Measuring the relative positions of two objects involves correcting digitised sensor signals for amplitude, offset or 90 degree phase errors and using to determine at least two position values

摘要

The method involves sensing a scale connected to one object with at least two read heads connected to the other object to produce read signals that are digitised to form measurement values. The digitised signals are corrected for amplitude, offset or 90 degree phase errors and used to determine at least two position values that are produced as corrected position values in the form of corrected analogue output signals following arithmetic averaging