A circuit system and method of automatically recoverable available service clock

Abstract

The invention provides a circuit system capable of automatically recovering and using a service clock and a method thereof. The invention comprises a phase-locked loop, a 2-channel analog switch, an analog to digital converter, a digital to analog converter, a processor, and a nonvolatile memory. The phase-locked loop comprises a voltage-controlled oscillator. The phase-locked loop is connected with the 2-channel analog switch and the analog to digital converter, receives the clock from the optical recovery and provides the transmission reference clock. The analog to digital converter is connected with the 2-channel analog switch. The processor is connected with the analog to digital converter and the nonvolatile memory. The digital to analog converter is connected with the processor. The 2-channel analog switch is connected with the digital to analog converter and the voltage-controlled oscillator. The invention has the advantages of the lower cost, being easy to diagnose fault and improvement of the maintainability of the system.

Description

technical field [0001] The invention relates to the field of optical communication equipment, in particular to a circuit system and method capable of automatically recovering available service clocks. Background technique [0002] In the wavelength division transmission system, the main function of the optical transponder board is to use the optical / electrical / optical conversion method to convert the service optical signal of any manufacturer that meets the requirements of the G691 recommendation into an optical signal that meets the requirements of the G692. At the same time, it also completes error correction coding, Overhead detection processing. [0003] Inserting an alarm indication signal (Alarm Indication Signal, hereinafter referred to as AIS) into the output optical service signal is one of the contents of its overhead processing work: when the quality of the input optical signal of the system deteriorates and the service cannot be transmitted normally, the optical ...

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Problems solved by technology

[0004] When the optical signal input by the system has a quality problem, the optical transponder board loses a stable and reliable frequency source. At this time, the output service signal clock fails because there is no available synchronization source, and the optical transponder board sends the downstream service signal There will be obvious frequency deviation or frequency instability, so that downstream nodes may not be able to recognize the AIS alarm inserted in the service signal

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