Keysight Technologies N4960A User manual

User Guide
Keysight
N4960A
Serial BERT
17 and 32 Gb/s

2 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
Notices
© Keysight Technologies, Inc. 2012-2019
No part of this manual may be reproduced
in any form orbyany means (including
electronic storage and retrieval or
translation into a foreign language) without
prior agreement and written consent from
Keysight Technologies, Inc. asgoverned by
United States and international copyright
laws.
Manual Part Number
N4960-91021
Edition
Edition 9.0, April 2019
Printed in Germany
Keysight Technologies, Inc.
Keysight Technologies R&D and Marketing-
GmbH & Co.KG
Herrenberger Str. 130
71034 Böblingen, Germany
Warranty
THE MATERIAL CONTAINED IN THIS
DOCUMENT IS PROVIDED "AS IS," AND IS
SUBJECT TO BEING CHANGED, WITHOUT
NOTICE, IN FUTURE EDITIONS. FURTHER,
TO THE MAXIMUM EXTENT PERMITTED BY
APPLICABLE LAW, KEYSIGHT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR
IMPLIED WITH REGARD TO THIS MANUAL
AND ANY INFORMATION CONTAINED
HEREIN, INCLUDING BUT NOT LIMITED TO
THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE. KEYSIGHT SHALL
NOT BE LIABLE FOR ERRORS OR FOR
INCIDENTAL OR CONSEQUENTIAL
DAMAGES IN CONNECTION WITH THE
FURNISHING, USE, OR PERFORMANCE OF
THIS DOCUMENT OR ANY INFORMATION
CONTAINED HEREIN. SHOULD KEYSIGHT
AND THE USER HAVE A SEPARATE
WRITTEN AGREEMENT WITH WARRANTY
TERMS COVERING THE MATERIAL IN THIS
DOCUMENT THAT CONFLICT WITH THESE
TERMS, THE WARRANTY TERMS IN THE
SEPARATE AGREEMENT WILL CONTROL.
Technology Licenses
The hardware and/or software described in
this document are furnished under a
license and may be used or copied only in
accordance with the terms of such license.
Restricted Rights Legend
If software is for use in the performance of
a U.S. Government prime contract or
subcontract, Software is delivered and
licensed as “Commercial computer
software” as defined in DFAR 252.227-
7014 (June 1995), or as a “commercial
item” as defined in FAR 2.101(a) or as
“Restricted computer software” as defined
in FAR 52.227-19 (June 1987) or any
equivalent agency regulation or contract
clause. Use, duplication or disclosure of
Software is subject to Keysight
Technologies’ standard commercial license
terms, and non-DOD Departments and
Agencies of the U.S. Government will
receive no greater than Restricted Rights
as defined in FAR 52.227-19(c)(1-2) (June
1987). U.S. Government users will receive
no greater than Limited Rights as defined in
FAR 52.227-14 (June 1987) or DFAR
252.227-7015 (b)(2) (November 1995), as
applicable in any technical data.
Safety Notices
A CAUTION notice denotes a hazard. It calls
attention to an operating procedure,
practice, or the like that, if not correctly
performed or adhered to, could result in
damage to the product or loss of important
data. Do not proceed beyond a CAUTION
notice until the indicated conditions are
fully understood and met.
A WARNING notice denotes a hazard. It
calls attention to an operating procedure,
practice, or the like that, if not correctly
performed or adhered to, could result in
personal injury or death. Do not proceed
beyond a WARNING notice until the
indicated conditions are fully understood
and met.

