Keysight Technologies N4960A User Manual

Keysight
N4960A
Serial BERT
17 and 32 Gb/s

User Guide

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 or by any means (including
electronic storage and retrieval or
translation into a foreign language) without
prior agreement and written consent from
Keysight Technologies, Inc. as governed 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 Marketing­GmbH & 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.

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.

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 252.227­7014 (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

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

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

Environment Conditions

Before Applying Power

Ground the Instrument

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.

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 at altitudes of up to 2000 meters.

Refer to the specifications tables for the ac mains voltage requirements and
ambient operating temperature range.

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.

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 Remove the

Instrument Cover

Do not operate the instrument in the presence of flammable gases or fumes.

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.

3

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

information to avoid personal injury or damage to the product.

equipment’s metal frame.

with the Safety requirements.

standard.

Requirements and may be imported to Australia and New Zealand.

Medical Group 1 Class A product.

paper/fiberboard packaging.

normal use. Forty years is the expected useful life of the product.

Safety Symbols

Symbol Description

Table 1. Safety Symbol

Indicates warning or caution. If you see this symbol on a product, you
must refer to the manuals for specific Warning or Caution

Frame or chassis ground terminal. Typically connects to the

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

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

The RCM mark indicates that this product meets EMS/Product Safety

This mark indicates compliance with the Canadian EMC regulations.

ISM 1-A This text denotes the instrument is an Industrial Scientific and

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

Indicates the time period during which no hazardous or toxic
substance elements are expected to leak or deteriorate during

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

more information.

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

5

6 Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide
Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 7

1

Setting Up the System .......................................................................... 11

2

Operation Overview .............................................................................. 17

3

Operation .............................................................................................. 25

Contents

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

2.1 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

3.1 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

8 Keysight 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

4

Applications .......................................................................................... 97

5

Performance Specifications ................................................................ 101

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

4.1 Introduction ................................................................................. 97

4.2 Testing Transceivers Used in Fibre Channel Networks ............. 98

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/N4951B

7

Pattern 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

7

Returning the N4960A to Keysight ..................................................... 233

8

Appendix A Preset State ..................................................................... 235

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

Setting Up the System

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 11

1 Setting Up the System

1.1 Rack Mount Kit

1.2 Unpacking

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:

o N4960A Serial BERT 17 and 32 Gb/s user guide
o N4960A Serial BERT 17 and 32 Gb/s getting started guide
o N4960A Serial BERT 17 and 32 Gb/s datasheet

he N4951A, N4951B, and N4952A are shipped in protective boxes with

T
all the accessories required for operation. Each shipping box contains:

• N4951A, N4951B, or N4952A with remote head/controller cable.

• CD-ROM, which includes:

o N4960A Serial BERT 17 and 32 Gb/s user guide
o N4960A Serial BERT 17 and 32 Gb/s getting started guide
o N4960A Serial BERT 17 and 32 Gb/s datasheet

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.

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

1.4 Measurement Best Practices

• Use ESD protection at all times when using the instrument.

• Before connecting any cable to the instrument, discharge the cabl

by
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 remot
he

e

shorting the center and outer connectors of the cable together to

e

ad.

• 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

Table 3

Before installing the N4960A serial BERT, review the specifications in

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

•

•

1.6 Safety and Regulatory

Technologies

Parameter Specification

EMC

Safety

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.

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

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
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.

in the premise electrical system. Failure, to ensure adequate earth grounding by

1.6.1

Declaration of Conformity

http://regulations.corporate.Keysight.com/doc/search.htm

1.7 Installation

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

not using the correct components may cause product damage, and serious
injury.

A EU declaration of conformity is available at

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

e is

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
within the specified range.

Operation Overview

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

2 Operation Overview

2.1 Introduction

2.2 Features

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.

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)

o Operation from 2.5 to 16 GHz (32 Gb/s system)
o Operation from 2 to 8.5 GHz (17 Gb/s system)
o Two independent sinusoidal jitter injection sources (one for

N4960A-CJ0)

o True Gaussian random jitter stress (N4960A-CJ1 only)
o Spread spectrum clock (N4960A-CJ1 only)
o Fully programmable clock output parameters
o Low intrinsic jitter
o Jittered, non-jittered, and divided outputs
o Remote control through GPIB (IEEE 488.2) or USB2.0
o User 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

o N4951A-P32 data rate from 5 Gb/s to 32 Gb/s
o N4951A-P17 data rate from 4 Gb/s to 17 Gb/s
o 1 V (p-p) output voltage (single-ended)
o Single ended or differential AC coupled data output with

integrated bias tee

o User definable offset and termination voltage
o Family of PRBS patterns and predefined sample patterns
o User programmable patterns (up to 8 Mbit memory depth)

• N4951B-D17/N4951B-D32 programmable pattern generator

o N4951B-D32 data rate from 5 Gb/s to 32 Gb/s
o N4951B-D17 data rate from 4 Gb/s to 17 Gb/s, 1.5 V (p-p)

output voltage (single-ended)

o 5-tap de-emphasis
o Single ended or differential AC coupled data output with

integrated bias tee

o User definable offset and termination voltage
o Family of PRBS patterns and predefined sample patterns
o User programmable patterns (up to 8 Mbit memory depth)

• N4951B-H17/N4951B-H32 programmable pattern generator

o N4951B-H32 data rate from 5 Gb/s to 32 Gb/s
o N4951B-H17 data rate from 4 Gb/s to 17 Gb/s
o 3 V (p-p) output voltage (single-ended)
o Single ended or differential AC coupled data output with

integrated bias tee

o User definable offset and termination voltage
o Family of PRBS patterns and predefined sample patterns
o User programmable patterns (up to 8 Mbit memory depth)

• N4952A-E17/N4952A-E32 programmable error detector

o N4952A-E32 data rate from 5 Gb/s to 32 Gb/s
o N4952A-E17 data rate from 4 Gb/s to 17 Gb/s
o Auto sample voltage and delay alignment (can be manually set)
o Auto detects PRBS patterns
o Single ended or differential AC coupled data input
o User definable termination voltage

Operation Overview

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 19

2.3 Control

2.4 Introduction to Stress

100 ps

100 ps

100 ps

100 ps

10 GHz Clean Clock

96 ps

94 ps

102 ps

105 ps

10 GHz Stressed Clock

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.

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.

Operation Overview

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

2.4.1

Quantifying Jitter

Jitter

Receiver

Decision Point

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.

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.

Operation Overview

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 21

2.4.2

Types of Jitter / Stress

-4 ps

-3 ps

+2 ps

-3 ps

+2

+0

-2

-4

Edge Displacement (ps)

The jitter that a serial data receiver is exposed to in an operating
environment is a composite of several elemental types. These types
correspond to mechanisms in the environment which create the jitter,
and are duplicated in the data pattern generator clock used to test a
receiver.

The “type” of jitter represents its distribution when looking at a
continuous measurement of edge displacement over time. The
representation of this is a time interval error (TIE) plot. The TIE plot is a
graph of the absolute displacement of each transition edge in the
jittered waveform with respect to its ideal location versus time (or bit
location).

Figure 3. Time Interval Error plot of edge displacement

The resulting TIE plot shows the modulation of the jitter. The wave
shape of the modulation envelope (TIE plot), relates to the type of jitter
in the signal.

Jitter can be qualified as being one of a combination of several types,
which again refer to the wave shape of the deviation versus time. The
most basic distinction is deterministic versus non-deterministic. As its
name implies, deterministic jitter forms a pattern which can be
recognized. Deterministic jitter can be further broken down into data
dependent, which is synchronous to the data pattern, and periodic,
which has frequency components that are asynchronous to the data.
While periodic jitter can have any wave shape, sinusoidal (SJ) is the
most common.

Operation Overview

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

Figure 4

The jitter amplitude (deviation in time from ideal location) of
deterministic jitter is bounded. Once enough transition edges have been
sampled to determine the peaks of the TIE envelope, additional
sampling will not show an increase in the peak instantaneous jitter. A
common graphical representation of jitter is referred to as a TIE
histogram, or simply a jitter histogram. The histogram shows peak
deviation versus number of samples.

shows a typical TIE

histogram plot of sinusoidal jitter.

Figure 4. TIE histogram of pure sinusoidal jitter

The horizontal axis is jitter magnitude—deviation in time of the actual
edge location relative to its ideal location. The axis has polarity, with 0
deviation occurring in the center. Points to the right of center are from
transitions which occur after the ideal location (lag), while those to the
left of center occur before the ideal location (lead).

The vertical axis shows the number of occurrences, plotted on a log
scale. The characteristic shape reflects what is expected from a sine
wave. The amplitude is near the positive and negative peak for most of
the time, and in the zero crossing point for the least amount of time.

Generating a jitter histogram of pure deterministic jitter with a
measurement instrument which updates the plot as additional samples
are taken would quickly fill out the envelope, with no change in shape or
peaks as additional samples are taken.

Because deterministic jitter is bounded, its magnitude is usually
expressed as a peak to peak value. The units are either absolute time,
for example picoseconds (ps), or relative to bit time, in unit intervals
(UI).

Operation Overview

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 23

Figure 5

Non-deterministic jitter is composed primarily of random jitter
components. As the name implies, the envelope of random jitter will
have no recognizable pattern. Random jitter results from noise artifacts
in the system. Non-deterministic jitter is un-bounded. As more samples
are measured, the TIE histogram will show ever increasing peak jitter,
occurring at small number of samples, with the process unending. The
TIE histogram of pure random jitter (RJ) will have a true Gaussian
deviation, as shown in

.

Figure 5. Typical TIE Histogram of Random Jitter

When only random jitter is present in the signal, the majority of
transitions will occur at the ideal location in time (zero deviation), with
decreasing numbers of transitions occurring at increasing levels of
deviation in time. Due to the distribution, the magnitude of random jitter
is usually expressed as a root mean squared (rms) value. The RJ
magnitude can also be expressed as a peak to peak value, at a given
confidence level. The confidence level can be computed from the
number of samples. As with deterministic jitter, the units are either
absolute time, for example ps, or relative to bit time, in UI.

Data and clock signals in real life operating systems will usually contain
jitter which has both deterministic and non-deterministic components
within it.

Operation Overview

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

2.4.3

Stress for Jitter Tolerance Testing

Stressed clock synthesizers such as the N4960A serial BERT controller
are used to clock a data pattern generator, which in turn is used to test
a serial data receiver’s susceptibility to jitter. The jitter tolerance test is
the basic method generally used to characterize a receiver. The test is
performed with a BERT, used to monitor the receiver detected output
and determine when it does and when it does not operate error free.
The test is started by operating the receiver and initializing the test
setup to achieve error free operation. Then stress is added, usually as a
single tone of SJ at a specific frequency with low amplitude. The SJ
amplitude is increased until bit errors start to occur. The stress
amplitude at this point is recorded, the SJ amplitude reduced and the
frequency changed. The process then repeats at the new SJ frequency.
The resulting jitter tolerance plot shows the limits of error free operation
as jitter amplitude versus jitter frequency.

Some communication standards include a base line mixture of RJ and
SJ to be constant throughout the test, with the larger SJ used for the
measurement summed into the baseline. The addition of the baseline
represents the intended operating environment.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 25

3 Operation

3.1 General Information

3.1.1

Performance Recommendations

The N4960A serial BERT should be used in accordance with the
following:

• Read and follow operating instructions of all system equipment and

do not exceed min/max specifications.

• Use ESD protection at all times, but especially when handling RF

inputs/outputs.

• Before connecting any cable to the instrument, discharge the cable

by shorting the center and outer connectors of the cable together to
ground momentarily.

• Situate the instrument away from heat sources.

• Do not block airflow to the fans or exhaust vents and do not allow

foreign material into enclosure.

• Do not modify the power plug or wall outlet to remove the third

(ground) pin.

• Do not drop or shake the instrument, minimize vibration, and handle

with care.

• Power must be turned off before connecting/disconnecting a remote

head.

There are no user-serviceable parts within. Return damaged instruments for
factory-authorized repair. Refer to instrument warranty for more information.

The following recommendations ensure best performance:

• When using differential mode connection for outputs, ensure the

cables are phase balanced. If the electrical length of one cable is a
significant fraction of a unit interval longer than the other, the
quality of the differential signal will be degraded.

• Keep cable lengths short and minimize number of cable bends.

It is not usually necessary to terminate unused outputs of a differential
pair when a single ended signal is used. However, when the N4952A
error detector is driven with a single ended signal, it is good practice to
terminate the unused input to avoid errors from external noise.

