Acoustic and electronic echo cancellation
US6421443B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 23, 1999 |
| Grant date | Jul 16, 2002 |
| Priority date | — |
| Expiry date | Jul 23, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06J1/00
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A transmitted signal is coupled through a coarse delay and a fine delay to one input of a correlator. Another input of the correlator is coupled to a received signal. The delays are adjusted for maximum correlation and the output of the fine delay is subtracted from the received signal to reduce or eliminate an echo. The delays operate by sampling the signal and storing the samples at successive storage sites. The storage sites are read a predetermined time later, producing the delay. The read operation for the coarse echo includes three readings from separate sites and using the correlation products to indicate the magnitude and direction for changing the delay.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.