د MP1900A برټ فشار کیلیبریشن غوره طریقې

PCI Express 6.0 CEM:
BERT Stress Calibration
غوره کړنې

تخنیکي به

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

پیژندنه

The PCI Express (PCIe) CEM Specification requires testing both transmitters and receivers to ensure that devices comply with the specification. Tektronix  provides automated BERT receiver (RX) stress calibration  and receiver test software for PCIe 6.0 CEM testing.  This software automates the calibration process for a  system composed of a Tektronix DPO70000SX real time  oscilloscope and Anritsu MP1900A Bit Error Rate Tester  (BERT). Features are implemented in TekRXTest Software  publicly available today supporting RX characterization,  debug, pre-compliance and compliance testing per the 6.0  CEM specification.

TekRxTest software offers a wizard-based approach  to intuitively guide users through the complex receiver  calibration process. The process, when done manually, can  easily take two to three days, while with this new solution  calibration can typically be completed in hours.

TekRxTest لاندې ځانګړي طریقې پلي کړې ترڅو دا د نورو شته تخنیکونو په پرتله ډیر اغیزمن کړي:

• Patented Tx EQ calibration shortens the process from several hours on comparable systems to ~30 mins, without compromising accuracy required by the specifications.
• Hardware accelerated FastFrame™ approach shortens the waveform averaging process required in the TP2 calibration process by hours.

برسېره پردې، د TekRxTest مدغم رسیدونکي کیلیبریشن او ازموینه د PCI ایکسپریس معیار د ټولو نسلونو لپاره د ازموینې ملاتړ کوي.

پس منظر

PCIe receiver testing specifies the calibration of test signals. During actual operation of a high-speed serial link, numerous impairments will close an eye. PCIe standards  offer a well-defined CEM Test Spec that specifies  combinations of impairments to use for testing. Stressed  eye targets are defined with the full pad-to-pad channel,  with Compliance Base Board (CBB) and Compliance Load  Board (CLB) in the path through the CEM connector. The  BERT PPG acts as a surrogate PCIE transmitter in the  scenario of receiver testing. Once the recipe for the  stressed eye target is determined, one removes the  fixturing that isn’t used in testing — CLB for Add-In-Card  testing, or CBB for System testing. This effectively refunds  the loss budget permitted for the device-under-test (DUT).

Users must perform BERT stress calibration before RX  tests are conducted on a DUT. This BERT calibration  ensures the magnitude of stresses applied to the DUT  RX are in accordance with PCIe 6.0 spec limits. This RX  testing determines RX pass/fail and margin performance.  During BERT stress calibration, the user controls multiple  parameters during the calibration run. Receiver stressed  eye calibration is a complex, iterative process and human  error is a significant risk. As such, manual calibration is  unsustainable for routine testing. This technical brief  discusses those controls and provides recommendations  to maximize the probability of successful calibration  after all steps are complete. Guidance is given on when  different modes should be used, and troubleshooting tips  are provided.

۲ | WWW.TEK.COM

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې تخنیکي به

د TekRXTest RX سافټویر

TekRXTest is a software framework that supports automated BERT stress calibration for multiple technologies including PCIe 6.0 CEM. شکل 1 shows the start screen for TekRXTest, and the RX personalities supported as of May 2025.

More info on TekRXTest is available دلته.

شکل ۱. د TekRXTest او RX شخصیتونو لپاره د پیل سکرین.

WWW.TEK.COM

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې تخنیکي به

د PCI ایکسپریس 6.0 CEM لپاره د BERT فشارونه

BERT stress calibration for PCIe 6.0 RX testing is broken into two parts: short channel (TP3, شکل 3) and long channel (TP2,  شکل 2). TP3 signal validation is performed first with BERT output signals connected directly through RF coaxial cables to  scope inputs. BERT tests using TP3 connections are pulse width jitter, differential amplitude, AC-DC balance, preset, random  jitter (RJ) and sinusoidal jitter (SJ). 6dB external attenuators should be installed on the front of each oscilloscope ATI channel  to ensure the best combination of voltage range and noise performance. These attenuators are available as part of the  DPO7RFKx connector kits from Tektronix.

