Filter coefficient setting technique for variable filtering process and variable sampling frequency conversion
US7072429B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 19, 1997 |
| Grant date | Jul 4, 2006 |
| Priority date | — |
| Expiry date | Aug 19, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H17/0642
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A first series of filter coefficients stored in a memory itself corresponds to a given filter characteristic such as a given high cutoff frequency. A second series of filter coefficients is generated by performing an interpolation process on the first series of filter coefficients. At that time, the contents, such as interpolation coefficients, of the interpolation process are varied in correspondence to a desired filter characteristic to be achieved, so that the interpolation process generates a second series of filter coefficients according to an impulse response characteristic that is obtained as a consequence of expanding or compressing, in a time-axis direction, an impulse response characteristic represented by the given first series of the filter coefficients. Thus, by the interpolation process, there is produced such a second series of filter coefficients that achieves a different filter characteristic (e.g., different high cutoff frequency). Where the sampling frequency of a time series of digital signals is to be changed from a given first frequency to a second frequency, an aliasing noise frequency may vary depending on a value of the first or second sampling frequency, i…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.