Method and apparatus for canceling echo accounting for delay variations
AssigneeQUALCOMM Incorporated
InventorGilbert C. Sih
Life of this patent
Estimating the term…
Abstract
A method and apparatus for detecting and correcting for variations in the flat delay, which permits smooth echo canceller operation even under dynamic delay conditions. In a delay monitor, the received signal is compared against delayed versions of the echo estimate to determine whether a shift in the echo delay has occurred. If such a shift in delay has occurred then a signal indicating the amount of the shift is to the adaptive filter of the echo canceller and the filter taps are updated in accordance with the delay shift value.
Claims18
An echo canceller comprising:
- delay monitor means for receiving an echo estimate signal and a received signal and for monitoring an echo flat delay and providing a delay signal indicative of said monitored echo flat delay;
- and
- adaptive filter means for generating an echo estimate responsive to said delay signal.
A method for echo cancellation comprising the steps of:
- monitoring an echo flat delay based upon a received signal and an echo estimate signal;
- providing a delay signal indicative of said monitored echo flat delay;
- and
- generating an echo estimate responsive to said delay signal.
An echo canceller comprising:
- delay monitor having a first input for receiving a received signal and having a second input for receiving an echo estimate signal and having an output;
- and
- adaptive filter means having an input coupled to said delay monitor output and having an output.
Dependencies are inferred from the claim text.