调制技术是把基带信号变换成传输信号的技术。它将模拟信号抽样量化后，以二进制数字信号“1”或“0”对光载波进行通断调制，并进行脉冲编码（PCM）。-Modulation technique is the transmission signal into a baseband signal transform technique. It converts analog signal sampling to quantify, in binary digital signal "1" or "0" on the optical carrier is on-off modulation, and pulse code modulation (PCM).