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
3
Safety Summary
The following general safety precautions must be observed during all phases of
operation of this instrument. Failure to comply with these precautions or with
specific warnings or operating instructions in the product manuals violates
safety standards of design, manufacture, and intended use of the instrument.
Keysight Technologies assumes no liability for the customer's failure to comply
with these requirements. Product manuals are provided with your instrument
on CD-ROM and/or in printed form. Printed manuals are an option for many
products. Manuals may also be available on the Web. Go to www.keysight.com
and type in your product number in the Search field at the top of the page.
General This product is a Safety Class 1 instrument (provided with a protective earth
terminal). The protective features of this product may be impaired if it is used in
a manner not specified in the operation instructions.
All Light Emitting Diodes (LEDs) used in this product are Class 1 LEDs as per
IEC 60825-1.
Environment Conditions This instrument is intended for indoor use in an installation category II, pollution
degree 2 environment. It is designed to operate at a maximum relative humidity
of 15 to 85% and ataltitudes of up to2000 meters.
Refer to the specifications tables for the ac mains voltage requirements and
ambient operating temperature range.
Before Applying Power Verify that all safety precautions are taken. The power cable inlet of the
instrument serves as a device to disconnect from the mains in case of hazard.
The instrument must be positioned so that the operator can easily access the
power cable inlet. When the instrument is rack mounted the rack must be
provided with an easily accessible mains switch.
Ground the Instrument To minimize shock hazard, the instrument chassis and cover must be
connected to an electrical protective earth ground. The instrument must be
connected to the ac power mains through a grounded power cable, with the
ground wire firmly connected to an electrical ground (safety ground) at the
power outlet. Any interruption of the protective (grounding) conductor or
disconnection of the protective earth terminal will cause a potential shock
hazard that could result in personal injury.
Do Not Operate in an
Explosive Atmosphere
Do not operate the instrument in the presence of flammable gases or fumes.
Do Not Remove the
Instrument Cover
Operating personnel must not remove instrument covers. Component
replacement and internal adjustments must be made only by qualified
personnel.
Instruments that appear damaged or defective should be made inoperative and
secured against unintended operation until they can be repaired by qualified
service personnel.

4 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
Safety Symbols
Table 1. Safety Symbol
Symbol Description
Indicates warning or caution. If you see this symbol on a product, you
must refer to the manuals for specific Warning or Caution
information to avoid personal injury or damage to the product.
Frame or chassis ground terminal. Typically connects to the
equipment’s metal frame.
Indicates hazardous voltages and potential for electrical shock.
Indicates that antistatic precautions should be taken.
Indicates hot surface. Please do not touch.
CSA is the Canadian certification mark to demonstrate compliance
with the Safety requirements.
CE compliance marking to the EU Safety and EMC Directives.
ISM GRP-1A classification according to the international EMC
standard. ICES/NMB-001 compliance marking to the Canadian EMC
standard.
The RCM mark indicates that this product meets EMS/Product Safety
Requirements and may be imported to Australia and New Zealand.
This mark indicates compliance with the Canadian EMC regulations.
ISM 1-A This text denotes the instrument is an Industrial Scientific and
Medical Group 1 Class A product.
China RoHS regulations include requirements related to packaging,
and require compliance to China standard GB18455-2001. This
symbol indicates compliance with the China RoHS regulations for
paper/fiberboard packaging.
Indicates the time period during which no hazardous or toxic
substance elements are expected to leak or deteriorate during
normal use. Forty years is the expected useful life of the product.
The South Korean Class A EMC declaration (KC) mark indicates that
this product is Class A suitable for professional use and is for use in
electromagnetic environments outside of the home.
The KC mark includes the marking’s identifier code that has up to 26
digits and follows this format: KCC-VWX-YYY-ZZZZZZZZZZZZZ.

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
5
Compliance and Environmental Information
Table 2. Compliance and Environmental Information
Safety Symbol Description
This product complies with WEEE Directive (2002/96/EC) marking
requirements. The affixed label indicates that you must not discard
this electrical/electronic product in domestic household waste.
Product Category: With reference to the equipment types in WEEE
Directive Annex I, this product is classed as a “Monitoring and
Control instrumentation” product.
Do not dispose in domestic household waste.
To return unwanted products, contact your local Keysight office for
more information.

