Patent ID: 7809129
Filing Date: 2010-10-05
Classification: H04M

Abstract:
1. An echo canceller, comprising: a noise environment classifier that detects a level of noise present on an uplink signal path and generates a noise classifier based on the level of noise; a double talk detector that: a first multi-band filter that receives a first input signal and generates a first plurality of sub-band signals, each of the first plurality of sub-band signals comprising a respective sub-band of the first input signal; a second multi-band filter that receives a second input signal and generates a second plurality of sub-band signals, each of the second plurality of sub-band signals comprising a respective sub-band of the second input signal; a plurality of adaptive filters, each of the adaptive filters receiving the double talk flag and a respective one of the second sub-band signals, and filtering the second sub-band signal in accordance with the double talk flag to generate a filtered second sub-band signal; a plurality of adders, each of the adders generating a respective third sub-band signal that is a difference of a respective one of the first sub-band signals and a respective one of the respective filtered second sub-band signals; and a non-linear filter that processes the double talk flag, the noise classifier and an uplink signal to generate an output signal having reduced echo.