The embodiment of the invention designs a variable-reluctance stimulation and decoding module for measuring
position angle of a rotor of a
permanent magnet synchronous motor. The variable-reluctance stimulation and decoding module comprises a
signal stimulation circuit, a
signal decoding circuit, wherein the
signal stimulation circuit is used for converting a digital square signal of a signal processor into a
sine wave stimulation signal for driving a rotating
transformer and comprises a multi-stage filtering amplification circuit for generating a
sine wave signal, a push-pull circuit connected with the output end of the multi-stage filtering amplification circuit, and a stimulation winding for improving the driving capability of the signal so as to drive the rotating
transformer; the
signal decoding circuit is used for decoding the output signal of the rotating
transformer and comprises a
differential amplification circuit, a rectification turning circuit and a filtering circuit; the
differential amplification circuit is used for receiving a differential signal output by the
rotary transformer and outputting an amplified
echo signal; the rectification turning circuit is used for extracting an envelope line of an
echo signal; the filtering circuit is used for filtering the turned
echo signal into a flat level signal. According to the embodiment, the cost is effectively reduced, and the function of a decoding
chip can be achieved by using only resistance-
capacitance devices and operational amplifiers.