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CONCLUSION ON CABLES FOR 280 MBITS/S. SPD cables: 24-25 m length: receiver side simple termination. Compensation on driver side (R+L) Use of 3.3->3.6 Volts +/or pull up current to increase signal margin (165mv-> 200 mv)
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CONCLUSION ON CABLES FOR 280 MBITS/S SPD cables: 24-25 m length: receiver side simple termination. Compensation on driver side (R+L) Use of 3.3->3.6 Volts +/or pull up current to increase signal margin (165mv-> 200 mv) To control skew : first choice, Cat5 rigid; 100 m cut in 4 “identical 25m cables”. Or cat 6 cut in middle but problems at the end-> add short patch cables (8 euros each?). Anyhow problem on FE side Drawing of solution needed=> Orsay? (information sent from Orsay to David on 13/12/03 ) Upper SPD cables shorter => Annecy defines minimum length? If possible is it better to make them shorter by exactly 50ns?(about 11meter) Smaller compensation but still skew problem=> 4 cables identical or cut each cable in half and cross. Jacques Lefrancois
Trigger cables: Between crates of one rack: length 1-2 meter => use standard patch cables Cat 5 may have too much skew => characterize cat6 commercial patch cables. (Orsay+ Barcelona or Clermont?) Between two racks; calculate length (<4m?) Is cat 6 patch cables OK ? Between HCAL and ECAL about 10 meters probably some “small” compensation receiver side (validation card) Skew compensation by cutting and reconnecting cable probably needed Jacques Lefrancois