CN216437465U

CN216437465U - Television echo cancellation system based on single-directional microphone

Info

Publication number: CN216437465U
Application number: CN202123077741.4U
Authority: CN
Inventors: 雷伟
Original assignee: Sichuan Changhong Electric Co Ltd
Current assignee: Sichuan Changhong Electric Co Ltd
Priority date: 2021-12-09
Filing date: 2021-12-09
Publication date: 2022-05-03
Anticipated expiration: 2031-12-09

Abstract

The utility model relates to a TV set echo cancellation field, concretely relates to TV echo cancellation system based on single directional microphone, simple structure has reduced the distortion that electro-acoustic conversion process introduced. The utility model discloses TV echo cancellation system based on single directional microphone includes a microphone group at least, and the microphone group comprises first microphone and second microphone, and the positive phase output of first microphone is connected with the inverting output of second microphone, as the positive phase output of microphone group; the inverting output end of the first microphone is connected with the non-inverting output end of the second microphone to be used as the inverting output end of the microphone set; the first microphone is arranged facing a user and used for collecting a user voice instruction; the second microphone is a single-direction microphone, is arranged facing the sound outlet surface of the television loudspeaker and is used for collecting sound signals of the loudspeaker. The utility model is suitable for a TV set echo cancellation.

Description

Television echo cancellation system based on single-directional microphone

Technical Field

The utility model relates to a TV set echo cancellation field, concretely relates to TV echo cancellation system based on single directional microphone.

Background

The far-field voice technology for realizing the non-contact control equipment just conforms to the trend of television intellectualization, along with the booming of the technology in recent years, so-called far-field voice television products are more and more common, and various families in the industry actively match the agility of television response users, wherein echo cancellation is of great importance as a key technology for directly influencing the quality of front-end signals. The basic principle of echo cancellation is to use the sound of the television itself as a reference signal and subtract the reference signal from the mixed signal recorded by the microphone, so as to achieve the purpose of extracting pure human voice, i.e. so-called echo cancellation. The echo and reference signals are here equivalent two expressions and the following description does not distinguish.

The current echo cancellation method of the smart television is divided into soft mining and hard mining. The soft picking does not need an external circuit, and the signal of the main chip push power amplifier is directly sent to the voice module for echo cancellation; and in the hard acquisition, a signal output to a loudspeaker by a power amplifier is used as a reference signal, and the reference signal is sent to a voice module for echo cancellation through a filtering circuit, a voltage reduction circuit and a direct current isolation circuit. The former method limits the television aq (audio quality) debugging and has poor cancellation effect. The latter method cannot include nonlinear distortion introduced by a loudspeaker, has a large difference with a signal recorded by a microphone, and has a complex circuit structure and poor compatibility with a multi-functional amplifier architecture.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing a TV echo cancellation system based on single directional microphone, simple structure has reduced the distortion that the electroacoustic conversion process introduced, and the signal of collecting with actual microphone array is pressed close to completely to the reference signal, does not influence TV AQ moreover and debugs.

The utility model adopts the following technical scheme to realize the purpose, the television echo cancellation system based on the single directional microphone at least comprises a microphone group, the microphone group is composed of a first microphone and a second microphone, and the positive phase output end of the first microphone is connected with the reverse phase output end of the second microphone to be used as the positive phase output end of the microphone group; the inverting output end of the first microphone is connected with the non-inverting output end of the second microphone to be used as the inverting output end of the microphone set; the first microphone is arranged facing a user and used for collecting a user voice instruction; the second microphone is a single-direction microphone, is arranged facing the sound outlet surface of the television loudspeaker and is used for collecting sound signals of the loudspeaker.

Further, in order to improve the ability of the first microphone to collect sound signals, the first microphone is an omni-directional microphone.

Furthermore, in order to improve the anti-interference capability of the output signal, the first microphone and the second microphone are analog microphones of a differential output interface.

Furthermore, in order to supply power to the microphones, the power input ports of the first microphone and the second microphone are connected to the positive pole of the external power supply, and the ground ports of the first microphone and the second microphone are connected to the negative pole of the external power supply.

Further, in order to improve the signal acquisition capability, the number of the microphone sets is determined according to the number of the speakers which need to acquire signals.

Compare in the echo cancellation mode of current soft mining and hard mining, the utility model discloses the reference signal of collection has contained the whole details of whole vocal system, including AQ processing of audio front end and rear end, all contents such as nonlinear distortion that the electro-acoustic conversion speaker introduced, guaranteed from the essence that its reference signal is truest and first microphone gathers TV originally and make an uproar completely unanimous, guaranteed the quality of echo cancellation's echo like this with regard to fundamentally. When the television sounds, the first microphone and the second microphone are excited by the loudspeaker, and synchronous analog signals are output in a time domain. The second microphone is connected in parallel to a group of data output by adopting a connection method in reverse phase with the first microphone, the phases of the analog differential audio frequencies are just opposite and offset with each other, and the effects of eliminating echo, reducing noise and retaining human voice signals can be achieved.

Drawings

Fig. 1 is a schematic diagram of the circuit structure of the microphone set of the present invention.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings.

