Abstract: 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 centered about 0 and .pi. radians of the carrier signal, the harmonic content can be expressed as a function of the angle of the rectangular pulses. This concept is realized by producing two opposite phase carrier signals which are compared with the modulation input signal to form two opposite phase rectangular pulse signals whose pulse widths are a function of the modulation input signal. Alternate phase pulses are extracted from these two rectangular pulse signals by two NOR gates, and the extracted pulses are combined and filtered to obtain an amplitude modulated output signal.