NTSC Color-Field Identification
There are four different color fields in an NTSC color signal, which are exactly defined by EIA RS170A. This paper argues that field identification derived from a comparison of horizontal sync, vertical sync, and subcarrier will always have an ambiguity of field identification. It further argues that if the video signal had an independent identification of color field, the system subcarrier phase could then be adjusted correctly in relation to horizontal sync at every source. An appropriate independent field identification flag would also provide the means to measure accurately the sync to subcarrier phase relationship using only a standard waveform monitor. Broadcast manufacturers of videotape equipment and digital equipment presently claim color-field recognition based on measurement of SCH (the sync to subcarrier relationship). It is suggested that an independent identification of the proper color field, irrespective of SCH, is the ultimate solution to the problem.
- Print ISSN
- 0036-1682
- Published
- 1982-07
- Content type
- Original Research
- DOI
- 10.5594/J00290