Patent ID: 8466751

Claim:
A precise, low-consumption low-frequency oscillator, comprising: a low-consumption low-frequency oscillator A, operating at a frequency F A , said oscillator A emitting a signal S A , a temperature-compensated quartz (TCXO) oscillator B used as a frequency standard, operating at a frequency F B , and a digital circuit suitable for supplying a stable frequency Fcor comprising at least: an input receiving a power supply signal, an input permanently receiving the signal S A from the oscillator A, an input receiving the signal S B from the TCXO oscillator B during calibration, produced at a rate R 1 , when a switch is activated by a sequencer managing all the components that form a circuit formed by the low-consumption low-frequency oscillator, a counter counting a number of pulses emitted by the TCXO oscillator B during a given period, so as to represent an error between the oscillators A and B, a memory storing a number N B from the counter in the given period, and numbers N B-1 , N B-2 , N B-3 , . . . , N B-n of pulses emitted by the TCXO oscillator B and counted by the counter during preceding periods, a module of calculation to estimate a correction for analyzing the number N B at a given moment and those of the numbers N B-n , previously stored, and for deducing therefrom the correction to be applied to the number N B , an adder receiving values from the counter and from the module of calculation, and an output of said adder delivers a number representing a corrected error E that is stored, an accumulator, where said corrected error E is added with a rate R 2 comprising a predefined threshold value M; when a value of the accumulator, taken as an absolute value, exceeds the predefined threshold value M, said accumulator delivers, to a variable-rank divider, an overshoot and a sign of the overshoot, such that when the overshoot exists, the predefined threshold value M is subtracted from, or added to, the accumulator to cancel the overshoot, and the variable-rank divider having a nominal value K; such that when the overshoot exists in the accumulator, the nominal value K is modified by K+1 or K−1 according to a sign of the corrected E contained in the accumulator, during a period of an output signal Scorr, said variable-rank divider produces a desired and corrected value of the output signal Scorr.