Today each CEB suspension crate has its owm Timing Distribution box (TDB) receiving by fibers the IRIGB signal and 10MHz clock from the DAQ room , then inside a suspension rack the Timing signals are propaged using RJ45 cables to the DSP boards .
At the DAQ room level (scheme),
- the TDB05B provides the timing optical signals to the NI, SR, BS and BS suspensions
- the TDB06B provides the timing optical signals to the WI, IB and OB suspensions, to the DBOX located in the EEROM
Today there is not a direct monitoring of the Timing loop stability of the suspension DSPs . An indirect monitoring is performed using the emitted GPS time stamp of the Tolm packet with the channels Daq_S{a,c}_XX_Tolm_Send_Start_min.
The attached plots shows the differents Daq_S{a,c}_XX_Tolm_Send_Start_min signals, the timing _error signals of the DAQ boxes located in the EEROOM, the DBOX located in the CEB platform and the monitoring of the IRIGB pulse at the level of the first TDB04B . The red rectangle highlight the suspensions where there was some timing jumps : Sc_BS, S{a,c}_NI, and S{a,c}_WI. There was 2 jumps space by 4mn . The jump level was not the same on all these suspensions, the big jumps occurred only on the WI suspension DSPs .
it seems unlikely that the troubles occurred in the fiber propagation , it 's not obvious to find where these glitches comes from but the only way to recover the correct situtation it is to reconfigure the Suspension timing part., at least the WI one