شکل ۲. د PCIe 6.0 RX ازموینې لپاره د BERT اوږد چینل فشار کیلیبریشن.

شکل ۳. د PCIe 6.0 RX ازموینې لپاره د BERT لنډ چینل فشار کیلیبریشن.

۲ | WWW.TEK.COM

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

Once TP3 calibrations are complete, a differential loss ISI channel is added between the BERT PPG and scope inputs. An  example connection diagram is shown in شکل 4. TP2 calibrations are performed including insertion loss (IL) verification,  common-mode interference (CMI) and differential mode interference (DMI), optimal preset and CTLE selection and stressed  eye. Final stressed eye parameters are compared to spec limits to determine successful completion of the BERT calibration.

شکل 4. پخوانیampد اتصال ډیاګرام چې د BERT PPG او اوسیلوسکوپ ان پټونو ترمنځ اضافه شوی د توپیر ضایع ISI چینل ښیې.

WWW.TEK.COM | ۳

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې تخنیکي به

د BERT کیلیبریشن پرمهال د کارونکي کنټرولونه

TekRXTest Software prompts the user to specify some settings prior to performing TP3 and TP2 BERT stress calibration.  جدول 1 lists these controls, their description, and how to set these values to complete a successful calibration.

Table 1. List of parameters set during calibration.

Note 1: Versions of Sigtest & SEASIM will be updated when fully tested and recommended by PCI-SIG.

Note 2: Although not required for PCIe 6.0 CEM-RX pass/fail testing, the user may enable JTOL testing with up to 14 SJ separate frequency tones to perform RX  margin testing. These SJ tones must be calibrated during TP3.

د کارونکي تنظیمات:

برخه	پیرامیټر	ډیفالټ	وړاندیز شوی	یادښتونه
د RT ساحه	Positive ch	Ch1	Ch1
د RT ساحه	Negative ch	Ch2	Ch2
د ټیک آر ایکس خدمت	وخت ختم شو	300 ثانیه	300 ثانیه
د ټیک آر ایکس خدمت	Sigtest   نسخه	6.1.10	6.1.10	نوټ 1
د ټیک آر ایکس خدمت	Seasim   نسخه	2.0.103 f	2.0.103f	نوټ 1
TP3 attenuator  settings	Acquisition  mode	چټک   چوکاټ	چټک چوکاټ
TP3 attenuator  settings	له مینځه وړل	معلول	معلول
TP3 attenuator  settings	Ch1   تنزل	6 dB	6 dB
TP3 attenuator  settings	Ch2   تنزل	6 dB	6 dB
TP3   کیلیبریشنونه	Ampدرود	800 mV	800 mV
TP3   کیلیبریشنونه	RJ	0.25 پی ایس   RMS	0.25 ps RMS
TP3   کیلیبریشنونه	SJ @   100 MHz	1.563 ps	1.563 ps
TP3   کیلیبریشنونه	Multi-tone  Calibration	معلول	د کارن لخوا تعریف شوی	نوټ 3
TP2 attenuator  settings	Acquisition  mode	چټک   چوکاټ	چټک چوکاټ
TP2 attenuator  settings	له مینځه وړل	معلول	معلول
TP2 attenuator  settings	De-embed  (channel)	معلول	معلول
TP2 attenuator  settings	Ch1   تنزل	6dB	6dB

