Calculation of filter factors for digital filter
US4896285A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 15, 1988 |
| Grant date | Jan 23, 1990 |
| Priority date | — |
| Expiry date | Jan 15, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/0211
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An apparatus for calculating a filter factor for a digital filter which can be simply constructed and in which the time period for calculation can be shortened as compared with conventional techniques. The apparatus has an input circuit for inputting a desirable frequency property, a division circuit for dividing the inputted frequency property into a plurality of frequency bands, and a calculating circuit for obtaining filter factors for realizing a frequency property of each of the divided frequency bands. The input circuit inputs the frequency property with a frequency resolution corresponding to the number of the filter factors. The division circuit performs a correction for a division so that the frequency property becomes zero from a frequency over the high cut-off frequency of a band-pass filter toward the Nyquist frequency of the frequency band corresponding to the transversal filter, the Nyquist frequency being 1/2 of the sampling frequency. The calculating circuit has a transformation unit for performing a Hilbert transformation or a linear phase transformation with respect to the respective frequency properties divided by the division circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.