Crosstalk cancelling circuit for removing crosstalk component from reproduced signal
US5091788A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 5, 1989 |
| Grant date | Feb 25, 1992 |
| Priority date | — |
| Expiry date | Oct 5, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/7917
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A crosstalk cancelling circuit for use in video tape recorders. The cancelling circuit comprises a first multiplier for multiplying a frequency-lowered conversion chrominance signal reproduced from a magnetic tape by a local oscillating signal with a predetermined frequency and a delay device for delaying the frequency-lowered conversion chrominance signal by one horizontal scanning period. The local oscillating signal is further supplied to a phase-shifting circuit which in turn produces either a signal leading the local oscillating signal by a phase angle of 90.degree. or a signal lagging the local oscillating signal by a phase difference of 90.degree. in synchronism with a field frequency of the frequency-lowered conversion chrominance signal. Also included in the cancelling circuit is a second multiplier for multiplying the output of the delay device by the output of the phase-shifting circuit, the output of which is fed to an operation circuit for effecting addition or subtraction between the output of the first multiplier and the output of the second multiplier to output the result as a carrier chrominance signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.