Programmable/tunable active RC filter
US7358800B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 2006 |
| Grant date | Apr 15, 2008 |
| Priority date | — |
| Expiry date | Apr 25, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H11/1291
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A programmable/tunable active low-pass filter at least has the resistors, capacitors and shunt control means. It uses the resistor ladder that is structured with various fixed resistors to implement the shunt control means. The cut-off frequency of a filter is associated with the time constant, which is determined by equivalent resistance and equivalent capacitance value in the filter circuit; therefore, the filter of the present invention allowed users to fine tune the cut-off frequency linearly through the shunt control means when the variation of the environment or process parameters of manufacture cause the cut-off frequency drift, thus, the cut-off frequency can be kept in a constant value. The present invention also provides a means for programming the cut-off frequency to a desirous frequency value dependent upon the conditions of application within a big range. Thus, it can be used in many purposes widely with the same filter circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.