۲ | WWW.TEK.COM

برخه	پیرامیټر	ډیفالټ	وړاندیز شوی	یادښتونه
TP2 attenuator  settings	Ch2   تنزل	6 dB	6 dB
TP2 DMI and   CMI	DMI	15 mV	15 mV
TP2 DMI and   CMI	CMI	75 mV	75 mV
TP2 stressed  eye params	# حسابونه	3	3
TP2 stressed  eye params	د سترګو عرض   هدف	3.125 پی ایس	3.125 پی ایس	System  Host
TP2 stressed  eye params	Eye height  target	6 mV	6 mV	System  Host
TP2 stressed  eye params	د DMI دقیقه	5 mV	5 mV	System  Host
TP2 stressed  eye params	د DMI اعظمي	25 mV	25 mV	System  Host
TP2 stressed  eye params	SJ دقیقه	1 پی ایس	1 پی ایس	System  Host
TP2 stressed  eye params	د SJ اعظمي	3 پی ایس	3 پی ایس	System  Host
TP2 stressed  eye params	Amplitude  min	720 mV	720 mV	System  Host
TP2 stressed  eye params	Amplitude  max	800 mV	800 mV	System  Host
Remote access  – Config	سیمه ایز IP   پته	کوربه کمپیوټر   IP	د کوربه کمپیوټر IP
Remote access  – Config	اوریدل   بندر	4004	4004
Remote access  – Config	وخت ختم شو	20 ثانیه	20 ثانیه

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې تخنیکي به

د TP3 کیلیبریشن پیل او چلول

When a user starts a short channel calibration, the RX software provides a connection diagram to ensure signals are connected properly from the BERT PPG to the scope inputs. Proper care should be used in making RF connections between cables and components. (Details are not covered in this technical brief). Refer to the High Performance Oscilloscopes Best  Practices Manual او DPO70000SX Quick Start User Manual, and use good lab practices. For assistance making proper  connections, please contact your local Tektronix field application engineer.

شکل ۵. د TP3 کیلیبریشن اتصال ډیاګرام.

WWW.TEK.COM | ۳

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

With RX software launched and “connected” via IP address to scope and BERT, the user may INITIALIZE equipment for TP3  calibration. The RX software will automatically initialize instruments when the user clicks the INITIALIZE EQUIPMENT button  within TP3 calibration test flow. Initialization of the scope and BERT takes less than five minutes. By default, the scope will  perform signal validation during the initialization process. To speed up initialization, the user may select the check-box to  SKIP SIGNAL VALIDATION DURING INITIALIZATION. These controls are shown in شکل 6 لاندې.

شکل ۶. د TP3 کیلیبریشن اتصال وزرډ د پیل کولو مرحلې ښیې.

The user may run all TP3 calibrations automatically, or one at a time. It is recommended that new users manually perform and  observe results for each calibration step. Manual mode is also recommended if hardware setup is new to ensure each TP3  calibration test completes correctly. For subsequent stress calibration runs, auto mode may be considered.

Baseline pulse width jitter (PWJ) is needed during TP3 to provide a reference for Seasim. During the PWJ Calibration  step, the user may opt for the scope to measure PWJ (default), or enter known values for PWJ RJ and PWJ DJ for their  specific setup.

کله چې د PWJ کیلیبریشن بشپړ شي، راتلونکي درې کیلیبریشن مرحلې به د کارونکي ان پټ پرته پرمخ لاړ شي (د AC-DC توازن،  Amplitude, Preset). During the Preset calibration step, all presets (Q0 to Q9) are calibrated. An IL measurement is performed  after Preset and is required only if the user plans to perform IL verification step during TP2. If the user will use VNA loss  measurements to establish and adjust ISI channel losses during TP2 calibration, TP3 IL measurement step can be skipped to  save time. If the IL measurement step is performed, the scope will measure short-channel loss (specify # scope acquisitions  and # averages) using step response from BERT and analysis via Seasim. The user may alternatively manually enter in the  short-channel loss (dB at 16 GHz) if known.

۲ | WWW.TEK.COM

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې

تخنیکي به

The next three calibration steps will proceed without user input (RJ, SJ, SJ@210MHz). After the last TP3 calibration step is  complete, the user may provide information to identify the calibration: Unique ID, Generated by, and comments field. Click  the SAVE button to save this TP3 calibration in the RX software for future use.