Operation

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

3.1.2

Connector Care

3.2 Power on Settings

8 Appendix A Preset State

The N4960A serial BERT controller features high-quality SMA
connectors for the front and rear panel input and output connections
while the N4951A pattern generator and N4952A error detector use

2.92 mm. The N4951B pattern generators use type 2.4 mm connectors
for data output and SMA for auxiliary input/output connectors.
Connector damage will degrade signal fidelity.

Use high quality SMA-connectors on the SMA ports. Always leave dust
jackets on unused ports. Tighten the connectors to 8 in-lbs (90 N-cm)
to assure proper mating.

Refer to the N4960-90030 N495xA through N498xA Connector Care
Reference Guide at www.Keysight.com/find/N4951A

Inspect the connectors for the following:

• Worn or damaged threads

• Scratches to mating surface

• Burrs and loose metal particles

• Dust or foreign material in the space surrounding the center pin

• Ensure that female contacts are straight and aligned

.

Clean the connectors as described in the following procedure. Cleaning
connectors with alcohol shall only be done with the instruments power
cord removed, and in a well-ventilated area. Allow all residual alcohol
moisture to evaporate, and the fumes to dissipate prior to energizing the
instrument.

1. Remove any dust or loose particles using a low-pressure air

2. Moisten a lint-free swab with isopropyl alcohol. Do not saturate

3. Minimize the wicking of the alcohol into the connector structure.

4. Clean the mating plane surfaces and threads.

5. Allow alcohol to evaporate, and then use a low-pressure air

6. Make sure no particles or residue remains.

7. Inspect connector for damage.

On power on, the instrument always returns to the factory preset
settings, listed in
return to last used settings may save them in one of the 5 saved settings
locations, and recall them on power on.

source.

the swab.

source to blow surfaces clean.

. Users who wish to quickly

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 27

3.3 N4960A Serial BERT Controller Front Panel

Figure 6

Table 4

The N4960A serial BERT controller front panel indicates the system
status and contains the control panel for local operation of the
instrument.

shows the front panel of the N4960A serial BERT controller.

Figure 6. N4960A serial BERT controller front panel

describes the N4960A serial BERT controller front panel

functions.

Table 4. N4960A serial BERT controller front panel

Item Description

Display The display is part of the control panel and is used to view the menu structure.
Softkey buttons The four softkey buttons to the right of the display are part of the control panel

and are used to switch between menu items, move the highlight up or down,
and edit or select parameters.

Rotary knob The rotary knob is part of the control panel and is used to increase or decrease

a numeric value and move the highlight to the next digit, character, or item in a
list.

Keypad The keypad is part of the control panel and is used to enter numeric values for

parameters. The PRST hardkey button is used to perform an instrument preset.

Operation

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

Item Description

Clock outputs
Jitter The jitter output is the main stressed clock output. The clock phase can be

modulated in time with one or more calibrated jitter sources. The output
amplitude, offset, and termination voltage are also user settable.

The jitter sources are:

• Sinusoidal jitter 1 (SJ1)

• Sinusoidal jitter 2 (SJ2) (N4960A-CJ1 only)

• Sinusoidal periodic jitter (PJ)

• Externally supplied jitter

• Random jitter (RJ) is internally sourced (N4960A-CJ1 only)

Sinusoidal jitter 1, Sinusoidal jitter 2, random jitter, and external jitter (high
frequency band) can be enabled simultaneously. However, the sum of these
paths must be kept below the specified maximum modulation level. In
addition, the periodic jitter path or external low band (high deviation) jitter
path cannot be enabled if any of the other jitter paths are enabled.

By disabling the stress sources, this output can be used to provide a clean
(non-jittered) clock.

The jitter output also provides the clock source for the pattern generator.
When used as a BERT, the synthesizer clock frequency is set to 1/2 of the
BERT data rate. Any stress applied to the jitter clock output will appear on the
pattern generator output (channel 0 only) at 2x the amplitude of the clock
jitter.

Delay The delay differential output provides a non-stressed clock output with

adjustable phase offset (in UI) as well as amplitude, offset, and termination
voltage adjustment.

The delay clock is also used to clock the error detector. When operating as a
BERT, both auto and manual detector alignment will alter the delay setting for
the front panel output. Conversely, manually setting the delay output delay
value may degrade the error detector operation by misaligning the detector
sample point. The value of delay applied to the delay clock output will appear
on the error detector or pattern generator output (channel 1 only) at 2x the
value of the clock delay.

Divided The divided differential clock output produces a non-stressed signal that is

related to the clock frequency by a divider factor. The divided clock output
signal also has amplitude, offset, and termination voltage adjustment.

By setting the divide ratio to 1, this output can be used as a non-divided clean
(non-jittered) clock.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 29

Item Description

Ext Clock In Accepts an external clock to be substituted for the internal synthesizer across

the entire supported frequency range. When used to source the clock for the
pattern generator or error detector, this input is a half-rate clock.

Note: The instrument calibration requires knowledge of the clock frequency.
To facilitate externally sourced clock input, it contains a frequency counter
with sufficient resolution and accuracy to support this calibration. The counter
and instrument systems require a finite time to respond to large frequency
changes. Thus, in order to maintain calibration, the external clock must be
either a stable CW (Continuous Wave) signal, or modulated over relatively low
frequency (< 100 MHz) at low rates of change.

Delayed Clk In Accepts an external signal which can be used to clock the error detector. This

would commonly be sourced from an external clock recovery unit. When used
with the error detector, this input is a half-rate clock (one half the error
detector data rate).

Note: The instrument calibration requires knowledge of the applied clock
frequency. Unlike the external clock input, the instrument does not have an
internal counter to determine the delay clock frequency, and so the frequency
should be entered by the user. If no value is entered, the instrument defaults

to the main clock frequency.
Status LEDs
Outputs On

Jitter On

SSC

Attention

The Outputs On LED indicator is lit when any of the clock outputs are turned

on.

The Jitter On LED indicator is lit when any stress source is enabled.

The SSC LED indicator is lit when the spread spectrum clock function is

enabled.

The Attention LED indicator is lit when an error has occurred. The indicator will

not turn off until the error message has been cleared in the Error Log in the

System menu.

Operation

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

3.4 N4960A Serial BERT Controller Rear Panel

Figure 7

Table 5

Item Description

Delay An error detector or pattern generator can be connected to the Delay

connector (channel 1). The clock signal for the error detector or pattern

generator is derived from the Delay clock output.
Jitter A pattern generator can be connected to the Jitter connector (channel 0). The

clock signal for the pattern generator is derived from the Jitter clock output.

shows the N4960A serial BERT controller rear panel.

Figure 7. N4960A serial BERT controller rear panel

describes the N4960A serial BERT controller rear panel

functions.

Table 5. N4960A serial BERT controller rear panel

Item Description

USB Connector The USB connector is a type B USB port that connects the N4960A serial

BERT controller to an external PC for remote operation.

GPIB Connector The GPIB connector is a general purpose interface bus (GPIB, IEEE 488.1)

connection that can be used for remote operation.

Ext Jit In Accepts an external jitter source for either the low or high frequency band

modulation paths. Low band input must be sinusoidal wave shape, with
frequency in the range of 1 Hz to 4 MHz.

RJ Out and RJ In
Connectors

The RJ loop through path is used for inserting modulation frequency
contour filters in the random jitter path. The signal impedance is 50 Ω.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 31

3.5 N4951A Front Panel

Item Description

10 MHz In Connector The 10 MHz In connector accepts a 10 MHz reference signal from an

external source to allow the synthesizer to be phase locked to an external
reference clock.

10 MHz Out Connector The 10 MHz Out connector is a 10 MHz reference output used to lock the

frequency reference of other equipment to the N4960 serial BERT

controller.
Label N4960A serial BERT controller serial number.
Fuse Drawer Contains the primary power mains fuse. To replace, remove the fuse by

depressing the snap in tab and withdrawing the fuse drawer. A blown

primary fuse generally indicates a significant component failure. The

instrument should be returned to Keysight Technologies for service in the

event the fuse blows.
Power Switch N4960A serial BERT controller main power switch (1=On; 0=Off).
Power Input Connector Connect to power mains using approved power cable.

Figure 8. N4951A front panel

Item Description

Ch ID LED The Channel ID LED indicator is lit when connected to the N4960A serial BERT

controller.

Atten LED The Attention LED indicator is lit when an error has occurred. The indicator will

not turn off until the error message has been cleared in the Error Log in the
System menu.

On LED
Output Off
Output On

The On LED indicator is off when the data output is turned off.
The On LED indicator is lit when the data output is turned on.

Table 6. N4951A front panel

Data Output The differential data outputs are 2.92 mm connectors.

Operation

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

3.6 N4951A Rear Panel

Item Description

Connectors
Aux In This connector is reserved for future enhancements.
Aux Out The Auxiliary Output 2.92 mm connector provides a pattern trigger.

Item Description

Controller Connector The D-subminiature connector receives clock signals, control signals, and

power supplies from the controller via the 1 meter remote head/controller
cable.

Label Shows the N4951A option number (-P17 or -P32) and serial number.

Figure 9. N4951A rear panel

Table 7. N4951A rear panel

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 33

3.7 N4951B-D17/-D32 Front Panel

Figure 10. N4951B-D17/-D32 front panel

Table 8. N4951B-D17/-D32 front panel

Item Description

Ch ID LED The Channel ID LED indicator is lit when connected to the N4960A serial BERT

controller.

Atten LED The Attention LED indicator is lit when an error has occurred. The indicator will

not turn off until the error message has been cleared in the Error Log in the
System menu.

On LED
Output Off
Output On

Data Output

The On LED indicator is off when the data output is turned off.
The On LED indicator is lit when the data output is turned on.

The differential data outputs are 2.4 mm connectors.

Connectors
Aux In This connector is reserved for future enhancements.
Aux Out The Auxiliary Output SMA connector provides a pattern trigger.

Operation

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

3.8 N4951B-D17/-D32 Rear Panel

3.9 N4951B-H17/-H32 Front Panel

Figure 11. N4951B-D17/-D32 rear panel

Table 9. N4951B-D17/-D32 rear panel

Item Description

Controller Connector The D-subminiature connector receives clock signals, control signals, and

power supplies from the controller via the 1 meter remote head/controller
cable.

Label Shows the N4951B option number (-D17 or -D32) and serial number.

Figure 12. N4951B-H17/-H32 front panel

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 35

3.10 N4951B-H17/-H32 Rear Panel

Table 10. N4951B-H17/-H32 front panel

Item Description

Ch ID LED The Channel ID LED indicator is lit when connected to the N4960A serial BERT

controller.

Atten LED The Attention LED indicator is lit when an error has occurred. The indicator will

not turn off until the error message has been cleared in the Error Log in the
System menu.

On LED
Output Off
Output On

Data Output

The On LED indicator is off when the data output is turned off.
The On LED indicator is lit when the data output is turned on.

The differential data outputs are 2.4 mm connectors.

Connectors
Aux In This connector is reserved for future enhancements.
Aux Out The Auxiliary Output SMA connector provides a pattern trigger.

Figure 13. N4951B-H17/-H32 rear panel

Table 11. N4951B-H17/-H32 rear panel

Item Description

Controller Connector The D-subminiature connector receives clock signals, control signals, and

power supplies from the controller via the 1 meter remote head/controller
cable.

Label Shows the N4951B option number (-H17 or -H32) and serial number.

Operation

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

3.11 N4952A Front Panel

Table 12. N4952A front panel

Item Description

Ch ID LED The Channel ID LED indicator is lit when connected to the controller.

Figure 14. N4952A front panel

Atten LED The Attention LED indicator is lit when an error has occurred. The indicator will

not turn off until the error message has been cleared in the Error Log in the

System menu.
Run LED BLUE while an accumulated BER measurement is running.
Errors LED OFF when no errors are detected, RED when errors are detected.
Data Loss LED RED when data is not detected.
Sync Loss LED RED when data is detected but the data pattern cannot be synchronized.
Data Input

The differential data inputs are 2.92 mm connectors.
Connectors

Aux In This connector is reserved for future enhancements.
Aux Out The Auxiliary Output connector provides an error trigger.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 37

3.12 N4952A Rear Panel

Figure 15. N4952A rear panel

Table 13. N4952A rear panel

Item Description

Controller Connector The D-subminiature connector receives clock signals, control signals, and

power supplies from the controller via the 1 meter remote head/controller
cable.

Label Shows the N4952A option number (-E17 or -E32) and serial number.

Operation

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

3.13 Block Diagram (32 Gb/s system)

Figure 16

is a simplified block diagram of the 32 Gb/s system that

emphasizes all inputs and outputs.

