Tektronix BERTScope Manual

www.tektronix.com
0140-703-00
Tektronix BERTScope
Digital Pre-Emphasis Processor
Quick Start User Manual
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www.tektronix.com
0140-703-00
Tektronix BERTScope
Digital Pre-Emphasis Processor
DPP125
Quick Start User Manual

Copyright© Tektronix. All rights reserved. Licensed software products are owned by Tektronix or its
subsidiaries or suppliers, and are protected by national copyright laws and international treaty provisions.
Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication
supersedes that in all previously published material. Specifications and price change privileges reserved.
TEKTRONIX, TEK, and BERTScope are registered trademarks of Tektronix, Inc.
FastFrame, OpenChoice, iView, iCapture, Pinpoint, RT-Eye, MyScope, TekLink, TekVPI, Error Location
Analysis, and MultiView Zoom are trademarks of Tektronix, Inc.
Contacting Tektronix
Tektronix, Inc.
14200 SW Karl Braun Drive
P.O. Box 500
Beaverton, OR 97077 USA
For product information, sales, service, and technical support:
In North America, call 1-800-833-9200.
Worldwide, visit www.tektronix.com to find contacts in your area.
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Warranty
DPP125 Digital Pre-Emphasis Processor Quick Start User Manual i
Warranty
All Tektronix DPP125 Digital Pre-Emphasis Processor Instruments are covered under the standard 1-year
product warranty.
Tektronix warrants that this product will be free from defects in materials and workmanship for a period of one
(1) year from the date of shipment. If any such product proves defective during this warranty period, Tektronix,
at its option, either will repair the defective product without charge for parts and labor, or will provide a
replacement in exchange for the defective product. Parts, modules, and replacement products used by Tektronix
for warranty work may be new or reconditioned to like new performance. All replaced parts, modules and
products become the property of Tektronix.
In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the
expiration of the warranty period and make suitable arrangements for the performance of service. Customer
shall be responsible for packaging and shipping the defective product to the service center designated by
Tektronix, with shipping charges prepaid. Tektronix shall pay for the return of the product to Customer if the
shipment is to a location within the country in which the Tektronix service center is located. Customer shall be
responsible for paying all shipping charges, duties, taxes, and any other charges for products returned to any
other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or
inadequate maintenance and care. Tektronix shall not be obligated to furnish service under this warranty a) to
repair damage resulting from attempts by personnel other than Tektronix representatives to install, repair or
service the product; b) to repair damage resulting from improper use or connection to incompatible equipment;
c) to repair any damage or malfunction caused by the use of non-Tektronix supplies; or d) to service a product
that has been modified or integrated with other products when the effect of such modification or integration
increases the time or difficulty of servicing the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX WITH RESPECT TO THE PRODUCT IN LIEU OF ANY
OTHER WARRANTIES, EXPRESS OR IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY
IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
TEKTRONIX’ RESPONSIBILITY TO REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE
AND EXCLUSIVE REMEDY PROVIDED TO THE CUSTOMER FOR BREACH OF THIS WARRANTY.
TEKTRONIX AND ITS VENDORS WILL NOT BE LIABLE FOR ANY INDIRECT, SPECIAL,
INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE OF WHETHER TEKTRONIX OR
THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH DAMAGES.

