COORDINATE MEASURING DEVICE

摘要

A measuring signal in the form of an induction signal produced in a transducer or in activated coordinate wires is fed to a linear filter to reduce the frequency components caused by wire switching. The filter output signal is fed to an analysing circuit. The switching intervals are pref. shorter by a factor of at least 3 and pref. 10 than the wire activation times. The filter is pref. a higher order low pass device whose cut-off frequency is lower than the wire switching frequency. The transducer may be supplied with a sawtooth current, whereby the wires are activated during the rising and falling portions.