DOI: 10.3724/SP.J.1146.2013.00312

Journal of Electronics & Information Technology (电子与信息学报) 2013/35:12 PP.3030-3036

Micromachined Electric-field Sensor System Based on Direct Digital Synthesizer and Lock-in-amplifier to Measure AC and DC Fields

A novel and high-performance micromachined electric-field sensor system circuit which can measure both AC (50 Hz) and DC fields is presented based on Direct Digital Synthesizer (DDS) and Lock-In-Amplifier (LIA). The system combines low-noise analog circuits and digital control scheme, using DDS to generate the excitation signal and the orthogonal reference signals, ensures the frequency and amplitude stability of the excitation signal and precise phase difference between the orthogonal reference signals. Using demodulator chip and high-speed filter to build quadrature lock-in amplifier circuit, combining with the ARM microcontroller, the system achieves a faster response and saves much more sources than the simple digital processing circuit.

Key words:Micromachined electric-field sensor,DC and AC (50 Hz) electric field,Direct Digital Synthesizer (DDS),Quadrature Lock-In-Amplifier (LIA),Resolution

ReleaseDate:2014-07-21 17:01:13