Low power decimation system and method of deriving same
AssigneeBroadcom Corporation
InventorMinsheng Wang
Life of this patent
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Abstract
A decimation system comprising a plurality, L, of cascaded Finite Impulse Response (FIR) decimation filters. Each decimation filter has a transfer function of the form H(z)=(1+z−1)N, where N is an integer. Each FIR decimation filter performs decimation by a common factor I. The cascaded FIR decimation filters together achieve a decimation result substantially identical to that of an Nth-order CIC filter (that is, a CIC filter having N integrator stages) that performs decimation by a factor IL.
Claims20
A decimation system, comprising:
- a plurality of cascaded Finite Impulse Response (FIR) decimation filters, each of the FIR decimation filters having a transfer function H(z)=(1+z−1)N, where N is an integer.
A decimation system, comprising:
- a plurality, L, of cascaded Finite Impulse Response (FIR) decimation filters, each of the FIR decimation filters having a transfer function H(z)=(1+z−1)N and being configured to perform decimation by a common decimation factor I, where N and I are integers,
- wherein the plurality, L, of cascaded FIR decimation filters together achieve a decimation result substantially identical to that of a Cascaded Integrator-Comb (CIC) filter having N cascaded integrator stages that performs decimation by a factor IL.
A polyphase decimation filter, comprising:
- an input stage for generating, from an input signal, a first sub-sampled signal and a second sub-sampled signal;
- first and second gain stages for applying respective first and second weights to the first sub-sampled signal, to produce respective first and second weighted signals;
- third and fourth gain stages for applying respective third and fourth weights to the second sub-sampled signal, to produce respective third and fourth weighted signals;
- a first combiner for combining
- the second signal, and
- the first weighted signal, to produce a first combined signal;
- a first unit delay for producing a delayed first combined signal;
- a second combiner for combining
- the delayed first combined signal,
- the second weighted signal,
- the third weighted signal, and
- the fourth weighted signal, to produce a second combined signal;
- a second unit delay for producing a delayed second combined signal;
- and
- a third combiner for combining
- the delayed second combined signal, and
- the second signal, to produce a decimated output signal.
A method of performing decimation, comprising:
- (a) performing successive stages of Finite Impulse Response (FIR) decimation filtering, each of the stages of FIR decimation filtering using a transfer function H(z)=(1+z−1)N, where N is an integer.
A method of performing polyphase filtering, comprising:
- generating, from an input signal, a first sub-sampled signal and a second sub-sampled signal;
- applying first and second weights to the first sub-sampled signal to produce respective first and second weighted signals;
- applying third and fourth weights to the second sub-sampled signal to produce respective third and fourth weighted signals;
- combining
- the second signal, and
- the first weighted signal, to produce a first combined signal;
- producing a delayed first combined signal;
- combining
- the delayed first combined signal,
- the second weighted signal,
- the third weighted signal, and
- the fourth weighted signal, to produce a second combined signal;
- producing a delayed second combined signal;
- and
- combining
- the delayed second combined signal, and
- the second signal, to produce a decimated output signal.
Dependencies are inferred from the claim text.