Rapid measurement method for micro-machined resonators

To reduce measurement time of micro-machined resonator and improve measurement efficiency, a novel frequency character measurement method for micro-machined resonator based on piezoresistive detection is put forward. An Ohm phase sensitive detector (Ohm-PSD), an integrator and MCU are used to achieve the effective detection of weak signal. The phase detecting function of the 'Ohm-PSD' is achieved by the detective resistance with multiplying the reference signal and measured signal using Ohm's law. The integration of the multiplication results is carried out to restrain the interference and noise;MCU is used to process the sampling data in integration. Experimental results show that the equivalent input noise of rapid measurement method prototype is 2.7 nV√Hz, and measurement time at every frequency point is 4 ms. Comparing it with the commercial Lock-in amplifier(LIA), measurement efficiency increases greatly.