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

• Published in: IET optoelectronics Vol. 11; no. 6; pp. 237 - 241
• Main Author: Morgan, Dennis R
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 01.12.2017
• Subjects: bandpass filter; bandpass signals; band‐pass filters; complex band‐limited Gaussian baseband input; encoding; fibre‐optic links; Long Term Evolution; LTE‐A signal; microwave photonics; narrowband analog signal reconstruction; narrowband RF signal reconstruction; negative rectangular pulses; optical information processing; optical links; optical noise; positive rectangular pulses; radio‐over‐fibre; Research Article; robust ternary pulse‐encoding; signal‐to‐noise ratio; spatial filters; ternary pulse‐coding scheme; timing code; UHF filters; radio-over-fibre; optical links; timing code; positive rectangular pulses; bandpass filter; narrowband RF signal reconstruction; microwave photonics; ternary pulse-coding scheme; optical information processing; fibre-optic links; encoding; spatial filters; UHF filters; narrowband analog signal reconstruction; band-pass filters; LTE-A signal; negative rectangular pulses; signal-to-noise ratio; complex band-limited Gaussian baseband input; robust ternary pulse-encoding; optical noise; Long Term Evolution; bandpass signals
• ISSN: 1751-8768; 1751-8776; 1751-8776
• DOI: 10.1049/iet-opt.2017.0031

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.