څو ټون SJ کیلیبریشن

The user may enable multi-tone SJ calibration during TP3 to perform JTOL margin testing. The multi-tone SJ feature is  disabled by default but may be enabled in SETTINGS ➞ TP3 Calibrations via checkbox. Longer calibration times will be  incurred the more SJ frequencies that are specified (about five to seven minutes per SJ tone), and the higher number  calibration points tested between Min and Max SJ values. Even after passing compliance testing, it may be desirable to test  design margins. TekRXTest software makes it straightforward to retroactively add multi-tone SJ calibration to an existing  TP3 calibration.

شکل ۷. د څو ټون SJ فریکونسۍ تنظیم کول او ampدرود

د څو ټون SJ ځانګړتیا ملاتړ کوي:

• SJ sweep across frequencies from 30 kHz up to 100 MHz.

• ≤14 SJ frequencies.

• Two to eight calibration points per SJ frequency.

• Min SJ value determined by BERT hardware intrinsic jitter.

• Max SJ value determined by BERT hardware SJ limits.

WWW.TEK.COM | ۳

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

د TP3 د کیلیبریشن وخت

د TP3 کیلیبریشن د ډیفالټ سافټویر ترتیباتو په کارولو سره شاوخوا 45 دقیقې وخت نیسي. دا د چلولو وخت فرض کوي چې هارډویر او سافټویر اړتیاوې پوره شوي، د کوربه کمپیوټر چلونکي TekRXTest او د ازموینې وسیلو ترمنځ مناسب اړیکه شتون لري، د هر اتصال ډیاګرام لپاره سمې اړیکې جوړې شوي او وسایل په ښه کاري ترتیب کې دي.

Several factors allow TP3 calibrations to run faster:

• Skip signal validation during initialization.

• Manually enter BERT PWJ values.

• Skip IL measurement if using VNA to measure ISI channel loss in TP2.

• Use auto-calibration mode.

د TP2 کیلیبریشن پیل او چلول

Several factors will cause longer TP3 run-time including:

• Signal validation during initialization.

• Performing BERT PWJ measurement.

• Performing short-channel IL measurement.

• Using manual run mode, and pausing between  calibration steps.

The same RF cables used to connect the BERT PPG to the scope inputs during TP3 calibration should remain in place when  performing TP2 calibration. In the shift from TP3 to TP2 setup, these RF cables are disconnected from scope inputs and  connected to PCI-SIG 6.0 CEM test fixtures. These connections are shown in شکل 8 لاندې.

 

شکل ۸. د TP3 او TP2 RF کیبل اتصال.

نښلونکی WORD? Attenuator

له ۶.۳۵ ملي میتر څخه تر ۳.۵ ملي میتر پورې اډاپټر

۲ | WWW.TEK.COM

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

The user must perform and save a TP3 short channel calibration prior to running a long channel calibration. TP2 stress  calibration will prompt the user for DUT type (System Host or Add-in Card) and the TP3 calibration to use for TP2 calibration.  Similar to TP3:

1. TekRXTest software provides a connection diagram to ensure signals are connected properly from BERT PPG to the  scope inputs. See شکل 8.

2. The user will initialize instruments using INITIALIZE EQUIPMENT button before performing TP2 calibration steps.

3. TP2 calibration settings are provided in the SETTINGS menu. These user settings are shown in Table 1.

4. TekRXTest software provides BERT calibration steps that may be run manually (one at a time) or in auto mode.

5. TP2 test report with plots and BERT calibrated values are available upon completion.

د آی ایس آی چینل ضایع کول

The user should acquire approved PCIe 6.0 fixtures including ISI board and cables from PCI- SIG to enable signal path  connections shown in شکل 8. VNA insertion loss measurements are recommended on ISI channel fixtures and associated  cables to ensure the prescribed amount of loss is in place during TP2 calibration.

Target ISI channel loss depends on whether a System Host or Add-in Card is being tested. For System Host, the total ISI  channel loss target is 24 dB @ 16 GHz (Add-in Card is 28 dB @ 16 GHz). These targets are shown in the RX software at the IL for  DMI/CMI calibration step shown in شکل 9 لاندې.

