BPSK And QPSK transmission systems having phase locked loop for regenerating the carrier wave

摘要

The invention relates to a device for regenerating a carrier wave from a BPSK or QPSK modulation signal. The device multiplies the received signal by two or four depending on whether it has a BPSK or QPSK modulation. The multiplication delivers a reference signal. The device also has a locked loop comprising a voltage-controlled oscillator. A frequency divider is connected between the oscillator output and a second input of a comparator, the output of which is connected to the control input of the oscillator. The central frequency of the oscillator is equal to three times the nominal frequency fo of the received modulated signal. The output of the oscillator is connected to one input of a mixer having another input which receives the reference signal and the output of which is connected to the first input of the phase comparator. The frequency divider divides by three to deliver the regenerated carrier wave. Identical band-pass filters have a central frequency equal to fo and are disposed between (a) the output of the mixer and the first input of the phase comparator and (b) between the output of the divider by three and the second input of the phase comparator.