The utility model discloses TV echo cancellation system based on single directional microphone includes a microphone group at least, the microphone group comprises first microphone and second microphone, the positive phase output of first microphone is connected with the inverting output of second microphone, as the positive phase output of microphone group; the inverting output end of the first microphone is connected with the non-inverting output end of the second microphone to be used as the inverting output end of the microphone set; the first microphone is arranged facing a user and used for collecting a user voice instruction; the second microphone is a single-direction microphone, is arranged facing the sound outlet surface of the television loudspeaker and is used for collecting sound signals of the loudspeaker. A unidirectional microphone means that its sensitivity is highest at 90 degrees on its front side and that it only responds to the loudspeaker signals emitted by the sound-emitting side of the facing loudspeaker, i.e. it only captures the signals of the television loudspeaker.

In this scheme, the first microphone is an omni-directional microphone. The ability of the first microphone to collect sound signals is improved.

The first microphone and the second microphone are analog microphones of the differential output interface. The differential output is different from the traditional method of one signal wire and one ground wire, the differential transmission transmits signals on the two wires, the amplitudes of the two signals are equal, and the phases of the two signals are opposite. The signals transmitted on these two wires are differential signals. Therefore, the anti-interference capability of the output signal can be improved.

The power supply input ports of the first microphone and the second microphone are connected with the positive pole of an external power supply, and the grounding ports of the first microphone and the second microphone are connected with the negative pole of the external power supply, so that the power supply of the microphones is realized. Of course, the ground port may be grounded.

The number of the microphone groups is determined according to the number of the loudspeakers needing to collect signals, so that the comprehensive signal collection capacity is improved.

Fig. 1 is a schematic circuit diagram of a microphone set of the present invention, as shown in fig. 1, including two microphone sets, where the first microphone set includes a first microphone U1 and a second microphone U2, and a positive phase output terminal OUT + of the first microphone U1 is connected to a negative phase output terminal OUT-of the second microphone U2, and serves as a positive phase output terminal MIC1+ of the first microphone set; the inverting output end OUT-of the first microphone U1 is connected with the non-inverting output end OUT + of the second microphone U2 to serve as the inverting output end MIC 1-of the first microphone group; the power supply input ports VDD of the first microphone U1 and the second microphone U2 are respectively connected to an external power supply MIC _3V3, the MIC _3V3 provides 3.3V, and the ground ports GND of the first microphone U1 and the second microphone U2 are grounded.

The second microphone set comprises a third microphone U3 and a fourth microphone U4, which are connected in the same manner as the microphones of the first microphone set.

When echo is processed, firstly, the system is powered on, the sound reproduction system outputs audio, and an external user activates voice control equipment with a voice function; the first microphone is opposite to the user and used for collecting a user voice instruction and a loudspeaker signal of the television; a second single directional microphone facing the speaker collects only speaker audio emitted by the television; the first microphone and the second microphone adopt an inverse connection method, respond to the same reference signal, output differential audio signals with completely same content and completely opposite phases in a time domain, the loudspeaker signals output by the first microphone and the loudspeaker signals output by the second microphone are mutually offset to perform echo cancellation, and only pure human voice signals are output after the first microphone is denoised to complete the echo cancellation.

However, in practical applications, due to the reverberation of the space, there are many paths for the speaker signal to pass through to the first microphone, such as walls, furniture, appliances, moving people, and pets, various sound reflections are formed, and the time when the same signal reaches the first microphone is different, so that the signal output by the first microphone inevitably still contains part of the speaker signal after the echo cancellation.

However, compared with the existing echo cancellation modes of soft mining and hard mining, the reference signal acquired by the acquisition method contains all details of the whole sounding system, including all contents of AQ processing at the front end and the rear end of an audio frequency, nonlinear distortion introduced by an electroacoustic conversion loudspeaker and the like, and the reference signal is guaranteed to be truest and completely consistent with the noise of a television acquired by a microphone 1, so that the quality of echo cancellation is guaranteed fundamentally.

To sum up, the utility model provides a current echo cancellation effect relatively poor, can't gather whole sound reproduction system tuning details, speaker distortion completely, restriction AQ debugging, the realization is complicated moreover, and problem with high costs can help effectively promoting whole far field voice system's front end output signal quality, guarantees far field voice user's experience.

Claims

1. The television echo cancellation system based on the single directional microphone is characterized by at least comprising a microphone set, wherein the microphone set consists of a first microphone and a second microphone, and a positive phase output end of the first microphone is connected with an inverse phase output end of the second microphone to be used as a positive phase output end of the microphone set; the inverting output end of the first microphone is connected with the non-inverting output end of the second microphone to be used as the inverting output end of the microphone set; the first microphone is arranged facing a user and used for collecting a user voice instruction; the second microphone is a single-direction microphone, is arranged facing the sound outlet surface of the television loudspeaker and is used for collecting sound signals of the loudspeaker.

2. The unidirectional microphone based television echo cancellation system of claim 1, wherein the first microphone is an omni-directional microphone.

3. The single-directional-microphone-based television echo cancellation system of claim 1, wherein the first microphone and the second microphone are analog microphones of a differential output interface.

4. The single-directional microphone based television echo cancellation system of claim 1, wherein the power input ports of the first and second microphones are connected to a positive terminal of an external power source, and the ground ports of the first and second microphones are connected to a negative terminal of the external power source.

5. The single-directional-microphone-based television echo cancellation system of claim 1, wherein the number of microphone sets is determined by the number of speakers that are required to acquire signals.