Speech coding method applying noise reduction by modifying the codebook gain

摘要

The invention refers to a method for encoding an acoustic signal (y(n)) containing a speech component and a noise component by using an analysis through synthesis method, wherein for encoding the acoustic signal a synthesised signal is compared with the acoustic signal for a time interval, said synthesised signal being described by using a fixed codebook and an associated fixed gain, comprising the steps: Determining a fixed gain (gy(m)) of the acoustic signal (y(n)) for the time interval; Extracting an estimated fixed gain (g/< ANd> n) of the noise component from the acoustic signal (y(n)) for the time interval; Deriving an estimate of the fixed gain (g/< ANd> s(m)) of the speech component by subtracting said fixed gain of the noise component from the fixed gain (gy(m)) of the acoustic signal for the time interval.