General Safety Summary
ii DPP125 Digital Pre-Emphasis Processor Quick Start User Manual
General Safety Summary
Review the following safety precautions to avoid injury and prevent damage to this product or any products
connected to it.
To avoid potential hazards, use this product only as specified.
NOTE: Only qualified personnel should perform service procedures.
While using this product, you may need to access other parts of a larger system. Read the safety sections of the
other component manuals for warnings and cautions related to operating the system.
WARNING
Maintain Proper Grounding to avoid electrical shock.
No operator serviceable parts inside.
Do not remove cover.
Refer to qualified service personnel.
Use Proper Power Cord. Use only the power cord specified for this product and certified for the country of
use.
Connect and Disconnect Properly. Do not connect or disconnect probes or test leads while they are
connected to a voltage source.
Ground the Product. This product is grounded through the grounding conductor of the power cord. To avoid
electric shock, the grounding conductor must be connected to earth ground. Before making connections to the
input or output terminals of the product, ensure that the product is properly grounded.
Observe All Terminal Ratings. To avoid fire or shock hazard, observe all ratings and markings on the
product. Consult the product manual for further ratings information before making connections to the product.
Power Disconnect. The power cord disconnects the product from the power source. Do not block the power
cord; it must remain accessible to the user at all times.
Do Not Operate Without Covers. Do not operate this product with covers or panels removed.
Do Not Operate With Suspected Failures. If you suspect that there is damage to this product, have it
inspected by qualified service personnel.
Avoid Exposed Circuitry. Do not touch exposed connections and components when power is present.
Use Proper Fuse. Use only the fuse type and rating specified for this product.
Wear Eye Protection. Wear eye protection if exposure to high-intensity rays or laser radiation exists.
Do Not Operate in Wet/Damp Conditions
Do Not Operate in an Explosive Atmosphere
Keep Product Surfaces Clean and Dry
Provide Proper Ventilation. Refer to the manual's installation instructions for details on installing the
product so it has proper ventilation.

General Safety Summary
DPP125 Digital Pre-Emphasis Processor Quick Start User Manual iii
Terms in this Manual
These terms may appear in this manual:

WARNING. Warning statements identify conditions or practices that could result in injury or
loss of life.

CAUTION. Caution statements identify conditions or practices that could result in damage to
this product or other property.
NOTE. A notice statement identifies conditions which may result in unintended operating
modes, incorrect measurement results, or require resetting the instrument or personal
computers operating software interacting with it.
Symbols and Terms on the Product
These terms may appear on the product:
DANGER indicates an injury hazard immediately accessible as you read the marking.
WARNING indicates an injury hazard not immediately accessible as you read the marking.
CAUTION indicates a hazard to property including the product. The following symbols may appear on the
product:

Compliance Information
iv DPP125 Digital Pre-Emphasis Processor Quick Start User Manual
Compliance Information
This section lists the EMC (electromagnetic compliance) safety, and environmental standards with which the
instrument complies.
EMC Compliance
EC Declaration of Conformity – EMC
Meets intent of Directive 2004/108/EC for Electromagnetic Compatibility. Compliance was demonstrated to the
following specifications as listed in the Official Journal of European Communities:
EN 61326-1 2006. EMC requirements for electrical equipment for measurement, control, and
laboratory use.123
CISPR 11:2003. Radiated and conducted emissions, Group 1, Class A
IEC61000-4-2:2001. Electrostatic discharge immunity
IEC61000-4-3:2002. RF electromagnetic field immunity
IEC61000-4-4:2004. Electrical fast transient / burst immunity
IEC61000-4-5:2001. Power line surge immunity
IEC61000-4-6:2003. Conducted RF immunity
IEC61000-4-11:2004. Voltage dips and interruptions immunity
EN61000-3-2:2006. AC power line harmonic emissions
EN61000-3-3:1995. Voltage changes, fluctuations, and flicker
European Contact
Tektronix UK, Ltd.
Western Peninsula
Western Road
Bracknell, RG12 1RF
United Kingdom
Australia / New Zealand Declaration of Conformity–EMC
Complies with the EMC provision of the Radiocommunications Act per the following standard, in accordance
with ACMA:
CISPR 11:2003. Radiated and Conducted Emissions, Group 1, Class A, in accordance with EN61326-
1:2006.

1This product is intended for use in nonresidential areas only. Use in residential areas may cause electromagnetic interference.
2Emissions which exceed the levels required by this standard may occur when this equipment is connected to a test object.
3To ensure compliance with the EMC standards listed here, high quality shielded interface cables should be used.