6 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 7
Contents
1
Setting Up the System..........................................................................11
1.1 Rack Mount Kit............................................................................ 11
1.2 Unpacking ................................................................................... 11
1.3 Important Notes.......................................................................... 12
1.4 Measurement Best Practices...................................................... 12
1.5 General Specifications ................................................................ 13
1.6 Safety and Regulatory ................................................................ 14
1.6.1 Declaration of Conformity .............................................. 15
1.7 Installation................................................................................... 15
2
Operation Overview ..............................................................................17
2.1 Introduction................................................................................. 17
2.2 Features ...................................................................................... 17
2.3 Control......................................................................................... 19
2.4 Introduction to Stress ................................................................. 19
2.4.1 Quantifying Jitter............................................................ 20
2.4.2 Types of Jitter / Stress................................................... 21
2.4.3 Stress for Jitter Tolerance Testing................................. 24
3
Operation..............................................................................................25
3.1 General Information.................................................................... 25
3.1.1 Performance Recommendations ................................... 25
3.1.2 Connector Care .............................................................. 26
3.2 Power on Settings....................................................................... 26
3.3 N4960A Serial BERT Controller Front Panel.............................. 27
3.4 N4960A Serial BERT Controller Rear Panel............................... 30
3.5 N4951A Front Panel ................................................................... 31
3.6 N4951A Rear Panel..................................................................... 32
3.7 N4951B-D17/-D32 Front Panel................................................. 33
3.8 N4951B-D17/-D32 Rear Panel .................................................. 34
3.9 N4951B-H17/-H32 Front Panel................................................. 34
3.10 N4951B-H17/-H32 Rear Panel.................................................. 35

8Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
3.11 N4952A Front Panel ................................................................... 36
3.12 N4952A Rear Panel..................................................................... 37
3.13 Block Diagram (32 Gb/s system)................................................ 38
3.14 Block Diagram (17 Gb/s system)................................................ 39
3.15 N4960A Serial BERT Controller.................................................. 40
3.15.1 Divided Clock Output ..................................................... 40
3.15.2 Delayed Clock Output .................................................... 41
3.15.3 Jittered Clock Output..................................................... 42
3.15.4 Sinusoidal, Random, and External High Band Paths .... 42
3.15.5 Low Frequency Band Periodic or External Jitter Path .. 44
3.15.6 Spread Spectrum Clock Modulation (N4960A-CJ1 only)45
3.15.7 External Clock Input ....................................................... 45
3.15.8 Delayed Clock Input ....................................................... 46
3.15.9 N4960A Serial BERT Controller Output Stages ............ 47
3.16 Pattern Generator ....................................................................... 48
3.16.1 Library of Patterns.......................................................... 48
3.16.2 Programmable Patterns ................................................. 48
3.16.3 Error Injection ................................................................. 49
3.16.4 Pattern Generator Output Stage ................................... 50
3.16.5 Dual Pattern Generator Operation................................. 50
3.16.6 N4951B-D17/-D32 Pattern Generator with 5-tap De-
emphasis......................................................................... 51
3.17 Error Detector ............................................................................. 52
3.17.1 Error Detector Input Stage............................................. 53
3.17.2 Pattern Selection............................................................ 53
3.17.3 Synchronization.............................................................. 54
3.17.4 Auto Pattern ................................................................... 54
3.17.5 Alignment ....................................................................... 55
3.18 Half Rate Clock Architecture...................................................... 56
3.18.1 Jitter Relationship Between Clock Output and Pattern
Generator Output ........................................................... 57
3.18.2 Delay Relationship Between Remote Head and Delay
Clock Output................................................................... 57
3.19 Bit Error Rate Tests..................................................................... 58
3.19.1 Setting up a Basic BER Test .......................................... 58
3.19.2 Accumulated and Instantaneous BER ........................... 59
3.20 Control Panel Operation ............................................................. 60
3.20.1 Menu Navigation ............................................................ 60

