Simple and robust ternary pulse-encoding and reconstruction of narrowband RF signals over low-cost fibre-optic links

摘要

An existing ternary pulse-coding scheme for bandpass signals, whereby a timing code specifies positive and negative rectangular pulses as well as a third zero state formed by skipping pulses, is adapted to transmission and reconstruction of narrowband RF signals over inexpensive fibre-optic links. The main feature of this technique is that reconstruction of the narrowband analog signal is particularly simple, requiring only a bandpass filter. Simulations using a complex band-limited Gaussian baseband input to represent a 20-MHz LTE-A signal establish the ideal theoretical performance, which is then compared to experimental results obtained by transmission on a 1.6-GHz carrier over a fibre-optic link consisting of an electro-absorption modulated laser, 10 km of standard single-mode fibre (SSMF), and avalanche photodiode detector. The experimental results are only slightly impaired from ideal performance, even for only 6 dB signal-to-noise ratio, thereby demonstrating the viability and robustness of the proposed technique.