Sine-Cosine Angular Position Encoders

Sine-Cosine Angular Position Encoders are useful in coupling an analog device to a digital computer. The desired result is increased accuracy of the analog equipment and simplification of the digital equipment. An estimate is made of the accuracy that can be obtained from sine-cosine angular position encoders. It is shown that a balanced design results in a constant absolute error in the coded value of the function. When used to transform spherical to cartesian coordinates, this results in errors in the computed value of the cartesian coordinates that are constant fraction of the slant range. A geared system is described which permits an increase in accuracy. Special output switching requirements and special anti-ambiguity circuits are described which are required by the geared system. A prototype sine-cosine angular position encoder is described.