NTSC color television transmission without chroma crawl

DETAILED DESCRIPTION In accordance with the present invention, the upward moving pattern at the edges of luminance is eliminated by control of the vertical scan rate to end each scan line with one full cycle of the color subcarrier, instead of one half of a cycle, by causing the horizontal sync generator to drop one half cycle at the end of each line.
This is accomplished by feedback control on a clock pulse counter for the vertical and horizontal sync generator to reset at the end of every line, i.
e.
, at the occurrence of every horizontal sync pulse (H), thereby shortening the line by one half cycle of the color subcarrier during each raster line.
Consequently, there will be 227 cycles of the color subcarrier per line, instead of 227.
5 cycles, except at the end of a field, for a phase inversion of the color subcarrier from field to field, thus eliminating chroma crawl.
This is all done at the transmitter; the receiver will respond to the horizontal and vertical sync pulses (H and V) thus generated and transmitted to assure that each field displayed includes 525 lines of 227 cycles of the color carrier.
The novel features of the invention are set forth with particularity in the appended claims.
The invention will best be understood from the following description when read in conjunction with the drawings.