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APV25, Clock and Trigger

APV25, Clock and Trigger. M.Friedl HEPHY Vienna. APV25. Please refer to my December 2008 meeting slides for details about APV25 (SVD session) In Nov/Dec 2008 beam test, we confirmed that APV works perfectly fine with both 42.4 MHz clock (=RF/12)  3.5 µs max L1 latency

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APV25, Clock and Trigger

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  1. APV25, Clock and Trigger M.Friedl HEPHY Vienna

  2. APV25 • Please refer to my December 2008 meeting slides for details about APV25 (SVD session) • In Nov/Dec 2008 beam test, we confirmed that APV works perfectly fine with both • 42.4 MHz clock (=RF/12)  3.5 µs max L1 latency • 31.8 MHz clock (=RF/16)  4.7 µs max L1 latency • We can make the APV25 clock switchable Schematics of one channel Markus Friedl (HEPHY Vienna)

  3. APV25 Pipeline & TriggerSimulation Markus Friedl (HEPHY Vienna)

  4. APV25 Trigger Restrictions • Minimum L1 distance of 6 APV clocks – Irrelevant in case of 500ns dead time as requested by ECL (2) Maximum pipeline filling – also affected by such dead time requirement Markus Friedl (HEPHY Vienna)

  5. APV Trigger Simulation • Input:CLK, L1 rate • Model:APV25 state machine, exponential trigger distribution • Output:FIFO filling histogram, trigger loss, Poisson distribution to check randomness of simulated triggers Download:http://belle.hephy.at/apvtrg.zip (needs Labwindows/CVI 8.1 run-time engine from http://ni.com) Markus Friedl (HEPHY Vienna)

  6. 25.9 12.8 Results – No External Dead Time Requirement • Min Lost: trigger restriction (1) = too little distance • FIFO Lost: trigger restriction (2) = too many pending readouts • Nakao-san wishes <3% dead time @ L1=30kHz •  OK (0.87%) for 42.4MHz clock, slightly higher (3.43%) at 31.8MHz Markus Friedl (HEPHY Vienna)

  7. Results – External 500 ns Dead Time Requirement • Nakao-san‘s wish (<3% dead time @ L1=30kHz) met in both cases •  0.42% for 42.4MHz clock and 2.7% at 31.8MHz • 500ns dead time (as required by ECL) not accounted for APV25 • Hence no minimum lost figure always zero 24.0 11.4 Markus Friedl (HEPHY Vienna)

  8. Summary Markus Friedl (HEPHY Vienna)

  9. Summary • APV25 has trigger limitations due to (1) Minimum L1 distance of 6 APV clocks (2) Maximum pipeline filling • APV25 can operate at both 42.4MHz (RF/12) or 31.8MHz (RF/16) clocks • In case of no external limitation, we get @ 30kHZ L1: • 0.87% for 42.4MHz clock, 3.43% at 31.8MHz (see December slides for more detail) • With 500ns dead time as requested by ECL we get • 0.42% for 42.4MHz clock, 2.7% at 31.8MHz • Conclusion: With 500ns ECL dead time, both frequencies are fine according to Nakao-san‘s wish of<3% APV25 dead time@ L1=30kHz Markus Friedl (HEPHY Vienna)

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