Pre-stage circuit for realizing DSP (Digital Signal Processor) function by using band switch

Abstract

A pre-stage circuit for realizing a DSP function by using a band switch comprises a first channel input circuit and a second channel input circuit, and the first channel input circuit sequentially comprises a first operational amplifier, a high-pass filter and a buffer amplifier from an input end to an output end. The second channel input circuit sequentially comprises a second operational amplifier, a low-pass filter and a phase inverter from the input end to the output end, and the output ends of the first operational amplifier and the high-pass filter are connected with the input end of the buffer amplifier through the first band switch; the output end of the first operational amplifier and the output end of the second operational amplifier are connected through the second band switch, then connected with the output end of the low-pass filter and then connected with the non-inverting input end of the phase inverter through the third band switch, and the output end of the buffer amplifier is connected with the inverting input end of the phase inverter. And the output end of the buffer amplifier and the non-inverting input end of the phase inverter are grounded through a fourth band switch. A preceding-stage signal can be changed through the manual change-over switch.

Description

Technical Field

[0001] The invention relates to the technical field of audio, in particular to a pre-stage circuit that uses a band switch to realize a DSP function. Background Art

[0002] In the process of audio development, pre-stage audio processing is a relatively cumbersome task. The common practice is to add DSP to the circuit, and also add MCU and display for control. The solution of adding DSP for pre-stage audio processing has the following defects: it requires panel display and control, which makes the operation complicated; it increases the workload of hardware and software, and the overall workload is large; it generally requires DSP chips and MCU chips, plus some auxiliary devices, which is costly. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a pre-stage circuit that realizes DSP function by using a band switch, which has simple operation, small workload and low cost.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a pre-stage circuit that realizes DSP function by using a band switch, comprising a first channel input circuit and a second channel input circuit, wherein the first channel input circuit comprises a first operational amplifier circuit, a high-pass filter circuit and a buffer amplifier circuit in sequence from the input end to the output end, the first operational amplifier circuit comprises an operational amplifier U1A, the high-pass filter circuit comprises a high-pass filter U1B, the buffer amplifier circuit comprises a buffer amplifier U1C, the input end of the first channel input circuit is connected to the input end of the operational amplifier U1A, the output end of the operational amplifier U1A is connected to the input end of the high-pass filter U1B, the output ends of the operational amplifier U1A and the high-pass filter U1B are connected to the input end of the buffer amplifier U1C through the first band switch, and the output end of the buffer amplifier U1C is connected to the output end of the first channel input circuit The second channel input circuit includes a second operational amplifier circuit, a low-pass filter circuit and an inverter circuit in sequence from the input end to the output end. The second operational amplifier circuit includes an operational amplifier U2A, the low-pass filter circuit includes a low-pass filter U2B, and the inverter circuit includes an inverter U2C. The input end of the second channel input circuit is connected to the input end of the operational amplifier U2A, the output end of the operational amplifier U1A is connected to the input end of the low-pass filter U2B, the output ends of the operational amplifier U1A and the operational amplifier U2A are connected through a second band switch and then connected to the output end of the low-pass filter U2B and then connected to the positive phase input end of the inverter U2C through a third band switch, the output end of the buffer amplifier U1C is connected to the inverting input end of the inverter U2C, and the output end of the buffer amplifier U1C and the positive phase input end of the inverter U2C are grounded through a fourth band switch. The principle of the invention is as follows: the pre-stage signal can be changed by manually switching the switch to provide the signal required by the power amplifier, such as the anti-phase signal, the same-phase signal, the high and low frequency division signal and the stereo signal; the function of DSP and MCU circuit synthesis can be realized without complex circuits; the hardware design can be completed without the participation of software.

[0005] As an improvement, the first band switch and the third band switch are combined into a double-pole double-throw band switch, and the second band switch and the fourth band switch are combined into a double-pole triple-throw band switch.

[0006] As an improvement, the output end of the operational amplifier U1A is connected to the first pin of the double-pole double-throw band switch, the output end of the high-pass filter U1B is connected to the third pin of the double-pole double-throw band switch, the second pin of the double-pole double-throw band switch is connected to the input end of the buffer amplifier, the output end of the operational amplifier U1A is connected to the fourth pin of the double-pole triple-throw band switch, the output end of the operational amplifier U2A is connected to the first and second pins of the double-pole triple-throw band switch, the third pin of the double-pole triple-throw band switch is connected to the fourth pin of the double-pole double-throw band switch, the output end of the low-pass filter U2B is connected to the sixth pin of the double-pole double-throw band switch, the fifth pin of the double-pole double-throw band switch is connected to the positive phase input end of the inverter U2C, the output end of the buffer amplifier U1C is connected to the sixth and eighth pins of the double-pole triple-throw band switch, the positive phase input end of the inverter U2C is connected to the fifth pin of the double-pole triple-throw band switch, and the seventh pin of the double-pole triple-throw band switch is grounded.

