1 / 12

40 MHz patterns

1. 40 MHz patterns. 40 MHz patterns. C. Willmott. CMS Week Sep 20 th , 2005. 40 MHz patterns. 2. 15.10 6 events. 40 MHz patterns. C. Willmott. CMS Week Sep 20 th , 2005. Simulation. 3. 40 MHz patterns. C. Willmott. CMS Week Sep 20 th , 2005. Pattern Analysis. 4.

chaz
Download Presentation

40 MHz patterns

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 1 40 MHz patterns 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  2. 40 MHz patterns 2 15.106 events 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  3. Simulation 3 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  4. Pattern Analysis 4 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  5. Analytical Pattern Reconstruction 5 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  6. TDC Specifications 6 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  7. TDC DNL and INL 7 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  8. Nasty Histograms 8 27%pp 8% RMS 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  9. Mathematics 9 Some mathematical relationships • Time-box histograms are a kind of “code density plots” which are directly related to differential non linearity (DNL). • But we are interested in integral non linearity (INL) which can be calculated from DNL plot by integration. Receipt • Calculate DNL: dnl(i) = h(i)/histogram_mean_value – 1 • Calculate INL : inl(i) = inl(i-1)+dnl(i) • Find MAX, MIN in INL. These are maximum time deviation in TDC LC’s. Hints: to have meaningful results statistics fluctuations must be negligible. In practice counts per bin should be 10000 counts or higher. Use a flat region of the time-box. 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  10. Example 10 0.35 LC pp ~ 140 ps 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  11. Conclusions 11 • This effect can be explained as a phase modulation by clock harmonics. • Small arrival time shifts may cause large visual effects in drift time histograms. • Worst case configurations we manage to setup in our Lab seem to correspond to arrival time variations in the range of 100-200 ps, compatible with TDC specifications (INL). • Most likely there is not a single source of phase modulation, but a sum of small effects across the whole system. Next steps • Isolate and quantify possible sources: TDC, ROB, TRB, cabling, PS, grounding ... • Study multiple pulses case. 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

  12. Simulated patterns 12 40 MHz patterns. C. Willmott CMS Week Sep 20th , 2005

More Related