METHOD AND DEVICE FOR DISPLACEMENT MEASUREMENTS Russian patent published in 1997 - IPC

FIELD: measurement technology. SUBSTANCE: field winding 2 of transformer transducer with linear conversion function and with movable core 1 nonuniform along displacement axis is supplied with sine-wave current of two frequencies from ac voltage generators 5, 6, voltage-to-current changers 12, 13, and adder 15. Voltage across field winding cophasal to supply current at first and second frequencies is separated by synchronous detectors 8, 9 and voltage picked off differentially connected metering half-windings, 3, 4, by synchronous detectors 10, 11. Two first voltages are used to equalize transconductance of transducer conversion characteristic by comparing these voltages across differential amplifier 16 and applying error signal to voltage-to-current changer 13 with adjustable conversion factor. Two other voltages are used for correcting transducer conversion transconductance by comparing across differential amplifier 17 and passing results to variable-gain amplifier 14 where signal equal to ratio of voltage measured across metering winding at first frequency to difference in measured voltages across metering winding at first and second frequencies is built up across its output. EFFECT: improved measurement accuracy. 2 cl, 6 dwg