Patent ID: 8222891

Claim:
A method of compensating for an error parameter between first and second members in a displacement transducer, comprising: producing a first signal at the first member; producing a second signal at the first member; modulating the first and second signals at the second member so that, as the first and second members are displaced relative to one another along a measurement axis, the first signal includes a region with an invariant amplitude and the second signal includes a region with a variant amplitude; determining a first relation between a sample of the second signal from within the region of variant amplitude and the invariant amplitude of the first signal as an indication of an error parameter; generating a first compensated sample based upon the first relation; modulating the first signal at the second member to include at least one region with a variant amplitude as the first and second members are displaced relative to one another along the measurement axis; modulating the second signal at the second member to include at least one region with an invariant amplitude as the first and second members are displaced relative to one another along the measurement axis; determining a second relation between a sample of the first signal from within the at least one region with a variant amplitude and the invariant amplitude of the second signal as an indication of the error parameter; and generating a second compensated sample based upon the determined second relation.