes the initial amplification of weak signals and suppresses common-mode interference; Second-stage differential amplifier: ±5V dual power supply, configured with 2.5V DC bias, and fixed gain of 10dB; 2. Gain configuration: 20dB + 10dB = 30dB, which can be adapted to weak signal acquisition from microphone input and reduce the impact of background noise; Low-gain path: operates using only a single-stage differential amplifier for processing medium-intensity signals from microphone input; 1. Amplification stage configuration: Single-stage differential amplifier, +5V single power supply, configured with 2.5V DC bias; 2. Gain configuration: The gain is fixed at -2dB to moderately attenuate medium-strength signals and avoid slight signal overload.

[0048] In line input mode, each analog switch is in... Figure 4 As shown, the dual-channel system operates in the following configuration to adapt to the acquisition of audio signals from the line input; High-gain path: Multiplex the second-stage differential amplifier and change the input resistance of the second-stage differential amplifier; 1. Amplification stage configuration: Second-stage differential amplifier, +5V single power supply, configured with 2.5V DC bias; 2. Gain Configuration: The gain is fixed at 0dB after the input resistance is changed, allowing direct transmission of strong signals and avoiding clipping distortion; 3. Key features: The signal does not pass through the first stage of differential amplification, reducing redundant noise superposition and avoiding saturation of strong signals due to high gain; Low-gain path: Multiplex a single-stage differential amplifier and change the input resistance of the single-stage differential amplifier; 1. Amplification stage configuration: Single-stage differential amplifier, +5V single power supply, configured with 2.5V DC bias; 2. Gain Configuration: After the input resistance is changed, the gain is fixed at -18dB, which reasonably attenuates strong signals and keeps the signal amplitude within a safe range, effectively preventing overvoltage of the subsequent analog-to-digital conversion circuit.

[0049] Secondly, such as Figure 5 As shown, in one embodiment, the present invention provides an audio system, which includes a signal input interface 200, a signal conditioning circuit 300, an analog-to-digital conversion circuit 400, a digital processing circuit 500, and an audio signal gain circuit 100 as described in any of the above embodiments.

[0050] The signal input interface 200, signal conditioning circuit 300, audio signal gain circuit 100, analog-to-digital conversion circuit 400 and digital processing circuit 500 are electrically connected in sequence. The audio signal gain circuit 100 is used to receive the original audio signal VIN to be gained from the signal conditioning circuit 300 and output the target audio signal after gain (including the first audio signal VOUT1 after high gain and the second audio signal VOUT2 after low gain) to the analog-to-digital conversion circuit 400.

[0051] The analog-to-digital converter circuit 400 synchronously acquires the first audio signal VOUT1 and the second audio signal VOUT2. The digital processing circuit selects the optimal path or smoothly merges the output based on the signal strength, and finally outputs a high dynamic range, low distortion audio signal.

[0052] The audio signal gain circuit 100 included in the above audio system is configured with a switch module 110 and an input resistor module 120. The switch module 110 is used to connect the corresponding resistor channel in the input resistor module 120 to the differential amplifier module 130, thereby adjusting the actual input resistance of the input resistor module 120 connected to the differential amplifier module 130. This achieves adjustable input resistance, enabling the differential amplifier module 130 to be reused to achieve gain processing of audio signals of different formats. While achieving high dynamic range gain processing, it saves hardware consumption, has low cost, and good consistency.

[0053] like Figure 6 As shown, in one embodiment, the audio system also includes a phantom power control circuit 600.

[0054] The phantom power control circuit 600 is electrically connected to the signal conditioning circuit 300 and the audio signal gain circuit 100 respectively, and is used to provide phantom power.

[0055] The phantom power control circuit 600 is used to protect and control the incoming raw audio signal VIN through soft-start / soft-stop timing, which can avoid inrush current and popping noise.

[0056] like Figure 6 As shown, in one embodiment, the audio system also includes an interactive interface 700.

[0057] The interactive interface 700 is electrically connected to the digital processing circuit 500 for interacting with external devices to enable program upgrades, audio output, and / or system power supply.

[0058] Among them, the interaction interface 700 includes, but is not limited to, the TYPE-C interface.