[0007] Compared with the prior art, the present invention has the following beneficial effects: By manually switching the switch, the front-stage signal can be changed to provide the signal required by the power amplifier, such as the anti-phase signal, the same-phase signal, the high and low frequency division signal and the stereo signal; the function of DSP and MCU circuit synthesis can be realized without complex circuits; the hardware design can be completed without the participation of software. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is the front-stage circuit diagram for the in-phase signal output.

[0009] Figure 2 This is the pre-stage circuit diagram for high and low frequency division output.

[0010] Figure 3 This is the front-stage circuit diagram of the direct-through mode.

[0011] Figure 4 This is the front-stage circuit diagram for inverted signal output. DETAILED DESCRIPTION

[0012] The present invention will be further described below in conjunction with the accompanying drawings.

[0013] A pre-stage circuit that implements DSP functions by using a band switch. This embodiment is described by taking a two-channel power amplifier input as an example. The pre-stage circuit includes a first channel input circuit and a second channel input circuit.

[0014] like Figures 1 to 4As shown, the first channel input circuit includes a first operational amplifier circuit, a high-pass filter circuit and a buffer amplifier circuit in sequence from the input end to the output end; the first operational amplifier circuit includes an operational amplifier U1A, the high-pass filter circuit includes a high-pass filter U1B, and the buffer amplifier circuit includes a buffer amplifier U1C; the input end of the first channel input circuit is connected to the input end of the operational amplifier U1A, the output end of the operational amplifier U1A is connected to the input end of the high-pass filter U1B, the output ends of the operational amplifier U1A and the high-pass filter U1B are connected to the input end of the buffer amplifier U1C through a first band switch, and the output end of the buffer amplifier U1C is connected to the output end of the first channel input circuit.

[0015] like Figures 1 to 4 As shown, the second channel input circuit includes a second operational amplifier circuit, a low-pass filter circuit and an inverter circuit in sequence from the input end to the output end; the second operational amplifier circuit includes an operational amplifier U2A, the low-pass filter circuit includes a low-pass filter U2B, and the inverter circuit includes an inverter U2C; the input end of the second channel input circuit is connected to the input end of the operational amplifier U2A, the output end of the operational amplifier U1A is connected to the input end of the low-pass filter U2B, the output ends of the operational amplifier U1A and the operational amplifier U2A are connected through a second band switch and then connected to the output end of the low-pass filter U2B and then to the positive phase input end of the inverter U2C through a third band switch, the output end of the buffer amplifier U1C is connected to the inverting input end of the inverter U2C, and the output end of the buffer amplifier U1C and the positive phase input end of the inverter U2C are grounded through a fourth band switch.

[0016] like Figures 1 to 4As shown, the first band switch and the third band switch are combined into a double-pole double-throw band switch SW-2, and the second band switch and the fourth band switch are combined into a double-pole triple-throw band switch SW-1. The output end of the operational amplifier U1A is connected to the first pin of the double-pole double-throw band switch, the output end of the high-pass filter U1B is connected to the third pin of the double-pole double-throw band switch, the second pin of the double-pole double-throw band switch is connected to the input end of the buffer amplifier, the output end of the operational amplifier U1A is connected to the fourth pin of the double-pole triple-throw band switch, the output end of the operational amplifier U2A is connected to the first and second pins of the double-pole triple-throw band switch, the third pin of the double-pole triple-throw band switch is connected to the fourth pin of the double-pole double-throw band switch, the output end of the low-pass filter U2B is connected to the sixth pin of the double-pole double-throw band switch, the fifth pin of the double-pole double-throw band switch is connected to the positive phase input end of the inverter U2C, the output end of the buffer amplifier U1C is connected to the sixth and eighth pins of the double-pole triple-throw band switch, the positive phase input end of the inverter U2C is connected to the fifth pin of the double-pole triple-throw band switch, and the seventh pin of the double-pole triple-throw band switch is grounded.

