Transmission system

The invention relates to a method for fast phase synchronisation of the clock pulses in the QAM demodulator of a transmission system which contains a device for monitoring the sign change of the QAM signal demodulated by multiplication by the regenerated carrier by means of time windows and an evaluating circuit, which accumulates unacceptable sign changes and which, when a predetermined counting threshold overflows, effects a single inversion of the clock pulses, and is characterised by the fact that the time windows are formed by periodic sampling of one or both quadrature signals with a clock of twice the bit clock rate, and an examination for acceptable or unacceptable sign changes being carried out within the time windows by means of an exclusive-OR operation on in each case two successive samples.