Reference signal generation and management in SDH-WDM-based equipment and networks

This paper describes a new system that functions as both conventional SDH Equipment Clock (SEC) and a new reference signal generation and management device. The system is basically intended for new telecommunication networks based on a combination of Synchronous Digital Hierarchy (SDH) and Wavelength Division Multiplex (WDM) techniques. The new processor-based system is composed of decision-making and selection circuits for reference signals, and advanced 155 MHz phase-locked oscillators (PLO) for generating the SDH frequency, IPPS time signal. This configuration can also achieve highly reliable signal generation and autonomous management independently of conventional network operation systems.