Analysis and compensation circuit for an inductive displacement sensor

A circuit arrangement for evaluation and compensation of the signals from an inductive position sensor, comprising:

• a first operational amplifier to a first of whose inputs a first reference voltage is supplied for a frequency measurement or a second reference voltage is supplied for a compensation measurement, and to a second of whose inputs an output signal from the first operational amplifier or a compensation signal is supplied;
• a second operational amplifier, to a first of whose inputs the output signal from the first operational amplifier is supplied and to a second of whose inputs a feed-back signal is supplied for closed-loop amplitude control;
• a first coil having a first coil inductance and a first coil resistance for a position measurement, which coil is connected in parallel with an output of the second operational amplifier and the first input of the second operational amplifier, and, at a first of end of the first coil and in conjunction with a capacitance which is connected in series with the coil inductance and the coil resistance, forms an RLC series resonant circuit;
• and
• a second coil having a second coil inductance and a second coil resistance for at least one of temperature and disturbance voltage compensation, which second coil is connected at a first of end of the second coil's coil winding to a second end of a coil winding of the first coil, and is arranged to be connected at a second end of the second coil's coil winding to the second input of the first operational amplifier.