Linear phase finite impulse response filter with pre-addition
US5777912A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 28, 1996 |
| Grant date | Jul 7, 1998 |
| Priority date | — |
| Expiry date | Mar 28, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/06
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A linear phase FIR filter includes a multiplication/accumulator engine which is operable to receive the multi-level data stream and multiply it by predetermined filter coefficients. The coefficients are symmetrical to allow a pre-addition operation wherein the data is first stored in a buffer and then the data for symmetrical coefficients added before multiplication by the coefficient. This results in a reduction of multiplications by a factor of two, thus allowing the multiplication/accumulator engine to operate at one-half the clock rate of the oversampled multi-level data bit stream. The pre-addition operation results in values of greater than "1" and less than "-1" which are then converted in the multiplication/accumulator engine to restrict the values that are input to the multiplication/accumulator engine to values of "+1", "0" and "-1", to allow the multiplication/accumulator engine to only perform a "pass through" of the coefficient value, an "inversion" of the coefficient value or replace the coefficient value with a "null" value. This is facilitated by processing the tri-level data through two paths, one for the "-1" and one for the "-1" term and providing a common mode o…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.