Pulse generator including a memory for storing pulses for modulation on a carrier of a television signal

摘要

A pulse generator for generating pulses for modulation onto a carrier or subcarrier of a composite television signal is provided. The pulse generator includes a memory such as an EPROM for storing one or more waveshapes. Each stored waveshape is defined by a sequence of addressable values representing the amplitude of the waveshape as a function of time. A selecting circuit such as a microprocessor selects one of the waveshapes in the memory. A counting circuit responsive to a clock signal controls the address lines of the memory to read the amplitude values corresponding to the selected waveshape from the memory. The amplitude values are supplied to a digital to analog converter to convert the amplitude values to an analog pulse. The pulse may then be filtered to remove clock noise. The resultant signal is supplied to an amplitude modulator for modulating the signal onto a carrier or subcarrier of a composite television signal.