Magnetoresistive sensors and a new hardware-based interpolation method for length and angle measurements

This paper describes a new method for length and angle measurements of a sensor system which is based on a magneto-resistive sensor element. The system consists of the sensor element, a magnetic scale and a mixed signal ASIC which processes the sensor signals. The sensor signals are interpolated to achieve an enhanced resolution. The interpolation algorithm is implemented in the ASIC by a new architecture, where the essential procedure can be realized in the analogue subsystem. This new architecture will lead to a drastically reduced ASIC chip area. By using the signal symmetry all components can be used to process the sensor signals several times. This results in a topology with a minimum of components, which saves chip area, by the costs of some additional switching components.