Filter device and method of acquiring filter coefficients
US6404832B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 16, 2001 |
| Grant date | Jun 11, 2002 |
| Priority date | — |
| Expiry date | Feb 16, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/0294
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A filter device includes a first section for receiving data of a desired cutoff frequency. A second section operates for deciding whether the desired cutoff frequency is in a predetermined low frequency band or a predetermined high frequency band. The predetermined low frequency band is lower in frequency than the predetermined high frequency band. A third section stores data of filter coefficients corresponding to different cutoff frequencies in the predetermined low frequency band. A fourth section stores data of precalculated basic coefficients corresponding to different cutoff frequencies in the predetermined high frequency band. The precalculated basic coefficients are equal to values resulting from a part of calculation to provide final filter coefficients. A fifth section operates for calculating final filter coefficients from precalculated basic coefficients through a coefficient expanding process. In cases where the second section decides that the desired cutoff frequency is in the predetermined low frequency band, data of filter coefficients corresponding to the desired cutoff frequency are read out from the third section, and are set in a filtering section. In cases wher…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.