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Digital audio automatic gain control method and its system

An automatic gain control, digital audio technology, applied in gain control, amplification control, two-way working system, etc., can solve the problem of excessive signal gain, rarely considering gain control background noise, overflow and other problems

Inactive Publication Date: 2009-02-18
昆山杰得微电子有限公司
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Problems solved by technology

This type of gain method is nonlinear and time-varying. Since the gain cannot be flexibly combined with changes in current signal energy and historical signal energy to automatically adjust the gain, this will cause some signals with large energy to gain too much, resulting in overflow, and some energy Smaller signals don't have enough gain, and simply clipping the overflow signal energy breaks the continuity of the signal and introduces uncomfortable noise
Moreover, the existing technology rarely takes into account the background noise in the gain control process

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  • Digital audio automatic gain control method and its system
  • Digital audio automatic gain control method and its system
  • Digital audio automatic gain control method and its system

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Embodiment Construction

[0020] figure 1 It is a schematic diagram of the digital audio automatic gain control system of the present invention, which is divided into the following functional modules:

[0021] (1) The first power calculation module 101 . This module is used to calculate the power P of the input signal x(n) x (n), where n is the time sequence number. The calculation formula can be

[0022] P x (n) = αP x (n-1)+(1-α)x 2 (n) (1)

[0023] Among them, α is a smoothing factor. The larger α is, the smoother the power change is; the smaller α is, the power changes with the sharp change of the signal. In order to better reflect the volatility of the signal without violent jitter, generally choose 0<α<<1.

[0024] (2) Adaptive filtering module 103 . This module includes three sub-modules: an adaptive filter learning step update module, a filter coefficient update module and a new output signal calculation module. The filter coefficient, that is, the update formula of the gain coefficie...

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Abstract

The invention discloses a automatic gain control method for digital audio frequency comprising following steps: (1) computing instant power of input signal, (2) detecting if signal of step 1 is background noise, (3) updating gain coefficient g(n) according to power information of input signal of step 1 and self-adaptive filtering study step update, (4) producing new output signal according to newgain coefficient of step 3, (5) computing instant power of output signal, (6) shaping gain (7) performing saturation control and output digital audio frequency signal. The inventive digital audio frequency automatic gain system comprises: a first power computing module, self-adaptive filter module, a second power computing module and gain shaping module. The inventive method and system can automatically control gain for digital audio frequency signal, enable output signal more balanced and smooth, and can be used in voice communication and recording system.

Description

technical field [0001] The present invention relates to an automatic gain control technology, in particular to a digital audio automatic gain control technology applied to applications such as voice communication, audio and video conferencing, and digital recording. Background technique [0002] Digital audio automatic gain control (Automatic Gain Control, AGC) is used to perform automatic dynamic gain control on digital audio signals, so that the signal level tends to a user-defined target signal level, and finally obtains a balanced and harmonious voice. This technology is generally used in voice communication and recording systems, and its specific applications include audio and video conferencing, Internet telephony, and digital recording. An efficient digital audio automatic gain control method can ensure that the signal after gain does not appear to be distorted to a certain extent, and cannot perform gain on background noise. The existing digital AGC technology gener...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04M3/56H04N7/15G10L21/00H03G3/20
Inventor 欧阳合程荣周毅汪永宁邹艳
Owner 昆山杰得微电子有限公司
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