Figure 16. Simplified block diagram (32 Gb/s system)

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 39

3.14 Block Diagram (17 Gb/s system)

Figure 17

is a simplified block diagram of the 17 Gb/s system that

emphasizes all inputs and outputs.

Figure 17. Simplified block diagram (17 Gb/s system)

Operation

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

3.15 N4960A Serial BERT Controller

3.15.1

Divided Clock Output

Figure 18

Figure 19

The N4960A serial BERT controller has the capability to divide the clock
frequency over a broad range of divide ratios and return the divided
signal as fully differential non-stressed outputs with adjustable
amplitude and offset. This provides the user a convenient method for
generating a trigger signal to use with a scope, or other applications
requiring a sub rate clock.

The divide ratios are 1 to 99,999,999 with no missing integers. The
divided clock settings can be controlled programmatically or through
the front panel.

The divided clock output duty cycle varies between 33% and 66% as a
function of the divide ratio, N. When N is a power of two, the duty cycle
is exactly 50%. As N deviates from a power of two, the duty cycle
deviates from 50%. For example, N=64 has 50% duty cycle, N=60 has
47% duty cycle, and N=56 has 43% duty cycle.
formulas for calculating pulse width and duty cycle as a function of N,
for any integer N from 2 to 99,999,999. The duty cycle of the divided
clock is 50% ± 10% when the divide ratio is set to 1.

shows the

Figure 18. Calculating pulse width and duty cycle

1024.

is a plot of the duty cycle versus the divide ratio for N = 2 to

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 41

3.15.2

Delayed Clock Output

Figure 19. Duty cycle versus divide ratio

The Delayed Clock output is a non-stressed clean output with
adjustable phase that can be set from -1000 UI to 1000 UI in 0.001 UI
increments. When used as a clock source for a BERT, the Delayed Clock
would generally be used to clock the error detector.

The Delayed Clock settings can be controlled programmatically or
through the front panel.

Operation

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

3.15.3

Jittered Clock Output

2.4 Introduction to Stress

3.15.4

Sinusoidal, Random, and External High Band Paths

Enabling periodic jitter or external low band jitter enables the low frequency

random jitter, or external high frequency band enables the high frequency band

urces or between jitter sources within the same band may cause a phase shift

measurements, enable the jitter source to be used for the measurement, set the

The Jittered Clock output is the main stressed output signal. When used
with a BERT, it would normally provide the clock for the pattern
generator connected to the Jitter connector on the front panel of the
N4960A.

The Jittered Clock output parameters can be controlled
programmatically or through the front panel.

Refer to section
stress implementation in the N4960A serial BERT controller.

The total stress appearing in the output is a summation of the individual
active stress components available in the instrument model.

For the N4960-CJ0, the stress can be either high frequency band
sinusoidal jitter (SJ1) plus externally applied high band jitter, or low
frequency periodic jitter (PJ), or low frequency (high deviation)
externally applied jitter.

For the N4960-CJ1, the stress source choices are one or two tones of
high frequency sinusoidal (SJ1 + SJ2), summed with Random Jitter (RJ)
and any externally applied high band jitter, or low frequency periodic
jitter (PJ), or low frequency (high deviation) externally applied jitter.

, for a full description of the

The SJ1, SJ2, random jitter, and the external high frequency band (low
deviation) jitter input paths can be enabled simultaneously. However,
the sum of these paths must be kept below the specified maximum
modulation level.

band path (the low frequency band is the default path). Enabling SJ1, SJ2,

path. Switching between low frequency band and high frequency band jitter
so
in the jittered clock and the pattern generator. Before performing

amplitude to 0 UI then perform an auto alignment.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 43

Applying an external jitter signal with amplitude which exceeds the specified

cannot

The RJ is settable to as low as 0 UI-rms. However, each N4960A-CJ1 will have

maximum phase deviation from itself or as a sum with SJ1, SJ2, and/or RJ may
overdrive the high frequency band modulator. Overdriving the modulator may
result in distorted or intermittent clock output (clock slips). The N4960A
detect conditions which overdrive the modulator.

The RJ source provides true Gaussian random jitter with a crest factor
of at least 14. The unfiltered spectral content is flat from DC to the
contour of the high frequency band modulator, which has a -3 dB
bandwidth (BW) at approximately 320 MHz. For applications which
require a specified RJ frequency contour, an external filter can be
placed in the RJ modulation signal path. Both a low pass and a high
pass filter can be used in series when both ends of the spectrum require
filtering. The RJ signal is available on the rear panel (N4960A-CJ1 only)
between the RJ Out and RJ In connectors. The impedance of the signal
is 50 Ω.

The calibrated RJ modulation range is 0 to 0.025 UI-rms. However, if a
filter is inserted in the RJ path, then the modulation amplitude will be
attenuated by the insertion loss and bandwidth of the filter. For this
reason, the user can program the RJ modulation amplitude to a
maximum of 0.150 UI-rms. However, RJ is uncalibrated above 0.025
mUI.

its own intrinsic RJ minimum, below which, the system cannot achieve the
desired value. Typically, this lower limit is between 5 to 12 mUI-rms. It is
suggested that the intrinsic RJ be checked for operation in the intended
application.

The SJ1, SJ2, random jitter, and external low deviation settings can be
controlled programmatically or through the front panel.

Operation

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

3.15.5

Low Frequency Band Periodic or External Jitter Path

5 Performance Specifications

Enabling periodic jitter or external low band jitter enables the low frequency

random jitter, or external high frequency band enables the high frequency band

e same band may cause a phase shift

measurements, enable the jitter source to be used for the measurement, set the

Applying excessive amplitude to the external jitter input will overdrive the

linear operation or intermittent output (clock

A second modulation path is available for low frequency (high deviation)
stress injection. It can only be operated when all of the high frequency
band (low deviation) stress sources (SJ1, SJ2, RJ, and external low
deviation) are disabled. The low band path operates over lower
modulation frequencies, up to 17 MHz (using internal PJ), or up to 4
MHz (external). The modulation source can be either an internally
generated sinusoid (Periodic Jitter, or PJ), or externally supplied
through the Ext Jitter In connector. Externally applied low band jitter
must have a sinusoidal wave shape. Both internal and external jitter
modulation amplitude decreases as a function of modulation frequency.
Refer to

band path (the low frequency band is the default path). Enabling SJ1, SJ2,

path. Switching between low frequency band and high frequency band jitter
sources or between jitter sources within th
in the jittered clock and the pattern generator. Before performing

for exact ranges.

amplitude to 0 UI then perform an auto alignment.

modulation driver, resulting in non­slips). The instrument does not detect an external modulation overdrive
condition.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 45

3.15.6

Spread Spectrum Clock Modulation (N4960A-CJ1 only)

3.15.7

External Clock Input

Setting the clock source to External with no signal applied to the Ext Clock In

The main synthesizer in the N4960A-CJ1 controller can be modulated
to enable spread spectrum clocking (SSC). Spread spectrum clocking is
not generally considered to be a stress, but rather a method of
controlling electromagnetic interference (EMI), by spreading the peak
energy of the system clock over a broad portion of the spectrum. In
practice, SSC modulates the system clock in the device with a large
phase deviation at a relatively low frequency, generally 30 or 33 kHz.
The modulation wave shape is usually triangle, to keep the power
spectrum even over the modulation band. To emulate a transmitter of a
device employing SSC, the clock synthesizers used in BERTs include
SSC. To assure proper tracking of the BERT or sampling scope testing a
device with SSC, all three clock outputs of the N4960A-CJ1 controller
(Jittered, Delayed and Divided) are modulated with the same SSC
signal. The SSC deviation range is 0 – 1%
a triangle waveform. The modulation frequency can be set from 1 Hz to
50 kHz. In addition, there are three settings for deviation direction:
down, center and up (relative to the clock frequency setting).

The spread spectrum clock modulation settings can be controlled
programmatically or through the front panel.

1

. The modulation envelope is

The external clock input accepts an external clock to be substituted for
the internal synthesizer. The supplied signal can be driven across the
same frequency range as the internal synthesizer. Spread spectrum
clock modulation is not available when using the external clock input.

The external clock input can be enabled or disabled programmatically or
through the front panel.

The pattern generator and error detector remote heads incorporate half
rate clock architecture. When used as a BERT, any externally supplied
clock input must be at 1/2 the desired data rate.

connector will result in unstable operation.

1

(1% = 10,000 ppm)

Operation

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

3.15.8

Delayed Clock Input

Figure 16

Figure 17

If the Delayed Clock In is set to External to drive the Delay Clock Outputs of the

The front panel Delayed Clk In allows users to employ an alternate clock
source in the delay path. For an error detector, this may be desired
when used with a clock recovery device. For a pattern generator
connected to the Delay port, this may be useful to provide an
asynchronous clock for a generator used as an aggressor in cross talk
testing.

By default, the delay clock and error detector/pattern generator clock
are sourced from the main synthesizer (refer to
block diagram). When the External Delay Clock input is used to source a
different clock, the instrument needs to know the external delay clock
frequency to assure proper operation.The user must enter the correct
external delay clock rate. When no value is entered, the instrument
defaults to the frequency of the clock used in the main clock path.

Because the error detector and pattern generator remote heads
incorporate a half rate clock architecture, any externally applied clock to
the Delay Clock In must be at one half the desired data rate for the error
detector or pattern generator. Some clock recovery units generate half­rate clock outputs. If this is not the case, use an external divide by two
clock divider to provide the correct clock frequency.

or

,

N4960A and the clock source is set to External, a valid clock signal MUST be
applied to the Ext Clock In connector for the Delay Clock Outputs to function
properly.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 47

3.15.9

N4960A Serial BERT Controller Output Stages

Figure 14

The three clock outputs are AC coupled. Certain devices will not
function properly and cannot be connected to AC coupled equipment
unless an offset and termination voltage can be applied to the signal. To
meet these requirements, each output stage has an integrated bias tee.

On each output of the N4960A serial BERT controller, the amplitude,
offset voltage, termination voltage, and AC/DC coupling can be set
independently. These settings affect the signal at the Jitter, Delay, and
Divided front panel output connectors. The signals driven into the
pattern generator and error detector are not affected by these settings.
Before setting termination voltage and offset voltage, DC coupling must
be selected.

is a simplified diagram of the N4960A serial BERT

controller output stages.

Figure 20. N4960A serial BERT controller output stages

Operation

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

3.16 Pattern Generator

3.16.1

Library of Patterns

3.16.2

Programmable Patterns

The pattern generator utilizes a half rate clock architecture that enables
patterns to be generated at data rates from 5 to 32 Gb/s or
4 to 17 Gb/s. The differential output has fully adjustable output
amplitude, crossover, termination, and DC offset.

All features can be controlled through the control panel on the front
panel of the N4960A serial BERT controller, remote SCPI commands, or
through the N4980A multi-instrument BERT software.

Provided with the pattern generator is a large library of common stress
patterns:

• Family of hardware generated PRBS patterns (2n – 1, n = 7, 9, 10,

11, 15, 23, 29, 31, 33, 35, 39, 41, 45, 47, 49, 51)

• Clock patterns (÷2, ÷4, ÷8,…, ÷64)

• K28 series patterns (K28.3, K28.5, K28.7)

• CJ series patterns (CJPAT, CJTPAT, CRPAT)

• JSPAT and JTSPAT patterns

Pattern inversion is available for all patterns.

The pattern generator allows custom designed patterns from 1 bit – 8
Mbit memory depth to be created and uploaded to meet application
requirements. User patterns must fit into the internal 512-bit memory
boundary; therefore, all odd-length patterns will be replicated 512 times
before loading into the N4960A, and even-length patterns will be
replicated between 1 and 256 times (depending on the actual length of
the pattern). Patterns are created and loaded into the N4960A Serial
BERT using the N4980A Multi-instrument BERT Software package; the
pattern editor in this software performs the necessary replication
calculations and will advise the user of any patterns that will not fit into
the 8 Mb memory (after replication) along with suggestions on the
nearest pattern lengths that will fit.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 49

3.16.3

Error Injection

ErrInjSingle

Pattern Menu

EXEC

ErrInjRate

Pattern Menu

The N4980A multi-instrument BERT software enables users to create
their own unique patterns, and has several built-in tools to facilitate
pattern creation. A library of factory and utility patterns is provided,
such as
PRBS and clock patterns, which can be used in conjunction with custom
designed patterns in any combination to create complex patterns. Users
have a number of editing tools at their disposal, such as viewing the
pattern as a waveform, inverting a selection of bits, and finding a
sequence of bits or the longest run of ones or zeroes, all in an attempt
to assist users in what can be a tedious task.

