Numerical encoder for angular position - compares trigonometric functions derived from input

摘要

The encoder is designed to furnish a numerical value THETA c representing an angular position of an analogue value corresponding to two input signals A sin THETA and A cos THETA and has a preadjustable means to provide analogue forms of trigonometric functions of predetermined angles THETA nc and to select one of the angles which is closest to THETA c. An assembly (19) works out sin (THETA-THETA c) from the input signals. Analogue means (20) works out cos (THETA-(THETA nc +- alpha)) from the input signals and the preadjustable means, alpha being a predetermined angle. Analogue means works out THETA c - THETA n c and determine K(THETA-THETA nc)cos(THETA-(THETA nc+-a)). The sin and cos functions are compared so as to control the incremented increase and decrease of a counter such that its output is zero.