Signal trap device and method, recording medium replay device and method, and signal extraction device and method
US6081537A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 20, 1997 |
| Grant date | Jun 27, 2000 |
| Priority date | — |
| Expiry date | May 20, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/83
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A signal trap device and method for trapping a desired FM signal out of a frequency multiplexed signal where a plurality of FM signals are included in a frequency multiplexed form. A replay signal reproduced from a video cassette tape is supplied directly to a subtracter while being fed to a fixed delay circuit and a variable delay circuit to be delayed therein by a predetermined delay time. The delayed signal is supplied also to the subtracter, which then subtracts the delayed signal from the reproduced replay signal and outputs the result of such subtraction therefrom. The delay time of the fixed delay circuit is set to correspond to the center frequency of the carrier of the desired FM signal to be trapped. Meanwhile the delay time of the variable delay circuit is so set as to correspond to the signal obtained by demodulating the desired FM signal. Thus, the desired FM signal can be trapped properly without any harmful influence on the other FM signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.