Voice frequency RC active filter
US4185250A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 3, 1978 |
| Grant date | Jan 22, 1980 |
| Priority date | — |
| Expiry date | May 3, 1998 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H11/40
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A voice-frequency RC-active filter comprising a plurality of resistors and generalized impedance converter networks for synthesizing the frequency response of a preselected LC filter. Each generalized impedance converter network includes a pair of operational amplifiers and a plurality of impedances Z1, Z2, Z3, Z4 and Z5 interconnected with the amplifiers to provide the network with a driving point impedance ##EQU1## in which at least one of the impedances in both the numerator and the denominator of Zi includes a film-type resistor. At least one of the film-type resistors included in the impedances Z1, Z2, Z3, Z4 and Z5 is functionally trimmed to tune the filter. The capacitors in the filter are preferably discrete polycarbonate capacitors with a capacitance tolerance of .+-.5%, and all having the same value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.