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 9
3.20.2 Changing Parameters..................................................... 62
3.20.3 Menu Structure .............................................................. 64
3.20.4 Menu Label Descriptions ............................................... 69
3.21 Working with Setting Dependencies.......................................... 83
3.22 Verifying Operation ..................................................................... 85
3.22.1 Initial Hardware Setup – Controller and Pattern
Generator........................................................................ 85
3.22.2 Initial Settings................................................................. 86
3.22.3 Enabling Sinusoidal Jitter .............................................. 87
3.22.4 Enabling Random Jitter (N4960A-CJ1 controller only) 88
3.22.5 Enabling Spread Spectrum Clock (N4960A-CJ1
controller only) ............................................................... 89
3.22.6 Bit Error Rate Test.......................................................... 90
3.23 Setting Frequency and Output Amplitude ................................. 92
3.24 Setting Random Jitter Injection (N4960A-CJ1 controller only) 93
3.25 Setting Sinusoidal Jitter Injection .............................................. 93
3.26 Setting External Jitter High Frequency Injection....................... 94
3.27 Setting Delay Clock Output........................................................ 94
3.28 Setting Divided Clock Output..................................................... 95
3.29 Event/Error Log........................................................................... 96
4
Applications ..........................................................................................97
4.1 Introduction................................................................................. 97
4.2 Testing Transceivers Used in Fibre Channel Networks ............. 98
5
Performance Specifications ................................................................101
5.1 N4960A Clock Source/BERT Controller Non-stressed
Specifications............................................................................ 101
5.2 N4960A Clock Source/BERT Controller Jitter Specifications . 103
5.2.1 Maximum N4960A Clock Modulation Range without PG
Connected .................................................................... 106
5.2.2 Maximum N4960A Clock Modulation Range with PG
Connected .................................................................... 107
5.3 N4951A/N4951B7Pattern Generator Specifications............... 108
5.4 N4952A-E17/N4952A-E32 Error Detector Specifications ...... 111

10 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
6
Remote Operation...............................................................................113
6.1 GPIB Interface ........................................................................... 113
6.2 USB Interface ............................................................................ 114
6.2.1 USB Driver .................................................................... 115
6.2.2 USB Programming Note .............................................. 115
6.3 Remote Command Syntax........................................................ 116
6.3.1 Command Structure..................................................... 116
6.4 IEEE Common Commands........................................................ 117
6.5 SCPI Mandated Commands ..................................................... 118
6.6 SCPI Protocol Description ........................................................ 118
6.6.1 SCPI Example ............................................................... 118
6.7 SCPI Numeric Parameters and Optional Units ........................ 119
6.8 Pattern Generator Channelization............................................ 119
6.9 Command Conventions ............................................................ 121
6.10 SCPI Standard Negative Event/Error Codes............................ 121
6.10.1 "Settings Conflict" Used for Settings Dependencies .. 122
6.11 N4960A Serial BERT Controller Device Commands................ 123
6.12 Pattern Generator Device Commands ..................................... 166
6.13 Error Detector Device Commands ........................................... 184
6.14 Command Summary................................................................. 208
6.14.1 N4960A Serial BERT Controller Command Summary 208
6.14.2 Pattern Generator Command Summary...................... 212
6.14.3 Error Detector Command Summary............................ 214
6.15 Programming Example ............................................................. 217
6.16 Programming Tips..................................................................... 227
6.16.1 Example Using *OPC? .................................................. 228
6.16.2 Example Using *WAI..................................................... 228
6.16.3 Communication Timeouts ............................................ 229
7
Returning the N4960A to Keysight .....................................................233
8
Appendix A Preset State .....................................................................235

