A method and apparatus for amplitude modulating a carrier signal with an audio or information input signal utilizes an arcsine generator to cause the envelope of the carrier to follow the input signal. The invention stems from the realization that if rectangular pulses of bipolar amplitude are symmetrically...http://www.google.de/patents/US4346354?utm_source=gb-gplus-sharePatent US4346354 - Amplitude modulator using variable width rectangular pulse generator
