Patent ID: 6181791
Filing Date: 2001-01-30
Classification: H04B

Abstract:
An apparatus for communicating over a communications channel and having reduced undesired local echo, the apparatus comprising:a transmitter for generating a transmit signal to the communications channel in a frequency band outside a voice frequency band;a programmable scaler connected to said transmitter for generating a scaled replica of the transmit signal based upon a scale control signal;a receiver for receiving signals from the communications channel within or outside the voice frequency band and being susceptible to undesired local echo from the transmit signal, said receiver being connected to the scaler for reducing the undesired local echo by subtraction of the scaled replica of the transmit signal; andecho reducing means for sensing received signal power and for generating the scale control signal and comprising an encoder that generates the scale control signal based upon the received signal power and responsive to sensing a minimum received signal power to thereby reduce the undesired local echo.