For more information, refer to the N4980A multi-instrument BERT
software user guide.

The error injection feature can be configured either to inject a single
error or inject errors at a specified rate. Error injection is commonly used
to verify that the device under test (DUT) setup is correct when in a loop
back configuration.

A single error can be injected whether the error injection feature is
enabled or not. When the

, the

command is highlighted in the

softkey is selected to inject a single error.

Errors can also be injected at specified rates from 10-3 to 10-9 using the

command in the

. For example, if 10-3 is

selected, a single error is injected approximately every thousand bits.

Error injection can also be controlled using the corresponding remote
SCPI commands.

Operation

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

3.16.4

Pattern Generator Output Stage

Figure 21

3.16.5

Dual Pattern Generator Operation

Figure 36

The output of the pattern generator has its own amplitude, offset, and
termination voltage settings. However, there is no switch between AC
and DC coupling. The DC offset and termination paths are always active
but default to 0 V. Pre-defined settings allow the user to easily select
industry standard logic levels including ECL, LVPECL, and LVDS. The
termination voltage is used to meet the requirements of an external
device.
stage.

is a simplified diagram of the pattern generator output

Figure 21. Pattern generator output stage

Two pattern generators can be configured for dual channel pattern
generation with delay control for lane alignment.

In this configuration, the pattern generators have independent controls
that are identical except for jitter injection and delay control. Refer to

to the Jitter connector only.

. Jitter injection is applied to the pattern generator connected

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 51

[ (@<channel list>) ]

6.8 Pattern Generator Channelization

3.16.6

N4951B-D17/-D32 Pattern Generator with 5-tap De-emphasis

In order to send remote commands to the intended pattern generator,

defines which channel(s) to apply the command.
Channel 0 is the jitter channel and channel 1 is the delay channel. Refer
to

.

Dual pattern generators can also be controlled using the N4980A multi­instrument BERT software.

The N4951B de-emphasis options provide integrated 5-tap de­emphasis (1 pre-cursor, 2 post cursors) and are available in 17 Gb/s and
32 Gb/s versions. The de-emphasis head provides designers with the
signal pre-distortion capability required for transmitter emulation when
characterizing receivers, backplanes, and systems.

Figure 22. No de-emphasis

Figure 23. De-emphasis equalization applied

Operation

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

Deemphasis

Pat Gen-Jit Menu

3.17 Error Detector

The taps can be adjusted from the front panel of the N4960A, using the

functions in the

, or the N4980A multi-

instrument BERT software.

The N4980A includes a de-emphasis tap weight computation tool that
simplifies the process of computing tap weights into the following steps:

1. Load a measured or simulated s-parameter file of the channel

loss.

2. Click on the start calculation button (blue button). The software

calculates the minimum tap values necessary to create the ideal
compensation filter response.

3. Fine tune the taps if necessary for optimal fit.

4. Select the pattern generator with de-emphasis.

5. Click on the Set Taps button to load the computed tap weights

into the N4951B-D17/-D32 pattern generator head.

For more information about the N4980A de-emphasis tap weight
calculator, refer to the N4980A multi-instrument BERT software user
guide.

The error detector utilizes a half rate clock architecture that enables
error detection at data rates from 5 to 32 Gb/s or 4 to 17 Gb/s. The
differential output has adjustable input termination voltage.

All features can be controlled through the control panel on the front
panel of the N4960A serial BERT controller, remote SCPI commands, or
through the N4980A multi-instrument BERT software.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 53

3.17.1

Error Detector Input Stage

Figure 24

3.17.2

Pattern Selection

The input comparator of the error detector is AC coupled, with
programmable DC termination voltage. The termination voltage is
always active, but the default value is 0 V.
diagram of the error detector input stage.

is a simplified

Patterns are identical to those available for use with the pattern
generator. A pattern must first be selected before synchronization can
be attempted.

Figure 24. Error detector input stage

Operation

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

3.17.3

Synchronization

BER Thrshld

Sync Mode

Manual

Sync Now

Sync

Menu

3.17.4

Auto Pattern

Auto Pattern

Pat Type

PRBS

Auto Pattern

Synchronization is the process of bit aligning the detector internal
reference pattern with the input bit stream. Synchronization can be
initiated automatically or manually. Synchronization can be impacted by
several factors, including the detector decision point. The decision point
should be set appropriately for the test setup before synchronization is
attempted. The decision point can be automatically adjusted by the
error detector. However, if the eye is considerably closed from excessive
jitter or Inter Symbol Interference, the user may need to manually
perform the initial alignment.

In auto mode, synchronization can be configured to occur when a
specified BER threshold has been reached using the
command in the Sync Menu. The default mode is auto synchronization.
Auto synchronization can also be controlled using the corresponding
remote SCPI commands.

Changing the
performed each time the

. Manual synchronization can also be initiated using the

corresponding remote SCPI commands.

to

allows synchronization to be

command is executed in the

When the
the error detector automatically detects and synchronizes to PRBS
patterns. If
message “Unknown” is displayed.

feature is enabled,

cannot determine the pattern type, the

is set to

and

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 55

3.17.5

Alignment

Config AutoAlign

AutoAlign Menu.

Set SmplV

Set Delay

Set SmplV

Set Delay

Perform AutoAlign

SmplV

Delay

Input Adjust

align with memory based patterns (.fpt or .usr) is not recommended

Alignment is the process which places the detector decision point in the
optimal position in the eye. The two parameters which position the
detector are time (delay) and amplitude (sample threshold voltage). The
time (delay) parameter positions the decision point horizontally while
the amplitude (sample threshold voltage) parameter positions the
decision point vertically. Alignment can be done either automatically or
manually.

In auto mode, the sample threshold voltage and delay step size are
configured using the
In addition,
enabled (ON). The default for
auto alignment is performed by executing the

command in the

(sample voltage) and

and

(delay) must be

is enabled. The

command. After the auto alignment is performed, the results can be
viewed which includes eye height and eye width. Auto alignment can
also be controlled using the corresponding remote SCPI commands.

In manual mode, the sample voltage and delay can be adjusted using

and

in the

menu. Manual alignment can also

be controlled using the corresponding remote SCPI commands.

Use of auto­because it can be quite slow depending on the pattern length. Instead, perform
auto-align on a hardware PRBS pattern then switch to the memory based
pattern. Changing patterns does not affect alignment.

Operation

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

3.18 Half Rate Clock Architecture

When using remote SCPI commands, jitter, delay, and spread spectrum clock

The pattern generator and error detector utilize half rate clock
architecture relative to the N4960A serial BERT controller. This means
that the N4960A serial BERT controller settings for jitter, delay, and
spread spectrum clock, are half that of the pattern generator and error
detector settings.

Jitter and delay settings for the N4960A serial BERT controller, pattern
generator, and error detector are expressed in unit intervals. A unit
interval, also referred to as a bit period, is the time taken in a data
stream for one bit. For example, if the data rate is set to 10 Gb/s
(controller set to 5 GHz), the unit interval is 1 ÷ 10 Gb/s, which equals
100 ps, the time for one bit.

Jitter and delay unit intervals can be set at the N4960A serial BERT
controller or at the pattern generator and error detector. Therefore, it is
important to understand the relationship between the clock outputs
(N4960-CJ0/N4960-CJ1), the pattern generator, and the error detector
as described in the following sections.

can only be set at the N4960A serial BERT controller. Therefore, SCPI values
related to UI, such as jitter amplitude or delay, must be set to half of the value
desired on the pattern generator outputs or error detector delay.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 57

3.18.1

Jitter Relationship Between Clock Output and Pattern Generator Output

Figure 25

3.18.2

Delay Relationship Between Remote Head and Delay Clock Output

Figure 26

BERT controller relative to the jittered output of a pattern generator
connected to the Jitter port. Note that one clock period corresponds to
two bit periods. With SJ amplitude set to 0.1 UI in the N4960A serial
BERT controller, the SJ amplitude of the pattern generator will be set to

0.2 UI automatically. Conversely, if the SJ amplitude of the pattern
generator is set to 0.2 UI, the SJ amplitude of the N4960A serial BERT
controller will be set to 0.1 UI automatically.

illustrates the jittered clock output from the N4960A serial

Figure 25. Jitter relationship

BERT controller relative to the delay of a pattern generator or error
detector connected to the Delay port. Note that one clock period
corresponds to two bit periods. With the delay set to 0.1 UI in the
N4960A serial BERT controller, the delay of the pattern generator/error
detector will be set to 0.2 UI automatically. Conversely, if the delay of
the pattern generator/error detector is set to 0.2 UI, the delay of the
N4960A serial BERT controller will be set to 0.1 UI automatically.

illustrates the delayed clock output from the N4960A serial

Operation

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

3.19 Bit Error Rate Tests

3.19.1

Setting up a Basic BER Test

1. Set the clock frequency and pattern generator data rate.

Figure 26. Delay relationship

A bit error rate (BER) test is performed by driving the pattern generator
output into a DUT and back into the input of the error detector. Each bit
of the detector internal reference pattern is compared to the input bit
stream, and each mismatch is recorded as an error. The BER represents
the ratio of total number errors detected to total number of bits
received. For example, 1 error bit out of 1,000,000 total bits would
result in a BER of 1e-6 (1/1,000,000).

The N4960A serial BERT 17 and 32 Gb/s can be set up to run BER tests
using the front panel, remote SCPI commands, or N4980A multi­instrument BERT software.

Regardless of the method used to set up a BER test, the following
describes the setup requirements.

The pattern generator data rate is based on the clock frequency
setting. Due to the half rate clock architecture of the remote
heads, the clock frequency setting is half that of the remote
heads.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 59

2. Set the pattern generator logic level.

3. Select a pattern.

4. Enable the pattern generator output.

5. Synchronize the error detector.

6. Align the error detector.

7. Set the BER measurement criteria.

8. Start the BER measurement (accumulation).

3.19.2

Accumulated and Instantaneous BER

The data logic level sets the amplitude, offset, and termination
voltages appropriate for the DUT. Logic level choices include
ECL, LVPECL, and LVDS. Entering values other than ECL,
LVPECL, or LVDS values are considered “custom” entries.

For most devices which use conventional loop back, the pattern
generator and error detector patterns must match.

The pattern generator output defaults to disabled. Therefore,
ensure that the output is enabled. This is done using the Enable
function in the Data Output Menu (within the Pattern Gen
Menu).

Synchronize the error detector internal reference pattern with
the input bit stream. This may be done automatically or
manually.

The time (delay) parameter positions the decision point
horizontally while the amplitude (sample voltage) parameter
positions the decision point vertically. This may be done
automatically or manually.

Set the criteria for a BER test based on duration, number of bits,
or number of errors. The BER test can also be set to start/stop
manually.

The accumulated BER (aBER) tracks the currently accumulated bit error
rate, the total number of errors, the total number of logic 1 errors, the
total number of logic 0 errors, and the elapsed time. If the aBER is
cleared after the accumulation has stopped, all numbers are reset.

The instantaneous BER (iBER) displays the BER at the current instant in
time. The iBER is updated at a constant rate, regardless of whether an
accumulated BER test is running.

Operation

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

3.20 Control Panel Operation

Figure 27

3.20.1

Menu Navigation

Figure 28

This section describes how to use the Control Panel to operate the
N4960A serial BERT 17 and 32 Gb/s. Refer to

.

Figure 28. Softkey navigation buttons and rotary knob

Figure 27. Control panel

Navigation through the menus is accomplished with the four softkeys to
the right of the display and the rotary knob. Refer to

.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 61

Figure

29

SEL

Figure 30

Scroll through menu items using either the softkeys corresponding to
the up and down arrow labels, or using the rotary knob. Refer to

.

Figure 29. Scrolling through menu items

If a menu item has a lower-level menu that can be accessed, the
softkey appears. Press it to access the corresponding lower-level menu.
Refer to

Figure 30. Accessing lower-level menus

.

Operation

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

3.20.2

Changing Parameters

EDIT

Figure 31

EDIT

The keypad is used if a parameter is a numeric value only.

Figure 32

The
be changed or has multiple selections (for example, on and off). Refer to

When the softkey corresponding to the
function’s parameter can be changed using the rotary knob or the
keypad.

label appears when a menu item has a numeric value that can

.

Figure 31. EDIT label

label is pressed, the

is an example of changing parameters using the rotary knob.

