CN201185081Y

CN201185081Y - Echo arrester capable of eliminating a plurality of echoes

Info

Publication number: CN201185081Y
Application number: CNU2008200573465U
Authority: CN
Inventors: 刘晓露; 张子刚; 董必涛
Original assignee: SHANGHAI AVCON INFORMATION TECHNOLOGY Co Ltd
Current assignee: Information Technology Co., Ltd. Shanghai Avcon
Priority date: 2008-04-16
Filing date: 2008-04-16
Publication date: 2009-01-21
Anticipated expiration: 2018-04-16

Abstract

The utility model relates to an echo eliminator that can eliminates different echoes, which comprises a parameter adjustable subtracter that can adjust the subtract time parameter according to the time difference of the echoes so as to eliminate the corresponding echoes corresponding to the inputted mixed audio, and a non-linear processing circuit that is connected with the parameter adjustable subtracter and is used for performing the non-linear processing of the audio signal with the echoes being eliminated that is outputted by the subtracter so as to reduce the non-linear distortion factor of the audio signal, so that different echoes that are produced at different video conference fields can be effectively removed, thereby effectively improving the quality of the audio signal.

Description

Have and to eliminate the echo canceller of multiple echo

Technical field

The utility model relate to a kind of have can eliminate the echo canceller of multiple echo.

Background technology

Video conferencing system is exactly for people can't gather same place when carrying out meeting, and a kind of modernization means of a kind of high-tech communication, cooperation and decision-making is provided.When meeting is carried out, exist in the time of owing to microphone and audio amplifier, the sound that broadcasts in audio amplifier can enter the microphone generating echo once more.Present echo canceller designs at this kind situation just, the sound that but present echo canceller is just directly passed to microphone at audio amplifier carries out echo to be handled, and in fact because the difference of meeting occasion, the barrier of audio amplifier through the external world reflects the various situations that enter microphone once more, echo canceller is not correspondingly processed, and the sound signal that causes the received audio signal end to play out thus has noise or distortion etc.

Therefore, how can targetedly the quality that different echoes is handled to improve sound signal have been become the technical task that those skilled in the art need to be resolved hurrily in fact according to the field conditions of meeting.

The utility model content

The purpose of this utility model be to provide a kind of have can eliminate the echo canceller of multiple echo, to improve the tonequality of sound signal.

In order to achieve the above object, the utility model provides to have can eliminate the echo canceller of multiple echo, and it comprises: have and can regulate the parameter adjustable subtracter of subtract time parameter so that the corresponding echo in the mixed audio of input is removed according to the time order and function difference that echo forms; Be connected with the adjustable subtracter of described parameter and be used for the sound signal of removing echo of described adjustable subtracter output is carried out the non-linear processing circuit of Nonlinear Processing with the nonlinear distortion degree that reduces sound signal.

Wherein, described echo comprises the echo that the wall in the echo that the wall of echo that outdoor echo, small conference room wall produce, medium-sized meeting room produces, large-scale auditorium produces, wherein, described outdoor echo only comprises the echo that the local audio playing device produces, and the time order and function that each echo forms is in proper order: the required echo of echo that the wall in echo required time＜large-scale auditorium that the wall of echo required time＜medium-sized meeting room that the small conference room wall produces produces produces.

In sum, of the present utility model have the echo canceller that can eliminate multiple echo and have according to the required time of echo that forms in different Conference Rooms and adopted the adjustable subtracter of parameter that different echoes is removed afterwards earlier, can improve the effect of echo cancellation thus, effectively improve the tonequality of sound signal.

Description of drawings

Fig. 1 is the schematic block circuit diagram that can eliminate the echo canceller of multiple echo that has of the present utility model.

Fig. 2 for of the present utility model have the echo canceller that can eliminate multiple echo the embodiment illustration be intended to.

Audio frequency moved towards simple block diagram when Fig. 3 was video conference.

Fig. 4 is the convertible several modes figure of echo canceller for it.

Embodiment

See also Fig. 1 and Fig. 2, of the present utility model have the echo canceller that can eliminate multiple echo and mainly comprise: the adjustable subtracter of parameter, and non-linear processing circuit etc.

