Method and apparatus for digital time-variant filtering
US4535417A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 23, 1982 |
| Grant date | Aug 13, 1985 |
| Priority date | — |
| Expiry date | Dec 23, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V2210/22
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and apparatus for digital time-variant filtering are disclosed. The digital time-variant filters are implemented using the Hilbert transform and a time-varying instantaneous frequency control function for controlling the cutoff frequency. The digital time-variant filters are adaptable to various filtering processes, that is, as either a high-cut, low-cut, band-pass, or reject filter. The various digital time-variant filters are stable in that no unusual transients occur in the output signal; are flexible in that the cutoff frequency is controlled by a selectable time-varying control function signal; and are efficient in that computational requirements are only twice to 16 times that of known digital time-invariant filters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.