Measuring Hot TDR and Eye Diagrams with an Vector Network Analyzer?

Transcription

1 Measuring Hot TDR and Eye Diagrams with an Vector Network Analyzer? Gustaaf Sutorius Application Engineer Agilent Technologies Page 1

2 #TDR fit in Typical Digital Development Process System Design Interconnect Design Active Signal Analysis Compliance Test Accurate Models Accurate Simulations Hardware & Software Correlation Accurate Design Analysis Test & Analysis Capability Measurement Automation Increased Team Effectiveness Measurement Automation Test & Analysis Capability Measure

3 Agenda 1. RF Network Analyzer with TDR & EYE diagrams 2. Hot TDR 3. Compliance Support 4. Summary and Q&A Page 3

4 TDR in time domain OSCILLOSCOPE E i E r Z L TRANSMISSION SYSTEM UNDER TEST STEP GENERATOR E r Typical Step: 200 mv, 250 khz square wave with 35 ps rise time E i T Oscilloscope display when E r 0

5 Scope Displaying impedance in the Time Domain: 54754A TDR provides Instantaneous Impedance Typical TDR result A: 50 Ohm cable B: Launch to microstrip C: 50 Ohm microstrip A B C D E F D: 75 Ohm microstrip E: 50 Ohm microstrip F: open circuit With option 202 TDR results from 54754A now also available in S-parameters format (S11, S21)

6 Eye Masks & TDR with an Network Analyzer?

7 What is ENA E5071C Option TDR? The ENA Option TDR is an application software embedded on the ENA, which provides an one-box solution for high speed serial interconnect analysis. Time Domain Frequency Domain 3 Breakthroughs for Signal Integrity Design and Verification Eye Diagram Simple and Intuitive Operation Fast and Accurate Measurements ESD protection inside ESD Robustness

8 What is ENA E5071C Option TDR? Modes of Operation TDR/TDT mode 1/2/4 port TDR/TDT and S-parameters (SE and BAL) Setup Wizard Functional enhancements Zooming, horizontal autoscale, additional marker functions, Performance enhancements Z Peeling (lossless), robust DC extrapolation methods, Eye/Mask Mode (ENA measures Transmission) Simulated Eye diagram & Eye mask function In the oscilloscope, an eye diagram is often used to analyze signal quality. You can diagnose problems, such as attenuation, noise, jitter, and dispersion that arise or characterize specific parts of the system with one display. The E5071C option TDR provides simulated eye diagram analysis capability, eliminating the need for a hardware pulse pattern generator. The virtual bit pattern generator is used to define a virtual bit pattern. The defined bit pattern is then convolved with the device impulse response to create an extremely accurate measurement based eye diagram.

9 What about E5071C Option 010? Not Good Enough? E5071C already has high performance TDR functionality.(option 010) But Since the U/I is based on the traditional softkey architecture, high speed digital signal integrity engineers accustomed to using oscilloscopes seem to find the U/I unfamiliar and not so easy to use. Therefore To fill this gap, a new simple and intuitive U/I was developed to vastly improve the usability of TDR/TDT measurements. (from E5071C brochure) In addition TDR/TDT specific features are added to improve transmission line impedance measurements. (gating for example)

10 ENA #010 Operation Option 010 vs Option TDR Instrument Setup: Measurement Parameters: Nop=1601 Port Extension (P1~P4) Display allocation: Reflection Parameters Port1 (ENA) Port2 (ENA) Port3 (ENA) Port4 (ENA) Tdd11, Tdd22 Format Real Zreflection ON Transmission Parameters Sdd11, Sdd22 Format LogMag Tdd21, Tdd12 Format Real Zreflection ON Sdd21, Sdd12 Format LogMag E demo board Time Domain Frequency Domain

11 ENA #010 Operation: many steps needed Option 010 vs Option TDR > 40 steps!! * Refer to appendix of E5071C Option TDR demo guide for step-by-step setup procedure.

12 ENA #TDR Operation: Just 4 Steps needed Option 010 vs Option TDR Procedure: Start Option TDR Application Press [Analysis] > TDR Follow Setup Wizard Instructions [Step 1] Select DUT Type [Step 2] Deskew [Step 3] Set DUT length [Step 4] Set rise time 4 steps!!

13 ENA #TDR Operation: Default (for scope users) and Advanced Default Features Limited access to ENA firmware functions and capabilities Sufficient for majority of digital users Limited access to front panel hard-keys Advanced Features Full access to ENA firmware functions and capabilities. To enter the Advanced mode, press the advanced mode checkbox under the Settings tab on the Option TDR user interface. Operation is possible by front panel keys, soft-key menus, and Option TDR U/I. Operation is done through Option TDR U/I Operation by soft-key menu is not allowed

14 # TDR has 2 modes: TDR/TDT and Eye/Mask TDR/TDT Mode: Reflection Eye/Mask Mode: Transmission Txy Marker Lines Zoom x-scale annotation horizontal autoscale delta time (skew) trace copy & coupling set bit pattern peeling set mask scale control using scroll mouse selectable rise time definition (10-90%, 20-80%)

15 Time Domain View & Frequency Domain View Time Domain Response The default lowpass step mode is equivalent to the TDR scope response Frequency Domain Response Sdd11 results shows that signals are reflected across a wide frequency range. High frequency components have a larger impact on high speed systems. Touch the board to observe the corresponding point change on the time domain response in real time. Which section of the DUT is causing the most high frequency reflections?

16 Gating in Time Domain: Observe Frequency Response at specific physical location

17 Enhance sensitivity by using Bandpass Impulse Data analysis using bandpass impulse mode Time Domain Response (lowpass step) Time Domain Response (bandpass impulse) bandpass impulse lowpass step A large peak at the input connector is measured in the bandpass impulse response, whereas no significant peak appears in the lowpass step response.

