Rotary Encoder Using Amorphous Star-Shaped Core Field Sensor

The authors describe a magnetic rotary encoder consisting of a ring-shaped multi-pole magnet and amorphous magnetic core multivibrator sensors positioned radially around the magnet. The frequency-modulated output is sinusoidal, with a distortion of less than 1% when operating at 50 kHz; the encoder is impervious to mechanical disturbances, and can be used at relatively high temperatures.