Patent ID: 6298139
Filing Date: 2001-10-02
Classification: H03G

Abstract:
A method for maintaining a constant speech envelope using automatic gain control comprising:sampling actual audio signal amplitudes;computing a running mean on each sample by weighting a previous mean, weighting a current sample and adding the weighted previous mean and weighted current sample;using the running mean to alter the current sample;selecting the weighting by comparing the amplitude of the current sample with the value of the previous mean;if the amplitude of the current sample is larger than the value of the previous mean, weighting the previous mean and current sample more heavily towards the current sample;if the amplitude value of the current sample is smaller than the value of the previous mean, weighting the previous mean and current sample more heavily towards the previous mean;so that an indication of an increasing signal relative to previous mean results in an automatic gain control level that more rapidly follows the actual signal and an indication of decreasing signal relative to previous mean results in an automatic gain control level that more slowly follows the actual signal.