Method for self-calibrating a frequency of a modulator circuit, and circuit using said method

Circuit for calibrating a frequency, comprising:

• a go path, including, in series, a resonator circuit and an analog to digital conversion block, said resonator circuit comprising an integrator filter having on its feedback path a variable gain amplifier;
• and
• a circuit feedback path including a digital to analog conversion block;
• Wherein said variable gain of said amplifier is configured to be modified in a proportional way as a function of a comparison between an output signal frequency present at an output of said resonator circuit as a response to a pulsed signal present at an input thereof and a frequency known a priori, while said circuit feedback path is opened.

A method, comprising:

• opening a feedback path of a sigma-delta modulator;
• applying a pulsed signal to an input of a resonant circuit in a go path of the modulator;
• comparing an output frequency of the resonant circuit with a selected frequency;
• adjusting a gain of an amplifier in a feedback circuit of the resonant circuit as a function of a difference between the output frequency and the selected frequency.