electronics Article Performance Enhancement Methods for the Distributed Acoustic Sensors Based on Frequency Division Multiplexing Yanzhu Hu 1, Zhen Meng 1,* , Mohammadmasoud Zabihi 2 , Yuanyuan Shan 3, Siyi Fu 2, Feng Wang 2 , Xuping Zhang 2,*, Yixin Zhang 2,* and Bin Zeng 4,* 1 ...