Generator for reference carrier - is used in apparatus for pseudo-coherent demodulation of four-phase keyed data signal

摘要

The signal is demodulated by two demodulators to which the received data signal and the reference signal shifted by +45 deg. and -45 deg. are applied carrier is delivered by a phase controlled oscillator output signal whose phase is shifted in accordance with the output signals of the two demodulators, is compared for phase with the received data signal obtained by this comparison is used, after passing through a low-pass filter, for the oscillator readjustment. A part of the difference signal is gated near the scanning instant, and only this gated value is for the oscillator readjustment.