Title:
DEVICE FOR MEASURING THE VARIATIONS IN THE CAPACITANCE OF A CAPACITOR, PARTICULARLY A DETECTOR
Document Type and Number:
WIPO Patent Application WO1991009812
Kind Code:
A3
Abstract:
PCT No. PCT/FR90/00961 Sec. 371 Date Aug. 28, 1992 Sec. 102(e) Date Aug. 28, 1992 PCT Filed Dec. 28, 1990 PCT Pub. No. WO91/09812 PCT Pub. Date Jul. 11, 1991.A circuit for measuring variations in the capacitance of a variable capacitor forming part of a sensor includes an oscillator which generates an alternating signal which is supplied to two branches of a detection bridge. The first branch includes the variable capacitor connected in series with a variable capacitance diode. The second branch includes a capacitor connected in series with a variable capacitance diode. A differential stage has each of its in puts connected to the common point of a respective one of the branches. Synchronous demodulation means connected to the oscillator, are connected to the output of the differential stage for delivering a DC unbalance voltage Ve which is injected by a feedback line to the common point of the first branch, thereby continuously balancing the detection bridge.
Inventors:
PERMUY ALFRED (FR)
Application Number:
PCT/FR1990/000961
Publication Date:
August 22, 1991
Filing Date:
December 28, 1990
Export Citation:
Assignee:
VECTAVIB (FR)
International Classes:
G01D5/24; G01D5/241
Foreign References:
| DE2659807B2 | 1978-03-23 | |||
| US4673869A | 1987-06-16 | |||
| US4684886A | 1987-08-04 | |||
| US4241303A | 1980-12-23 |
Other References:
See also references of EP 0510061A1
Download PDF: