Phase noise compensation circuit - is for synchronous information transmission system and uses self-adaptive complex de-phaser of at least second order phase slave type

摘要

A phase noise compensation circuit for a synchronous information transmission system has a double digital sampler (30) which receives at its two inputs an 'in phase' signal and an 'in quadrature' signal from a receiver two-carrier quadrature demodulator. A long self-adaptive linear complex equaliser (31) corrects linear amplitude and group time propagation distortions in the sampled signals and applies sampled couples of equalised signals to a self-adaptive complex dephaser (32) which corrects frequency drift and adjusts the phase angle of the complex signal. A short self-adaptive linear complex equaliser (33) then corrects the periodic and uncertain phase deviations and applies the resulting signals to a decision circuit formed by two threshold sensing circuits (41,42) which are connected to a decoder of the receiver. The operation of the sampler (30), dephaser (32) and equalisers (31,33) are controlled by a beat recovery circuit which reproduces the frequency of information symbol transmission or modulation rate.