German Patent Publication DE 28 34 519 A1 discloses a digital linear measuring device having two parts which are displaceable with respect to each other, one of which supports a scale and the other a detector for scanning the scale and for generating electrical signals which correspond to the scanned length of the scale. An electronic device processes the detector signals. The scale has a marking support with material which can be magnetized and is magnetized at predefined distances to form readable markings. The detector includes a reading head for reading the markings of the scale. A digital display device can be used for performing further processing. The marking support can be a magnetic layer with the markings formed by sinusoidal magnetization of two tracks and a reading head being respectively provided for each track. The detector can have at least one magnetic head sensitive to flux which is connected between the detector and the marking support in accordance with the principle of a magnetic modulator for reading at low relative speed. Detailed information regarding the embodiment of the detector is absent in the mentioned reference.
European Patent Publication EP 0 069 392 A2 discloses a digital position measuring device wherein a detector having a magneto-resistive sensor is provided. Magneto-resistive sensors with different characteristic curves are described therein and bridge circuits having such sensors are disclosed.