Frequency synthesizer.

This frequency synthesizer comprises a first frequency synthesizer (1) comprising a direct digital synthesizer performing a synchronization of a signal (fck) of a reference clock (11) and supplying signals at a frequency (fd) based the parameter (k) of the frequency adjustment, a frequency converter (13) converting an output of said frequency synthesizer (1) and supplying the converted frequency (fr), and a second frequency synthesizer (2) converting the frequency Release of the frequency converter (13) as a function of an adjustment parameter and outputting the converted frequency (fout), adjusting the parameters (k, R, N) to the synthesizer (1), the converter (13) and the synthesizer (2) being adjusted as a function of the synthesizer output frequency. applicable in particular in a transmitter / receiver of a radio communication system.