Infinite impulse response filters with dithering and methods of operation thereof
AssigneeSTMicroelectronics S.r.l.
InventorRyo Tsutsui
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Abstract
An infinite impulse response filter includes a plurality of lower order filter stages and a random number generator circuit. The plurality of lower order filter stages include a first filter stage coupled to a second filter stage. The random number generator circuit includes a first output coupled to the first filter stage and a second output coupled to the second filter stage. The random number generator circuit is configured to generate the same random value at both the first output and the second output. The infinite impulse response filter is an nth-order filter. The respective order of each of the lower order filter stages is less than n.
Claims20
An infinite impulse response (IIR) filter comprising:
- a plurality of lower order filter stages comprising a first filter stage coupled to a second filter stage;
- and
- a random number generator circuit comprising a first output coupled to the first filter stage and a second output coupled to the second filter stage, the random number generator circuit configured to generate a same random value at both the first output and the second output, wherein the IIR filter is an nth-order filter, and wherein a respective order of each of the plurality of lower order filter stages is less than n.
An infinite impulse response (IIR) filter comprising:
- a string of biquadratic filters comprising a first biquadratic filter coupled to a second biquadratic filter;
- and
- a random number generator circuit coupled to the string of biquadratic filters, the random number generator circuit being configured to generate a same random value at both the first biquadratic filter and the second biquadratic filter.
A method of filtering comprising:
- generating a same random value at both a first lower order filter stage and a second lower order filter stage using a random number generator circuit;
- dithering a first signal filtered by the first lower order filter stage using the same random value to form a dithered first signal;
- and
- dithering a second signal filtered by the second lower order filter stage using the same random value.
Dependencies are inferred from the claim text.