US 2016/0079960 A1 · Fast FIR Filtering Technique for Multirate Filters

Abstract

Data samples are filtered by using a digital filter where the length of an impulse response of the digital filter is finite, an impulse response of the digital filter is symmetric and the operation of the digital filter is multi-rate. The method uses a polyphase decomposition to break down the input data stream into N parallel substreams and the multi-rate digital filter is separated by a polyphase decomposition into multiple lower-rate sub-filters where each of the sub-filters is separated into a set of simpler sub-sub-filters which operate upon the same set of input samples and which have impulse responses which are jointly centro-symmetric, a set of pre-filtering arithmetic structures, and a set of post-filtering arithmetic structures and performing each such pair of sub-sub-filtering operations using a single shared filter structure, a set of pre-filtering combining adders, and a set of post-filtering separating adders.

Claims15

Dependent claims

A method for filtering data samples comprising:

using a digital filter to act upon a input data stream in order to transform it into an output data stream, wherein:
the length of an impulse response of the digital filter is finite;
an impulse response of the digital filter is symmetric;
the operation of the digital filter is multi-rate;
using a polyphase decomposition to break down the input data stream into N parallel substreams;
the multi-rate digital filter being separated by a polyphase decomposition into multiple lower-rate sub-filters;
each of the sub-filters being separated one or more times into a set of simpler sub-sub-filters, a set of pre-filtering arithmetic structures, and a set of post-filtering arithmetic structures, according to a fast FIR filtering decomposition algorithm;
the set of sub-sub-filters comprising one or more pairs of sub-sub-filters which operate upon the same set of input samples and which have impulse responses which are jointly centro-symmetric;
and performing each such pair of sub-sub-filtering operations using a single shared filter structure, a set of pre-filtering combining adders, and a set of post-filtering separating adders.

6 more elements

Dependencies are inferred from the claim text.

Fast FIR Filtering Technique for Multirate Filters

Life of this patent

Fast FIR Filtering Technique for Multirate Filters

Life of this patent

Abstract

Claims15