CN201054780Y

CN201054780Y - Automatic noise reduction earphone

Info

Publication number: CN201054780Y
Application number: CNU2007200523601U
Authority: CN
Inventors: 何积军
Original assignee: Actions Semiconductor Co Ltd
Current assignee: ACTIONS (ZHUHAI) TECHNOLOGY CO., LTD.
Priority date: 2007-06-05
Filing date: 2007-06-05
Publication date: 2008-04-30
Anticipated expiration: 2017-06-05

Abstract

The utility model discloses an automatic noise reduction earphone, comprising a voice collector used to collect outside background noise, an A/D transformation module, an adder, a D/A transformation module and a voice terminal player. The voice collector is installed on an external earphone jack connection line. The output of the voice collector is connected with the signal input end of the adder through the A/D transformation module. The playback electrical signal output by the system is connected to the other signal input end of the adder. The adder output end is connected with the voice terminal player through the D/A transformation module. The utility model can reduce the noise actively and effectively in various noise background environments. And the utility model is simple in circuit structure and the cost is low.

Description

Automatic noise cancelling headphone

Technical field

The utility model relates to a kind of earphone, especially relates to a kind of automatic noise cancelling headphone.

Background technology

In voice applications, earphone is the most portable the most common output equipment, and the portable applied environment of earphone has determined the complexity of its background, wherein is no lack of abominable background noise is arranged.Present earphone noise-reduction method all is that audion terminal is delivered in background noise sampling back paraphase, produces the acoustical signal close with the background noise amplitude, that phase place is opposite, and the two offsets, thereby arrives the purpose of noise reduction.As described in the patent No. 02227931.8, gather behind the background noise through the anti-phase ear port that feeds back to of simple discrete analog element being positioned on the same circuit board of microphone and earphone with microphone; But this structure noise reduction is poor, can not effectively use under complex environment, and is too big as background noise, can not normally use at all, realizes that in addition cost is also higher.As described in number of patent application 200410058578.9, its block diagram is formed as Fig. 1, gather the voice signal that background noise and earphone send simultaneously with microphone, the voice output parts of microphone and earphone lean on very closely, behind the A/D conversion module, the recipient's signal that must receive through the earphone that just can inversely add after sef-adapting filter and the Noise Estimation resume module again, send voice signal by D/A conversion module and earphone at last, this framework noise reduction is better, but complex structure realizes that cost is also higher.

The utility model content

The purpose of this utility model is to provide a kind of automatic noise cancelling headphone, in various noise background environments, can both effectively reach active noise reduction, and circuit structure is simple simultaneously, realizes that cost is also low.

The purpose of this utility model can realize by following technical measures: a kind of automatic noise cancelling headphone comprises the sound collector that is used to gather extraneous background noise, the A/D conversion module that is used for the analog electrical signal that sound collector produces is converted to anti-phase noisy digit level signal output; Be used for system is exported the signal of telecommunication of playback and the adder that anti-phase noisy digit level signal is carried out computing; Be used for the digital signal of adder output is converted to the D/A conversion module of analog electrical signal output; The audio terminal player; Described sound collector places on the line of the outer jointing holes of earphone; The output of sound collector is through a signal input part of A/D conversion module access adder, and the signal of telecommunication of system's output playback inserts another signal input part of adder, and the output of adder inserts the audio terminal player through the D/A conversion module.

The utility model connects digital raising frequency circuit and digital filter circuit successively between the signal of telecommunication access adder of system's output playback; The raising frequency circuit needs the digital signal of playback to do the raising frequency processing system; Filter circuit is done low-pass filtering treatment with up-conversion signal, during the filtering raising frequency signal energy at the composition that duplicates of HFS, thereby eliminate the influence of raising frequency to high frequency spectrum, guaranteed the quality of signal.

The utility model maintains a certain distance microphone and earphone, makes microphone can't collect the voice signal that earphone sends, and only can collect the real background noise that needs processing.Microphone picks up background noise automatically, is superimposed with the paraphase composition of this background noise in audio frequency output prime, thereby offsets at current this paraphase composition of final body and this background noise of earphone, reaches active noise reduction.Its concrete advantage is as follows:

1. the applied environment of suitable complexity that can be initiatively, no matter the size of its background noise realizes noise reduction preferably easily;

2. owing to can reach excellent using character easily, thus the user can be under the less situation of output sound use equipment, very little to the damage of auditory system, prevented damage to auditory system;

3. simplified structure is simple greatly for the framework of Shi Xianing, is easy to integratedly, realizes that cost is low relatively.

Description of drawings

Fig. 1 is the principle composition frame chart of prior art;

Fig. 2 is a principle composition frame chart of the present utility model;

Embodiment

As shown in Figure 2, the utility model comprises a microphone voice collector, gathers extraneous background noise; The Audio Players of a general earphone is play the useful signal that really will broadcast; A general A/D conversion module is used to receive the analog electrical signal that sound collector produces, and exports anti-phase noise digital signal level; A raising frequency circuit commonly used needs the digital signal of playback to do raising frequency system and handles; A low-pass filter circuit commonly used is done low-pass filtering treatment with up-conversion signal; A general adder Module, the anti-phase addition of digital signal of the ambient noise signal that signal that filter circuit is sent here and A/D conversion module are sent here; A general D/A conversion module, the hybrid digital signal Vout that adder is produced is transformed to analog signal.

Microphone fixedly places on the line of the outer jointing holes of earphone, so only gathers background noise, does not gather the voice signal that the audio terminal player sends; Background noise becomes analog electrical signal by microphone, then is transformed to digital electric signal Vnoise by the A/D conversion module, is input to the reverse port of adder; Microcontroller output in the original system will be by the digital signal of headphones playback, earlier after after buffer, raising frequency processing of circuit and the filter circuit processing, the signal Vsignal of generation is input to the forward port of adder; In adder Vsignal and the reverse addition of Vnoise are obtained hybrid digital signal Vout, deliver to the D/A conversion module then and be transformed to the continuous signal of telecommunication of simulation, the sound playing by earphone is transformed to sound wave and sounds at last.Owing to be superimposed with the constant amplitude paraphase composition of background noise in the sound wave that the sound playing of this earphone produces, just in time offset with the background noise stack back of external environment, thereby arrive the purpose of automatic noise reduction, make the earphone wearer only hear the melodious signal sound of system plays, and do not have outside noise.

Claims

1. automatic noise cancelling headphone is characterized in that comprising:

Be used to gather the sound collector of extraneous background noise;

Be used for the analog electrical signal that sound collector produces is converted to the A/D conversion module of anti-phase noisy digit level signal output;

Be used for system is exported the signal of telecommunication of playback and the adder that anti-phase noisy digit level signal is carried out add operation;

Be used for the digital signal of adder output is converted to the D/A conversion module of analog electrical signal output;

The audio terminal player;

Described sound collector places on the line of the outer jointing holes of earphone; The output of sound collector is through a signal input part of A/D conversion module access adder, and the signal of telecommunication of system's output playback inserts another signal input part of adder, and the output of adder inserts the audio terminal player through the D/A conversion module.

2. automatic noise cancelling headphone according to claim 1 is characterized in that connecting digital raising frequency circuit and digital low-pass filtering circuit successively between the signal of telecommunication access adder of system's output playback.