Application of Perpendicular Magnetic Recording for Use in Angular Encoders

In this paper a newly developed magnetic encoder system is presented that can detect absolute and incremental angular positions. The encoding is performed by combining a perpendicularly oriented code disk and a magnetoresistive read array that is placed at a distance of 50μm above the medium. Results of numerical calculations show the influence of track width and sensor height on the signal. A carrier-to-noise-ratio of 35 dB was achieved with a 400μm wide absolute code track and an appropriate barber-pole-type read sensor.