18 Gating + bandpass impulse mode: specific physical locations have different Frequency responses! Which section of the DUT is causing the most reflections? The low frequency reflections are mainly from the stepped impedance and the high frequency reflections are mainly from the connector. To reduce the reflection of high frequency components, the connector match must be improved. reflections from stepped impedance reflections from connector

19 Actual Measurements at Amstelveen Office

20 Connector launch: good SWR at low freq, worse at high freq Note: good SWR = low return loss = little or no reflections

21 First 50 to 25 ohm step on PCB stripline: Good SWR at high freq, worse SWR at low freq

22 What about the distance resolution? Time domain response resolution: the ability to resolve two closely spaced responses, or a measure of how close two responses can be to each other and still be distinguished from each other. Response resolution depends upon whether it is a reflection or a transmission measurement, and the relative propagation velocity of the signal path. For responses of equal amplitude, the response resolution is equal to the step rise time. response resolution = step rise time * speed of light * velocity of propagation E5071C 20GHz 14GHz 8.5GHz 6.5GHz 4.5GHz 3GHz Rise Time (LP Step) Spec. min (10-90%) Response Typ. min LP Step mode, reflection meas, in air (εr = 1) Typ. LP Step mode, reflection meas, in FR4 (εr = 4.9) 22.3 ps 31.9 ps 52.5 ps 68.6 ps 99.1 ps 149. ps 3.3 mm 4.8 mm 7.9 mm 10.3 mm 14.9 mm 22.4 mm 1.5 mm 2.2 mm 3.5 mm 4.6 mm 6.7 mm 10.1 mm [Example] Time domain response resolution for responses of equal amplitude, using 20 GHz model, reflection measurement, in FR4 (εr=4.9, vf=1/ εr=0.45) response resolution (transmission) = (22.3 ps) x (3.0e8 m/s) x (0.45) = 3.0 mm response resolution (reflection) = (22.3 ps) x (3.0e8 m/s) x (0.45) / 2 = 1.5 mm 22

23 EYE Diagram Time domain Eye Diagram Frequency domain Eye mask editor Eye mask test Eye diagram Virtual bit pattern generator Automated eye diagram measurement results 23

24 Agenda 1. RF Network Analyzer with TDR & EYE diagrams 2. Hot TDR 3. Compliance Support 4. Summary and Q&A Page 24

25 Hot TDR Measurements 2007 HDMI Developers Conference, HDMI and HDMI 1.3 A Technical Overview, Silicon Image 25 Confidentiality Label April 2, 2011

26 Hot TDR Measurements 2007 HDMI Developers Conference, HDMI and HDMI 1.3 A Technical Overview, Silicon Image 26 Confidentiality Label April 2, 2011

27 Hot TDR Measurements 2007 HDMI Developers Conference, HDMI and HDMI 1.3 A Technical Overview, Silicon Image 27 Confidentiality Label April 2, 2011

28 Advantages of ENA Option TDR for Hot TDR Fast and Accurate Measurements For Hot TDR measurements, data signals from the transmitter cause measurement error... TDR Scopes ENA Option TDR Tx t t wideband receiver captures all of the signal energy from the transmitter Wideband Receiver t Tx t t narrowband receiver minimizes the effects of the data signal from the transmitter Narrowband Receiver t fc freq fc freq time time To obtain a stable waveform, extensive averaging is necessary. In many cases, averaging is not necessary to obtain a stable waveform.

29 Agenda 1. RF Network Analyzer with TDR & EYE diagrams 2. Hot TDR 3. Compliance Support 4. Summary and Q&A Page 29

30 Measurement Correlation between TDR ENA and TDR scope Eye Diagram DUT: differential PCB trace PRBS 1Gbps ENA Option TDR N4903B C Simulated Eye ENA Option TDR Live Eye NOTE: For further details, refer to Application Note, Correlation between TDR oscilloscope and VNA generated time domain waveform ( EN)

31 Both ENA #TDR and 86100C #TDR Comply To SATA

32 SATA Hot TDR Measurement Results 160 Gbyte hard-disc 32 Confidentiality Label April 2, 2011

33 Compliance Support Agilent E5071C is certified equipment for,, and Cable/Connector Compliance Tests E5071C Method of Implementation (MOI) for USB3.0 and DisplayPort Cable Compliance Test VBA program and operation guide also available for USB3.0, HDMI, and DisplayPort Cable Compliance Test [Example] USB3.0 Cable measurement using the VBA program Refer to following links for further information: DisplyPort USB

34 Compliance Support SuperSpeed USB Developers Conference (Taiwan, April 1-2, 2010) ENA Option TDR introduced as recommended solution for CabCon compliance test 34

35 Agenda 1. RF Network Analyzer with TDR & EYE diagrams 2. Hot TDR 3. Compliance Support 4. Summary and Q&A Page 35

36 Summary The Agilent ENA Option TDR application Provides one-box solution for high speed serial interconnect analysis Time domain Frequency domain Eye diagram Brings three breakthroughs for signal integrity design and verification Simple & Intuitive Operation Fast & Accurate Measurements ESD Robustness

37 Additional Resources ENA Option TDR Reference Material Technical Overview ( EN) Configuration Guide ( EN) Application Notes: Correlation between TDR oscilloscope and VNA generated time domain waveform ( EN) Comparison of Measurement Performance between Vector Network Analyzer and TDR Oscilloscope ( EN) Accuracy Verification of Agilent s ENA Option TDR Time Domain Measurement using a NIST Traceable Standard ( EN) 37

38 Page 38 Questions?