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Mean Method Algorithm

Mean Method Algorithm. For the 128 channels* of each APV: Finds third lowest value Adds user-definable Noise Threshold (NT) Common Mode Noise is the mean of all values below (3 rd lowest value + NT) Can divide 128 APV channels into blocks of 64 or 32

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Mean Method Algorithm

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  1. Mean Method Algorithm • For the 128 channels* of each APV: • Finds third lowest value • Adds user-definable Noise Threshold (NT) • Common Mode Noise is the mean of all values below (3rd lowest value + NT) • Can divide 128 APV channels into blocks of 64 or 32 • Algorithm takes ~270 clks, so calculation can begin after reordering (unlike Median method) * Disabled channels ignored James Leaver

  2. Mean Method FPGA Utilisation One fibre pair: Complete FE design: James Leaver

  3. Mean Method Results 1 James Leaver

  4. Mean Method Results 2 James Leaver

  5. Mean Method Results 3 James Leaver

  6. Mean Method Results 4 James Leaver

  7. Mean Method Results 5 James Leaver

  8. Mean Method Results 6 James Leaver

  9. Mean Method Results 7 James Leaver

  10. Mean Method Results 8 James Leaver

  11. Mean Method Results 9 James Leaver

  12. Mean Method Results 10 James Leaver

  13. New Cluster Finding Algorithm • Cluster finding algorithm show in LabVIEW at last meeting has been converted to VHDL (test system for 1 APV) • FPGA utilisation: James Leaver

  14. Cluster Finding Example James Leaver

  15. Cluster Finding Issues • Iterative process, requiring 131 clks per step • Can fit in ~6 iterations at 100 kHz • Very bad frames may require more, leading to reduction in trigger rate… • …or apply a limit to number of steps and readout potentially ‘unfinished’ results • Variable processing time for each APV incompatible with current throttle system • Would require significant additional firmware modifications in order to implement it in the FED • Will leave as a working prototype for now… James Leaver

  16. TOTEM Tests • TOTEM – intend to run with an average occupancy of ~8% • Too high for a fully populated FED, but what if half of the channels are disabled? James Leaver

  17. TOTEM Results 1 James Leaver

  18. TOTEM Results 2 James Leaver

  19. TOTEM Evaluation • FED can cope with 8% occupancy when half of the inputs are disabled, but: • Assumes that TOTEM can sustain a 400 MB/s readout rate • 200 MB/s reduces maximum occupancy to 5.4% • Assumes that cluster width distribution matches CMS • e.g. single strip clusters would significantly reduce maximum occupancy James Leaver

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