Page 1
Keysight U2701A/U2702A
USB Modular Oscilloscopes
User’s Guide
Page 2
Page 3
Page 4
Notices
CAUTION
WARNING
Copyright Notice
© Keysight Technologies 2009 - 2017
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 as governed by
United States and international
copyright laws.
Trademarks
Pentium is a U.S. registered trademark
of Intel Corporation.
Microsoft, Visual Studio, Windows, and
MS Windows are trademarks of
Microsoft Corporation in the United
States and/or other countries.
Manual Part Number
U2702-90013
Edition
Edition 10, June 1, 2017
Printed in:
Printed in Malaysia
Published by:
Keysight Technologies
Bayan Lepas Free Industrial Zone,
11900 Penang, Malaysia
Technology Licenses
The hard ware 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.
Declaration of Conformity
Declarations of Conformity for this
product and for other Keysight
products may be downloaded from the
Web. Go to http://www.keysight.com/
go/conformity. You can then search by
product number to find the latest
Declaration of Conformity.
U.S. Government Rights
The Software is “commercial computer
software,” as defined by Federal
Acquisition Regulation (“FAR”) 2.101.
Pursuant to FAR 12.212 and 27.405-3
and Department of Defense FAR
Supplement (“DFARS”) 227.7202, the
U.S. government acquires commercial
computer software under the same
terms by which the software is
customarily provided to the public.
Accordingly, Keysight provides the
Software to U.S. government
customers under its standard
commercial license, which is embodied
in its End User License Agreement
(EULA), a copy of which can be found
at http://www.keysight.com/find/
sweula. The license set forth in the
EULA represents the exclusive authority
by which the U.S. government may use,
modify, distribute, or disclose the
Software. The EULA and the license set
forth therein, does not require or
permit, among other things, that
Keysight: (1) Furnish technical
information related to commercial
computer software or commercial
computer software documentation that
is not customarily provided to the
public; or (2) Relinquish to, or
otherwise provide, the government
rights in excess of these rights
customarily provided to the public to
use, modify, reproduce, release,
perform, display, or disclose
commercial computer software or
commercial computer software
documentation. No additional
government requirements beyond
those set forth in the EULA shall apply,
except to the extent that those terms,
rights, or licenses are explicitly required
from all providers of commercial
computer software pursuant to the FAR
and the DFARS and are set forth
specifically in writing elsewhere in the
EULA. Keysight shall be under no
obligation to update, revise or
otherwise modify the Software. With
respect to any technical data as
defined by FAR 2.101, pursuant to FAR
12.211 and 27.404.2 and DFARS
227.7102, the U.S. government
acquires no greater than Limited Rights
as defined in FAR 27.401 or DFAR
227.7103-5 (c), as applicable in any
technical data.
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 OF 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 SHALL
CONTROL.
Safety Information
A CAUTION notice denotes a hazard. It
calls attention to an operating
procedure, practice, or the like that, if
not correctly performed or adhered to,
could result in damage to the product
or loss of important data. Do not
proceed beyond a CAUTION notice
until the indicated conditions are fully
understood and met.
A WARNING notice denotes a hazard. It
calls attention to an operating
procedure, practice, or the like that, if
not correctly performed or adhered to,
could result in personal injury or death.
Do not proceed beyond a WARNING
notice until the indicated conditions are
fully understood and met.
4 Keysight U2701A/U2702A User’s Guide
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Safety Symbols
The following symbols on the instrument and in the documentation indicate
precautions which must be taken to maintain safe operation of the instrument.
Direct current (DC) Off (mains supply)
Alternating current (AC) On (mains supply)
Both direct and alternating current Caution, risk of electric shock
Three-phase alternating current
Earth (ground) terminal Caution, hot surface
Protective earth (ground) terminal Out position of a bi-stable push control
Caution, risk of danger (refer to this
manual for specific Warning or Caution
information)
Frame or chassis (ground) terminal In position of a bi-stable push control
Equipotentiality
Equipment protected throughout by
double insulation or reinforced
insulation
CAT I
Category I Overvoltage Protection
Keysight U2701A/U2702A User’s Guide 5
Page 6
General Safety Information
WARNING
CAUTION
The following general safety precautions must be observed during all phases of
operation, service and repair of this instrument. Failure to comply with these
precautions or with specific warnings elsewhere in this manual violates safety
standards of design, manufacturer and intended use of the instrument. Keysight
Technologies assumes no liability for the customer’s failure to comply with these
requirements.