Setting Up the System
Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 11
1
Setting Up the System
The N4960A serial BERT controller 17 and 32 Gb/s is shipped in a
protective box. Each shipping box contains:
•N4960A-CJ0 or N4960A-CJ1 serial BERT controller.
•AC power cord.
•CD-ROM, which includes:
oN4960A Serial BERT 17 and 32 Gb/s user guide
oN4960A Serial BERT 17 and 32 Gb/s getting started guide
oN4960A Serial BERT 17 and 32 Gb/s datasheet
The N4951A, N4951B, and N4952A are shipped in protective boxes with
all the accessories required for operation. Each shipping box contains:
•N4951A, N4951B, or N4952A with remote head/controller cable.
•CD-ROM, which includes:
oN4960A Serial BERT 17 and 32 Gb/s user guide
oN4960A Serial BERT 17 and 32 Gb/s getting started guide
oN4960A Serial BERT 17 and 32 Gb/s datasheet
1.1
Rack Mount Kit
The optional N4978A rack mount kit can be purchased separately for
rack mounting the N4960A as a single unit or two instruments mounted
side-by-side.
1.2
Unpacking
Carefully remove the instrument from the packaging in an ESD-safe
environment.

Setting Up the System
12 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
1.3
Important Notes
•Use ESD protection at all times when using the instrument.
•Before connecting any cable to the instrument, discharge the cable
by shorting the center and outer connectors of the cable together to
ground momentarily.
•Review min/max specifications before applying input signals.
•Use high quality connectors on all ports. The N4951A pattern
generator output and N4952A error detector input connectors are
2.92 mm, while all clock output and input connectors on the
N4960A serial BERT controller are SMA. The N4951B pattern
generator data output connectors are 2.4 mm.
•Leave dust jackets on unused back panel connectors.
•Situate the instrument away from heat sources, do not block the
fans, and do not block the exhaust vents on the sides of the BERT
controller and remote heads (minimum of 3 inches clearance).
•The bottom of a remote head can become hot to the touch. The
airflow should not be blocked as this will increase the temperature.
•Power must be turned off before connecting/disconnecting a remote
head.
1.4
Measurement Best Practices
•When using differential-mode connections, ensure the cables are
phase balanced for best performance.
•Use high quality cables and connector savers (or adaptors).
•Keep cable lengths short and minimize the number of cable bends.
•Use an 8 in-lbs (90 N-cm) torque wrench when attaching
connectors.

Setting Up the System
Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 13
1.5
General Specifications
Before installing the N4960A serial BERT, review the specifications in
Table 3
.
Table 3. Specification considerations before installation
Parameter Specification
Connector Type
Controller
All signals except 10 MHz Ref
In/Out –
10 MHz In/Out
N4951A/N4952A
N4951B
SMA
BNC
2.92 mm female
2.4 mm female (data output connectors), SMA female (auxiliary
connectors)
Remote Control Interface USB2.0 and IEEE-488 (GPIB)
Operating Temperature +15 ºC to +35 ºC
Storage Temperature –40 ºC to +70 ºC
Line Power
Voltage 100 to 240 VAC autoranging
Frequency 50/60 Hz
Power 170 Watts MAX
Fuse 250 V 2 A 5x20 mm (p/n 12260-002)
Always replace instrument fuse with one of the same type and
rating.
Dimensions (Height, Width,
and Depth)
N4960A 100 mm (3.9 in) x 214 mm (16.7 in) x 425 mm (16.7 in)
N4951A/N4952A 50 mm (1.9 in) x 109 mm (4.3 in) x 222 mm (8.7 in)
N4951B 50 mm (1.9 in) x 109 mm (4.3 in) x 273 mm (10.75 in)
Remote head/controller cable 1.0 m (39.7 in)
Weight
N4960A 3.2 kg (7.0 lbs)
N4951A/N4952A (with cable) 0.86 kg (30.3 oz)
N4951B (with cable) 1.0 kg (35.3 oz)

