Tuning circuit for a filter
US7002404B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 6, 2004 |
| Grant date | Feb 21, 2006 |
| Priority date | — |
| Expiry date | Apr 2, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H2210/043
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
The invention relates to a tuning circuit for tuning a filter stage, which has an RC element (1) with an RC time constant (τ), with the RC time constant (τ) being the product of the resistance of a resistor (R1) in the RC element (1) and the capacitance of a capacitor (C1), which is connected in series with the resistor (R1), in the RC element (1), having a comparator (10) for comparison of the voltage which is produced at the potential node (4) between the resistor (R1) and the capacitor (C1), with a reference ground voltage; and having a controller (15) which varies the charge on the capacitor (C1) in the RC element (1) until the comparator (10) indicates that the voltage which is produced at the potential node (4) is equal to the reference ground voltage, with the controller (15) switching a capacitor array (26) as a function of the charge variation time, which capacitor array (26) is connected in parallel with the capacitor (C1) in the RC element (1), in order to compensate for any discrepancy between the RC time constant (τ) of the RC element (1) and a nominal value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.