Current mode biquadratic active filter
US4340868A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 12, 1980 |
| Grant date | Jul 20, 1982 |
| Priority date | — |
| Expiry date | May 12, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H11/1213
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A configuration of two transistors and two capacitors provides a current mode second-order active filter for IC implementation with low-pass, bandpass and high-pass capabilities. The filter frequency is tunable over a wide range, independently of filter Q and gain, by varying a DC bias current. The filter can provide one-port impedance functions, and two-port voltage, current and impedance transfer functions. With the addition of a second biasing current source, the filter Q can be controlled by adjusting the ratio of the two biasing current sources. Enhanced dynamic range and large-signal performance can be achieved by the addition of linear resistors, with trade-offs in tunable frequency range and frequency linearity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.