Primary reference clock (PRC) as the first class synchronization equipment of digital network is intended for generation of the reference clock synchronization signals 2048 kHz and is to meet all requirements and recommendations of ITU G.811.
PRC model VCH-001 designed by “VREMYA-CH” for SDH networks meets all these requirements.
VCH-001 is based on a Passive Hydrogen Maser having relative frequency accuracy ± 5x10E–13 and maximum time interval error (MTIE) in 10 - 20 times better then the requirements of ITU-T G.811.
Due to double reserve equipment, VCH-001 provides the highest reliability and stability of output signals. MTIE of switching over to the reserve equipment is less then 1ns.
The PRC VCH-001 contains Primary Reference Source VCH-1006 (two units) based on Passive Hydrogen Maser, Rubidium Reference Oscillator disciplined by GPS-GLONASS VCH-311C, frequency comparator VCH-310 and HP 55400A Signal Synchronization Unit (Smart SSU).
Primary Reference Source VCH-1006 having the best time and frequency stability - 2x10E-14 per day; 2x10E-12 per second, permits to solve the problem of timing at SDH networks easily.
Built in frequency comparison system based on the frequency comparator VCH-310 and the GLONASS/GPS PRS VCH-311C provides PRC diagnostics and self-calibration.
The HP 55400A Network Synchronization Unit (Smart SSU) is specially designed by Hewlett – Packard to provide the best timing at SDH network. It has E1 and T1 signals inputs. Smart SSU is a modular, fully redundant timing distribution system for 2048 kbps primary rate networks. The unit tracks incoming timing references, qualifies the signals against network timing standards, then filters and distributes precise timing to all equipment in the node. Incoming reference signals may come from frequency standards, GPS reference sources, or E1 signals. 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 jitter, excessive pointer adjustments, operator errors, frequency standard failure or transmission problems in the network, the unique system HP 55400A provides insurance from slips switching over to the reserve inputs.
Expecting VCH-001 lifetime is 20 years.