"Color Command"-A Digital Method for Extracting the Color Information from the NTSC SIGNAL

A new color-signal processing system is described which utilizes digital methods to decode the three color-difference signals from the NTSC signal. Using a 3.58 MHz crystal multivibrator as the basic time element, sampling pulses, initiated by the color burst and terminated by the following horizontal synchronizing pulse, are generated by low-level digital logic elements. These sampling pulses, delayed the appropriate time, are then used to demodulate the color-difference signals from the chrominance signal. Since the sampling pulses exist only during the active time following each color burst, no color killer is required. The system, referred to at Texas Instruments as "Color Command," uses Monolithic Integrated Circuits to generate the reference waveform and the sampling pulses, and to demodulate the chrominance signal.