Abstract: A conventional demodulator for digital transmission includes means (12) for splitting the received HF signal into two identical auxiliary signals, mixers (20, 30) for transposing the auxiliary signals into in-phase and quadrature baseband components by multiplying them with in-phase and quadrature output signals from a local oscillator (14), and respective filter and amplifier means (22, 24; 32, 34) and analog-to-digital converters (26, 36) on the in-phase and quadrature channels. In addition, the demodulator includes estimation means (100) suitable for estimating faults on groups of samples (Y.sub.p,k, Y.sub.q,k) taken from the outputs of the analog-to-digital converters (26, 36), with the faults being estimated in the form of five parameters, and correction means (200) for correcting current samples (Y.sub.p, Y.sub.q) on the basis of the parameters estimated on an earlier group of samples.

Abstract: A bit error performance monitor in which the input signal is equally shared by two substantially identical monitors whose outputs in turn are connected to an adder. The output of the adder passes through a divider-by-2 to a counter.