شکل ۹. د TP2 د اندازې هدفونه.

WWW.TEK.COM | ۳

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې تخنیکي به

PCIe 6.0 ISI channel loss boards provide traces with about 0.5 dB loss increments to allow for adjustment. The user will vary  channel loss together with other BERT stress parameters to meet stress calibration closure requirements. Because each ISI  board will vary in its loss profile, it is recommended the user measure ISI channel loss on the fixture to be used prior to TP2  calibration. The goal is to identify a cable + ISI channel pair that exhibit the target channel loss (24 dB @ 16 GHz for System  Host, 28 dB @ 16 GHz for add-in card). It is Tektronix’ experience that lanes meeting ISI channel requirements do vary. Actual  convergence during the March 2025 pre-FYI plugfest was obtained using ISI pair 2 and 14 for System Host, ISI pair 23 and 0 for Add-in Card. This lane variation is dependent on RF cable, connector and fixture loss differences.

TekRXTest software will embed the appropriate package loss onto the scope’s acquired waveform during TP2 calibration so that the step waveforms passed to Seasim represent the entire 30-33 dB ISI channel loss required for CEM compliance testing. This total loss is shown in the IL Measurement in شکل 10.

شکل ۱۰. د ټول بسته ضایع.

Once an ISI channel is chosen, TP2 stress calibration can begin. The recommendation from PCI- SIG is to begin with max  ISI channel loss for initial TP2 calibration run. The user may perform the IL measurement for DMI/CMI step, but this step is  optional and may be skipped if VNA measured data was used to verify target channel loss. DMI and CMI calibrations will run  without any user input. At the IL Measurement step, the user may select MANUAL ENTRY and enter in the total ISI channel  loss (i.e. VNA measured loss + embedded package loss). For System Host this target is 30-33 dB.

۲ | WWW.TEK.COM

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

Optimal preset calibration is performed next shown by شکل 11. The user may use the CONFIGURATION button to determine  what presets are considered during this step (Q0 to Q9). As shown in شکل 11, presets Q5, Q6, Q8, Q9 were selected based on  recommendation from PCIe 6.0 PHY Test spec working group. In Tektronix’ experience, successful calibrations have been  achieved using Q5, Q7 and Q8. The user may control the number of acquisitions for optimal preset step. The default number of acquisitions is three, but this value may be increased to ≥5, resulting in more waveform averages used to for preset eye area calculation.

شکل ۱۱. غوره مخکینۍ کیلیبریشن.

WWW.TEK.COM | ۳

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

د TekRXTest سافټویر به هغه پریسیټ غوره کړي چې پایله یې د سترګو ترټولو لوی اوسط ساحه وي. په پخواني کېampپه کې ښودل شوي شکل 12,  preset Q5 was found to yield the highest eye area of 5.274. In this example, the RX software will use Q5 in the final Stressed  Eye Cal step.

In some cases, more than one preset may result in a large eye area. To choose the best preset, the ratio of eye width /  eye height should be evaluated. With these ratios computed, the preset resulting in the ratio being closest to 50% is  recommended. An exampلاندې وړاندې کیږي:

Converged eye #1: Converged eye #2:

Preset = Q5 Preset = Q7

Eye width (EW) = 1.484 Eye width (EW) = 1.645

Eye height (EH) = 3.554 Eye height (EH) = 3.487

Ratio = EW / EH = 0.42 Ratio = EW / EH = 0.47

Choose this setting

شکل ۱۲. د TP2 کیلیبریشن غوره CTLE او مخکینۍ انتخاب example. Note that the “Bad” results for Q8, Q9 presets are normal in this case, when searching for the  optimum CTLE.

