1. ASIC & System State Key Lab, Dept. of Microelectronics, Fudan University, Shanghai, China
2. ASIC & System State Key Lab, Dept. of Microelectronics, Fudan University, Shanghai, China and Dept. of EE, University of Texas at Dallas, Dallas, USA
3. School of Mathematical Sciences, Fudan University, Shanghai, China
4. Dept. of ECE, Duke University, Durham, USA and Institute of Applied Physical Sciences and Engineering, Duke Kunshan University, Kunshan, China