US 11,522,557 B1Granted

System and method of calibration of sigma-delta converter using tone injection

AssigneeNXP B.V.

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

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Abstract

A digital conversion system including a sigma-delta converter, a tone generator that generates injects a tone signal into the conversion path of the sigma-delta converter at a frequency that is outside operating signal frequency range, a tone detector that isolates and detects a level of the injected tone signal and provides a corresponding tone level value, a tone ratio comparator that converts the tone level value into a tone level ratio and that compares the converted tone level ratio with an expected tone level ratio to provide an error signal, and a loop controller that converts the error signal to a correction signal to adjust a loop filter frequency the sigma-delta converter. Tones may be serially injected one at a time or simultaneously in parallel for determining a measured tone level ratio for comparison with a corresponding one of multiple stored expected tone level ratios.

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 tone generator having an output coupled to the injection input of the sigma-delta converter, wherein the tone generator is configured to generate a tone signal at a selected tone frequency;
a tone detector having an input coupled to the digital output of the sigma-delta converter and having an output, wherein the tone detector is configured to isolate and detect a level of the tone signal and to provide a tone level value indicative thereof;
a tone level ratio comparator having an input coupled to the output of the tone detector, wherein the tone level ratio comparator is configured to convert the tone level value into a measured tone level ratio and to compare the measured tone level ratio with an expected tone level ratio and provide an error signal indicative thereof;
and
a loop controller having an input coupled to the output of the tone level ratio comparator for receiving the error signal and having an output for providing a correction signal to the frequency adjust input of the sigma-delta converter.

3 more elements

Dependencies are inferred from the claim text.