DIGITAL FREQUENCY SHIFT KEY MODULATOR

摘要

DIGITAL FREQUENCY SHIFT KEY MODULATOR A frequency shift key modulator producing sine wave output signals of different frequencies for mark ("1") and space ("0") signal levels on an input "send data" lead including a counter which divides the frequency of an input oscillator by different denominators for the mark and space signals and the output of which is synthesized to produce a stepped output approximating a sine wave and a final filter for smoothing the steps out of the output. In cases in which the mark and space output frequencies are approximately in the ratio of 1 to 2, a frequency divider is used for the mark output frequencies.