Demodulator for continuous-phase modulated signals, and transmission system involving such a demodulator

Abstract

Abstract 1. Demodulator of signals modulated in accordance with a continuous phase modulation for the transmission of binary data at a rhythm F, characterized in that it comprises : - means (600) for the determination and sampling of the phase of the modulated signal ; - means (700) for the determination of a value (ai ) of a bit from the phase values of two successive samples ; - means (13) for estimation of the value of the value of the bit (a'i ) that has been most probably transmitted, as a function of the phase values of two successive samples (phi i-1 , phi i ) received for this bit, these phase values being corrected by means of stored data being characteristic of the average effects of the distortion on the phase corresponding to sequences of p bits (p being a fixed integer equal to or exceeding 2) the first bit of which is formed by the preceding bit (a i-1 ) ; - means (12) for the estimation of these characteristic data, and determining for each sample the difference between the phase (phi i ) determined by the means (600) for the determination and sampling of the phase of the modulated signal and a theoretical phase (theta i ) computed from the theoretical phase (theta i-1 ) computed for the preceding sampling and from the value (ai-1 ) of the preceding bit, the latter being determined by the means (700) for the determination of the value of a bit, from the phase values of two successive samples, said means estimating, from the thus determined distortion values, data which are characteristic of the average effects of the distortion on the phase for all possible sequences of p bits, and storing these characteristic data.

Inventors

• 👤 Gérard Sorton
• 👤 André Marguinaud

Bibliographic Details