– Observe all markings on the equipment before connecting any wiring to
the equipment.
– This equipment is under CAT1 measurement category, do not connect the
test probe to MAIN.
CAT1:
Maximum Working Voltage: 30 Vrms or 42 Vpeak or 60 Vdc
– Do not measure more than rated voltage (as marked on the equipment).
– Inspect the test probe for damaged insulation or expose metal and check
for continuity. Do not use test probe if found damaged.
– Do not operate the equipment in an explosive atmosphere or in the
presence of flammable gases or fumes.
– Do not use the equipment if it does not operate properly. Have the
equipment inspected by qualified service personal. If necessary, return
the equipment to Keysight for service and repair to ensure that safety
features are maintained.
– Always disconnect the probes from the measuring circuit before
disconnecting the adapter.
– Use the device with the cables provided.
– Repair or service that is not covered in this manual should only be
performed by qualified personnels.
– Applying excessive voltage or overloading the device will cause
irreversible damage to the circuitry.
6 Keysight U2701A/U2702A User’s Guide
Page 7
Environmental Conditions
CAUTION
This instrument is designed for indoor use and in an area with low condensation.
The table below shows the general environmental requirements for this
instrument.
Environmental condition Requirement
Operating Temperature 0 °C to 50 °C
Storage Temperature –20 °C to 70 °C
Operating Humidity 20 to 85% RH (non-condensing)
Storage Humidity 5 to 90% RH (non-condensing)
The Keysight U2701A/U2702A are safety-certified in compliance with the
following safety and EMC requirements:
– IEC 61010-1: 2001/EN 61010-1: 2001 (2nd edition)
– CAN/CSA-C22.2 No. 61010-1-04
– IEC 61326-2002/EN 61326: 1997+A1: 1998+A2: 2001+A3: 2003
– ICES-001: 2004
– AS/NZS CISPR11: 2004
– USA: ANSI/UL 61010-1:2004
Keysight U2701A/U2702A User’s Guide 7
Page 8
Regulatory Markings
The CE mark is a registered trademark
of the European Community. This CE
mark shows that the product complies
with all the relevant European Legal
Directives.
ICES/NMB-001 indicates that this ISM
device complies with the
Canadian ICES-001.
Cet appareil ISM est conforme a la
norme NMB-001 du Canada.
The CSA mark is a registered
trademark of the Canadian
Standards Association.
The RCM mark is a registered
trademark of the Australian
Communications and Media Authority.
This instrument complies with the
WEEE Directive (2002/96/EC) marking
requirement. This affixed product label
indicates that you must not discard
this electrical or electronic product in
domestic household waste.
8 Keysight U2701A/U2702A User’s Guide
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Waste Electrical and Electronic Equipment (WEEE) Directive 2002/ 96/EC
This instrument complies with the WEEE Directive (2002/96/EC) marking
requirement. This affixed product label indicates that you must not discard this
electrical or electronic product in domestic household waste.
Product category:
With reference to the equipment types in the WEEE directive Annex 1, this
instrument is classified as a “Monitoring and Control Instrument” product.
The affixed product label is as shown below.
Do not dispose in domestic household waste.
To return this unwanted instrument, contact your nearest Keysight Service Center,
or visit http://about.keysight.com/en/companyinfo/environment/takeback.shtml
for more information.
