Secondary master oscillator model VCH-002 is intended for use as slave node clock in SDH networks.
In normal operation it is operating as a slave clock, traceable to a primary reference clock. For purposes of redundancy it has multiple reference inputs. In the event that all links between the master(s) and the node clock fail, the VCH-002 is capable of maintaining operation within prescribed performance limits (the hold-over mode of operation).
Secondary master oscillator contains:
– rubidium GPS/GLONASS Primary Reference Source
VCH-311C
;
– signal Synchronization Unit (SSU) — OSA 5548C.
Secondary master oscillator VCH-002 characteristics completely meet the requirements of ITU-T G.812. In addition to this, Rubidium GPS/GLONASS Primary Reference Source VCH-311C, having the fre-quency accuracy better than 3×10
–12
, can be used as a reserved timing source that meets the requirements of the first class synchronization equipment ITU-T G.811.
Built in frequency comparison system based on the OSA 5548C monitoring system and the GLONASS/GPS PRS VCH-311C provides self-diagnostic and self-calibration.
The OSA 5548C Network Synchronization Unit (Smart SSU) is designed to provide the best timing at SDH network. Smart SSU is a modular, fully redundant timing distribution system for 2048 kbps primary rate networks. The unit tracks incoming clock references, qualifies the signals against network timing standards, then filters and distributes precise timing to all equipment in the node.
Smart SSU meets ETSI and ITU-T synchronization standards and provides holdover that exceeds the requirement for stratum-2 transit and local node performance.
Smart SSU has vast memory of up to 1000 events. In case such as operator errors, frequency standard failure or transmission problems in the network, the unique system OSA 5548C provides insurance from slips by switching to the reserve inputs.
