PULSE POSITION MODULATION FOR DISTRIBUTION OF VIDEO SIGNALS ON OPTICAL FIBER

Abstract

Optical fiber distribution networks are being exploited for the provision of video and other wide band services. Digital transmission of these signals is expensive because of the requirement for a complex and costly codec. For short length subscriber links, analog transmission could be preferred for the low cost of the modulator. This thesis investigates the performance of multichannel video transmission over optical fibers using pulse position modulation (PPM). The performance of PPM is compared to amplitude modulation vestigial sideband (AM-VSB), frequency modulation (FM), and pulse code modulation (PCM), in terms of the demodulated signal-to-noise ratio (SNR) relative to the SNR at the optical receiver. It is shown that PPM SNR performance is comparable to PCM and FM modulation methods. Furthermore, PPM permits some transmission nonlinearity and allows the use of low cost optical transmitters. Integrated services using PPM video signals and multiplexed PCM voice and data signals are also possible.