Method and device for detecting the error on the frequency of a carrier

Abstract

In order to detect the error on the frequency of an M-PSK phase-modulated carrier, the phase .psi.(n) of the samples is restored to the interval �-.pi., +.pi.�; .phi.(n)=mod(.psi.(n), 2.pi./M) is calculated; d(n)=mod(.phi.(n)-.phi.(n-1), 2.pi./M) is calculated; p'(n)=mod(d(n)+p(n-1), 2.pi./M) is calculated, where p(n)=mod(p*(n), 2.pi./M), where p*(n) is obtained by subtracting the current output from p'(n); d'(n)=p'(n)-p(n-1) is calculated; a parameter 'tri' is defined by tri=1 if .vertline.d'(n).vertline.<S and tri=.beta. if .vertline.d'(n).vertline..gtoreq.S, where S is a threshold; det.sub.-- tri(n)=.alpha..p'(n).tri is calculated, det.sub.-- tri(n) constituting the current output, representative of the error on the frequency of the carrier.