Signal filter with adjustable analog impedance selected by digital control
US6559714B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 28, 2001 |
| Grant date | May 6, 2003 |
| Priority date | — |
| Expiry date | Mar 28, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H1/02
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A signal filter employs digital control signals to selectively establish and adjust analog impedance components of the filter. In the case of a first-order R-C filter, adjustable resistance and reactance assemblies are coupled in series. The resistance assembly has multiple parallel signal paths sharing a common input and output. Each signal path includes a prescribed electrical resistance and a digital switch to selectively enable and disable the resistance. Between the common input and output, the signal paths provide a collective resistance which varies depending upon which switches have been activated. The reactance assembly is similar to the resistance assembly, with capacitors or inductors instead of resistors. A digital controller selectively activates the switches to adjust the assemblies' respective resistance and reactance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.