APPARATUS AND METHOD FOR PROCESSING SIGNALS OBTAINED FROM A POSITION ENCODER

摘要

Processing circuitry is provided for processing a plurality of signals received from sense coils (21, 23 and 25) forming part of a position encoder used to encode the relative positions of two relatively movable members. The position encoder is such that each of the plurality of signals from the sense coils varies sinusoidally with the relative position of the members but out of phase with respect to each other. The processing apparatus comprises mixers (71, 73 and 75) for multiplying each of the received signals with one of a corresponding plurality of periodic time varying signals, each having the same predetermined period and a different predetermined phase, and an adder (93) for adding the signals from the mixers. The phase of the mixing signals are chosen so that the output signal from the adder contains a single periodic component having the predetermined period whose phase varies with the relative position of the two members.