CN213342607U

CN213342607U - Circuit for eliminating microphone audio common ground noise

Info

Publication number: CN213342607U
Application number: CN202022182486.9U
Authority: CN
Inventors: 雷彦行
Original assignee: Zhongshan Yuechen Electronic Industry Co ltd
Current assignee: Zhongshan Yuechen Electronic Industry Co ltd
Priority date: 2020-09-28
Filing date: 2020-09-28
Publication date: 2021-06-01
Anticipated expiration: 2030-09-28

Abstract

The utility model discloses a circuit for eliminating the common ground noise of microphone audio, which comprises a wireless communication module, an audio processing module, an isolation module, a DA conversion module and an audio output module which are electrically connected in sequence; the isolation module comprises a power input port, a power output port, an I2S bus input port and an I2S bus output port, wherein signal isolation processing is performed between the power input port and the power output port and between the I2S bus input port and the I2S bus output port; the power supply input port is electrically connected with a direct current power supply, and the power supply output port supplies power to the DA conversion module; the I2S bus input port is electrically connected with the audio processing module, and the I2S bus output port is electrically connected with the DA conversion module; and the grounding ports of the DA conversion modules are isolated and grounded. The utility model discloses can effectively eliminate the noise that arouses because of being altogether.

Description

Circuit for eliminating microphone audio common ground noise

Technical Field

The utility model belongs to the technical field of the audio signal processing technique and specifically relates to a circuit of eliminating microphone audio frequency common ground noise.

Background

With the development of science and technology, audio equipment is miniaturized more and more, gradually walks into ordinary family, and people can easily enjoy the enjoyment of K song at home. When the user is using the microphone, the speaker occasionally makes an annoying squeak, greatly reducing the user experience. Generally, the noise is caused by the noise of the analog audio signal connected to the common ground, which is also a difficult problem of analog circuits, and no good solution is provided all the time.

SUMMERY OF THE UTILITY MODEL

The utility model provides an eliminate circuit of microphone audio frequency common ground noise can effectively eliminate the noise that arouses because of common ground.

In order to solve the above problem, the utility model adopts the following technical scheme:

a circuit for eliminating common-ground noise of microphone audio comprises a wireless communication module, an audio processing module, an isolation module, a DA conversion module and an audio output module which are electrically connected in sequence; the isolation module comprises a power input port, a power output port, an I2S bus input port and an I2S bus output port, wherein signal isolation processing is performed between the power input port and the power output port and between the I2S bus input port and the I2S bus output port; the power supply input port is electrically connected with a direct current power supply, and the power supply output port supplies power to the DA conversion module; the I2S bus input port is electrically connected with the audio processing module, and the I2S bus output port is electrically connected with the DA conversion module; and the grounding ports of the DA conversion modules are isolated and grounded.

Preferably, the power output port is electrically connected to the first filter circuit, and the I2S bus output port is electrically connected to the second filter circuit.

Preferably, the first filter circuit comprises a first filter capacitor, and the second filter circuit comprises a second filter capacitor; the ground ports of the DA conversion modules are electrically connected with an isolated ground terminal; one end of the first filter capacitor is electrically connected with the power output port, and the other end of the first filter capacitor is electrically connected with the isolation grounding end; one end of the second filter capacitor is electrically connected with the I2S bus output port, and the other end of the second filter capacitor is electrically connected with the isolation grounding end.

Preferably, the power input port is provided with a third filter circuit.

Preferably, the DA conversion module comprises a DA conversion chip PCM5100A, and the

pins

13, 14 and 15 of the DA conversion chip PCM5100A are electrically connected with the I2S bus output port; and the 6 pin and the 7 pin of the DA conversion chip PCM5100A are electrically connected with the audio output module.

Preferably, the audio output module comprises a LINE OUT interface, and the 6 pin and the 7 pin of the DA conversion chip PCM5100A are both electrically connected with the LINE OUT interface.

Preferably, the audio processing module includes an MCU unit, a DSP unit, and an AD conversion unit electrically connected to each other.

