Multitone telephone dialing circuit employing digital-to-analog tone synthesis

摘要: A circuit is provided for generating combinations of digitally synthesized sinusoidal waveforms used voiceband signaling in multitone telephone station sets. The features plural variable frequency dividers which function under the control set keyboard to divide a single digital master clock signal into predetermined sequences multifrequency components are shifted phase amounts. summed suitable proportions form acceptable approximations dialing waveforms.