Final calibration step is Stressed Eye Cal. This step uses the preset determined in the previous step yielding the largest eye  area. With this preset configured in the BERT, a step waveform is captured and averaged then sent to Seasim for analysis.  Tektronix has implemented HW- assisted 10Ktrace averaging across 960 UIs to accelerate this process. Combinations of SJ,  DMI and amplitude are swept in Seasim. Tie-breakers are used to make decisions in cases where different values result in  similar final stressed eye conditions.

۲ | WWW.TEK.COM

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

TekRXTest software will use target values defined in TP2 STRESSED EYE PARAMETERS to adjust variable parameters to  meet eye target value. The default number of waveforms for Stressed Eye Cal is three, but this value may be adjusted by the  user. (A higher number of acquisitions yields more data but takes longer to acquire and process.) Tektronix recommends to  leave this value set to # acqs for stressed eye = 3 for initial TP2 runs. If three acquisitions are not sufficient, increase to ≥5 to  achieve stable results.

Nominal eye height and eye width targets for PCIe 6.0 are:

• Eye width: 3.125 ps (range of 2.825 ps to 3.425 ps)

• Eye height: 6 mV (range of 5.5 mV to 6.5 mV)

Figure 13. Configuring number of waveforms averaging for stressed eye.

که چیرې د RX سافټویر د ټولو شته پیرامیټرو له پاکولو وروسته د متغیر فشارونو یو متقابل سیټ ونه موندل شي، نو کارونکی ممکن څو اقدامات وکړي:

• Change ISI lane pairs to reduce channel loss by 0.5 dB. This will require a re-run of TP2 calibrations with reduced  channel loss.

• In the case of changing the ISI pair, the user should rerun the two steps that are dependent on the ISI pair: the Preset  Selection, and the Stressed Eye Cal. These should be rerun to 1) find the optimal Preset and CTLE based on the current ISI  pair, and 2) find the final stress recipe based on the current ISI pair.

Consider using manual sweep settings while holding other variables constant. An addendum will be added to this document  providing guidance on how best to use sweep mode in this case.

WWW.TEK.COM | ۳

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې تخنیکي به

د TP2 د کیلیبریشن وخت

TP2 calibration takes two and a half to four hours to run using standard software settings. This run time is affected by  several factors including:

• Is IL Verification step run, or is VNA data used?

• Is ISI channel loss within target range?

• Can convergence be obtained with combination of BERT variable stresses and ISI channel loss?

• Variable stress sweep settings (Min, Max, granularity).

• Run modes (explained in the following section).

کارونکي د سټریسډ آی کال د بریالي بشپړولو لپاره ډیری کنټرولونه لري په شمول:

• معیاري حالت: This is the default and recommended run mode for Stressed Eye Cal. Preset and CMI/DMI stresses  are enabled, and BERT step response is captured and averaged, then passed to Seasim for analysis. This process is  repeated multiple times while sweeping stresses in the allowable range. Seasim computes eye width and eye height, and  TekRXTest software computes eye area then checks for convergence. A linear sweep of stresses (amplitude, SJ, DMI) is  performed to close the calibration.

• لاسي حالت: Allows the user to manually enter SJ, DMI and amplitude values for Stressed Eye Cal. This mode is valuable  for “what-if” testing or debug to try discrete combinations of stresses for calibration closure.

• Exhaustive sweep mode: Allows the user to run Stressed Eye Cal for all combinations of amplitude, SJ and DMI within  the sweep range with defined step sizes. The user controls sweep ranges and step sizes as shown in شکل 14. The wider  the range and smaller the step size, the longer the run will take. This sweep نه به ودریږي when a converged eye is found,  rather it will perform a complete sweep of parameters and ranges defined by the user. The user may stop the sweep prior  to completion. If the user sees a combination of stresses that is desired then enable manual mode and perform stressed  eye verification with these settings to test for convergence.

Figure 14. User can control sweep ranges and step sizes.