Figure 32. Changing parameters using the rotary knob

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 63

EXIT

Figure 33

When using the rotary knob, changes to numeric values occur instantly. This

EDIT

ENT

Figure 34

If you are using the rotary knob to change numeric values, use the
right/left arrows on the keypad to highlight the digit you wish to
change. The right arrow highlights the digit to the right. The left arrow
highlights the digit to the left. When finished, press the softkey
corresponding to the
to

.

label to return to the previous screen. Refer

Figure 33. Highlighting digits to change

applies to almost all numeric values.

In addition to the rotary knob, the numeric keypad can be used to
change numeric values. Once the softkey corresponding to the
label is pressed, simply enter the value using the numeric keypad. When
finished, either press the

hardkey on the keypad, or press the
softkey corresponding to the associated units label to accept the entry.
Refer to

.

Figure 34. Using the numeric keypad

Operation

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

When changing values using the numeric keys, the change is not accepted until

3.20.3

Menu Structure

Figure 35

the ENT hardkey in the keypad, or a unit softkey is pressed.

shows the hierarchical structure of the Synthesizer, Jitter,
Delay, and Divided menus. Note that some parameters such as data
rate and jitter control, appear in both the synthesizer and the pattern
generator menus. This is to accommodate the half rate clock of the
pattern generator and error detector. When entered in the synthesizer
menu, the values correspond to the clock outputs on the front panel.
When entered in the pattern generator menu, the 2X conversion factor
is automatically applied so the values correspond to the pattern
generator output.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 65

Figure 35. Synthesizer, jitter, delay, and divided menu structure

Operation

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

Figure 36

menus.

shows the hierarchical structure of the pattern generator

Figure 36. Pattern generator menu structure

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 67

Figure 37

shows the hierarchical structure of the error detector menus.

Figure 37. Error detector menu structure

Operation

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

Figure 38

shows the hierarchical structure of the System menus.

Figure 38. System menu structure

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 69

3.20.4

Menu Label Descriptions

Table 14

Refer to

for the Synthesizer Menu descriptions.

Table 14. Synthesizer Menu descriptions

Label Name Description

Frq Sets the clock source frequency. The optional units are kHz, MHz, and GHz.

The resolution is 1 kHz. Displays EXTERNAL when External clock source is
selected.

ClkSrc Sets the clock source to INT for using the internal clock source or EXT for

using an external clock source.

SSC cannot be enabled if the clock source is external. If the SSC enabled state
conflicts with the clock source, a message indicating a conflict appears in the
N4960A-CJ1 controller display. Selecting Yes to resolve the conflict will set
the SSC enabled state to an appropriate value.

DlyClkSrc Sets the delay clock to be System for using the internal delay clock, or Ext for

using an external delay clock. Setting the DlyClkSrc to System will use either
the internal synthesizer or the external clock, whichever ClkSrc is set to.

DlyFrq Sets the delay clock frequency when DlyClkSrc is set to Ext. When DlyClkSrc is

set to System, the message “See Frq” is displayed referring to the frequency of
the system clock.

10MHzRef Sets the 10 MHz reference to INT for using the internal 10 MHz reference, EXT

for using an external 10 MHz reference, or AUTO for detecting and connecting
to an external reference automatically.

SSCDev1 Sets the spread spectrum clock deviation. The units are PPM (parts per

million). The resolution is 1 PPM.

SSCType1 Sets the spread spectrum clock deviation direction from down (DWN) spread,

up (UP) spread, or center (CNTR) spread.

SSCFrq1 Sets the spread spectrum clock frequency. The optional units are Hz and kHz.

The resolution is 1 Hz.

SSCEnable1 Enables/disables the spread spectrum clock function.

SSC cannot be enabled if the clock source is external. If the clock source
conflicts with the SSC enabled state, a message indicating a conflict appears
in the N4960A-CJ1 controller display. Selecting Yes to resolve the conflict will
set the clock source to an appropriate value.

1

Feature available in N4960A-CJ1 only.

Operation

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

If the clock source is set to External without a valid clock signal connected, then

If the 10 MHz Reference is set to Auto mode, whenever it switches between

(“REF,INTERNAL” and “REF,EXTERNAL”) respectively. If the 10 MHz Reference is

Table 15

the results from the :SOUR:FREQ? query may fluctuate or return “0000 Hz”. In
addition, a “FREQ/OOR” (frequency out of range) error may be generated. If
either of these conditions is detected, check the external clock source.

Internal and External, a message indicating the switch is generated

using an External source and there is a loss of signal, a loss of signal error will
be generated (“REF,LOS”).

Refer to

for the Jit Clk Out menu descriptions.

Table 15. Jit Clk Out menu descriptions

Label Name Description

OutEnable Enables/disables the jittered clock output.
Amp Sets the amplitude of the jittered clock. The optional units are mV and V. The

resolution is 0.005 V.

Offs Sets the offset of the jittered clock. The maximum range is a function of the

termination voltage setting. The optional units are mV and V. The resolution is

0.005 V.

The offset may be limited by the current termination voltage. If the desired
offset value conflicts with the current termination value, a message indicating
a conflict appears in the N4960A serial BERT controller display. Selecting Yes
to resolve the conflict will set the termination to an appropriate value.

Term Sets the termination voltage of the jittered clock. The maximum range is a

function of the offset setting. The optional units are mV and V. The resolution
is 0.005 V.

The termination may be limited by the current offset voltage. If the termination
value conflicts with the offset value, a message indicating a conflict appears in
the N4960A serial BERT controller display. Selecting Yes to resolve the
conflict will set the offset to an appropriate value.

Coupling Selects AC or DC output coupling.

Coupling must be set to DC before offset or termination can be set to a non­zero value. If an attempt to change the offset or termination to a non-zero
value conflicts with the AC coupling setting, a message indicating a conflict
appears in the N4960A serial BERT controller display. Selecting Yes to resolve
the conflict will set the coupling to DC.

SJ1 Sets the sinusoidal jitter 1 frequency. The optional units are Hz and MHz. The

resolution is 1 Hz.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 71

Label Name Description

SJ1Amp2 Sets the sinusoidal jitter 1 amplitude. The optional units are mUI and UI (p-p).

The resolution is 0.001 UI.

During the setting of SJ1 amplitude, if SJ1 and/or SJ2/RJ are enabled
simultaneously, keep the sum of all 3 components below the specified
maximum modulation level.

SJ1Enable Enables/disables the sinusoidal jitter 1.

SJ1 cannot be enabled if PJ or external jitter (low band) is enabled. If the SJ1
enabled state conflicts with these other jitter sources, a message indicating a
conflict appears in the N4960A serial BERT controller display. Selecting Yes to
resolve the conflict will disable all conflicting jitter sources.

SJ21 Sets the sinusoidal jitter 2 frequency. The optional units are Hz and MHz. The

resolution is 1 Hz.

SJ2Amp

1,2

Sets the sinusoidal jitter 2 amplitude. The optional units are mUI and

UI (p-p). The resolution is 0.001 UI.

During the setting of SJ1 amplitude, if SJ1 and/or SJ2/RJ are enabled
simultaneously, keep the sum of all 3 components below the specified
maximum modulation level.

SJ2Enable1 Enables/disables the sinusoidal jitter 2.

SJ2 cannot be enabled if PJ or external jitter (low band) is enabled. If the SJ2
enabled state conflicts with these other jitter sources, a message indicating a
conflict appears in the N4960A-CJ1 controller display. Selecting Yes to
resolve the conflict will disable all conflicting jitter sources.

PJ Sets the periodic jitter frequency. The optional units are Hz and MHz. The

resolution is 1 Hz.

The maximum PJ amplitude is a function of PJ frequency. If the PJ frequency
conflicts with the current PJ amplitude, a message indicating a conflict
appears in the N4960A serial BERT controller display. Selecting Yes to resolve
the conflict will set PJ amplitude to an appropriate value.

PJAmp Sets the periodic jitter amplitude. The optional units are mUI and UI (p-p). The

resolution is 0.001 UI. The maximum PJ amplitude is a function of PJ
frequency.

Operation

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

should not exceed the specified

Sinusoidal 1 jitter, Sinusoidal 2 jitter, random jitter, and external jitter high
frequency band (low deviation) can be enabled simultaneously. However, when

Label Name Description

PJEnable Enables/disables the periodic jitter.

Periodic Jitter cannot be enabled if any other internal or external jitter source
is enabled. If the PJ enabled state conflicts with other jitter sources, a
message indicating a conflict appears in the N4960A serial BERT controller
display. Selecting Yes to resolve the conflict will disable all other jitter
sources.

RJAmp1 Sets the random jitter amplitude in RMS. The optional units are mUI-rms and

UI-rms. The resolution is 1 mUI-rms. The maximum calibrated RJ amplitude is
25 mUI-rms, but the system allows values up to 150 mUI-rms to offset any
amplitude loss caused by use of a filter on the RJ input.

When used in combination with other high frequency band stresses (SJ1, SJ2,
and external high band jitter), keep the sum of all 3 components below the
specified maximum modulation level.

RJEnable1 Enables/disables the random jitter output.

RJ cannot be enabled if PJ or external jitter (low band) is enabled. If the RJ
enabled state conflicts with these other jitter sources, a message indicating a
conflict appears in the N4960A-CJ1 controller display. Selecting Yes to
resolve the conflict will disable all conflicting jitter sources.

ExtJit Selects the external jitter input path.

High band external jitter can be enabled in combination with SJ1, SJ2, and RJ.
Low band external jitter cannot be enabled if any other jitter source is enabled.
If the low band external jitter enabled state conflicts with other jitter sources, a
message indicating a conflict appears in the N4960A serial BERT controller
display. Selecting Yes to resolve the conflict will disable all other jitter
sources.

LB Gain Sets the gain of the external low band gain. The optional units are mUI/V or

UI/V.

1

Feature available in N4960A-CJ1 only.

2

Note that the sum of SJ1, SJ2, RJ, and external jitter low deviation amplitude

maximum deviation. However, the system only checks SJ1 and SJ2.

used in combination, make sure that the sum of these paths does not exceed
the specified maximum modulation level. In addition, periodic jitter or external
low band jitter cannot be enabled if any of the other jitter paths are enabled.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 73

Table 16

Refer to

for the Dly Clk Out menu descriptions.

Table 16. Dly Clk Out menu descriptions

Label Name Description

OutEnable Enables/disables the delayed clock output.
Amp Sets the amplitude of the delayed clock. The optional units are mV and V. The

resolution is 0.005 V.

Offs Sets the offset of the delayed clock. The maximum range is a function of the

termination voltage setting. The optional units are mV and V. The resolution is

0.005 V.
The offset may be limited by the current termination voltage. If the desired

offset value conflicts with the current termination value, a message indicating
a conflict appears in the N4960A serial BERT controller display. Selecting Yes
to resolve the conflict will set the termination to an appropriate value.

Term Sets the termination voltage of the delayed clock. The maximum range is a

function of the offset setting. The optional units are mV and V. The resolution
is 0.005 V.

The termination may be limited by the current offset voltage. If the termination
value conflicts with the offset value, a message indicating a conflict appears in
the N4960A serial BERT controller display. Selecting Yes to resolve the conflict
will set the offset to an appropriate value.

Coupling Selects AC or DC output coupling.

Coupling must be set to DC before offset or termination can be set to a non­zero value. If an attempt to change the offset or termination to a non-zero
value conflicts with the AC coupling setting, a message indicating a conflict
appears in the N4960A serial BERT controller display. Selecting Yes to resolve
the conflict will set the coupling to DC.

Delay Sets the delay of the delayed clock. The optional units are mUI and UI. The

resolution is 0.001 UI.

Operation

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

Table 17

Refer to

for the Div Clk Out menu descriptions.

Table 17. Div Clk Out menu descriptions

Label Name Description

OutEnable Enables/disables the divided clock output.
Amp Sets the amplitude of the divided clock. The optional units are mV and V. The

resolution is 0.005 V.

Offs Sets the offset of the divided clock. The maximum range is a function of the

termination voltage setting. The optional units are mV and V. The resolution is

0.005 V.
The offset may be limited by the current termination voltage. If the desired

offset value conflicts with the current termination value, a message indicating
a conflict appears in the N4960A serial BERT controller display. Selecting Yes
to resolve the conflict will set the termination to an appropriate value.

Term Sets the termination voltage of the divided clock. The maximum range is a

function of the offset setting. The optional units are mV and V. The resolution
is 0.005 V.

The termination may be limited by the current offset voltage. If the termination
value conflicts with the offset value, a message indicating a conflict appears in
the N4960A serial BERT controller display. Selecting Yes to resolve the conflict
will set the offset to an appropriate value.

Coupling Selects AC or DC output coupling.

