Filter circuit providing low distortion and enhanced flexibility to obtain variable gain amplification
US7138873B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Nov 17, 2004 |
| Grant date | Nov 21, 2006 |
| Priority date | — |
| Expiry date | Mar 22, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H11/1291
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A low distortion filter circuit implementing variable gain amplification (VGA). An aspect of the present invention increases the degrees of freedom (number of components which can be independently programmed/changed to corresponding desired values) to achieve a desired combination of D.C. gain and filter characteristics (e.g., corner frequency, Q-factor, notch frequency, etc.). Such additional degrees of freedom are attained by including additional components in either on input block or a feedback block (implemented with reference to an operational amplifier), and by redesigning the other block using principles such as admittance concellation to remove the effects of such additional components. The blocks are designed such that a terminal of the programmable components is connected to a fixed/constant voltage (e.g., ground). Embodiments implementing bi-quad single amplifier with and without notch are disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.