Compliance Information
DPP125 Digital Pre-Emphasis Processor Quick Start User Manual v
Safety Compliance
EC Declaration of Conformity – Low Voltage
Compliance was demonstrated to the following specification as listed in the Official Journal of the European
Communities:
Low Voltage Directive 2006/95/EC
EN61010-1: 2001. Safety requirements for electrical equipment for measurement control and
laboratory use.
U.S. Nationally Recognized Testing Laboratory Listing
UL 61010-1:2004, 2nd Edition. Standard for electrical measuring and test equipment.
Canadian Certification
CAN/CSA-C22.2 No. 61010-1:2004. Safety requirements for electrical equipment for measurement,
control, and laboratory use. Part 1.
Additional Compliances
IEC 61010-1: 2001. Safety requirements for electrical equipment for measurement, control, and
laboratory use.
Equipment Type
Test and measuring equipment.
Safety Class
Class 1 – grounded product.
Pollution Degree Description
A measure of the contaminants that could occur in the environment around and within a product. Typically the
internal environment inside a product is considered to be the same as the external. Products should be used only
in the environment for which they are rated.
Pollution Degree 1. No pollution or only dry, nonconductive pollution occurs. Products in this category
are generally encapsulated, hermetically sealed, or located in clean rooms.
Pollution Degree 2. Normally only dry, nonconductive pollution occurs. Occasionally a temporary
conductivity that is caused by condensation must be expected. This location is a typical office/home
environment. Temporary condensation occurs only when the product is out of service.
Pollution Degree 3. Conductive pollution or dry, nonconductive pollution that becomes conductive due
to condensation. These are sheltered locations where neither temperature nor humidity is controlled.
The area is protected from direct sunshine, rain, or direct wind.
Pollution Degree 4. Pollution that generates persistent conductivity through conductive dust, rain, or
snow. Typical outdoor locations.
Pollution Degree
Pollution Degree 2 (as defined in IEC61010-1). Note: Rated for indoor use only.

Compliance Information
vi DPP125 Digital Pre-Emphasis Processor Quick Start User Manual
Installation (Overvoltage) Category Descriptions
Terminals on this product may have different installation (overvoltage) category designations. The installation
categories are:
Measurement Category IV. For measurements performed at the source of low-voltage installation.
Measurement Category III. For measurements performed in the building installation.
Measurement Category II. For measurements performed on circuits directly connected to the low-
voltage installation.
Measurement Category I. For measurements performed on circuits not directly connected to MAINS.
Overvoltage Category
Overvoltage Category II (as defined in IEC61010-1)
Environmental Considerations
Product End-of-Life Handling
Observe the following guidelines when recycling an instrument or component:
Equipment Recycling. Production of this equipment required the extraction and use of natural resources. The
equipment may contain substances that could be harmful to the environment or human health if improperly
handled at the product’s end of life. In order to avoid release of such substances into the environment and to
reduce the use of natural resources, we encourage you to recycle this product in an appropriate system that will
ensure that most of the materials are reused or recycled appropriately.

This symbol indicates that this product complies with the applicable European Union
requirements according to Directives 2002/96/EC and 2006/66/EC on waste electrical
and electronic equipment (WEEE) and batteries. For information about recycling
options, check the Support/Service section of the Tektronix Web site
(www.tektronix.com).

Restriction of Hazardous Substances. This product has been classified as Monitoring and Control
equipment, and is outside the scope of the 2002/95/EC RoHS Directive.


Table of Contents
DPP125 Digital Pre-Emphasis Processor Quick Start User Manual vii
Table of Contents
Introduction........................................................................................................................................................1
Product Description...........................................................................................................................................1
Features and Benefits.......................................................................................................................................1
Documentation ...................................................................................................................................................2
Options.............................................................................................................................................................2
Other Documentation.......................................................................................................................................2
Installation..........................................................................................................................................................3
Standard Accessories .......................................................................................................................................3
Operating Requirements ..................................................................................................................................3
Preventing ESD................................................................................................................................................3
Configuration .....................................................................................................................................................4
Connectors .......................................................................................................................................................4
Clock / Data Input Skew..................................................................................................................................5
Operation............................................................................................................................................................7
Power On .........................................................................................................................................................7
Use with Other Instruments..............................................................................................................................9
Maintenance .....................................................................................................................................................10
Cleaning.........................................................................................................................................................10
Connector Replacement.................................................................................................................................10
Fuse Replacement..........................................................................................................................................10
Calibration......................................................................................................................................................10
Specifications....................................................................................................................................................11
Index..................................................................................................................................................................12