Coupling must be set to DC before offset or termination can be set to a non­zero value. If an attempt to change the offset or termination to a non-zero
value conflicts with the AC coupling setting, a message indicating a conflict
appears in the N4960A serial BERT controller display. Selecting Yes to resolve
the conflict will set the coupling to DC.

Div Sets the divided clock divide ratio.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 75

Table 18

Refer to

for the Pattern Gen Menu descriptions for a pattern

generator connected to the Jitter (Channel 0) connector.

Common settings between the synthesizer and pattern generator are
superseded by the pattern generator settings. The jitter and delay
settings are replicated in the pattern generator menu for the users'
convenience. All jitter amplitude and delay ranges, settings, and
resolutions are double that of the Jitter Clock Output, due to the half
rate clock architecture of the pattern generator remote head.

Table 18. Pat Gen-Jit menu descriptions

Label Name Description

Data Output Menu

Enable Enables/disables the pattern generator output.
DRate Displays the pattern generator data rate. DRate is not settable.
Amp Sets the pattern generator output amplitude. Resolution is 0.005 V.
Offs Sets the DC offset of the data eye presented at the data outputs of the pattern

generator. The maximum range is a function of the termination voltage setting.
The optional units are mV and V. The resolution is 0.005 V.

The offset may be limited by the current termination voltage. If the desired
offset value conflicts with the current termination value, a message indicating a
conflict appears in the N4960A serial BERT controller display. Selecting Yes to
resolve the conflict will set the termination to an appropriate value.

Term Sets the DC output offset of the data eye to support a specified termination

voltage of a DUT having a 50 Ω input port. The maximum range is a function of
the offset setting. The optional units are mV and V. The resolution is 0.001 V.

The termination may be limited by the current offset voltage. If the termination
value conflicts with the offset value, a message indicating a conflict appears in
the N4960A serial BERT controller display. Selecting Yes to resolve the conflict
will set the offset to an appropriate value.

Logic Sets the data logic level. The levels are ECL, LVPECL, and LVDS. Editing any

parameter will automatically change the logic level to “CUST” (custom).
Xover Sets the data crossover point (percentage).
SJ1 Sets the sinusoidal jitter 1 frequency. The optional units are Hz and MHz. The

resolution is 1 Hz.
SJ1Amp2 Sets the sinusoidal jitter 1 amplitude relative to the output of the pattern

generator (which has double the amplitude range of SJ1 of the controller). The

optional units are mUI and UI (p-p). The resolution is 0.002 UI.

During the setting of SJ1 amplitude, if SJ1 and/or SJ2/RJ are enabled

simultaneously, keep the sum of all 3 components below the specified

maximum modulation level.

Operation

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

Label Name Description

SJ1Enable Enables/disables the sinusoidal jitter 1.

SJ1 cannot be enabled if PJ or external jitter (low band) is enabled. If the SJ1

enabled state conflicts with these other jitter sources, a message indicating a

conflict appears in the N4960A serial BERT controller display. Selecting Yes to

resolve the conflict will disable all conflicting jitter sources.
SJ21 Sets the sinusoidal jitter 2 frequency. The optional units are Hz and MHz. The

resolution is 1 Hz.
SJ2Amp

1,2

Sets the sinusoidal jitter 2 amplitude relative to the output of the pattern

generator (which has double the amplitude range of SJ2 of the controller). The

optional units are mUI and UI (p-p). The resolution is 0.002 UI.

During the setting of SJ1 amplitude, if SJ1 and/or SJ2/RJ are enabled

simultaneously, keep the sum of all 3 components below the specified

maximum modulation level.
SJ2Enable1 Enables/disables the sinusoidal jitter 2.

SJ2 cannot be enabled if PJ or external jitter (low band) is enabled. If the SJ2

enabled state conflicts with these other jitter sources, a message indicating a

conflict appears in the N4960A-CJ1 controller display. Selecting Yes to resolve

the conflict will disable all conflicting jitter sources.
PJ Sets the periodic jitter frequency. The optional units are Hz and MHz. The

resolution is 1 Hz.

The maximum PJ amplitude is a function of PJ frequency. If the PJ frequency

conflicts with the current PJ amplitude, a message indicating a conflict appears

in the N4960A serial BERT controller display. Selecting Yes to resolve the

conflict will set PJ amplitude to an appropriate value.
PJAmp Sets the periodic jitter amplitude relative to the output of the pattern generator

(which has double the amplitude range of PJ of the controller). The optional

units are mUI and UI (p-p). The resolution is 0.002 UI. The maximum PJ

amplitude is a function of PJ frequency.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 77

Label Name Description

PJEnable Enables/disables the periodic jitter on the pattern generator connected to the

Jitter connector only.

Periodic Jitter cannot be enabled if any other internal or external jitter source is

enabled. If the PJ enabled state conflicts with other jitter sources, a message

indicating a conflict appears in the N4960A serial BERT controller display.

Selecting Yes to resolve the conflict will disable all other jitter sources.
RJAmp1 Sets the random jitter amplitude in RMS relative to the output of the pattern

generator (which has double the amplitude range of RJ of the controller). The

optional units are mUI-rms and UI-rms. The resolution is 2 mUI-rms.

When used in combination with other high frequency band stresses (SJ1, SJ2,

and external high band jitter), the sum of all jitter source amplitudes should not

exceed the maximum specified modulation level.
RJEnable1 Enables/disables the random jitter output.

RJ cannot be enabled if PJ or external jitter (low band) is enabled. If the RJ

enabled state conflicts with these other jitter sources, a message indicating a

conflict appears in the N4960A-CJ1 controller display. Selecting Yes to resolve

the conflict will disable all conflicting jitter sources.
ExtJit Selects the external jitter input path.

High band external jitter can be enabled in combination with SJ1, SJ2, and RJ.

Low band external jitter cannot be enabled if any other jitter source is enabled.

If the low band external jitter enabled state conflicts with other jitter sources, a

message indicating a conflict appears in the N4960A serial BERT controller

display. Selecting Yes to resolve the conflict will disable all other jitter sources.
LB Gain Sets the gain of the external low band gain. The optional units are mUI/V or

UI/V.

Operation

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

Label Name Description

Pattern Menu

Pat Displays the current pattern name (read only). Use the Pat Type and Name

menu items to select the desired pattern.
Pat Type Sets the type for the list of selectable patterns under “Name”. Available types

are PRBS, Factory, and User.
Name Sets the pattern name from the list of patterns filtered by Pat Type.
Pat Invert Inverts all patterns.
ErRateInjEna Enables/disables error injection.
ErrInjRate Sets the error injection rates from 1E-3 to 1E-9.
ErrInjSingle Injects a single error each time the EXEC softkey is pressed.

Deemphasis3

Pre Adjusts the impulse response sample of the bit before the cursor bit.
Post1 Adjusts the impulse response sample of the first bit after the cursor bit.
Post2 Adjust the impulse response sample of the bit that is two bits after the cursor

bit.
Post3 Adjust the impulse response sample of the bit that is three bits after the cursor

bit.

1

Feature available in N4960A-CJ1 for pattern generator connected to Jitter connector only.

2

Note that the sum of SJ1, SJ2, RJ, and external jitter low deviation amplitude should not exceed the maximum

specified modulation level. However, the system only checks SJ1 and SJ2.

3

Feature available in pattern generator with de-emphasis only.

Sinusoidal 1 jitter, Sinusoidal 2 jitter, random jitter, and external jitter high
frequency band (low deviation) can be enabled simultaneously. However, when
used in combination, make sure that the sum of these paths does not exceed
the specified maximum modulation level. In addition, periodic jitter or external
low band jitter cannot be enabled if any of the other jitter paths are enabled.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 79

Table 19

ted by the current termination voltage. If the desired offset

Refer to

for the Pat Gen-Dly menu descriptions for a pattern

generator connected to the Delay (Channel 1) connector.

Table 19. Pat Gen-Dly menu descriptions

Label Name Description

Data Output Menu

Enable Enables/disables the pattern generator output.
DRate Displays the pattern generator data rate. DRate is not settable.
Amp Sets the pattern generator output amplitude. Resolution is 0.005 V.
Offs Sets the DC offset of the data eye presented at the data outputs of the pattern

generator. The maximum range is a function of the termination voltage setting.
The optional units are mV and V. The resolution is 0.005 V.

The offset may be limi
value conflicts with the current termination value, a message indicating a
conflict appears in the N4960A serial BERT controller display. Selecting Yes to
resolve the conflict will set the termination to an appropriate value.

Term Sets the DC output offset of the data eye to support a specified termination

voltage of a DUT having a 50 Ω input port. The maximum range is a function of

the offset setting. The optional units are mV and V. The resolution is 0.001 V.

The termination may be limited by the current offset voltage. If the termination
value conflicts with the offset value, a message indicating a conflict appears in
the N4960A serial BERT controller display. Selecting Yes to resolve the conflict
will set the offset to an appropriate value.

Logic Sets the data logic level. The levels are ECL, LVPECL, and LVDS. Editing any

parameter will automatically change the logic level to “CUST” (custom).

Xover Sets the data crossover point (percentage).

Delay Adjust

Delay This sets the amount the clock must be shifted when aligning the pattern

generator connected to the Delay connector on the front panel of the N4960A.
Resolution is 0.002 UI.

Pattern Menu

Pat Displays the current pattern name (read only). Use the Pat Type and Name menu

items to select the desired pattern.

Pat Type Sets the type for the list of selectable patterns under “Name”. Available types

are PRBS, Factory, and User.
Name Sets the pattern name from the list of patterns filtered by Pat Type.
Pat Invert Inverts all patterns.
ErRateInjEna Enables/disables error injection.
ErrInjRate Sets the error injection rates from 1E-3 to 1E-9.

Operation

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

Table 20

be centered in the received eye for best performance using the auto alignment

Label Name Description

ErrInjSingle Injects a single error each time the EXEC softkey is pressed.

Deemphasis1

Pre Adjusts the impulse response sample of the bit before the cursor bit.
Post1 Adjusts the impulse response sample of the first bit after the cursor bit.
Post2 Adjust the impulse response sample of the bit that is two bits after the cursor

bit.
Post3 Adjust the impulse response sample of the bit that is three bits after the cursor

bit.

1

Feature available in pattern generator with de-emphasis only.

Refer to

for the Error Det menu descriptions.

Table 20. Error Det menu descriptions

Label Name Description

iBER Displays the instantaneous bit error rate. The iBER is updated at a constant

rate, regardless of whether an accumulated BER test is running.

Input Adjust

SmplV Sets the sampling voltage that the error detector uses to sample the incoming

data. If Set SmplV is on, this value will be updated to the optimal value found
during an auto alignment. Resolution is 0.001 V.

Delay Sets the sampling delay. This sets the amount the clock must be shifted to

sample the incoming data to the error detector. In most cases, this value will

feature. If Autoalign parameter - Set Delay is on, this value will be updated to
the optimal value found during an auto alignment. Resolution is 0.002 UI.

TermV Sets the input termination voltage applied to the inputs of the error detector.

Resolution is 0.001 V.

DRate Displays the current data rate.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 81

Label Name Description

Pattern Menu

Auto Pattern Enables/disables the detected pattern selection feature. This feature detects

and syncs to PRBS patterns only. When enabled, Pat Type is set to PRBS and
cannot be changed.

Pat Displays the current pattern name (read only). Use the Pat Type and Name

menu items to select the desired pattern.

Pat Type Sets the filter for the list of selectable patterns under “Name”. Available filters

are PRBS, Factory, and User. If Auto Pattern is enabled and it cannot

determine the pattern type, the message “Unknown” is displayed.
Name Sets the pattern name from the list of patterns filtered by Pat Type.
Pat Invert Inverts all patterns. Cannot be changed when Auto Pattern is ON.

Sync Menu

Sync Now Executes a synchronization to synchronize to the incoming data stream

regardless of the setting for Sync Mode.
Sync Type Displays the synchronization type (Normal).
Sync Mode Specifies whether the error detector will attempt to automatically synchronize

(Auto) to the incoming data stream or will synchronize only when the Sync

Now command is executed (Manual).
Sync Loss /

Displays whether the system is synchronized or has lost synchronization.
Synchronized

BER Thrshld Sets the synchronization threshold to trigger a synchronization attempt. When

the Sync Mode is set to Auto and the BER rises above this threshold, the error

detector will attempt to synchronize to the incoming data stream

automatically. Range is 1E-2 to 1E-9.

AutoAlign Menu

Perform AutoAlign Executes an auto alignment to adjust to the optimal sampling and delay

voltage.
Config AutoAlign Set SmplV: enables/disables auto sample voltage alignment.