Setting Up the System
14 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
Parameter Specification
EMC
•
Complies with European EMC Directive 2004/108/EC
•IEC/EN 61326-1
•CISPR Pub 11 Group 1, class A
•AS/NZS CISPR 11
•ICES/NMB-001
This ISM device complies with Canadian ICES-001.
Cet appareil ISM est conforme a la norme NMB-001 du Canada.
Safety
•
Complies with European Low Voltage Directive
2006/95/EC
•IEC/EN 61010-1, 2nd Edition
•Canada: CSA C22.2 No. 61010-1
•USA: UL std no. 61010-1, 2nd Edition
Acoustic noise emission Geraeuschemission
LpA <70 dB LpA <70 dB
Operator position Am Arbeitsplatz
Normal position Normaler Betrieb
Per ISO 7779 Nach DIN 45635 t.19
1.6
Safety and Regulatory
This product has been designed and tested in accordance with
accepted industry standards, and has been supplied in a safe condition.
The documentation contains information and warnings that must be
followed by the user to ensure safe operation and to maintain the
product in a safe condition.
Do not remove instrument covers. There are no user serviceable parts within.
Operation of the instrument in a manner not specified by Keysight
Technologies
may result in personal injury or loss of life.
For continued protection against fire hazard, replace fuses, and or circuit
breakers only with same type and ratings. The use of other fuses, circuit
breakers or materials is prohibited.

Setting Up the System
Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 15
To prevent electrical shock, disconnect instrument from mains before cleaning.
Use a dry cloth or one slightly dampened with water to clean the external case
parts. Do not attempt to clean internally.
The Mains wiring and connectors shall be compatible with the connector used
in the premise electrical system. Failure, to ensure adequate earth grounding by
not using the correct components may cause product damage, and serious
injury.
1.6.1
Declaration of Conformity
A EU declaration of conformity is available at
http://regulations.corporate.Keysight.com/doc/search.htm
1.7
Installation
The following procedure describes how to install the N4960A serial
BERT.
1. Install on a flat surface with unobstructed airflow to the back
panel and side vents.
2. Plug the AC power cord into a suitable wall socket (100 to 240 V
AC, 50/60 Hz).
If this product is not used as specified, the protection provided by the
equipment could be impaired. This product must be used in a normal condition
(in which all means for protections are intact) only.
3. Plug the AC power cord into the N4960A serial BERT.
4. Connect the pattern generator to the Jitter connector on the
front panel.
5. Connect the error detector or a pattern generator to the Delay
connector on the front panel.

Setting Up the System
16 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
Before switching on this instrument, make sure the supply voltage is in the
specified range.
This instrument has autoranging line voltage input. Be sure the supply voltag
e is
within the specified range.

Operation Overview
Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 17
2
Operation Overview
2.1
Introduction
The N4960A serial BERT consists of a controller, which is a stressed
clock source with multi-sourced jitter capability, and support for an
externally connected pattern generator and error detector to form a
BERT. When used as a clock synthesizer, the range is 1 to 16 GHz.
When used with a remote head attached, the range of the clock
synthesizer is 2.5 to 16 GHz for the 32 Gb/s system, or 2 to 8.5 GHz for
the 17 Gb/s system. The pattern generator and error detector remote
heads use half rate clock architecture, giving a data rate range of 5 to
32 Gb/s for the 32 Gb/s system, or 4 to 17 Gb/s for the 17 Gb/s system.
2.2
Features
All features can be controlled through the control panel, remotely
through the GPIB or USB interface using the remote commands, or
through the N4980A multi-instrument BERT software.
•Controller (stressed clock synthesizer)
oOperation from 2.5 to 16 GHz (32 Gb/s system)
oOperation from 2 to 8.5 GHz (17 Gb/s system)
oTwo independent sinusoidal jitter injection sources (one for
N4960A-CJ0)
oTrue Gaussian random jitter stress (N4960A-CJ1 only)
oSpread spectrum clock (N4960A-CJ1 only)
oFully programmable clock output parameters
oLow intrinsic jitter
oJittered, non-jittered, and divided outputs
oRemote control through GPIB (IEEE 488.2) or USB2.0
oUser interface along with SCPI command set for easy
automation and test system integration