Introduction
DPP125 Digital Pre-Emphasis Processor Quick Start User Manual 1
Introduction
This Quick Start User Manual supports the Tektronix BERTScope DPP125 Digital Pre-Emphasis Processor.
The DPP125 is a non-linear signal conditioning processor intended to add precision calibrated pre-emphasis to
a serial data waveform, generally supplied by the Pattern Generator of the Tektronix BERTScope Bit Error
Ratio Analyzer.
The Pre-Emphasis Processor reclocks the data, and passes through any calibrated stress (jitter) which appears on
the clock input signal. The output signal is buffered through a calibrated output stage, providing user control of
the amplitude and offset.
With the exception of the instrument's power switch, all control is through the software-based graphical user
interface. When used with a BERTScope Analyzer, the interface is found in “DPP Control,” listed in the top-
level ‘Views’ menu. The DPP125 can also be operated standalone, using the BERTScopePC Standalone
software supplied with the product and available at www.bertscope.com. BERTScopePC software must be
installed to support stand-alone operation.
Full descriptions of the operating controls are given in the Online Help, included in both the BERTScope
Analyzer and BERTScopePC applications. Detailed information on operation of the control interface can be
accessed at any time through the Help menus included in any control view.
The instrument communicates with its control host via USB 2.0. When used with a BERTScope Analyzer,
connect the included USB cable between the Type B connector on the rear panel of the DPP125 and an
available Type A connector on the rear panel of the Analyzer. If a BERTScope Clock Recovery instrument is
also being used with the Analyzer, connect the DPP125 through an available USB connector on the rear panel
of the Clock Recovery instrument. When used standalone, first install the BERTScopePC software and driver
into the host PC. Then connect the DPP125 USB cable to any available USB connector on the host computer.
Product Description
This Quick Start User Manual supports the Tektronix BERTScope DPP125 Digital Pre-Emphasis Processor,.
The BERTScope DPP Digital Pre-Emphasis Processor instrument provides programmable three-tap or optional
four-tap pre-emphasis for compliance testing to standards such as 802.3ap, Serial Attached SCSI, 10GBASE-
KR backplanes, DisplayPort™, and USB 3.0 — and flexible enough for the next-generation 8 GT/s PCI-
Express®standard.
Boosting the amplitude of the transition bits in a digital signal, or pre-emphasis, is an increasingly common
method employed in systems to overcome the frequency dependent loss of low cost circuit boards to allow the
passage of Gb/s data. The DPP125 covers the requirements for high data rate test, allowing the flexibility to
evaluate compliance to multiple standards and to explore the limits of device performance.
A key benefit of the DPP is the ease with which an engineer can adjust the precise characteristics of the pre-
emphasis signal being applied to the test device. This is achieved through a highly intuitive control interface
that simultaneously shows the step response, tap weightings, and frequency response of the signal, in keeping
with the BERTScope philosophy of multi-domain insight.
Features and Benefits
1 to 12.5 Gb/s range of operation with standard 3-tap configuration
Optional 4-tap non-linear signal conditioner available
Pre-cursor or post-cursor adjustment
Standards compliant
Exceptionally easy setup