۲ | WWW.TEK.COM

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

د TekRXTest سافټویر به تکرار او فشارونه تنظیم کړي تر هغه چې دا یو ترکیب ومومي چې د هدف حد کې د سترګو اوسط عرض او د سترګو لوړوالی رامینځته کړي. په مثال کېampپه کې ښودل شوي شکل 15, a successfully converged stress calibration is shown in the green rows. In this example، د سترګو اوسط پلنوالی = 2.929 ps او د سترګو اوسط لوړوالی = 6.657 mV. دا پایلې د مخکینۍ Q5، CTLE = 6 dB په کارولو سره ترلاسه شوې، ampعرض البلد = 726 mV، SJ = 1 ps، او DMI = 8.7 mV.

شکل ۱۵. شنه قطارونه یو پخوانی ښييampد فشار د بریالیتوب سره یوځای شوي کیلیبریشن.

د BERT د فشار اندازه کولو غوره طریقې

د BERT فشار کیلیبریشن چلولو دمخه، کارونکي باید ډاډ ترلاسه کړي چې لاندې شرایط پوره شوي ترڅو دقت او تکرار وړتیا اعظمي شي:

• Ensure scope and BERT have been powered on for ≥30 minutes. This ensures instruments are warmed up prior to  calibration.

• Ensure scope is running the latest versions of TekScope and waveform analysis software. To verify latest software  versions, please contact your local Tektronix field application engineer.

• On the scope with all RF cables disconnected, run signal path compensation (SPC) under UTLITITES ➞ INTRUMENT  CALIBRATION. SPC is recommended once every 30 days or if ambient temperature changes by >5 degrees C.

• Characterize PCIe 6.0 CEM fixture loss with VNA for TP2 ISI pair combination. For System Host, ISI trace pairs + RF cables  should measure ~24 dB loss @ 16 GHz (Add-in Card ~28 dB loss @ 16 GHz). Refer to PCIe 6.0 PHY Test Spec, Appendix C for more details.

WWW.TEK.COM | ۳

د PCI ایکسپریس 6.0 CEM: د BERT فشار کیلیبریشن غوره طریقې 

تخنیکي به

د BERT د فشار د اندازې هدف د څلورو تنظیم وړ فشار پیرامیټرو ترکیب موندل دي (ISI چینل ضایع، SJ، DMI، amp(litude) کله چې د ثابت فشار کونکو (لکه RJ، CMI) سره یوځای شي چې د ټاکل شوي حد دننه د سترګو اوسط لوړوالی او د سترګو پلنوالی ارزښتونه ترلاسه کوي. دا هدف حدونه دي:

• Eye width: 2.825 ps to 3.425 ps (nominally 3.125 ps).

• Eye height: 5.5 mV to 6.5 mV (nominally 6 mV).

The PCIe 6.0 PHY Test Specification specifies BERT stress calibration flow as follows:

1. Start with maximum ISI channel of 33 dB (HW ISI channel loss + embedded package model) for capturing the  step response.

2. Post process BERT step response with Seasim to find optimal preset and CTLE.

3. Post process BERT step response with Seasim to sweep adjustable parameters.

4. If a converged solution can be found, the calibration is successful. Record these values.

5. If no solution can be found with any combination of SJ, DMI, and amplitude, reduce ISI channel loss by one pair (nominally  0.5 dB step).

6. Repeat steps two through five until a solution converges within target eye width and eye height ranges.

VNA characterization of PCIe 6.0 fixtures along with RF cables is highly recommended prior to running BERT stress  calibration. TekRXTest software does provide a step-response based ISI channel verification, but this value may deviate  from a VNA-based measurement by several dB. The goal is to find a combination of ISI channel + RF cable loss that is ~24 dB  @ 16 GHz for System Host, ~28 dB @ 16 GHz for Add-in card. Once the ISI channel + RF cable combination is found, this is the  starting point for the TP2 portion of the calibration.

د ستونزو حل کول

In cases where TekRXTest does not successfully provide a converged BERT stress calibration at the end of TP2, below are  several areas to assess what changes should be made in the test setup or calibration settings:

• Check software revisions (scope, BERT, Sigtest, Seasim, etc.).