Operation Overview
18 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
•N4951A-P17/N4951A-P32 programmable pattern generator
oN4951A-P32 data rate from 5 Gb/s to 32 Gb/s
oN4951A-P17 data rate from 4 Gb/s to 17 Gb/s
o1 V (p-p) output voltage (single-ended)
oSingle ended or differential AC coupled data output with
integrated bias tee
oUser definable offset and termination voltage
oFamily of PRBS patterns and predefined sample patterns
oUser programmable patterns (up to 8 Mbit memory depth)
•N4951B-D17/N4951B-D32 programmable pattern generator
oN4951B-D32 data rate from 5 Gb/s to 32 Gb/s
oN4951B-D17 data rate from 4 Gb/s to 17 Gb/s, 1.5 V (p-p)
output voltage (single-ended)
o5-tap de-emphasis
oSingle ended or differential AC coupled data output with
integrated bias tee
oUser definable offset and termination voltage
oFamily of PRBS patterns and predefined sample patterns
oUser programmable patterns (up to 8 Mbit memory depth)
•N4951B-H17/N4951B-H32 programmable pattern generator
oN4951B-H32 data rate from 5 Gb/s to 32 Gb/s
oN4951B-H17 data rate from 4 Gb/s to 17 Gb/s
o3 V (p-p) output voltage (single-ended)
oSingle ended or differential AC coupled data output with
integrated bias tee
oUser definable offset and termination voltage
oFamily of PRBS patterns and predefined sample patterns
oUser programmable patterns (up to 8 Mbit memory depth)
•N4952A-E17/N4952A-E32 programmable error detector
oN4952A-E32 data rate from 5 Gb/s to 32 Gb/s
oN4952A-E17 data rate from 4 Gb/s to 17 Gb/s
oAuto sample voltage and delay alignment (can be manually set)
oAuto detects PRBS patterns
oSingle ended or differential AC coupled data input
oUser definable termination voltage

Operation Overview
Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 19
2.3
Control
System configuration settings are all available from the local control
panel interface, the remote GPIB (IEEE 488.2) interface, or the USB
interface. Instrument status is conveyed on the front panel by the
display.
The N4960A serial BERT is supported by the N4980A multi-instrument
BERT software Version 2.2 or higher, which provides a complete user
control interface and off line pattern editing and management tool.
2.4
Introduction to Stress
The N4960A serial BERT controller contains a stressed clock
synthesizer. The term “Stress” refers to the ability to modulate the
output signal with a calibrated level of timing jitter. Timing jitter is the
short term variation of a signal with respect to its ideal position in time.
Timing jitter can be seen and measured at the signal logic state
transitions.
Figure 1. Timing Jitter
Amplitude jitter, also known as “interference” or simply noise, will act on
the finite rise and fall times of transitions to produce effective timing
jitter. The N4960A serial BERT controller does not generate interference
(amplitude jitter). From this point forward, the term timing jitter will be
reduced to simply jitter.
100 ps
100 ps
100 ps
100 ps
10 GHz Clean Clock
96 ps
94 ps
102 ps
105 ps
10 GHz Stressed Clock

Operation Overview
20 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
In serial data systems, excessive jitter acts to “close the eye” which will
eventually result in bit errors, as the bit transition moves closer to the
receiver’s decision point time window.
Figure 2. Eye closure with low (left) and high level of jitter (right)
A common test for a serial data receiver is its susceptibility to jitter. The
test is performed by driving a known data pattern into the receiver using
the N4951A/N4951B pattern generator which is stressed with a known
amount of jitter. The received data is compared to an internal reference
pattern of the N4952A error detector, and the number of incorrect
detected bits is counted. By varying the characteristics of the jitter used
to modulate the test data generator, the receiver’s performance can be
characterized.
2.4.1
Quantifying Jitter
The level or “amplitude” of jitter refers to the instantaneous
displacement in time of the measure point (transition) from its ideal
location. When applied to a stress generator, the amplitude refers to a
level of reoccurring jitter, rather than a single instantaneous edge
displacement. The jitter amplitude will be stated as a peak to peak
displacement, or a root means squared (rms) value, depending on the
nature of the jitter distribution.
Jitter
Receiver
Decision Point