1. Science and Technology on Electronic Test and Measurement Laboratory, North University of China, Taiyuan 030051, China
2. School of Instrument and Electronics, North University of China, Taiyuan 030051, China
3. Shanxi Key Laboratory of Signal Capturing & Processing, North University of China, Taiyuan, Shanxi Province 030051, China
4. School of Materials Science and Engineering, North University of China, Taiyuan 030051, China