| 摘要 |
A method for calibrating a frequency of a sigma-delta modulator having a go path that includes, in series, a resonator circuit and of an analog to digital conversion block, and a feedback path including a digital to analog conversion block, including the steps: a) applying an input pulse to the resonator circuit; b) measuring the oscillating frequency of the output signal from the resonator circuit in response to the pulse, while the feedback path of the sigma-delta modulator is opened; c) comparing the oscillating frequency of the resonator circuit with a selected frequency; d) modifying the oscillating frequency proportionately as a function of the comparison step. The resonator circuit includes an integrator filter with a variable gain amplifier in its feedback path, the variable gain configured to be modified as a function of the comparison, performed while the modulator feedback path is opened.
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