CN211296933U

CN211296933U - Audio equipment for conference

Info

Publication number: CN211296933U
Application number: CN201921890539.3U
Authority: CN
Inventors: 成俊
Original assignee: Guangzhou Quanyu Technology Co ltd
Current assignee: Guangzhou Quanyu Technology Co ltd
Priority date: 2019-11-05
Filing date: 2019-11-05
Publication date: 2020-08-18
Anticipated expiration: 2029-11-05

Abstract

The utility model provides an audio equipment is used in meeting, including audio signal emitter, noise reduction circuit and sound output device, sound output device connects audio signal emitter, noise reduction circuit connects between sound output device and audio signal emitter, noise reduction circuit includes N type MOSFET pipe, control signal generater and charge-discharge circuit, noise reduction circuit includes N type MOSFET pipe, the drain electrode of N type MOSFET pipe is connected between sound output device and audio signal emitter, source ground connection, charge-discharge circuit connects between the grid of N type MOSFET pipe and control signal generater. The audio equipment for the conference utilizes the characteristics of the N-type MOSFET tube, controls the on-off time of the N-type MOSFET tube through the control signal generator and the charge-discharge circuit, and cannot cause instantaneous charge-discharge to the sound output device, so that the output noise of the sound output device is avoided, the sound quality is improved, and the aim of creating a good conference environment is fulfilled.

Description

Audio equipment for conference

Technical Field

The utility model relates to an audio information equipment technical field especially relates to an audio equipment is used in meeting.

Background

With the increasing communication requirements of modern enterprises, conferences become an indispensable part of daily work in enterprises and units, and speech is used as one of important links of the conferences, wherein audio equipment is required for speech. However, most of the conference sites are not specialized conference rooms, and have no good wiring environment, and the irrelevant lines affect the signal input and output of the audio equipment. The conventional audio device generates noise caused by circuit switching during outputting an audio signal, which affects the conference.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an audio equipment for meeting just in order to solve above-mentioned problem, can the noise abatement, improved sound quality.

The utility model provides a technical scheme that its technical problem adopted is:

the utility model provides an audio equipment is used in meeting, includes audio signal emitter, noise reduction circuit and sound output device, sound output device connects audio signal emitter for accept the audio signal of audio signal emitter output and output sound, noise reduction circuit connects between sound output device and audio signal emitter for slow down and smooth audio signal's that audio signal emitter output direct current level changes, noise reduction circuit includes N type MOSFET pipe, control signal generator and charge-discharge circuit, the drain electrode of N type MOSFET pipe is connected between sound output device and audio signal emitter, source ground connection, charge-discharge circuit connects between the grid of N type MOSFET pipe and control signal generator.

Furthermore, the charge and discharge circuit comprises a resistor and a capacitor, the resistor is connected between the grid of the N-type MOSFET and the control signal generator, one end of the capacitor is connected between the resistor and the grid of the N-type MOSFET, and the other end of the capacitor is grounded.

Furthermore, the sound output device comprises an operational amplifier and a loudspeaker, wherein the non-inverting input end of the operational amplifier is connected with the audio signal emitting device and the noise reduction circuit, the output end of the operational amplifier is connected with the loudspeaker, and the inverting input end of the operational amplifier is connected between the output end and the loudspeaker.

Further, the operational amplifier is connected with a power supply.

Further, the audio signal emitting device comprises a signal generator, a voltage output circuit and a voltage reduction resistor.

The utility model has the advantages that:

through adopting the technical scheme, the utility model discloses an audio equipment for meeting utilizes the characteristic of N type MOSFET pipe, controls the time that N type MOSFET pipe switched on and closed through control signal generater and charging and discharging circuit, can not cause momentary charge and discharge to sound output device to avoided sound output device output noise, improved sound quality, reached the purpose of building a good meeting environment.

Drawings

The present invention will be further explained with reference to the drawings and examples.

Fig. 1 is a circuit diagram of an embodiment of the audio device for conference;

fig. 2 is an output waveform diagram of the audio device for conference in the input starting state;

fig. 3 is an output waveform diagram of the audio device for conference in the input stop state.

Reference numerals: 1. an audio signal emitting device; 11. a signal generator; 12. a voltage output circuit; 2. a noise reduction circuit; 21. an N-type MOSFET; 22. a control signal generator; 23. a capacitor; 3. a sound output device; 31. an operational amplifier; 32. a loudspeaker.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and can implement the present invention, but the embodiments are not to be construed as limiting the present invention.

As shown in fig. 1, an audio device for a conference includes an audio signal emitting device 1, a noise reduction circuit 2 and a sound output device 3, wherein the sound output device 3 is connected to the audio signal emitting device 1 and is configured to receive an audio signal output by the audio signal emitting device 1 and output sound, the noise reduction circuit 2 is connected between the sound output device 3 and the audio signal emitting device 1 and is configured to slow and smooth a dc level change of the audio signal output by the audio signal emitting device 1, the noise reduction circuit 2 includes an N-type MOSFET tube 21, a control signal generator 22 and a charging and discharging circuit, a drain of the N-type MOSFET tube 21 is connected between the sound output device 3 and the audio signal emitting device 1, a source of the N-type MOSFET tube 21 is grounded, and the charging and discharging circuit is connected between a gate of the N-type MOSFET tube 21 and the control signal generator 22.

