Abstract

In M-ary optical pulse position modulation (M-PPM) communication systems, accurate timing synchronization is required at the receiver to minimize the probability of error. Timing recovery using phase-locked loops (PLLs)¹ is a particularly attractive approach because the PLL is relatively easy to implement. For this approach to be effective, it is essential for the input to the PLL to contain a strong signal at the slot frequency. For an M-ary optical PPM system which transmits square pulses that occupy the entire signal time slot, it can be shown that the output of the photodetector does not contain a spectral component at the slot frequency.

© 1985 Optical Society of America