Variable RF attenuator
US4236126A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1979 |
| Grant date | Nov 25, 1980 |
| Priority date | — |
| Expiry date | Apr 25, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03H7/255
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A variable pi RF attenuator includes shunt input and output branches, between which is connected a series branch. Each branch includes a voltage controlled variable impedance PIN diode. The level of a d.c. control input voltage is converted into a first d.c. current source having a magnitude proportional to an exponential function of the level. A first d.c. bias circuit supplies current of the first source as a d.c. bias for the series branch diode, while isolating the d.c. current of the first source from the diodes of the shunt branches. The control voltage is converted into a second d.c. current source having a magnitude proportional to the source voltage. A second d.c. bias circuit supplies current from the second source as d.c. biases for the diodes for both shunt branches, while isolating the d.c. current of the second source from the diode of the series branch.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.