Service manual

STP 11-25R13-SM-TG
S - 22
Figure S-20. Black and White Video Energy Distribution
Figure S-21. Placement of the Color Subcarrier
(6) A very objectionable 0.92 MHz (920 kHz) signal is generated from the beat between the sound
carrier and the color subcarrier (4.5 MHz to 3.58 MHz = 0.92 MHz). Experimental evidence has found
that the beat is much less objectionable if the sound carrier frequency is a multiple of the horizontal scan
frequency away from the video carrier frequency. In standard black-and-white TV, the 286th harmonic of
the horizontal line rate (15,750 Hz) is 4.5045 MHz. The line frequency whose 286th harmonic is 4.5 MHz
is 15,734.26 Hz.
F (line) =
4.5 MHz
= 15,734.26 Hz (new line frequency for color)
286