The oscillation frequency varies corresponding to the distance when the distance between the sensor coil surface and the opposed metal is no more than a few millimeters.

When the distance is 1 mm or less, the frequency varies significantly. As a result, the displacement resolution is become better.

Due to the high oscillation frequency, the sensor reacts to even metal foil and plating due to the skin effect.

When a measurement signal of a given length is input to the sensor, the counter in the IC integrates the frequency (the integrated value is 17-bit data). This integrated value is serially output bit by bit to provide a value corresponding to the oscillation frequency and which can be processed by a microcomputer (AD conversion is not required).