Abstract: In a method of detecting false locks between a reference signal and an input signal to be demodulated to produce a coherent demodulated signal comprising a number of phase states, the level of the input signal at a predetermined moment in the bit period of the input signal after demodulation and before regeneration is compared with the level of the input signal after regeneration, bit by bit. The reference signal is optionally corrected so as to lock its reference and phase to the input signal.

Abstract: An amplifier for correcting group time delay of electrical signals comprises first and second DC voltage supply terminals, an input transistor to which a signal to be amplified is applied, an output transistor, a group time delay corrector network, at least one capacitor and a choke. The input and output transistors have their respective collector-emitter junctions connected in series between the first and second supply terminals. They are configured as common-emitter voltage amplifiers. The collector of the input transistor is connected to the base of the output transistor through the group time delay corrector network. The emitter of the output transistor is connected to one of the supply terminals through the capacitor and to the collector of the input transistor through the choke.