Signal reproducing apparatus
US5218448A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 12, 1990 |
| Grant date | Jun 8, 1993 |
| Priority date | — |
| Expiry date | Dec 12, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/9204
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A signal reproducing apparatus reproduces a video signal from a recording medium in which a first modulation signal has a video signal frequency-modulated at carrier frequency fc and a second modulation wave has a second signal modulated in a lower frequency region than the frequency fc. A frequency demodulation circuit for frequency-demodulates a first modulation wave and subtracts the cross modulation interference generated in the demodulation signal depending on the output from a detecting circuit. A first filter separates the second modulation wave from the reproduced signal. A detecting circuit detects the cross modulation interference component remaining in the demodulation signal in a specified period from the output signal of the first filter and the output of the demodulation circuit. A closed loop for controlling the frequency demodulation circuit by the output of the detecting circuit is composed, so that the cross modulation interference component in the frequency demodulation signal in the frequency demodulation circuit is removed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.