Sales and Technical Support
To contact Keysight for sales and technical support, refer to the support links on
the following Keysight websites:
– www.keysight.com/find/usbscope
(product-specific information and support, software and
documentation updates)
– www.keysight.com/find/assist
(worldwide contact information for repair and service)
Keysight U2701A/U2702A User’s Guide 9
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10 Keysight U2701A/U2702A User’s Guide
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Table of Contents
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
General Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Regulatory Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Waste Electrical and Electronic Equipment (WEEE) Directive
2002/96/EC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Product category: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Sales and Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
1 Getting Started
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Product Outlook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Product Dimension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Package Contents Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Installations and Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
L-Mount Kit Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Modular Products Chassis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Soft Front Panel and User Interface Descriptions . . . . . . . . . . . . . . . . .27
2 Scope Features and Functions
Analog Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Vertical Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Channel Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32
Horizontal Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
Horizontal Mode Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
Trigger Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Trigger Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Trigger Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Trigger Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
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Trigger Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Measurements and Cursors Controls . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Cursors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Measurements Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
FFT & Math Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Fast Fourier Transform Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
FFT Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Math Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Options Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
Acquisition Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Display Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
AutoScale and Run/Stop buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
AutoScale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Run/Stop Button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Pan and Zoom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
3Characteristics and Specifications
12 Keysight U2701A/U2702A User’s Guide
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List of Figures
Figure 1-1 55-pin backplane connector pin configuration . . . . . . 26
Figure 2-1 Soft front panel vertical system controls . . . . . . . . . . .30
Figure 2-2 The waveform before inversion . . . . . . . . . . . . . . . . . .33
Figure 2-3 The waveform after inversion . . . . . . . . . . . . . . . . . . . .34
Figure 2-4 Soft front panel horizontal system controls . . . . . . . .37
Figure 2-5 Soft front panel of the Trigger Controls . . . . . . . . . . . .41
Figure 2-6 Soft front panel of the Measurements & Cursors
Figure 2-7 Auto marker automatically marks the maximum value
Figure 2-8 Automatic measurements on the Measurements &
Figure 2-9 Measurements panel and Measurements Results
Figure 2-10 Soft front panel of the FFT & Math controls. . . . . . . . .60
Figure 2-11 FFT controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
Figure 2-12 Waveform obtained with Hanning window selected . .64
Figure 2-13 First Peak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
Figure 2-14 Next Peak . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
Figure 2-15 Acquired waveform using Subtract function . . . . . . . .69
Figure 2-16 Soft front panel of the Options Controls . . . . . . . . . . . 70
Figure 2-17 The waveform before interpolation . . . . . . . . . . . . . . .73
Figure 2-18 The waveform after interpolation . . . . . . . . . . . . . . . . .73
Figure 2-19 Zoom reference panel . . . . . . . . . . . . . . . . . . . . . . . . .77
Figure 2-20 Zoom In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Figure 2-21 Zoom Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
Figure 2-22 Panning a waveform . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
of the waveform when Maximum measurement is
selected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Cursors panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
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List of Tables
Table 1-1 Descriptions of the User Interface . . . . . . . . . . . . . . . .28
Table 2-1 Probe attenuation factors and its corresponding
settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Table 2-2 Edge Trigger menu . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Table 2-3 Pulse Width Trigger menu . . . . . . . . . . . . . . . . . . . . . .45
Table 2-4 TV Trigger Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Table 2-5 Line (or count for Generic) numbers per field for each
non-HDTV/EDTV video standard . . . . . . . . . . . . . .47
Table 2-6 List of Time Measurements and Voltage
Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Table 2-7 List of Time Measurements and Voltage
Measurements for FFT . . . . . . . . . . . . . . . . . . . . . .57
Table 2-8 Comparison between the four FFT windows . . . . . . . .62
Table 2-9 List of Acquisition Modes . . . . . . . . . . . . . . . . . . . . . . .71
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16 Keysight U2701A/U2702A User’s Guide
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Keysight U2701A/U2702A USB Modular Oscilloscopes
User’s Guide
1 Getting Started
Introduction 18
Product Overview 20
Package Contents Checklist 22
Installations and Configurations 23
L-Mount Kit Installation 24
Soft Front Panel and User Interface Descriptions 27
Chapter 1 provides an overview of the U2701A and U2702A USB modular
oscilloscopes, the product outlook, and product dimensions. This chapter also
includes information on checklist, system requirements, and installation of
hardware.
17
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1 Getting Started
Introduction
The Keysight U2701A/U2702A USB modular oscilloscopes are PC-based, dual
play, low cost and mobile digital troubleshooting tools for bench and field site
work. These two channels, 8-bit oscilloscopes come in 100 MHz and 200 MHz
models respectively. The dual play functionality allows user to use the
oscilloscope as standalone or modular unit that enhanced the applications
flexibility. The product is a great personal troubleshooting tool that allows R&D
personnel, manufacturing personnel and field engineers to analyze and
troubleshoot analog or digital circuit designs flawlessly.
