A kind of feedback noise reduction earphone and its feedback circuit

Abstract

The invention discloses a feedback noise reduction earphone and a feedback circuit therefor, and the feedback circuit comprises a control circuit, and also comprises a noise reduction microphone, wherein the slope of the amplitude response of the noise reduction microphone is negative when the frequency of an input signal is switched to a high frequency from a first frequency value, and the slopeof the phase response is positive. The first frequency value is the frequency of the input signal corresponding to a start point of the phase transition band of an open loop transfer function GH. Theamplitude of the microphone at the first frequency value and the subsequent frequency band is in a negative slope, so that the amplitude decreases after the first frequency value, thereby reducing therise of the noise, destroying the instability condition, and avoiding howling. In addition, the phase with the positive slope can compensate for the high frequency phase, which enlarges the phase margin of a feedback noise control system, thereby further ensuring the stability of the system. The phase compensation can also delay the frequency point of the transition band and widen the phase transition band. The energy distribution of the noise in a wide frequency band can enable the rise of noise heard by the human ears not to be obvious, thereby improving the user experience.

Description

technical field [0001] The invention relates to the technical field of noise processing, in particular to a feedback noise reduction earphone and a feedback circuit thereof. Background technique [0002] With the continuous development of society, noise pollution has attracted more and more attention. Especially the low-frequency noise is more harmful to people's health, and it is also a problem that has not been effectively solved for a long time in the field of noise control. Traditional noise control has little effect on low-frequency noise, and modern active noise control technology can make up for the shortcomings of traditional technology. [0003] The active noise control technology mainly utilizes the principle of sound wave interference to offset the original noise signal by generating a secondary noise that is equal in value and out of phase with the original noise signal through the control circuit. Please refer to figure 1 and figure 2 , figure 1 It is a st...

AI Technical Summary

Problems solved by technology

Not only can effective noise reduction not be performed in this frequency band, but it can also cause an increase in noise and even howling, which affects the user experience.

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