Lookup-table-based sigma-delta adc filter

An analog-to-digital conversion circuit, comprising:

• a plurality of sigma-delta modulators;
• and
• a plurality of ADC filters respectively corresponding to the plurality of sigma-delta modulators,
• wherein the plurality of ADC filters are respectively configured to:
• store a plurality of partial sums as respective entries in a plurality of lookup tables,
• retrieve at least one of the plurality of partial sums based on an output of the sigma-delta modulator, and
• calculate a filter output by adding retrieved ones of the plurality of partial sums together.

A method of calculating an output in an analog-to-digital converter, comprising:

• storing, by an ADC filter, a plurality of partial sums as respective entries in a plurality of lookup tables;
• receiving, by the ADC filter and from a sigma-delta modulator, an output;
• retrieving, by the ADC filter, at least one of the plurality of partial sums based on the output;
• and
• adding, by the ADC filter, retrieved ones of the plurality of partial sums together so as to generate the output.