Abstract: A highly stable frequency generator (G) comprises an oscillator (10) for generating a first frequency (F1), andfurther comprises a time base (BT) providing a time stable frequency signal which is independent of the temperature, and a feedback circuit arranged to provide a first number of pulses (n.sub.T) coming from the oscillator (10) to a comparing circuit (13), a circuit (14) for providing a reference number of pulses (N.sub.T) to said comparing circuit (13), and a circuit (13,15,16) providing a correction signal (Sc) as a function of the difference (.DELTA.) between the first number (n.sub.T) and the reference number (N.sub.T), the generator (G) further comprising a correction circuit (17) of the oscillation frequency (F1) of said first oscillator (10), this correction circuit being controlled by said control signal (Sc).