Multiple frequency adaptive noise filter for removing interference signals from a frequency band having a desired signal
US4673982A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 4, 1984 |
| Grant date | Jun 16, 1987 |
| Priority date | — |
| Expiry date | Oct 4, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H21/0012
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A multiple frequency adaptive filter system for filtering undesired periodic and/or correlated interference signals contained in the same frequency band as a desired input signal. The filter system is capable of filtering at least two sinusoidal interference signals and incorporates a negative feedback loop having a transfer function of that of narrow band-pass multiple filter. The feedback loop using interference frequencies generates a corresponding interference enhanced output signal. This enhanced output signal is combined with the input signal whereby to produce an error signal which corresponds to the desired signal contained in the input frequency band. A double or quadruple filter system is also described as examples of the present invention. The filter system is suitable for removing modulated sinusoidal interference and particularly for reducing TV co-channel interference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.