SmplV Step: sets the sampling threshold voltage step size used during an

auto alignment to determine the optimal voltage.

Set Delay: enables/disables auto delay alignment.

Dly Step: sets the sampling delay step size used during an auto alignment to

determine the optimal sampling delay.
AutoAlign Results Eye Height: returns the eye height found during auto alignment.

Eye Width: returns the eye width found during auto alignment.

Last AutoAlign: returns the date and time of the last auto alignment.

Operation

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

Label Name Description

Accumulation Menu

Start Accum Executes an accumulated BER test.
Stop Manual: sets the accumulated BER test to run indefinitely (max 9999999.9

Config Stop Menu Dur: sets the duration of the accumulated BER test in seconds when Duration

seconds ~ 115 days) and is stopped by the user selecting the Stop softkey.

Duration: sets the accumulated BER test to run for the duration specified

using the Dur setting.

Bits: sets the accumulated BER test to run until the number of bits is reached,

as specified using the Bit command.

Errors: sets the accumulated BER test to run until the number of errors is

reached, as specified using the Err command.

is selected as the Stop criteria. Maximum is 9999999.9 seconds.

Bit: sets the number of bits to accumulate when Bits is selected as the Stop

criteria. Range is 1E8 to 1E17 bits.

Err: sets the number of errors to accumulate when Errors is selected as the

Stop criteria. Range is 1 to 99999999 errors.
Results aBER: displays the accumulated bit error rate. Selecting the LARGE softkey

displays the accumulated BER is a large font.

Clear: clears the current results after accumulation is stopped.

Errs: displays the number of errored bits.

Errored 1: displays the number of logic 1 errors.

Errored 0: displays the number of logic 0 errors.

Elapsed Time: displays the elapsed time of the BER test.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 83

Table 21

3.21 Working with Setting Dependencies

Table 22

Refer to

for the System menu descriptions.

Table 21. System menu descriptions

Label Name Description

Event Log Accesses the list of error messages. The Attention LED indicator on the front

panel is lit when an error occurs and added to the Error Log.

Save / Recall Stores the current instrument state into a buffer (1-5), which can then be

recalled.
GPIB Address Sets the GPIB Address from 0 to 30.
Real Time Clock Sets the instrument time and date.
Instrument Info Accesses the instrument serial number and firmware version information.
UI Info Accesses the user interface hardware version and build information.
Controller Info Accesses the controller hardware version and build information.
Jit Head Info Accesses the serial number, hardware version, and firmware version

information of a pattern generator head that is connected to the Jitter port.
Dly Head Info Accesses the serial number, hardware version, and firmware version

information of a pattern generator or error detector head that is connected to

the Delay port.

The N4960A serial BERT 17 and 32 Gb/s has a number of settings which
have a dependency on another setting, noted in the tables above in
italic text.

between multiple settings is detected, the N4960A serial BERT
controller front panel gives the user the opportunity to clear the
conflicts in order to proceed with the desired setting.

Settings Dependency

Clock Source and SSC Enable SSC cannot be enabled if the clock source is set to external and

Offset, Termination (all clock
outputs)

contains a summary of all dependent settings. When a conflict

Table 22. Summary of dependent settings

vice versa.
On all clock outputs, the range of the offset voltage is defined by

the current termination voltage and vice versa. See Figure 39.

Offset, Termination, and
Coupling (all clock outputs)

On all clock outputs, the coupling must be set to DC in order for the
offset and termination voltage to be set to a non-zero value.

PJ vs. all other jitter sources PJ cannot be enabled if any other jitter source is enabled and vice

Operation

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

Settings Dependency

versa.

PJ amplitude vs. PJ frequency The PJ amplitude range is a function of PJ frequency. The system

will resolve conflicts in the PJ amplitude when the PJ frequency is
adjusted. However it will simply limit the PJ amplitude range
according to the current PJ frequency.

External jitter low band vs. all
other jitter sources

External jitter low band cannot be enabled if any other jitter source
is enabled and vice versa.

SJ1, SJ2, RJ, external jitter
high band

These high frequency band jitters can all be enabled at the same
time, however, the sum of their amplitudes must be kept below the
specified maximum modulation level.

Figure 39. Relationship between offset and termination voltage of the clock outputs

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 85

3.22 Verifying Operation

3.22.1

Initial Hardware Setup – Controller and Pattern Generator

Figure 40

The following procedures will familiarize you with the features of the
N4960A Serial BERT 17 and 32 Gb/s and provide a quick check of
system operation. The procedures all assume starting from a power up
preset state. In all cases where the preset value of the setting parameter
can be used, no steps are included to set the value.

1. Connect the equipment as shown in

2. Tighten cables to 8 lbf-in (90 N-cm).

.

Figure 40. Setup for checking jitter

Operation

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

3.22.2

Initial Settings

For purposes of this example setup, an Keysight 86100C Infiniium DCA-J was

Trigger Setup

Timebase Setup

MAIN

MAIN

Synthesizer

Menu

SEL

Synthesizer Menu

Frq

EDIT

8

GHz

Refer to 3.20.2 Changing Parameters for instructions on how to use the rotary

1. Set up the high speed sampling scope as follows:

used. High-speed sampling scope setup option names may differ between
models. Signal path delays will be affected by cable lengths. It may be
necessary to adjust the scope delay values to center the waveform for proper
viewing.

Set the high speed sampling scope to Eye/Mask mode

Trigger Level: 0 V
Slope: Rising Edge
Trigger Bandwidth: Standard (DC-3.2 GHz)

Scale: 20 ps/div
Reference: center

Channel 2 Setup (data)
Attenuation: 10 dB (10 dB attenuator placed at the
input)
Bandwidth: set to maximum
Display: On
Scale: 100 mV/Div
Offset: 0.0 V
Units: Volt

2. Turn the N4960A serial BERT controller on and wait until the

menu appears on the display.

3. In the

menu position the arrow next to the

label then press the softkey corresponding to the

label.

4. In the

5. Enter

position the arrow next to the

then press the softkey corresponding to the

on the numeric keypad then press the softkey

corresponding to the

label to set the frequency to 8 GHz.

label.

label

knob or numeric keypad to make changes.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 87

BACK

MAIN

MAIN

Pat Gen-Jit

Menu

SEL

Pat Gen-Jit Menu

Data
Output Menu
SEL

Data Output Menu

Enable

EDIT

Enable

ON.

Figure 41

3.22.3

Enabling Sinusoidal Jitter

Data Output Menu

SJ1

EDIT

200

MHz

Data Output Menu

SJ1Amp

EDIT

0.200
UI

Data Output Menu
SJ1Enable
EDIT

6. Press the softkey corresponding to the

menu appears.

7. In the

menu position the arrow next to the

label then press the softkey corresponding to the

label.

8. In the

9. In the

label.

position the arrow next to the

label then press the softkey corresponding to the

position the arrow next to the

label then press the softkey corresponding to the

10. Use the rotary knob to set

should now be displayed on the high speed sampling scope
similar to the one shown in

to

label until the

A “clean” eye pattern

.

label.

Figure 41. “Clean” eye pattern example

1. In the

label then press the softkey corresponding to the

2. Enter

corresponding to the

3. In the

label then press the softkey corresponding to the

4. Enter

corresponding to the
UI.

5. In the

on the numeric keypad then press the softkey

on the numeric keypad then press the softkey

position the arrow next to the

label to set the SJ1 level to 200 MHz.

position the arrow next to the

label to set the SJ1 modulation to 0.2

position the arrow next to the

label then press the softkey corresponding to the

label.

label.

label.

Operation

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

SJ1Enable

SEL

Data Output Menu

Figure 42

Data Output Menu
SJ1Enable
EDIT

SJ1Enable

OFF

SEL

Data Output Menu

3.22.4

Enabling Random Jitter (N4960A-CJ1 controller only)

Data Output Menu

RJAmp

EDIT

050

mUI-rms

Data Output Menu

RJEnable

EDIT

RJEnable

SEL

Data Output Menu

Figure 43

6. Use the rotary knob to set

7. Press the softkey corresponding to the

entry and return to the
should now be displayed on the high speed sampling scope
similar to the one shown in

Figure 42. Jittered eye pattern example

to ON.

label to accept the

. A jittered eye pattern

.

8. In the

9. Use the rotary knob to set

label then press the softkey corresponding to the

label.

position the arrow next to the

10. Press the softkey corresponding to the

entry and return to the

1. In the

position the arrow next to the

label then press the softkey corresponding to the

2. Enter

on the numeric keypad then press the softkey

corresponding to the

label to set the RJ amplitude to

50 mUI-rms.

3. In the

label then press the softkey corresponding to the

position the arrow next to the

label.

4. Use the rotary knob to set

5. Press the softkey corresponding to the

entry and return to the
pattern should now be displayed on the high speed sampling
scope similar to the one shown in

to

to ON.

.

label to accept the

.

label.

label to accept the

. A random jittered eye

.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 89

Data Output Menu

RJEnable

EDIT

RJEnable

OFF

SEL

Data Output Menu.

BACK

MAIN

3.22.5

Enabling Spread Spectrum Clock (N4960A-CJ1 controller only)

MAIN

Synthesizer

Menu

SEL

Synthesizer Menu

EDIT

4500

PPM

Synthesizer Menu
SSCEnable
EDIT

SSCEnable

SEL

Synthesizer Menu

Figure 44

Figure 43. Random jittered eye pattern example

6. In the

label then press the softkey corresponding to the

position the arrow next to the

label.

7. Use the rotary knob to set

8. Press the softkey corresponding to the

entry and return to the

9. Press the softkey corresponding to the

the

menu.

to

1. In the

menu position the arrow next to the

label then press the softkey corresponding to the

label.

2. In the

position the arrow next to the SSCDev

label then press the softkey corresponding to the

3. Enter

on the numeric keypad then press the softkey

corresponding to the

label to set the spread spectrum to

4500 ppm.

4. In the

5. Use the rotary knob to set

6. Press the softkey corresponding to the

label.

label then press the softkey corresponding to the

entry and return to the
the one shown in

position the arrow next to the

to ON.

. A waveform similar to

should now be displayed on the high

speed sampling scope.

.

label to accept the

label to return to

label.

label to accept the

Operation

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

Synthesizer Menu
SSCEnable
EDIT

SSCEnable

OFF

SEL

MAIN

3.22.6

Bit Error Rate Test

Figure 45

Figure 44. Spread spectrum clock waveform example

7. In the

8. Use the rotary knob to set

9. Press the softkey corresponding to the

label.

label then press the softkey corresponding to the

entry and return to the

position the arrow next to the

menu. Note the waveform

to

.

label to accept the

displayed on the oscilloscope again shows a clean eye pattern.

1. Connect the equipment as shown in

.

2. Tighten cables to 8 lbf-in (90 N-cm).

Figure 45. Setup for BER test

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 91

3.22.2 Initial Settings

MAIN

Err Det Menu

SEL

Err Det Menu

AutoAlign

Menu

SEL

Perform AutoAlign

EXEC

Errors, Data Loss,

Sync Loss

BACK

Err Det Menu

Err Det Menu

Accumulation

Menu

SEL

Stop

EDIT

Stop

Duration

EXIT

Config Stop Menu

SEL

Dur

EDIT

60

SEC

BACK

Accumulation Menu

Start Accum

START

Run

Results

SEL

Errs

0.000e0

3. Ensure that the pattern generator output is enabled. Refer to

for the procedure to enable the pattern

generator output.

4. In the

5. In the

menu position the arrow next to the

label then press the softkey corresponding to the

label then press the softkey corresponding to the

position the arrow next to the

label.

label.

6. Position the arrow next to the

press the softkey corresponding to the

label. A small clock

label then

appears in the display. When the clock disappears, ensure that
the

and

LEDs on the front panel of

the error detector are off.

7. Press the softkey corresponding to the

the

8. In the

label then press the softkey corresponding to the

.

position the arrow next to the

label to return to

label.

9. Position the arrow next to the

corresponding to the

10. Use the rotary knob to set the

11. Press the softkey corresponding to the

label.

label then press the softkey

criteria to

.

label to accept the

entry.

12. Position the arrow next to the

the softkey corresponding to the

13. Position the arrow next to the

corresponding to the

14. Enter

on the numeric keypad then press the softkey

corresponding to the

label.

label then press the softkey

label then press

label.

label to set the duration to 60

seconds.

15. Press the softkey corresponding to the

the

16. Position the arrow next to the

softkey corresponding to the

.

label to return to

label then press the

label. The

LED on the

front panel of the error detector should be lit.

17. When the bit error rate test has completed, position the arrow

next to the
the

18. Ensure that

label.

label then press the softkey corresponding to

reads

.