• Perform scope self-test and signal path compensation.

• Ensure scope channels are correctly deskewed <1 ps.

• Ensure coaxial connections in the signal path are tight and torqued to the proper value where appropriate.

• With no signal applied, measure pk-pk ACrms voltage on scope ATI Channel 1 and Channel 2 using auto measurements.  This ACrms value should be in the range of 1.1 to 1.3 mV. The measured ACrms mean value should also match between  Channel 1 and Channel 2 within a tight tolerance (≤.3 mV). If either condition is not met, ensure proper airflow into and out  of the scope to provide proper cooling. A minimum six-inch clearance is recommended on all sides of the scope. Ensure  instruments sitting in close proximity to the scope are not blowing hot air into the scope air inlet located on the bottom of  each scope unit.

Your Tektronix field application engineer is standing by to assist you. If you have followed this guide and are still not achieving  convergence during BERT stress calibration, reach out to your local Tektronix application engineer for assistance.

For more information on Tektronix’ PCI Express test solutions, please visit tek.com.

۲ | WWW.TEK.COM

د اړیکو معلومات:

آسټرالیا 1 800 709 465

آسټریا* 00800 2255 4835

بالکان ، اسراییل ، ​​سویلي افریقا او نور ISE هیوادونه +41 52 675 3777

بیلجیم* 00800 2255 4835

برازیل +55 (11) 3530-8901

کاناډا 1 800 833 9200

Central East Europe / Baltics +41 52 675 3777

Central Europe / Greece +41 52 675 3777

ډینمارک +45 80 88 1401

فینلینډ +41 52 675 3777

فرانسه* 00800 2255 4835

جرمني* 00800 2255 4835

هانګ کانګ 400 820 5835

هند 000 800 650 1835

انډونیزیا 007 803 601 5249

ایټالیا 00800 2255 4835

جاپان 81 (3) 6714 3086

لوګزامبورګ +41 52 675 3777

ملایزیا 1 800 22 55835

مکسیکو، مرکزي/جنوبي امریکا او کیریبین 52 (55) 88 69 35 25

منځنی ختیځ ، اسیا او شمالي افریقا +41 52 675 3777

هالنډ* 00800 2255 4835

نيوزيلنډ 0800 800 238

ناروی 800 16098

د چین د خلکو جمهوریت 400 820 5835

فلیپین 1 800 1601 0077

پولینډ +41 52 675 3777

پورتګال 80 08 12370

د کوریا جمهوریت +82 2 565 1455

Russia / CIS +7 (495) 6647564

سینګاپور 800 6011 473

سویلي افریقا +41 52 675 3777

هسپانیه* 00800 2255 4835

سویډن* 00800 2255 4835

سویزرلینډ یا سویس* 00800 2255 4835

تایوان 886 (2) 2656 6688

تایلینډ 1 800 011 931

United Kingdom / Ireland* 00800 2255 4835

USA 1 800 833 9200

ویتنام 12060128

* د اروپا وړیا شمیره. که نه  

د لاسرسي وړ، زنګ ووهئ: +41 52 675 3777

Rev. 02.2022

په دې اړه نور ارزښت لرونکي سرچینې ومومئ ټیک کام

Copyright © Tektronix. All rights reserved. Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supersedes that  in all previously published material. Specification and price change privileges reserved. TEKTRONIX and TEK are registered trademarks of Tektronix, Inc. All other trade names  referenced are the service marks, trademarks or registered trademarks of their respective companies.

082125 SBG 65W-74165-1

اسناد / سرچینې

د ټیکټرونیکس MP1900A برټ فشار کیلیبریشن غوره طریقې [pdf] د کارونکي لارښود DPO70000SX، MP1900A، MP1900A د برټ فشار کیلیبریشن غوره طریقې، MP1900A، د برټ فشار کیلیبریشن غوره طریقې، د فشار کیلیبریشن غوره طریقې، د کیلیبریشن غوره طریقې، غوره طریقې

حوالې

• د کارن لارښود