US 11,502,699 B1Granted

System and method of calibration of sigma-delta converter using injected signal correlation

AssigneeNXP B.V.

InventorsRobert Rutten, Hendrik van der Ploeg, Lucien Johannes Breems, Martin Kessel, Muhammed Bolatkale, Bernard Burdiek, Manfred Zupke, Johannes Hubertus Antonius Brekelmans, Shagun Bajoria

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Abstract

A digital conversion system including a sigma-delta converter, a signal generator providing a substantially symmetrical injection signal that is injected into the sigma-delta converter conversion path, bandpass filters for filtering the injection signal and the output of the sigma-delta converter, a correlator that correlates the filtered signals for providing an error signal, and a loop controller that uses the error signal to adjust a resonant frequency of the sigma-delta converter to output a target notch frequency. The loop controller may adjust a resonant frequency of a loop filter of the sigma-delta converter, in which the bandpass filters may each be centered at the target notch frequency at the output of the sigma-delta converter. The correlator may include a complex conjugate block, a multiplier and a mean calculator. The loop controller may include a converter and an amplifier and an integrator or a least-mean square block.

Claims20

Dependent claims

A digital conversion system, comprising:

a sigma-delta converter having an input, having a digital output, having a conversion path with an injection input, and having a frequency adjust input;
a signal generator having an output coupled to the injection input of the sigma-delta converter, wherein the signal generator is configured to provide an injection signal that is substantially symmetrical around a target notch frequency;
a first bandpass filter having an input coupled to the output of the signal generator for receiving the injection signal and having an output, and a second bandpass filter having an input coupled to the digital output of the sigma-delta converter and having an output, wherein the first and second bandpass filters are configured to perform filtering based on the target notch frequency of the digital output of the sigma-delta converter;
a correlator having a first input coupled to the output of the first bandpass filter, having a second input coupled to the output of the second bandpass filter, and having an output configured to provide an error signal;
and
a loop controller having an input coupled to the output of the correlator for receiving the error signal and having an output coupled to the frequency adjust input of the sigma-delta converter.

3 more elements

Dependencies are inferred from the claim text.