The adjustable subtracter of described parameter has and can regulate the subtract time parameter will (being near-end echo and far-end echo in the mixed audio of input according to the time order and function difference that echo forms, promptly contain the adjustable subtracter of echo signal input parameter) corresponding echo removed, in existing video conferencing system, the place of being adopted of holding a meeting can be outdoor, small conference room, medium-sized meeting room, large-scale auditorium etc., therefore the echo that produces in different places has nothing in common with each other, for example, echo in outdoor generation only comprises the echo that the local audio playing device produces, the echo that produces at small conference room (10～50 square metres) comprises the echo that the local audio playing device produces, and the echo of small conference room wall generation, the echo that produces at medium-sized meeting room (50～100 square metres) comprises the echo that the local audio playing device produces, and the echo of the wall of medium-sized meeting room generation, the echo that (＞100 square metres) produce in large-scale auditorium comprises the echo that the local audio playing device produces, and the echo of the wall in large-scale auditorium generation, therefore the time order and function of the echo that produces in different places can be in proper order: the required echo of echo that the wall in echo required time＜large-scale auditorium that the wall of echo required time＜medium-sized meeting room that the small conference room wall produces produces produces, therefore can in the adjustable subtracter of described parameter, corresponding echo be removed by the adjusting of parameter.

Described non-linear processing circuit is connected with the adjustable subtracter of described parameter and is used for the sound signal of removing echo of described adjustable subtracter output is carried out Nonlinear Processing to reduce the nonlinear distortion degree of sound signal, because the inner structure and the principle of nonlinear distortion circuit and the adjustable subtracter of parameter are familiar with by those skilled in the art, so no longer describe in detail at this.

See also Fig. 3, audio frequency moved towards simple block diagram when it was video conference, promptly enter local audio amplifier, enter the sound that enters local microphone after local spokesman of having of local microphone and local audio amplifier sound and sound reflect through one or many once more from the long-range sound of bringing in.Only remaining local spokesman's sound need be transferred to far-end after the filtering of microphone process echo canceller.In this process, echo canceller is if with a kind of algorithm, cause possibly except that audio fruit efficient not high.At different scenes, algorithm corresponding with it arranged, the parallel effect that exists raising to greatest extent to eliminate echo of such various modes.Under outdoor pattern, what enter local microphone so does not then consider to reflect sound, and the just remote port of elimination transmits the sound that local audio amplifier enters.In small conference room (10～50 square metres) pattern, at such situation, the reflection sound relative spacing time of enunciator and audio amplifier is little, and the algorithm of echo processing module is respective change also.Medium-sized meeting room (50～100 square metres), the reflection sound is moderate at interval.And in large-scale auditorium (＞100 square metres), because the complicacy of scene, the sound of spokesman and audio amplifier may form repeatedly reflection, and the size of sound has certain variation, just increases the algorithm to the echo processing module under this pattern undoubtedly.The user selects different mode to come the specific aim operation, removal of impurities audio in meeting-place is really shown, but also improved echo processing module work efficiency greatly.

See also Fig. 4 again, it is the convertible several modes figure of echo canceller, has the signal of echo in echo processor input, the echo filtering, exports remaining useful sound through Nonlinear Processing by subtracter again.Under different mode, the computing of subtracter has subtract time degree varies sample, and further we can make DSP (digital signal processor) use LMS (self-adaptation) algorithm to reach accurate more purpose under every kind of pattern.Therefore, as long as extraneous echo changes, the echo processor can best efficient be removed echo.

In sum, of the present utility model have the echo canceller that can eliminate multiple echo and produce the required time according to echo and have and adopted the adjustable subtracter of parameter that different echoes is removed afterwards earlier, improved the effect of echo cancellation thus, effectively improve the tonequality of sound signal, make the user can hear teleconference the other side's sound clearly.

Claims

1. one kind has and can eliminate the echo canceller of multiple echo, it is characterized in that comprising:

Have and to regulate the parameter adjustable subtracter of subtract time parameter according to the time order and function difference that echo forms so that the corresponding echo in the mixed audio of input is removed;

Be connected with the adjustable subtracter of described parameter and be used for the sound signal of removing echo of described adjustable subtracter output is carried out the non-linear processing circuit of Nonlinear Processing with the nonlinear distortion degree that reduces sound signal.

2. as claimed in claim 1 have can eliminate the echo canceller of multiple echo, it is characterized in that: described echo comprises the echo that the wall in the echo that the wall of echo that outdoor echo, small conference room wall produce, medium-sized meeting room produces, large-scale auditorium produces, wherein, described outdoor echo only comprises the echo that the local audio playing device produces, and the time order and function that each echo forms is in proper order: the required echo of echo that the wall in echo required time＜large-scale auditorium that the wall of echo required time＜medium-sized meeting room that the small conference room wall produces produces produces.