Preferably, the MCU unit includes a chip AC6901AN, the DSP unit includes a DSP chip, and the AD conversion unit includes a chip PCM 1808.

Preferably, the wireless communication module comprises a chip BK9532, and the

pins

17 and 18 of the chip BK9532 are electrically connected to the DSP chip.

Preferably, the audio processing module is further electrically connected with the key module and the light indication module.

The utility model discloses has following technological effect: the utility model discloses an isolation module all keeps apart the processing to audio signal and signals, and DA conversion module is by keeping apart the complete independent power supply of module, and DA conversion module has adopted the mode of keeping apart ground connection, and DA conversion module's ground connection is kept apart with the ground connection of system to effectively eliminate the noise in the signals and the audio signal that arouse because of being altogether.

Drawings

Fig. 1 is a schematic circuit block diagram of a circuit for eliminating common ground noise of microphone audio according to an embodiment of the present invention;

fig. 2 is a schematic circuit diagram of an isolation module, a DA conversion module, and an audio output module according to an embodiment of the present invention;

fig. 3 is a schematic circuit diagram of an MCU unit according to an embodiment of the present invention;

fig. 4 is a circuit diagram of a DSP unit according to an embodiment of the present invention;

fig. 5 is a schematic circuit diagram of an AD conversion unit according to an embodiment of the present invention;

fig. 6 is a schematic circuit diagram of a wireless communication module according to an embodiment of the present invention;

fig. 7 is a schematic circuit diagram of a key module according to an embodiment of the present invention;

fig. 8 is a schematic circuit diagram of a light indication module according to an embodiment of the present invention.

Detailed Description

The electric connection in the present invention means that two components are directly electrically connected or indirectly connected through an intermediate component. The present invention will be described in further detail with reference to the accompanying drawings.

The embodiment of the utility model provides an eliminate circuit of microphone audio frequency common ground noise, as shown in fig. 1-8, it includes wireless communication module 1, audio processing module 2, isolation module 3, DA conversion module 4 and audio output module 5 that the electricity is connected in order. The wireless communication module 1 receives an audio signal transmitted by an external device, for example, a wireless audio signal transmitted by a microphone. The audio processing module 2 performs audio mixing processing on the received audio signal, and then sends the audio digital signal to the isolation module 3 through the I2S bus, the isolation module 3 sends the audio digital signal to the DA conversion module 4, the DA conversion module 4 converts the audio digital signal into an audio analog signal, and finally, the audio analog signal is output through the audio output module 5. The audio output module 5 can be connected to an audio player such as a sound box, so as to play music corresponding to the audio signal.

The isolation module 3 specifically comprises a power input port, a power output port, an I2S bus input port and an I2S bus output port, signal isolation processing is performed between the power input port and the power output port and between the I2S bus input port and the I2S bus output port, and an optical coupling isolation mode can be specifically adopted to avoid interference between signals. The power input port is electrically connected to a dc power supply, which may be provided by the power module or by the audio processing module 2. The power output port supplies power to the DA conversion module 4, so that the DA conversion module 4 is completely and independently supplied with power by the isolation module 3, and a power signal of the DA conversion module does not interfere with a power signal of a system. The I2S bus input port is electrically connected with the audio processing module 2, the I2S bus output port is electrically connected with the DA conversion module 4, and the audio signal is transmitted to the DA conversion module 4 through the I2S bus. All ground ports of the DA conversion module 4 are isolated from the ground, i.e., from the system ground, thereby eliminating noise of the audio signal due to the common ground.

The circuit for eliminating the common ground noise of the microphone audio frequency further comprises a power supply module, and the power supply module supplies direct current power to the wireless communication module 1, the audio frequency processing module 2 and the isolation module 3 so as to enable the modules to work. The power supply module may be an internal power supply, or may be connected to an external power supply through a USB interface 7 as shown in fig. 1.

In one embodiment, the isolation module 3 may include a DC-DC isolation chip, which may be specifically a chip NSiP884x or other isolation chip, as shown in fig. 2.

