Angle modulated waveform synthesizer

Abstract

An angle modulated periodic waveform is synthesized by generating three digital number sequences. In a first number sequence, one number thereof is generated on each occurrence of a periodic clock signal and has a magnitude which is a selected first periodic function of the number of prior occurring clock signals. In a second number sequence, one number thereof is generated on each occurrence of the clock signal and has a magnitude which is a selected second function of prior occurring numbers of the first number sequence and an applied constant carrier waveform frequency parameter. Each number of the second number sequence is added as it is generated to a stored second address number. In the third number sequence, one number thereof is generated on each occurrence of the clock signal and has a magnitude which is a selected third periodic function of the stored second address number. Each number of the third number sequence is converted to a voltage of proportional magnitude by a digital-to-analog converter, the output of which includes the synthesized angle modulated waveform. The second function may be selectively adjusted by application of an external control signal such that the output waveform may exhibit either frequency or phase modulation.