[0017] Functional implementation description: like Figure 1 As shown, (1) In-phase signal output: Set the double-pole triple-throw band switch to terminals 4 and 8, and the double-pole double-throw band switch to terminals 1 and 4. The channel 2 signal is turned off, and channel 1 is separated into two signals through the operational amplifier. The output ends are two signals with the same phase, providing two in-phase single signals for the power amplifier; like Figure 2 As shown, (2) high and low frequency division output: set the double-pole triple-throw band switch to terminals 2 and 6, and the double-pole double-throw band switch to terminals 3 and 6, the channel 2 signal is turned off, and channel 1 passes through the high-pass filter and low-pass filter circuits to output the high-frequency signal and bass signal of channel 1. The filter is a second-order (-12dB) circuit; like Figure 3 As shown, (3) Direct-through mode: Set the double-pole triple-throw band switch to terminals 2 and 6, and the double-pole double-throw band switch to terminals 1 and 4. The output signals of channel 1 and channel 2 are consistent with the input signals, that is, the direct-through state; like Figure 4 As shown, (4) Inverted signal output: Set the double-pole triple-throw band switch to terminals 1 and 5, and the double-pole double-throw band switch to terminals 1 and 4. The channel 2 signal is turned off, and channel 1 outputs positive and negative signals through the operational amplifier. The output end is two signals with opposite phases (providing a bridge signal for the power amplifier, and the power amplifier amplitude is increased by 6dB).

[0018] The principle of the invention is as follows: the pre-stage signal can be changed by manually switching the switch to provide the signal required by the power amplifier, such as the anti-phase signal, the same-phase signal, the high and low frequency division signal and the stereo signal; the function of DSP and MCU circuit synthesis can be realized without complex circuits; the hardware design can be completed without the participation of software.

Claims

1. A pre-stage circuit for realizing DSP function by using a band switch, comprising a first channel input circuit and a second channel input circuit, characterized in that: The first channel input circuit includes a first operational amplifier circuit, a high-pass filter circuit and a buffer amplifier circuit in sequence from the input end to the output end, the first operational amplifier circuit includes an operational amplifier U1A, the high-pass filter circuit includes a high-pass filter U1B, the buffer amplifier circuit includes a buffer amplifier U1C, the input end of the first channel input circuit is connected to the input end of the operational amplifier U1A, the output end of the operational amplifier U1A is connected to the input end of the high-pass filter U1B, the output ends of the operational amplifier U1A and the high-pass filter U1B are connected to the input end of the buffer amplifier U1C through a first band switch, and the output end of the buffer amplifier U1C is connected to the output end of the first channel input circuit; The second channel input circuit includes a second operational amplifier circuit, a low-pass filter circuit and an inverter circuit in sequence from the input end to the output end. The second operational amplifier circuit includes an operational amplifier U2A, the low-pass filter circuit includes a low-pass filter U2B, and the inverter circuit includes an inverter U2C. The input end of the second channel input circuit is connected to the input end of the operational amplifier U2A, the output end of the operational amplifier U1A is connected to the input end of the low-pass filter U2B, the output ends of the operational amplifier U1A and the operational amplifier U2A are connected to the output end of the low-pass filter U2B through a second band switch, and then connected to the positive phase input end of the inverter U2C through a third band switch, the output end of the buffer amplifier U1C is connected to the inverting input end of the inverter U2C, and the output end of the buffer amplifier U1C and the positive phase input end of the inverter U2C are grounded through a fourth band switch.

2. The pre-stage circuit for realizing DSP function by using a band switch according to claim 1, characterized in that: The first band switch and the third band switch are combined into a double-pole double-throw band switch, and the second band switch and the fourth band switch are combined into a double-pole triple-throw band switch.

3. The pre-stage circuit for realizing DSP function by using a band switch according to claim 2, characterized in that: The output end of the operational amplifier U1A is connected to the first pin of the double-pole double-throw band switch, the output end of the high-pass filter U1B is connected to the third pin of the double-pole double-throw band switch, the second pin of the double-pole double-throw band switch is connected to the input end of the buffer amplifier, the output end of the operational amplifier U1A is connected to the fourth pin of the double-pole triple-throw band switch, the output end of the operational amplifier U2A is connected to the first and second pins of the double-pole triple-throw band switch, the third pin of the double-pole triple-throw band switch is connected to the fourth pin of the double-pole double-throw band switch, the output end of the low-pass filter U2B is connected to the sixth pin of the double-pole double-throw band switch, the fifth pin of the double-pole double-throw band switch is connected to the positive phase input end of the inverter U2C, the output end of the buffer amplifier U1C is connected to the sixth and eighth pins of the double-pole triple-throw band switch, the positive phase input end of the inverter U2C is connected to the fifth pin of the double-pole triple-throw band switch, and the seventh pin of the double-pole triple-throw band switch is grounded.

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