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| Micromachined Electric-field Sensor System Based on Direct Digital Synthesizer and Lock-in-amplifier to Measure AC and DC Fields |
| Ren Dong-yu①② Peng Chun-rong① Xia Shan-hong① |
①(State Key Laboratory of Transducer Technology, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190, China)
②(University of Chinese Academy of Sciences, Beijing 100039, China) |
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Abstract 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.
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Received: 15 March 2013
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Corresponding Authors:
Ren Dong-yu
E-mail: rdyzju@hotmail.com
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2013, Vol. 35 
