High frequency differential filter with CMOS control
US5708391A · kind A · utility
Inventors
Key dates
| Filing date | May 2, 1996 |
| Grant date | Jan 13, 1998 |
| Priority date | — |
| Expiry date | May 2, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03F2203/7203
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A programmable high frequency active filter comprises a plurality of basic building blocks connected in parallel. A basic building block includes a transistor pair connected in a differential amplifier configuration, an impedance connected between the emitters of the transistors and a switching block for applying the necessary bias current to the transistors. The transfer function of the filter is programmed with a digital word, the length of which determines the number of basic building blocks included in the configuration. In this way, the equivalent high frequency impedance of the filter is controlled by selecting the configuration and the value of the impedance of each building block.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.