Abstract: A system for the coherent demodulation of Binary Phase Shift Keying (BPSK) signal at a frequency f, comprising means for recovering a carrier signal (C) at a frequency 2f from said BPSK signal; means for injecting said signal having a frequency 2f in an injection locking oscillator (ILO), which has a natural resonant frequency fr, being fr substantially equal to f, which provides with differential output (Op, On) signals which recover the original carrier with a phase shift of (?e?k)/2, where ? e = arcsin ? ( f r - f ? ? ? ? A i ? f ) where ? and k are parameters that depend on the type of predominant non-linearity in the injection locking oscillator (ILO), and Ai is the amplitude of the recovered carrier signal at a frequency of 2f, and means for combining the differential output (Op, On) signals with a copy of the incoming BPSK signal in order to generate a demodulated signal (DEMOD).

Abstract: The invention particularly relates to a system for demodulation of PSK signals which takes advantage from the effects that the locking of resonant circuits by superharmonic injection produce, together with the interference phenomena, and more particularly it relates to a demodulation system which is designed to avoid mutual locking between said resonant circuits.

Abstract: The system consists of a power divider, PDIV, with an input, into which a PSK signal at a frequency of 2f is injected, where f is half the frequency of a carrier signal and with an even number M of outputs, from which corresponding signals, i1 . . . iM, are obtained at equal frequency and phase, connected to M argument dividers with tuneable natural resonant frequency, Div1 . . . DivM, obtaining M output signals, O1 . . . OM, from the said dividers and M?1 power combiners, PC1 . . . PCM?1, the inputs of which are connected two by two to the said M output signals, O1 . . . OM, providing M?1 ASK signals at the outputs of the said power combiners, which correspond respectively to each of the M?1 possible changes in phase of the said input PSK signal.