Documentation
2 DPP125 Digital Pre-Emphasis Processor Quick Start User Manual
Concurrent multiple domain views, including a frequency domain Bode plot
Precise correction control for backplane ISI, optical effects, etc.
Adjustable through tap weights or step response
Differential output is amplitude and offset adjustable
Integrated operation with a BERTScope Bit Error Ratio Analyzer, or in a standalone fashion controlled
by a user-supplied PC
Features Benefits
Controllable pre-emphasis Required for compliance testing of newer standards including
PCIe, 10GBASE-KR, 40GBASE-KR-4, 100GBASE-CAUI,
40GBASE-XLAUI, SAS
De-embed channel between stress source
and DUT Calibrated stress testing at the DUT pin
Documentation
In addition to this Quick Start Guide, the following documents are available:
Online Help
Programmer Online Guide
Options
The DPP125 can be configured to include an optional 4-tap non-linear signal conditioner.
Other Documentation
Your instrument includes PDF files of relevant information:
Remote Control Programmer Guide PDF
Technical Specifications PDF

Installation
DPP125 Digital Pre-Emphasis Processor Quick Start User Manual 3
Installation
The DPP125 is intended to be operated in a controlled laboratory environment.
It is intended to operate on a bench top, or on top of another instrument such as the BERTScope Bit Error Ratio
Analyzer. There are four shock-absorbing feet located on the bottom of the instrument. Operate the instrument
only when positioned with the feet facing downward. Do not operate the instrument with the long axis vertical,
standing on its side, as this will block the path of air required for cooling.
This instrument uses a low voltage ‘soft’ power switch that activates the power supply. The primary power
control circuitry is always live whenever the power cable is connected to the mains. The instrument is fuse-
protected to reduce the risk of fire in the event of a power supply failure. Access t the power cable for
disconnection from the mains in an emergency may be required by local codes.
Standard Accessories
Power cord
USB interconnect cable
Rack mount hardware
BERTScopePC Standalone Software CD-ROM (installs the DPP125’s control interface on a user-
supplied PC)
Operating Requirements
Place the instrument on a cart or bench. The instrument should rest on its bottom or rear feet. An optional rack
mounting kit is available. Observe the following clearance requirements and dimensions:
Top 0 mm (0 in)
Left and right sides 76 mm (3 in)
Bottom 0 mm (0 in) standing on feet, flip stands down
Rear 0 mm (0 in) on rear feet
Width 394 mm (15.5 in)
Height 220 mm (8.7 in)
Before operating the instrument, verify the ambient temperature: +10° C to +40 °C (+41 °F to +113 °F)
Preventing ESD
CAUTION
A direct electrostatic discharge can damage the instrument input. To learn how to avoid this
damage, read the following information.
Electrostatic discharge (ESD) is a concern when handling any electronic equipment. The instrument is designed
with robust ESD protection; however it is still possible that large discharges of static electricity directly into the
signal input may damage the instrument. To avoid damage to the instrument, use the following techniques to
prevent electrostatic discharge to the instrument.
Discharge the static voltage from your body by wearing a grounded antistatic wrist strap while
connecting and disconnecting cables and adapters. The instrument provides a front panel connection
for this purpose.
A cable that is left unconnected on a bench can develop a large static charge. Discharge the static
voltage from all cables before connecting them to the instrument or device under test by momentarily
grounding the center conductor of the cable, or by connecting a 50 Ωtermination to one end, prior to
attaching the cable to the instrument.

Configuration
4 DPP125 Digital Pre-Emphasis Processor Quick Start User Manual
Configuration
The typical configuration with the BERTScope Analyzer is shown below.
Figure1.DPP125–BERTScopeAnalyzerSetupConfiguration
The DPP125 data output signal is differential, while the input data and clock are single-ended. Because the
output signal is re-clocked and buffered, low loss cables are not required for the input signals. To maintain
amplitude calibration and minimize intersymbol interference (ISI), high performance cables should be used to
connect the DPP125 output to the Device Under Test.
In the illustrated configuration, the BERTScope Analyzer Error Detector is clocked directly from the negative
clock output of the Pattern Generator. The inverted phase, along with any phase delay in the cables or DUT, is
corrected by the Auto Align process in the Detector. Other setup configurations may source the Error Detector
clock from a clock recovery source, or the DUT itself.
Connectors
Front Panel:
DATA IN : Single-ended data signal input to processing FIR filter. Input is AC-coupled, terminated into 50
ohms within the operating frequency range of the instrument. Normally connected to the BERTScope Analyzer
Pattern Generator DATA+ output.
CLOCK IN : Single-ended clock input used to clock the FIR filter. Input is AC-coupled, terminated into 50
ohms within the operating frequency range of the instrument. Normally connected to the BERTScope Analyzer
Pattern Generator CLOCK+ output.
DATA OUT+ / DATA OUT– : Differential data output from the FIR processor filter. Output is 50 ohms from
buffer amplifier. Signal amplitude and offset are controlled through the user interface. Normally connected to
the Device Under Test. Terminate unused outputs into 50 ohms if driving a single-ended load.
Rear Panel:
USB IN : USB 2.0 type B connector used to interface the instrument for control. When used with a BERTScope
Analyzer, connect to any available USB connector. The DPP125 can also be operated standalone with an

