Interpolation method and shaft angle encoder

Abstract From the Canadian patent

The present invention provides a method of interpolating between two signals comprising the conversion of each signal into digital form and use of the converted signals to address a memory device at each address of which is pre-stored the result of interpolation for a particular combination of values of the converted signals. One particular application of the invention resides in a shaft angle encoder comprising an encoder disc to be fixed to a shaft , sensor means, regulated by the disc to produce two analogue output signals , analogue to digital conversion means which convert the said analogue output signals to digital words each having a plurality of bits, a memory device in which the …