Patent ID: 7539300

Claim:
A method of switching between an infinite echo return loss (ERL) mode and a finite ERL mode in an echo cancellation system, said method comprising: determining a first echo return loss enhancement (ERLE) while said echo cancellation system is in said finite ERL mode; determining a first ratio of a first echo signal to a first near-end noise (first ENR) while said echo cancellation system is in said finite ERL mode; defining an infinite ERL threshold (TH infinite ) as a function of said first ENR; switching to said infinite ERL mode as a function of said first ERLE and said TH infinite ; determining a second ERLE while said echo cancellation system is in said infinite ERL mode; determining a second ratio of a second echo signal to a second near-end noise (second ENR) while said echo cancellation system is in said infinite ERL mode; defining a finite ERL threshold (TH finite ) as a function of said second ENR; and switching to said finite ERL mode as a function of said second ERLE and said TH finite .