Operation

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

3.23 Setting Frequency and Output Amplitude

MAIN MENU

Synthesizer

Menu

SEL

Synthesizer Menu

EDIT

Refer to 3.20.2 Changing Parameters for instructions on how to use the rotary

EXIT

The following procedure shows how to set the frequency and clock
output amplitude of the N4960A serial BERT controller. The settings are
output to either the Jitter or Delay clock connectors on the front panel
of the N4960A serial BERT controller.

1. In the

2. In the

3. Adjust the synthesizer frequency using the rotary knob or the

label then press the softkey corresponding to the

position the arrow next to the

label.

position the arrow next to the Frq label

then press the softkey corresponding to the

numeric keypad.

label.

knob or numeric keypad to make changes.

4. Press the softkey corresponding to the EXIT label to accept the

5. Determine which clock output will be used. Either the Jitter or

6. In the MAIN MENU position the arrow next to the Jit Clk Out

7. In the Jit Clk Out Menu or the Dly Clk Out Menu position the

8. Adjust the output amplitude using the rotary knob or the

9. Press the softkey corresponding to the

entry and return to the MAIN MENU.

Delay output can be used as a "clean" (non-jittered or non­delayed) output provided that the corresponding jitter enable
function is set to OFF and the delay is set to 0.

Menu (if using the Jitter clock output) or the Dly Clk Out Menu
label (if using the Delay clock output) then press the softkey
corresponding to the SEL label.

arrow next to the Amp label then press the softkey
corresponding to the EDIT label.

numeric keypad.

label to accept the

entry.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 93

3.24 Setting Random Jitter Injection (N4960A-CJ1 controller only)

MAIN MENU

Jit Clk Out

Menu

SEL

Jit Clk Out Menu

EDIT

Refer to 3.20.2 Changing Parameters for instructions on how to use the rotary

EXIT

RJEnabl

EDIT

RJEnabl

SEL

MAIN MENU

3.25 Setting Sinusoidal Jitter Injection

Jit Clk Out Menu

SJ1

EDIT

SJ1Amp

EDIT

SJ1Enabl

EDIT

The following procedure shows how to enable and set the random jitter
modulation. The settings are output to the Jitter clock connector on the
front panel of the N4960A-CJ1 controller and to a pattern generator
connected to the Jitter port.

1. In the

2. In the

3. Adjust the jittered clock output amplitude using the rotary knob

label then press the softkey corresponding to the

label.

then press the softkey corresponding to the

or the numeric keypad.

position the arrow next to the

position the arrow next to the Amp label

label.

knob or numeric keypad to make changes.

4. Press the softkey corresponding to the

entry.

5. Adjust the random jitter modulation using the rotary knob or the

numeric keypad.

6. Position the arrow next to the

softkey corresponding to the

7. Use the rotary knob to set

8. Press the softkey corresponding to the

entry and return to the

The following procedure shows how to set up a single sinusoidal jitter
path. The settings are output to the Jitter clock connector on the front
panel of the N4960A serial BERT controller and to a pattern generator
connected to the Jitter port.

1. In the

2. Adjust the SJ1 frequency using the numeric keypad.

3. Position the arrow next to the

4. Adjust the SJ1 modulation using the rotary knob or the numeric

5. Position the arrow next to the

then press the softkey corresponding to the

softkey corresponding to the

keypad.

softkey corresponding to the

label to accept the

position the arrow next to the

label then press the

label.

to ON.

label to accept the

.

label then press the

label.

label then press the

label.

label.

label

Operation

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

SJ1Enabl

SEL

MAIN MENU

3.26 Setting External Jitter High Frequency Injection

MAIN MENU

Jit Clk Out

Menu

SEL

Jit Clk Out Menu

ExtJit

EDIT

ExtJit

High Band

SEL

Jit Clk Out Menu

When the high frequency jitter path is enabled, there may be a phase shift in the
jittered clock and the pattern generator output. This shift only occurs when SJ1,

3.27 Setting Delay Clock Output

MAIN MENU

Dly Clk Out

Menu

SEL

Dly Clk Out Menu

OutEnabl

EDIT

OutEnabl

SEL

Dly Clk Out Menu

EDIT

6. Use the rotary knob to set

7. Press the softkey corresponding to the

entry and return to the

to ON.

.

The following procedure shows how to set up the external high
frequency (low deviation) jitter path. This procedure requires an external
jitter source be connected to the Ext Jitter In connector on the rear
panel of the N4960A serial BERT controller.

1. In the

2. In the

3. Use the rotary knob to set

4. Press the softkey corresponding to the

label then press the softkey corresponding to the

label.

label then press the softkey corresponding to the

entry and return to the

position the arrow next to the

position the arrow next to the

to

.

label to accept the

label.

.

label to accept the

SJ2, RJ, or ExtHiBand is enabled/disabled. It does not occur when the jitter
amplitude or frequency is changed.

The following procedure shows how to set up the delay clock output.
The settings are output to the Delay clock connector on the front panel
of the N4960A serial BERT controller.

1. In the

2. In the

3. Use the rotary knob to set

4. In the

5. Adjust the delayed clock output amplitude using the rotary knob

label then press the softkey corresponding to the

label.

label then press the softkey corresponding to the

softkey corresponding to the

then press the softkey corresponding to the

or the numeric keypad.

position the arrow next to the

position the arrow next to the

position the arrow next to the Amp label

to ON then press the

label to accept the entry.

label.

label.

Operation

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 95

Refer to 3.20.2 Changing Parameters for instructions on how to use the rotary

EXIT

3.28 Setting Divided Clock Output

MAIN MENU

Div Clk Out

Menu

SEL

Div Clk Out Menu

OutEnabl

EDIT

OutEnabl

SEL

Div Clk Out Menu

EDIT

EXIT

knob or numeric keypad to make changes.

6. Press the softkey corresponding to the

entry.

The following procedure shows how to set up the divided clock output.
The output is taken from the Divided clock output connector on the
front panel of the N4960A serial BERT controller.

1. In the

2. In the

3. Use the rotary knob to set

4. In the

5. Adjust the divided clock output amplitude using the rotary knob

label then press the softkey corresponding to the

label.

label then press the softkey corresponding to the

softkey corresponding to the

then press the softkey corresponding to the

or the numeric keypad.

label to accept the

position the arrow next to the

position the arrow next to the

to ON then press the

label to accept the entry.

position the arrow next to the Amp label

label.

label.

Refer to 3.20.2 Changing Parameters for instructions on how to use the rotary
knob or numeric keypad to make changes.

6. Press the softkey corresponding to the

entry.

label to accept the

Operation

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

3.29 Event/Error Log

Table 23

Table 24

Refer to

and

for the list of message origins and values

found in the event/error Log.

When an event/error is received, the Attention LED will illuminate.

Each event log entry contains the following information:

• Log Number: 1 to n, with 1 being the most recent error and ‘n’

being the oldest error.

• Message Origin: Identifies the sub-system which produced the

error.

• Message Value: The error.

• Datestamp: Date of error receipt (mm/dd/yy).

• Timestamp: Time of error receipt (hh/mm/ss).

Table 23. Message origin

Message Origin Description

IPC IPC protocol related codes
FREQ Frequency control
PHASE Phase control
REF 10 MHz reference clock

Table 24. Message values

Message Values Description

OK Status good, no errors
UNK Status unknown
ERR Misc. error
LOS Loss of signal/phase slip
OOR Value out of range
TIMEOUT Command or operation took too long. See Section 6.17.4.
AMPL_LIMIT_WARN Amplitude limited, non-fatal (warning), used for PJ amplitude

adjustment during SCPI PJ frequency setting. See Section 6.10.1.

INTERNAL Used to indicate the 10MHz reference clock is set to Internal
EXTERNAL Used to indicate the 10MHz reference clock is set to External

Applications

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 97

4 Applications

4.1 Introduction

Jitter connector

Delay

Divided

The N4960A serial BERT 17 and 32 Gb/s performs basic BER and jitter
tolerance testing or general receiver characterization applications.

In a general BERT application, the outputs would be configured as
follows:

applied for jitter tolerance testing or other receiver characterization
testing.

connector is used to clock the error detector. The delay feature
enables the detector to synchronize with the pattern, and align to
sample at the center of the eye (optimum decision point).

oscilloscope. Most sampling scopes have maximum trigger rates which
are substantially lower than the bandwidth of the sampler. When used
in high data rate applications, the data clock must be divided down to a
ratio within the maximum trigger rate. In addition, by setting the divider
ratio to the exact pattern length, the output will be locked to the
pattern. Using this signal to trigger the sampling scope allows the user
to view and measure the actual bit stream, rather than presenting an
“eye” of overlaid bits.

The divided output can also be used where a sub rate clock is required.

Output can provide a sub rate of the clock to trigger a sampling

is used to drive the pattern generator. Stress can be

Applications

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

4.2 Testing Transceivers Used in Fibre Channel Networks

MAIN

MAIN

Synthesizer

Menu

SEL

Synthesizer Menu

Frq

EDIT

GHz

BACK

MAIN

MAIN

Pat Gen Menu

SEL

Pattern Gen Menu

Data
Output Menu
SEL

Data Output Menu

Enable

EDIT

Enable

EXIT

Data Output Menu

BACK

Pattern Gen Menu

Pattern Gen Menu

Pattern
Menu

SEL

There are three topologies in this type of network including point-to­point, arbitrated loop, and switched fabric. The connections between
devices use transceivers for optimization. For example, in a switched

fabric topology, SFP+ (8GFC and 16GFC), XFP (10 Gb/s) and SFP (≤ 4

Gb/s) are types of transceivers that connect between the switched
fabric and various devices such as storage and computing equipment.
Typical patterns used to test transceiver devices include PRBS series,
JSPAT, and K28 series which are part of the preloaded library of
patterns in the N4960A 32G BERT.

For 16GFC applications (14.025 Gb/s), the N4960A can perform BER
measurements and can provide a stressed pattern generator signal for
receiver tests. The N4960A, used with the N4980A multi-instrument
BERT software, can also provide jitter tolerance tests for accurate
characterization.

1. Turn the N4960A serial BERT controller on and wait until the

menu appears on the display.

2. In the

menu position the arrow next to the

label then press the softkey corresponding to the

label.

3. In the

position the arrow next to the

then press the softkey corresponding to the

label.

4. Enter the frequency using the numeric keypad then press the

softkey corresponding to the

label. The data rate is double
the synthesizer frequency and is based on the type of transceiver
being tested.

5. Press the softkey corresponding to the

menu appears.

6. In the

menu position the arrow next to the

label then press the softkey corresponding to the

7. In the

8. In the

label.

position the arrow next to the

label then press the softkey corresponding to the

position the arrow next to the

label then press the softkey corresponding to the

9. Use the rotary knob to set

10. Press the softkey corresponding to the

entry and return to the

11. Press the softkey corresponding to the

the

12. In the

label then press the softkey corresponding to the

.

position the arrow next to the

to ON.

label until the

label to accept the

.

label to return to

label.

label

label.

label.

Applications

Keysight N4960A Serial BERT 17 and 32 Gb/s User Guide 99

Name

SEL

BACK

MAIN

MAIN

Err Det Menu

SEL

Err Det Menu

AutoAlign

Menu

SEL

Perform AutoAlign

EXEC

Errors

Data Loss

BACK

Err Det Menu

Err Det Menu

Accumulation

Menu

SEL

Start Accum

START

Run

STOP

Results

SEL

aBER

Errs

Errored 1

Errored 0

Elapsed Time

13. Position the arrow next to the

corresponding to the

Label.

label then press the softkey

14. Select the pattern based on the type of transceiver being tested.

15. Press the softkey corresponding to the

menu appears.

16. In the

menu position the arrow next to the

label then press the softkey corresponding to the

17. In the

label then press the softkey corresponding to the

position the arrow next to the

label until the

label.

label.

18. Position the arrow next to the

press the softkey corresponding to the

label. A small clock

label then

appears in the display. When the clock disappears, ensure that
the

and

LEDs on the front panel of the error

detector are off.

19. Press the softkey corresponding to the

the

20. In the

label then press the softkey corresponding to the

.

position the arrow next to the

label to return to

label.

21. Position the arrow next to the

softkey corresponding to the

label. The

label then press the

LED on the

front panel of the error detector should be lit.

22. To stop the BER measurement, press the softkey corresponding

to the

23. Position the arrow next to the

softkey corresponding to the

24. View accumulated BER (

(
(

label.

), zero errors (

).

), total errors (

label then press the

label.

), one errors

), and measurement time

Applications

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