A new kind of sensor for vibration measurement on the suspended axis is introduced.The function of vibration displacement is realized by the angle division sampling and microcomputer controlling

using capacitive sensor with conductive medium and the reflection type photoelectric encoder as the sensors

and using the oscillator and the difference frequency counter as the signal processing circuit.The design thoughts of every part of the sensor and parameters are described emphatically

and test results are also presented.Reflection mode photoelectric encoder is used to realize equal turning angle sampling

which can be applied to the angle and velocity measurement of suspended axis.At the same time

synchronous locking relation of the difference frequency counter between frequency measurement signal and sampling control signal is considered which can reduce count error and enhance the measuring accuracy.