The time base includes an oscillator generating a periodic signal, a frequency divider circuit formed by a division chain defining several division stages and a circuit for adjusting the divided frequency by inhibiting, in each inhibition period of a plurality of successive inhibition periods, an integer number of clocking pulses at the input of a given stage of the division chain. The time base is arranged to produce, in each inhibition period, a first real number corresponding to the real number of clocking pulses that must be removed to be precise and the adjustment circuit is arranged to calculate, in each inhibition period, a second real number equal to the addition of the first real number and the fractional part of the second real number obtained in the preceding inhibition period, the integer part of this second real number defining the number of clocking pulses to be inhibited in each inhibition period.