1. School of Electronic, Electrical Engineering and Physics, Fujian University of Technology, Fuzhou 350118, China
2. Fujian Key Laboratory of A.E.D, Fujian University of Technology, Fuzhou 350118, China
3. National Demonstration Centre for Experimental Electronic Information and Electrical Technology Education, Fujian University of Technology, Fuzhou 350118, China
4. School of Computer Science and Electronic Engineering, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
5. School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, SA 5005, Australia