Patent ID: 7697849
Filing Date: 2010-04-13
Classification: H04B,H04L

Abstract:
1. A data receiving method to receive data in a data transmission system wherein a transmission unit is a frame including an optical pilot signal of a predetermined optical phase and one or more optical data signals to carry data using phase modulation, and the optical pilot signal and the one or more optical data signals are disposed on timeslots at a predetermined time interval in each frame, the method comprising: generating a frame-timing signal from an optical signal received from an optical transmission line to indicate timing of the frame; generating an optical phase reference signal including a plurality of optical pilot signals temporally apart from each other by an integral multiple of the predetermined time interval, from the optical pilot signal in the signal light received from the optical transmission line; converting the optical signal received from the optical transmission line into an intensity-modulated optical signal according to the optical phase reference signal; photo-electrically converting the intensity-modulated optical signal into an electrical signal; generating a clock synchronized with an optical data signal from the optical signal received from the optical transmission line; and extracting the data from the electrical signal according to the clock and the frame-timing signal.