Television Synchronizing Signal Generator

This paper deals with the formation of low-frequency rectangular pulses from a train of higher-frequency pulses, using a pulse-coincidence type of frequency-dividing chain. The developed pulse has leading and trailing edges bearing a precise time relationship to the leading edges of pulses of the original train, and a width equal to the period of an integral number of these pulses. A second low-frequency pulse, concurrent with the first, and having its leading and trailing edges displaced from those of the first pulse by the period of an integral number of the high-frequency pulses, may also be formed. The rise time and precision of timing of each edge of each developed pulse are of the same order as those of the leading edge of the high-frequency pulse. A 60 cycle wave in which these quantities are within 0.2 microsecond may be readily obtained. The method is described by reference to a specific application, that of the formation of the keying waves in a television synchronizing signal generator.