Method and apparatus for computing measures of echo
US5943645A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1997 |
| Grant date | Aug 24, 1999 |
| Priority date | — |
| Expiry date | Apr 24, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B3/20
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In methods and apparatus for computing measures of echo of a far end signal in a near end signal, the evolution over time of frequency spectra of the near end and far end signals are compared to compute a measure of the echo. A far end spectrum of the far end signal and a near end spectrum of the near end signal are determined for each of a plurality of successive time intervals. A respective measure of correlation is determined for each of a plurality of spectrum pairs, each spectrum pair comprising a respective near end spectrum and a respective far end spectrum, the far end spectrum corresponding to a time interval which lags a time interval corresponding to the near end spectrum by a respective time lag. The measures of correlation are compared to determine a maximum measure of correlation which can be used as a measure of echo. The echo measure computation technique is particularly suitable for use in echo suppressors for digital cellular telephony systems, but has other applications.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.