Passive Hydrogen Maser (Primary Reference Clock)
Equipment that provides a timing signal that may be used as the basis of reference for the control of other clocks within a network. The long-term accuracy of that signal is maintained at 1 x 10-11 or better. This primary reference source generates a timing signal completely autonomous of other references using passive hydrogen maser technology. PRC provides the highest quality sync for telecom networking as required by international standards.
- Output signals: sine 5, 10 and 100 MHz, (1±0.3) V rms @ 50 Ohm; 2048 kHz G.703/13.
- Accuracy (over environment): ±1×10–12 (ten times better than ITU-T G.811 / 5 and ETS 300 462-6 / 4 recommendations).
- MTIE and TDEV meet requirements of ITU-T G.811 / 6.1 and ETS 300 462-6 / 5.1:
|MTIE (ns)||Time interval t(s)|
|0,275t+25||0,1 < t =< 1000;|
|0,01t+290||t > 1000.|
|TDEV (ns)||Time interval t(s)|
|3||0,1 < t =<100;|
|0,03t||100 < t =< 1000;|
|30||1000 < t =< 10 000.|
- Output signal 2048 KHz jitter meets requirements of ITU-T G.811 / 6.2 and ETS 300 462-6 / 5.2.
|Time interval||Allan variance|
Interfaces: RS-232C and LAN (10/100 Base-T Ethernet).
Power: -48 V DC nominal (-36 to -62 V DC).
Power consumption: < 80 W.
Dimensions: 200x470x513 mm.
Weight: 30 kg.
Maintenance is only for hydrogen tank replacement from 5 up to 10 years (depending of the size) and also in this case the standard exchange could be very easily implemented and this, without any special tools or need for re-calibration.
Lifetime: 15~ 20 years.
Some Differences between Cs and Passive H-Maser
- Cs clocks have poor short term stability (precision) and good long term stability (accuracy)
- H-maser have excellent short term stability (highly precise) and subject to a very low drift (~ ± 5 – 6 x10-15 / month)
- Cs is classified by DoT as hazardous material H maser is not
- H-maser instrument monitors the level of H-pressure in the molecular hydrogen source and schedule of hydrogen source replacement—every 7 to 8 years—can be easy predicted (pressure is displayed on front panel)
- Cs depletion causes failures in 3 – 7 years, and is very difficult to predict
The Passive Hydrogen Frequency and Time Standard provides the highest frequency stable output signals with the characteristics.