In one specific embodiment of the audio device, the voltage output circuit 12 outputs a bias voltage Vbias, and the sinusoidal signal output by the signal generator 11 is biased to around the voltage Vbias. The control signal generator 22 outputs a control signal Vpop _ ctrl according to the state of the audio device.

In the no-input state (default state), the audio signal issuing apparatus 1 is not conductive, and the control signal Vpop _ ctrl of the control signal generator 22 is kept at the high level, the gate of the N-type MOSFET tube 21 is at the high voltage, so that the N-type MOSFET tube 21 is conductive. The equivalent resistance of the noise reduction circuit 2 between the non-inverting input terminal and the ground is 0, and Vc on the non-inverting input terminal of the operational amplifier 31 is pulled down to the ground. Although the audio signal emitting device 1 suddenly outputs a signal, the output terminal of the operational amplifier 31 is maintained at 0 v, and the speaker 32 does not output a sound.

Referring to fig. 2, the curve is the voltage Vc at the non-inverting input terminal of the operational amplifier 31 in the initial input state over time. In the initial input state, the output voltage of the voltage output circuit 12 becomes the voltage Vbias, and at the same time, the control signal Vpop _ ctrl falls to the low level, which discharges the capacitor 13. The voltage at the gate of the N-type MOSFET transistor 21 gradually decreases and the drain-to-source impedance gradually increases. That is, the equivalent resistance of the noise reduction circuit 2 between the non-inverting input terminal and the ground gradually becomes infinite, and the voltage Vc of the non-inverting input terminal of the operational amplifier 31 is gradually pulled up from the ground to Vbias. Therefore, the voltage Vc at the output terminal of the operational amplifier 31 is also gradually pulled up. Therefore, the equivalent capacitor 33 at the output terminal of the operational amplifier 31 is gradually charged, no current pulse is generated, and no noise is output from the speaker 32.

Referring to fig. 3, the graph shows the change of the voltage Vc at the non-inverting input terminal of the operational amplifier 31 with time in the stopped input state. In the stop input state, the control signal Vpop _ ctrl rises to a high level to charge the capacitor 13. The voltage of the gate 4 of the N-type MOSFET transistor 21 gradually rises and the drain-to-source impedance gradually falls. That is, the equivalent resistance of the noise reduction circuit 2 between the non-inverting input terminal and the ground gradually becomes 0, and the voltage Vc of the non-inverting input terminal of the operational amplifier 31 is gradually pulled down to the ground. Therefore, the voltage Vc of the output terminal of the operational amplifier 31 is gradually pulled down to the ground. Therefore, the equivalent capacitor 33 at the output terminal of the operational amplifier 31 is gradually discharged, and no current pulse is generated, and no noise is output from the speaker 32.

In summary, the audio device can prevent the speaker 32 from being suddenly charged or discharged, so that pop sound is not generated, sound quality is improved, and power can be saved.

The above embodiments of the present invention are not right the utility model discloses the limited protection scope, the utility model discloses an embodiment is not limited to this, all kinds of basis according to the above-mentioned of the utility model discloses an under the above-mentioned basic technical thought prerequisite of the utility model, right according to ordinary technical knowledge and the conventional means in this field the modification, replacement or the change of other multiple forms that above-mentioned structure made all should fall within the protection scope of the utility model.

Claims

1. An audio device for a conference, characterized in that: the noise reduction circuit comprises an N-type MOSFET tube, a control signal generator and a charge and discharge circuit, wherein the drain electrode of the N-type MOSFET tube is connected between the sound output device and the audio signal emitting device, the source electrode of the N-type MOSFET tube is grounded, and the charge and discharge circuit is connected between the grid electrode of the N-type MOSFET tube and the control signal generator.

2. The audio apparatus for conference as set forth in claim 1, wherein: the charge and discharge circuit comprises a resistor and a capacitor, the resistor is connected between the grid of the N-type MOSFET and the control signal generator, one end of the capacitor is connected between the resistor and the grid of the N-type MOSFET, and the other end of the capacitor is grounded.

3. The audio apparatus for conference as set forth in claim 1, wherein: the sound output device comprises an operational amplifier and a loudspeaker, wherein the non-inverting input end of the operational amplifier is connected with the audio signal emitting device and the noise reduction circuit, the output end of the operational amplifier is connected with the loudspeaker, and the inverting input end of the operational amplifier is connected between the output end and the loudspeaker.

4. The audio apparatus for conference as set forth in claim 3, wherein: the operational amplifier is connected with a power supply.

5. The audio apparatus for conference as set forth in claim 1, wherein: the audio signal emitting device comprises a signal generator, a voltage output circuit and a voltage reduction resistor.