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Automatic gain control amplitude-limiting method capable of keeping effective dynamic range of voice digital signal and preventing peak clipping

An automatic gain control and digital signal technology, applied in signal processing, transducer circuits, sensors, etc., can solve problems such as digital signal peak clipping, signal distortion, and affecting voice quality, so as to avoid signal peak clipping and reduce signal spectrum Distortion, the effect of ensuring the effective dynamic range

Active Publication Date: 2018-06-29
SHANGHAI XIAODU TECHNOLOGY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The traditional clipping processing usually adopts the "hard cut" method with a fixed value threshold, which will cause the digital signal to clip, cause signal distortion, and affect voice quality
Usually, too much peak clipping and too strong will cause the voice signal to have a bad effect of "cracking sound". This is the defect of the traditional automatic gain control limiting method when controlling the signal overflow.

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  • Automatic gain control amplitude-limiting method capable of keeping effective dynamic range of voice digital signal and preventing peak clipping
  • Automatic gain control amplitude-limiting method capable of keeping effective dynamic range of voice digital signal and preventing peak clipping
  • Automatic gain control amplitude-limiting method capable of keeping effective dynamic range of voice digital signal and preventing peak clipping

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Embodiment Construction

[0021] In order to make the purpose, content and advantages of the present invention clearer, the specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0022] Assuming that a 16-bit sampling bit width is used, the absolute value of the amplitude of the voice digital signal is at most 32767. Set the amplitude upper limit threshold of PCM to UPPER_LIMIT (UPPER_LIMITfigure 1 This is the processing flow for all input signals in this processing method.

[0023] The processing method of the present invention performs segmentation processing on the signal which is close to overflow or even exceeds the overflow range in the floating-point signal domain. It is assumed that the signal amplitude is divided into k sub-intervals, which are intervals 0, 1, 2, ..., k-1. The lower threshold of each subinterval is ω j , the control coefficient is α j . The data is sequentially proc...

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Abstract

The invention provides an automatic gain control amplitude-limiting method capable of keeping the effective dynamic range of a voice digital signal and preventing peak clipping. The signal amplitude is divided into k sub-intervals; furthermore, a lower threshold (omega<j>) and a control coefficient (alpha<j>) are set for each sub-interval; a processed signal sub-interval is processed at the position approaching the upper threshold value; therefore, amplitude retarding approaches the upper limit; furthermore, the amplitude is controlled to not beyond the upper limit; therefore, the effective dynamic range of the signal is ensured; peak clipping of the signal due to use of an amplitude limiter is avoided; and the signal spectrum distortion is reduced.

Description

technical field [0001] The invention relates to the field of speech signal processing, and more precisely relates to automatic gain control processing and a solution for improving the quality of speech signals. technical background [0002] When the speech signal propagates in the air, its sound wave diverges in a spherical shape, and the sound wave energy decays exponentially with the increase of the propagation distance. When a microphone is used to pick up sound, the amplitude (or energy) of the signal collected by the microphone will be severely attenuated when the distance from the sound source increases. Therefore, usually after the signal is collected by the microphone, automatic gain control (AGC, Automatic Gain Control) processing is used to enhance the weak signal. [0003] The automatic gain control processing can usually be processed by hardware circuit or software. Hardware circuit processing is aimed at analog signals, and software processing is aimed at digi...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04R3/00
CPCH04R3/00H04R2430/00
Inventor 邓滨宋晨枫
Owner SHANGHAI XIAODU TECHNOLOGY CO LTD