The U2701A/U2702A also feature a large memory up to 32 Mpts and high
sampling rate up to 500 M/S/ch. This two features allowing a longer capture time,
as well as enabling more signals to be captured and analyzed in-depth. The
U2701A/U2702A are equipped with USB 2.0 high speed interface for easy setup
and hot swappable connectivity. On the other hand, the soft front panel offers a
simple interface for quick setup, configuration and measurement controls.
The U2701A/U2702A are compatible with a wide range of Application
Development Environment (ADE), such as Keysight VEE, Keysight T&M Toolkit, TM
Toolkits Patch, Microsoft Visual Studio, C/C++, .Net, Visual Basic 6.0, and
Labview. This will minimizes the time required by the developers as they can
directly program their work using IVI drivers.
18 Keysight U2701A/U2702A User’s Guide
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Getting Started 1
NOTE
Warm-up Procedures
Before performing any measurements, ensure that oscilloscope has gone through
the following warm-up procedures,
1 Connect the oscilloscope to the PC using a USB cable.
2 Power-up the oscilloscope.
3 Run the Keysight Measurement Manager.
4 Toggle channel 1 or channel 2 on.
5 Click on the Run button.
Test Considerations
For optimum performance, all procedures should comply with the following
recommendations,
– Ensure that the ambient temperature is stable.
– Ensure that the ambient relative humidity is less than 80%.
– Allow a 30 minutes warm-up period before calibration.
– Keep all the test connection cables as short as possible.
Under standalone use, users are only allowed to measure up to CAT1
30 Vrms maximum.
For high voltage measurement up to CAT1 300 Vrms, users must install
the L-mount kit on the U2701A/U2702A. Before plugging into the
instrument chassis, ensure that the L-Mount kit installed on your modular
oscilloscope is screwed to the instrument chassis for chassis grounding
purpose (see L-Mount Kit Installation). It is required to use the provided
10:1 probes (N2862A/N2863A) for high voltage measurements.
Keysight U2701A/U2702A User’s Guide 19
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1 Getting Started
Front Bumper
Rear Bumper
USB Indicator
Power Indicator
Channel 1 Input
Channel 2 Input
External Trigger
BNC Ground
Power Inlet
USB Inlet
55-pin Connector
Product Overview
Product Outlook
Top View
Front View
Rear View
20 Keysight U2701A/U2702A User’s Guide
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Product Dimension
Without Front and Rear BumperWith Front and Rear Bumper
Top View Top View
175.00 mm
180.00 mm
Front View
Front View
Rear View
Rear View
Getting Started 1
Keysight U2701A/U2702A User’s Guide 21
Page 22
1 Getting Started
Package Contents Checklist
Inspect and verify the following standard shipped items of the U2701A/U2702A
USB modular oscilloscope. If there are missing items, contact the nearest
Keysight Sales Office.
4 24 W AC/DC Power Adapter
4 Power Cord
4 USB Standard A to Mini-B Interface Cable
4 2 x 10:1 Passive Probe 150 MHz 1.2m (only applicable for U2701A), N2862A
4 2 x 10:1 Passive Probe 300 MHz 1.2m (only applicable for U2702A), N2863A
4 L-Mount Kit (used with modular instrument chassis)
4 Keysight Automation-Ready CD-ROM (contains the Keysight IO Libraries
Suite)
4 Keysight USB Modular Products and Systems Quick Start Guide
4 Keysight USB Modular Products and Systems Product Reference DVD-ROM
4 Keysight USB Modular Products Quick Reference Card
4 Certificate of Calibration
22 Keysight U2701A/U2702A User’s Guide
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Installations and Configurations
NOTE
If you are using the U2701A/U2702A USB modular oscilloscopes with the
Keysight Measurement Manager, follow the step-by-step instructions as shown in
the Keysight USB Modular Products and Systems Quick Start Guide.
– If you do not wish to specifically use the U2701A/U2702A USB modular
oscilloscopes with the Keysight Measurement Manager, and use the modular
oscilloscope with Keysight VEE, Labview or Microsoft Visual Studio only, you
can skip steps E and H in the following flowchart.
