Echo cancelling process with improved phase control
US6278785A · kind A · utility
22Cited by
23References
16Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 21, 1999 |
| Grant date | Aug 21, 2001 |
| Priority date | — |
| Expiry date | Sep 21, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M9/082
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An echo is cancelled from a composite signal by providing a coarse phase adjustment, a fine phase adjustment, an amplitude correction, and then subtracting the phase shifted signal from the composite signal. In the coarse adjustment, the phase is slightly under-corrected, thereby allowing the fine adjustment to proceed in a single direction and decreasing convergence time. Correlation is provided by an amplitude inverting multiplying circuit and phase adjustment is provided by an all-pass phase shift network combined with an impedance multiplier coupled to the phase shift network.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.