Transcoding apparatus
US4136358A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 20, 1977 |
| Grant date | Jan 23, 1979 |
| Priority date | — |
| Expiry date | Jun 20, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/85
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Composite color video signals, of the format, are applied to the input of a 1H delay line (exhibiting a 64 microsecond delay, when f.sub.H = 15,625 Hz.). Output of a first comb filter, using additive combination of delay line input and output signals, is applied to a lowpass filter having a cutoff frequency below the lowest color subcarrier sideband frequency. Output of a second comb filter, using subtractive combination of delay line input and output signals, is applied to: (1) a second 1H delay line; (2) a delay device, providing delay correpsonding to a quarter-cycle at the color subcarrier frequency; and (3) a low pass filter having a cutoff frequency below the lowest buried subcarrier sideband frequency. Outputs of two low pass filters are combined to form luminance signal. Outputs of quarter-cycle delay device and second 1H delay device are additively combined to obtain "V" component of signal, and subtractively combined to obtain "U" component thereof. "V" component is synchronously detected, de-switched, and remodulated on R-Y phase of buried subcarrier (e.g., with frequency at (189/2) f.sub.H + 1/2 f.sub.V), while " U" component is synchronously detected, and remodulated o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.