DHP-DHH Interconnect Characterisation Results of Time Domain - - PowerPoint PPT Presentation

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DHP-DHH Interconnect Characterisation Results of Time Domain - - PowerPoint PPT Presentation

Sep 15, 2022 164 likes •333 views

DHP-DHH Interconnect Characterisation Results of Time Domain Reflectometry measurements Philip Ptsch Interlink Design passive Challenges of Datatransmission 4 Links per Module 1.2 Gbit/s per Link, 8B10B encoded -> 1.6 GHz Clock

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SLIDE 1

Results of Time Domain Reflectometry measurements

Philip Pütsch

DHP-DHH Interconnect Characterisation

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SLIDE 2

Interlink Design

passive

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SLIDE 3

Challenges of Datatransmission

  • 4 Links per Module
  • 1.2 Gbit/s per Link, 8B10B encoded
  • > 1.6 GHz Clock
  • Mechanical Situation: Tight constraints

near Detector → KAPTON Flex

  • Distance DHP-DHH ~15m
  • At High Data Rates “Analogue”

characteristics are important:

  • Impedance:
  • Driver
  • Transmission Line
  • Receiver (Termination)
  • Reflections at Discontinuities
  • Damping of Transmission Lines
  • Noise
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SLIDE 4

Measurement Setup

KAPTON FLEX

  • Time Domain Reflectometry
  • Fast Rising/Falling Edge

sent to DUT

  • Reflected/Transmitted

Waveform recorded

  • DUT: KAPTON Test Figure,

8 differential Lines, different Trace Width 65u-100u Time Domain Reflectometer

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SLIDE 5

Measurement Setup II

12m CAT7 35cm KAPTON Flex FPGA Board TEKTRONIX TDR & Sampling Scope

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SLIDE 6

Impedance Measurement

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SLIDE 7

Damping Measurement

Frequency dependent transfer function of Kapton cable

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SLIDE 8

Measurement Setup II

FPGA

RocketIO IN+OUT

Sampling Scope

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SLIDE 9

Eye Diagram – RocketIO Output

RocketIO driver at the

  • utput @2GHz
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SLIDE 10

12m CAT7 + 35cm KAPTON

RocketIO driver 12m CAT7 + 35cm Kapton @2GHz

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SLIDE 11

Preemphasis

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SLIDE 12

Preemphasis

  • Increase high

frequency component

  • f the signal to

Compensate the Cable transfer function

  • Acts like high pass
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SLIDE 13

Preemphasis II

RocketIO driver at the output @2GHz Preemphasis turned on Preemphasis turned off

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SLIDE 14

Preemphasis III

RocketIO driver 12m CAT7 + 35cm Kapton @2GHz Preemphasis turned off Preemphasis turned on

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SLIDE 15

Eye DHP

DHP 0.1 Driver at the output @ 1.555GHz After 35cm KAPTON

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SLIDE 16

Summary

  • TDR Setup to characterise differential electrical

Transmission Lines working

  • Design and Measurements (Impedance, Damping)

match

  • Final geometry defined
  • 35cm Kapton+12m CAT7 together with preemphasis

works

  • DHP 0.2 will have preemphasis
  • Only passive repeater (Patch Panel) will be needed