METHOD AND APPARATUS FOR EFFICIENT IMPLEMENTATION OF A MULTIRATE LMS FILTER

摘要

An efficient implementation of a multirate filter with delayed error feedback is disclosed. The multirate filter prevents the instruction processing rate requirement from increasing by performingthe interpolation and decimation in the LMS filter element at the same time. The multirate filter calculates an ith coefficient value, wherein i is a set of consecutive integers, by obtaining an (i-1)th error value, obtaining an (i-1)th error value, multiplying the (i-1)th error value to obtain an ith coefficient product, obtaining Mth coefficient value from a coefficient register, wherein M is a predetermined integer, and adding the Mth coefficient value to the ith coefficient product to obtain an ith coefficient value; and calculates an ith data value by multiplying the (i-1)th data value and the Mth coefficient value to produce ith convolution product and adding a (I-1)th convolution sum to the ith convolution product to produce an ith convolution sum. Obtaining the Mth coefficient value decimates the convolution by M and interpolates the error by M. Otaining the (i-1)th data value further comprises incrementing a data register by one when new data is not written into the data register.