Abstract: A method and apparatus for transmitting and receiving a carrier signal which is simultaneously frequency and phase modulated, including a carrier signal, a frequency modulator for imposing on the carrier signal an analog information signal, a bi-phase shift key modulator for modulating the frequency modulated carrier with a digital information signal to provide an output frequency and phase modulated carrier signal, a receiving system including a multiplier by which the received composite signal is multiplied by two to cancel out the bi-phase modulation and thereby derive a frequency modulated only signal, demodulating the multiplied frequency modulated signal utilizing a frequency demodulation network and comparing the derived frequency modulated signal with the received transmitted signal to derive the digital information signal.