Pins

1 and 2 of the DC-DC isolation chip are power input ports,

pins

15 and 16 are power output ports,

pins

3, 4 and 5 are I2S bus input ports, and

pins

12, 13 and 14 are I2S bus output ports.

In one embodiment, the power output port is electrically coupled to a first filter circuit and the I2S bus output port is electrically coupled to a second filter circuit. The first filter circuit and the second filter circuit are respectively used for filtering impurity signals in the power signal and the audio signal, so that the power signal and the audio signal which are transmitted to the DA conversion module 4 are more pure.

Specifically, the first filter circuit includes a first filter capacitor, and the capacitor C77, the capacitor C71, and the capacitor C80 in fig. 2 are all first filter capacitors. The second filter circuit comprises a second filter capacitor, and the capacitor C86, the capacitor C84 and the capacitor C85 in fig. 2 are all second filter capacitors. The ground ports of the DA conversion modules 4 are all electrically connected to an isolated ground. One end of the first filter capacitor is electrically connected with the power output port, and the other end of the first filter capacitor is electrically connected with the isolation grounding terminal. One end of the second filter capacitor is electrically connected with the I2S bus output port, and the other end is electrically connected with the isolated grounding terminal. That is, the ground terminal of the filter capacitor shares a common isolated ground terminal with all the ground ports of the DA conversion module 4. Since the power output port and the I2S bus output port are both electrically connected to the DA conversion module 4 and are filtered by the filter capacitor, interference will not occur even if all the ground ports share one ground terminal, and at the same time, the circuit structure can be simplified.

In one embodiment, the power input port is provided with a third filter circuit, the third filter circuit is an LC filter circuit composed of an inductor and a capacitor, and the inductor L10, the capacitor C62, the capacitor C61 and the capacitor C79 in the figure form the third filter circuit.

In one embodiment, as shown in fig. 2, the DA conversion module 4 comprises a DA conversion chip PCM5100A, and the 13 pins, 14 pins and 15 pins of the DA conversion chip PCM5100A are all electrically connected with the I2S bus output port. The 6 pins of the DA conversion chip PCM5100A, the capacitor C63, the resistor R13 and the audio output module are electrically connected in sequence, and the 7 pins of the DA conversion chip PCM5100A, the capacitor C67, the resistor R12 and the audio output module are electrically connected in sequence.

In one embodiment, the audio output module comprises a LINE OUT interface, and the 6 pin and the 7 pin of the DA conversion chip PCM5100A are both electrically connected with the LINE OUT interface. The LINE OUT interface is also electrically connected with the LC filter circuit.

In one embodiment, the audio processing module 2 includes an MCU unit, a DSP unit, and an AD conversion unit electrically connected to each other. Further, as shown in fig. 3-5, the MCU unit includes a chip AC6901AN, the DSP unit includes a DSP chip, and the AD conversion unit includes a chip PCM 1808. The chip AC6901AN can be electrically connected with the DSP chip through an I2S bus and a UART serial port, and the DSP chip receives the audio signal sent by the wireless communication module 1 and sends the audio signal to the chip PCM1808 for AD conversion.

In one embodiment, as shown in fig. 6, the wireless communication module 1 includes a chip BK9532, and both

pins

17 and 18 of the chip BK9532 are electrically connected to the DSP chip. The signal received by the antenna is transmitted to 6 pins of the chip BK9532, and the chip BK9532 transmits the received signal to the DSP chip through 17 pins, 18 pins, and 19 pins. In this embodiment, a plurality of wireless communication modules 1 may be provided, so that audio signals sent by a plurality of external devices may be received simultaneously. For example, the audio signals of a plurality of microphones can be received simultaneously, and the method is suitable for a scene in which a plurality of persons sing songs.

In one embodiment, the audio processing module is further electrically connected to the key module 6 and the light indication module, the key module 6 can select a mode or a function of the whole circuit for eliminating the microphone audio common ground noise, and the light indication module indicates an operating state of the whole circuit for eliminating the microphone audio common ground noise.

