Abstract: A digital cellular radiocommunication system includes a circuit for evaluating the frequency difference between a local signal and the carrier wave of a receive signal which are close together in frequency, the receive signal having been subjected to phase state modulation by a modulation signal and thus having a phase that includes a transmission phase shift, a modulation phase shift corresponding to one of a plurality of phase states, and a synchronization phase shift due to the frequency difference. The circuit produces samples of the receive signal from which the transmission phase shift has been eliminated, detects the modulation phase shift of the samples in order to eliminate it, produces the mean phase of a series of samples, and produce the frequency difference on the basis of the mean phase of at least two series of samples and on the basis of the time interval between the middles of the series.