Configuration
DPP125 Digital Pre-Emphasis Processor Quick Start User Manual 5
external PC. When operated in this mode, connect the USB connector to an available USB connector in the PC.
BERTScopePC software must be installed to support standalone operation.
(AC POWER) : Connect with a suitable power cable to match the local power outlet type.
RS232 : Miniature type D connector; this connector is not connected in the current production version of the
instrument.
Figure2.ToapplyjittertotheDPPclockinput,selectStressedClockmode
fortheSubrateClockontheBERTScopeGeneratorview.
Clock / Data Input Skew
The DPP125 is a non-linear processor that re-clocks the input data. Any skew between the Data In and Clock In
signals will move the sample point in time, appearing as a reduction in eye opening. If the input signal has
sufficient jitter present, bit errors may appear in the DPP125 output when excessive clock/data delay is present.
Applications which require processing of stressed data use the BERTScope Subrate Clock Out, with the
Stressed Clock output selected. In this setup, the subrate clock output phase leads the data output signal by
approximately 5.4 ns. To correctly compensate for the delay in the Data Out, the cable interconnecting the
Subrate Out to the DPP125 should be approximately 1.6 meters (62 inches) longer than the cable connecting the
BERTScope Data Out to the DPP125 Data Input. With the additional cable length providing the rough delay
match, use the calibration method described below to fine tune the delay match.
1. Connect the DPP125 to the BERTScope Analyzer:
2. Connect the BERTScope Generator’s Positive Data Output to the DPP125 Data Input.
3. Connect the BERTScope Generator’s Subrate Clock Out to the DPP125 Clock In, using a cable
approximately 1.6 m (62”) longer than the data cable.
4. Loop back the DPP125 Outputs to the Analyzer Error Detector Inputs.
5. Set the SJ to 30% UI. The particular SJ frequency is not crucial, but should be set to a frequency that
will be used during testing.
6. Enable RJ, and set its amplitude to the intrinsic value.
7. Calibrate to remove the Clock to Data delay:
8. Set the Generator Delay to 1 UI.

Configuration
6 DPP125 Digital Pre-Emphasis Processor Quick Start User Manual
9. Run the Detector to check for error free operation. If not operating error free, advance the Generator
delay by another ½ UI. The Detector should be operating error free at this point. Record the Generator
Delay.
10. Once error free operation is obtained, find the boundary between error free and errored operation by
decreasing the Generator Delay and using a binary search method as shown in Figure 3 below. Record
the Generator Delay.
11. Return the Generator Delay to the error free point found in step 2.
12. Now find the boundary between error free and errored operation by increasing the Generator Delay
and using a binary search as shown in the figure below. Record the Generator Delay.
13. Set the Generator Delay to the average of the Delay values found in steps 3 and 5. This is an
approximate calibration point.
14. Increase the SJ and RJ amplitudes to be larger than the amplitudes you plan to use for testing (but not
so high as to close the eye completely).
15. Repeat steps 3-6, starting at the initial calibration point found in step 6. Use this as the calibrated
Generator Delay. This Delay value can continue to be used as long as the cabling setup remains the
same.
Figure3.Binarysearchmethodtofine‐tunetheClocktoDatadelaymatch