Title:
INTERFACE CIRCUIT FOR LINEAR VARIABLE DIFFERENTIAL TRANSFORMER
Document Type and Number:
WIPO Patent Application WO1989004949
Kind Code:
A3
Abstract:
A monolithic interface circuit for use with a linear variable differential transformer (LVDT) position transducer includes a drive circuit for providing an excitation signal of selectable frequency and amplitude to the LVDT primary winding. The interface circuit further includes a decoder responsive to signals induced in the LVDT secondary windings for computing the position p of the LVDT core as a solution to the equation p = K(A-B)/(A+B), where A and B represent the signals induced in the primary winding, and K is a constant scale factor. The decoder includes circuitry for rectifying (54,64) and filtering (56,66) the secondary signals (A,B), a charge balance loop (58,68,70,72,74) responsive to the detected signals for providing a binary signal having a duty cycle representative of B/(A+B), and an output circuit (80,82,86,88,90,92,94) responsive to the binary signal for providing the position output. The decoder provides excellent scale factor stability and linearity and is relatively insensitive to variations in primary drive amplitude.
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Inventors:
DEVITO LAWRENCE M (US)
BROKAW A PAUL (US)
BROKAW A PAUL (US)
Application Number:
PCT/US1988/003668
Publication Date:
November 02, 1989
Filing Date:
October 19, 1988
Export Citation:
Assignee:
ANALOG DEVICES INC (US)
International Classes:
G01D5/22; G06G7/161; (IPC1-7): G01D5/22
Foreign References:
| US4140998A | 1979-02-20 | |||
| US3737640A | 1973-06-05 | |||
| DE3602107A1 | 1987-07-30 | |||
| US3961206A | 1976-06-01 | |||
| EP0028743A1 | 1981-05-20 | |||
| GB2131558A | 1984-06-20 |
Other References:
PATENT ABSTRACTS OF JAPAN, Vol. 6, No. 137 (P-130) (1015), 24 July 1982 & JP-A-5759116 (Sakata Denki K.K.) 9 April 1982
Siemens-Zeitschrift, Vol. 45, No. 10, October 1971 G. Klebert et al.: "Analogrechen-Bausteine im Regelsystem TELEPERM C", pages 740-744
Elektronik, Vol. 36, No. 1, January 1987, (Munich, DE) W. Blaesner: "Durch Integrierte Ansteuerschaltung Zur Kostengunstigen Losung", pages 40-42
IEEE Journal of Solid-State Circuits, Vol. SC-20, No. 2, April 1985 IEEE (New York, NY, US) J.W. FATTARUSO et al.: "Triangle-to-Sine Wave Conversion With MOS Technology", pages 623-631
The Radio and Electronic Engineer, Vol. 44, No. 10, October 1974 C.J. PAULL et al.: "Waveform Shaping Techniques for the Design of Signal Sources", pages 523-532
Siemens-Zeitschrift, Vol. 45, No. 10, October 1971 G. Klebert et al.: "Analogrechen-Bausteine im Regelsystem TELEPERM C", pages 740-744
Elektronik, Vol. 36, No. 1, January 1987, (Munich, DE) W. Blaesner: "Durch Integrierte Ansteuerschaltung Zur Kostengunstigen Losung", pages 40-42
IEEE Journal of Solid-State Circuits, Vol. SC-20, No. 2, April 1985 IEEE (New York, NY, US) J.W. FATTARUSO et al.: "Triangle-to-Sine Wave Conversion With MOS Technology", pages 623-631
The Radio and Electronic Engineer, Vol. 44, No. 10, October 1974 C.J. PAULL et al.: "Waveform Shaping Techniques for the Design of Signal Sources", pages 523-532
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