[0059] like Figure 6 and Figure 7 As shown, in one embodiment, the signal input interface 200 includes a balanced audio input interface J1 for receiving a microphone audio signal MIC_IN or a line audio signal LINE_IN.

[0060] like Figure 6 and Figure 7 As shown, in one embodiment, the signal conditioning circuit 300 includes a radio frequency filter (RF_FILTER) for filtering out high-frequency electromagnetic interference, such as current noise, buzzing, beeping, and clicking sounds.

[0061] like Figure 6 and Figure 7 As shown, in one embodiment, the phantom power control circuit 600 includes a MOSFET for discharging, a MOSFET for supplying power, and a charge / discharge circuit LP.

[0062] Status 1: Phantom power is on.

[0063] When the gate of the MOSFET used for power supply receives a high level, the MOSFET used for power supply is turned on. The power supply voltage (e.g., 48V) is applied to the main circuit where the original audio signal VIN is located after passing through the MOSFET used for power supply and the two resistors in the charge / discharge circuit LP. The bidirectional diode in the charge / discharge circuit LP is in a clamping state to suppress surges and voltage spikes. The MOSFET used for discharging is in a turned-off state at this time and does not affect the power supply.

[0064] State 2: Phantom power off.

[0065] When the gate of the MOSFET used for power supply goes low, the MOSFET used for power supply is turned off, cutting off the power supply voltage. At the same time, the gate of the MOSFET used for discharge is driven to go high, and the MOSFET used for discharge is turned on. The residual charge on the main circuit where the original audio signal VIN is located is quickly discharged to GND through the charge-discharge circuit LP and the MOSFET used for discharge, avoiding the noise impact caused by voltage change.

[0066] Thirdly, in one embodiment, the present invention provides a recorder, the recorder including a recorder body and an audio signal gain circuit as described in any of the above embodiments or an audio system as described in any of the above embodiments disposed on the recorder body.

[0067] The audio signal gain circuit 100 included in the aforementioned recorder is configured with a switch module 110 and an input resistor module 120. The switch module 110 is used to connect the corresponding resistor channel in the input resistor module 120 to the differential amplifier module 130, thereby adjusting the actual input resistance of the input resistor module 120 connected to the differential amplifier module 130. This achieves adjustable input resistance, enabling the differential amplifier module 130 to be reused to achieve gain processing for audio signals of different formats. While achieving high dynamic range gain processing, it saves hardware consumption, has low cost, and good consistency.

[0068] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the detailed descriptions of other embodiments above, which will not be repeated here.

[0069] The above provides a detailed description of an audio signal gain circuit, audio system, and recorder provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

[0070] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. An audio signal gain circuit (100), characterized in that, The audio signal gain circuit (100) includes a switching module (110) composed of a high-gain switching unit (111) and a low-gain switching unit (112), an input resistor module (120) composed of a high-gain input resistor unit (121) and a low-gain input resistor unit (122), and a differential amplifier module (130) composed of a high-gain differential amplifier unit (131) and a low-gain differential amplifier unit (132). The input terminals of the high-gain input resistor unit (121) and the low-gain input resistor unit (122) are respectively used to input the original audio signal. The output terminal of the high-gain input resistor unit (121) is electrically connected to the input terminal of the high-gain differential amplifier unit (131), and the output terminal of the low-gain input resistor unit (122) is electrically connected to the input terminal of the low-gain differential amplifier unit (132). The output terminal of the high-gain differential amplifier unit (131) is used to output the first audio signal after high gain, and the output terminal of the low-gain differential amplifier unit (132) is used to output the second audio signal after low gain. The high-gain switching unit (111) is connected in series with the high-gain input resistor unit (121) and the high-gain differential amplifier unit (131) to adjust the actual input resistance of the high-gain input resistor unit (121) connected to the high-gain differential amplifier unit (131); the low-gain switching unit (112) is connected in series with the low-gain input resistor unit (122) and the low-gain differential amplifier unit (132) to adjust the actual input resistance of the low-gain input resistor unit (122) connected to the low-gain differential amplifier unit (132).

2. The audio signal gain circuit (100) according to claim 1, characterized in that, The high-gain switching unit (111) includes a first high-gain analog switch (K11), the high-gain input resistor unit (121) includes a first high-gain resistor (R11) and a second high-gain resistor (R12), and the high-gain differential amplifier unit (131) includes a first-stage differential amplifier (U11) and a second-stage differential amplifier (U12). The first end of the first high-gain resistor (R11) and the first end of the second high-gain resistor (R12) are respectively used to input the original audio signal. The second end of the first high-gain resistor (R11) is electrically connected to the input terminal of the first stage differential amplifier (U11). The output terminal of the first stage differential amplifier (U11) is electrically connected to the first input terminal of the first high-gain analog switch (K11). The second end of the second high-gain resistor (R12) is electrically connected to the second input terminal of the first high-gain analog switch (K11). The common terminal of the first high-gain analog switch (K11) is electrically connected to the input terminal of the second stage differential amplifier (U12). The output terminal of the second stage differential amplifier (U12) is used to output the first audio signal.

3. The audio signal gain circuit (100) according to claim 2, characterized in that, The high-gain switching unit (111) also includes a second high-gain analog switch (K12); The common terminal of the second high-gain analog switch (K12) is used to receive the original audio signal. The first input terminal of the second high-gain analog switch (K12) is electrically connected to the first terminal of the first high-gain resistor (R11), and the second input terminal of the second high-gain analog switch (K12) is electrically connected to the first terminal of the second high-gain resistor (R12).

4. The audio signal gain circuit (100) according to claim 1, characterized in that, The low-gain switching unit (112) includes a first low-gain analog switch (K21), the low-gain input resistor unit (122) includes a first low-gain resistor (R21) and a second low-gain resistor (R22), and the low-gain differential amplifier unit (132) includes a single-stage differential amplifier (U2). The first terminal of the first low-gain resistor (R21) and the first terminal of the second low-gain resistor (R22) are respectively used to input the original audio signal. The second terminal of the first low-gain resistor (R21) is electrically connected to the first input terminal of the first low-gain analog switch (K21). The second terminal of the second low-gain resistor (R22) is electrically connected to the second input terminal of the first low-gain analog switch (K21). The common terminal of the first low-gain analog switch (K21) is electrically connected to the input terminal of the single-stage differential amplifier (U2). The output terminal of the single-stage differential amplifier (U2) is used to output the second audio signal.

5. The audio signal gain circuit (100) according to claim 4, characterized in that, The low-gain switching unit (112) also includes a second low-gain analog switch (K22). The common terminal of the second low-gain analog switch (K22) is used to receive the original audio signal. The first input terminal of the second low-gain analog switch (K22) is electrically connected to the first terminal of the first low-gain resistor (R21), and the second input terminal of the second low-gain analog switch (K22) is electrically connected to the first terminal of the second low-gain resistor (R22).

6. The audio signal gain circuit (100) according to claim 1, characterized in that, The original audio signal includes audio signals from time-division multiplexing microphone input and audio signals from line input.

7. An audio system, characterized in that, The audio system includes a signal input interface (200), a signal conditioning circuit (300), an analog-to-digital conversion circuit (400), a digital processing circuit (500), and an audio signal gain circuit (100) as described in any one of claims 1 to 6. The signal input interface (200), the signal conditioning circuit (300), the audio signal gain circuit (100), the analog-to-digital conversion circuit (400), and the digital processing circuit (500) are electrically connected in sequence. The audio signal gain circuit (100) is used to receive the original audio signal to be gained from the signal conditioning circuit (300) and output the first and second audio signals after gain to the analog-to-digital conversion circuit (400).

8. The audio system according to claim 7, characterized in that, The audio system also includes a phantom power control circuit (600). The phantom power control circuit (600) is electrically connected to the signal conditioning circuit (300) and the audio signal gain circuit (100) respectively, and is used to provide phantom power.

9. The audio system according to claim 7, characterized in that, The audio system also includes an interactive interface (700). The interactive interface (700) is electrically connected to the digital processing circuit (500) and is used to interact with external devices to enable program upgrades, audio output, and / or system power supply.

10. A tape recorder, characterized in that, The recorder includes a recorder body and an audio signal gain circuit as described in any one of claims 1 to 6 or an audio system as described in any one of claims 7 to 9, disposed on the recorder body.

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