For black and white television, this video signal is quite straightforward and easy to comprehend. (Color gets a bit messier.) Sixty times per second, the signal contains a vertical sync pulse that indicates the beginning of a field. This pulse is 0 volts (ground) for about 400 microseconds. A horizontal sync pulse indicates the beginning of each scan line: The video signal is 0 volts for 5 microseconds 15,750 times per second. Between the horizontal sync pulses, the signal varies from 0.5 volt for black to 2 volts for white, with voltages between 0.5 volt and 2 volts to indicate shades of
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