Based on an electrostatically micromachined motor（EMM） used in the levitated rotor micromachined rotational gyroscope

the new capacitance signal detection method of the control system of EMM is presented.It is important for realizing the closed-loop control of the rotation of the levitated rotor.The main characteristic is using the cross-correlation detection & lock-in principle and sine wave generator with DDS controled by DSP.The feasibility is validated by the sine wave generate circuit and system simulation.It gives a way to solve some key problems got in the weak-small capacitance signal detection in practical circuit

it also provides a important reference for the cholce of practical circuit parameters.