As shown in fig. 7, the key module 6 includes a plurality of key switches, and an output terminal of the key module 6 may be electrically connected to a 5 pin of the chip AC6901 AN. As shown in fig. 8, the light indication module includes two LED lamps, one end of each of the two LED lamps is electrically connected to the dc power supply, and the other ends of the two LED lamps (the LED1 port and the LED2 port) are electrically connected to the 41 pin and the 42 pin of the chip AC6901AN, respectively.

The utility model discloses an eliminate circuit of microphone audio frequency common ground noise is of course not restricted to the use on the microphone, still can be applicable to other audio equipment such as audio amplifier, earphone.

The foregoing is a more detailed description of the present invention that is presented in conjunction with specific embodiments, and it is not to be understood that the specific embodiments of the present invention are limited to these descriptions. To the utility model belongs to the technical field of ordinary technical personnel, do not deviate from the utility model discloses under the prerequisite of design, can also make a plurality of simple deductions or replacement.

Claims

1. A circuit for canceling microphone audio common ground noise, comprising: the device comprises a wireless communication module, an audio processing module, an isolation module, a DA conversion module and an audio output module which are electrically connected in sequence; the isolation module comprises a power input port, a power output port, an I2S bus input port and an I2S bus output port, wherein signal isolation processing is performed between the power input port and the power output port and between the I2S bus input port and the I2S bus output port; the power supply input port is electrically connected with a direct current power supply, and the power supply output port supplies power to the DA conversion module; the I2S bus input port is electrically connected with the audio processing module, and the I2S bus output port is electrically connected with the DA conversion module; and the grounding ports of the DA conversion modules are isolated and grounded.

2. The circuit for canceling microphone audio common ground noise according to claim 1, wherein: the power output port is electrically connected with the first filter circuit, and the I2S bus output port is electrically connected with the second filter circuit.

3. The circuit for canceling microphone audio common ground noise according to claim 2, wherein: the first filter circuit comprises a first filter capacitor, and the second filter circuit comprises a second filter capacitor; the ground ports of the DA conversion modules are electrically connected with an isolated ground terminal; one end of the first filter capacitor is electrically connected with the power output port, and the other end of the first filter capacitor is electrically connected with the isolation grounding end; one end of the second filter capacitor is electrically connected with the I2S bus output port, and the other end of the second filter capacitor is electrically connected with the isolation grounding end.

4. The circuit for canceling microphone audio common ground noise according to claim 1, wherein: and the power input port is provided with a third filter circuit.

5. The circuit for canceling microphone audio common ground noise according to any one of claims 1 to 4, wherein: the DA conversion module comprises a DA conversion chip PCM5100A, and the pins 13, 14 and 15 of the DA conversion chip PCM5100A are electrically connected with the I2S bus output port; and the 6 pin and the 7 pin of the DA conversion chip PCM5100A are electrically connected with the audio output module.

6. The circuit for canceling microphone audio common ground noise according to claim 5, wherein: the audio output module comprises a LINE OUT interface, and the 6 pin and the 7 pin of the DA conversion chip PCM5100A are electrically connected with the LINE OUT interface.

7. The circuit for canceling microphone audio common ground noise according to any one of claims 1 to 4, wherein: the audio processing module comprises an MCU unit, a DSP unit and an AD conversion unit which are electrically connected with each other.

8. The circuit for canceling microphone audio common ground noise according to claim 7, wherein: the MCU unit includes chip AC6901AN, the DSP unit includes the DSP chip, AD converting unit includes chip PCM 1808.

9. The circuit for canceling microphone audio common ground noise according to claim 8, wherein: the wireless communication module comprises a chip BK9532, and the pin 17 and the pin 18 of the chip BK9532 are electrically connected with the DSP chip.

10. The circuit for canceling microphone audio common ground noise according to any one of claims 1 to 4, wherein: the audio processing module is also electrically connected with the key module and the light indication module.