– You need to install the IVI-COM driver if you are going to use the modular
product with Keysight VEE Pro, LabVIEW, or Microsoft
Getting Started 1
®
Visual Studio®.
Keysight U2701A/U2702A User’s Guide 23
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1 Getting Started
1 Unpack the L-Mount kit from the
packaging.
2 Remove both the rubber
bumpers from the modular
oscilloscope.
3 Using the Philip screw driver,
screw the L-Mount kit to your
USB modular oscilloscope.
L-Mount Kit Installation
The L-Mount kit is to be installed on your U2701A/U2702A USB modular
oscilloscopes. The following instructions describe the simple procedure of
installing the L-Mount kit and your modular oscilloscopes into the chassis.
24 Keysight U2701A/U2702A User’s Guide
Page 25
4 To slot in the modular oscilloscope
to your chassis, turn your USB
oscilloscope model perpendicularly
and ensure that the 55-pin back
pane connector is at the bottom
side of the modular oscilloscope.
5 Your modular oscilloscope is ready
to be plug into an instrument
chassis. Using the Philip screw
driver, screw the L-Mount kit
installed on your modular
oscilloscope to the instrument
chassis (for protective grounding
purpose).
Getting Started 1
Keysight U2701A/U2702A User’s Guide 25
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1 Getting Started
GND
NC
GND
TRIG4
nBPUB
NC
11
GND
NC
TRIG3
GND
CLK10M
NC
10
GND
NC
GND
TRIG5
GND
NC
9
GND
NC
STAR_TRIG
NC
8
TRIG2
GND
GND
NC
GND
TRIG6
GA2
NC
7
GND
NC
TRIG1
GND
GA1
NC
6
GND
NC
GND
TRIG7
GA0
NC
5
GND
NC
TRIG0
GND
NC
NC
4
GND
VBUS
GND
+12 V
+12 V
+12 V
3
GND
GND
GND
+12 V
+12 V
+12 V
2
GND
USB_D–
USB_D+
GND
+12 V
+12 V
1
F
E
D
C
B
A
Modular Products Chassis
55-Pin Backplane Connector Pin Configuration
The 55-pin backplane connector is used when your module is slotted into the
U2781A USB modular instrument chassis. For more details, refer to the Keysight
U2781A USB Modular Instrument Chassis User’s Guide.
Figure 1-1 55-pin backplane connector pin configuration
SSI timing signal Functionality
GND Ground
NC Not connected
VBUS USB bus power sensing input
USB_D+, USB_D– USB differential pair
TRIG0~TRIG7 Trigger bus
+12 V +12 V power with 4 A current
nBPUB USB backplane input detect
CLK10M 10 MHz clock source
STAR_TRIG Star trigger
GA0,GA1,GA2 Geographical address pin
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Soft Front Panel and User Interface Descriptions
Getting Started 1
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1 Getting Started
Tab le 1-1 Descriptions of the User Interface
No. Panel Description
1 Oscilloscope Toolbar Consists of oscilloscope tools
2 Waveform Acquisition Tab Displays time domain waveform for the oscilloscope
3 FFT Analysis Tab Displays the FFT spectrum of the signal
4 Configuration Summary Displays the configured functions and settings
5 Waveform graph display Displays the output of the data acquired
6 Scope control tabs Consists of all the sub functions of the oscilloscope
7 Measurement Results panel Displays the measurement results of the scope operations
8 Status tab Displays the status panel, which shows the history of operations
9 Refresh rate Displays the graph update rate in frame/sec.
10 Video Sampling Rate Displays video sampling rate (in number of samples per second taken from a
continuous signal)
11 Calibration Delta Temp. indicator Displays the calibration delta temperature of the connected device
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Keysight U2701A/U2702A USB Modular Oscilloscopes
User’s Guide
2 Scope Features and
Functions
Analog Controls 30
Trigger Controls 41
Measurements and Cursors Controls 49
FFT & Math Controls 60
Options Controls 70
AutoScale and Run/Stop buttons 75
Pan and Zoom 76
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2 Scope Features and Functions
Analog Controls
The analog controls panel consists of vertical control and horizontal control, which
are used to set the waveform of the graph display.
Vertical Controls
Vertical control is used to change the vertical scale and position of the waveform.
This section of the manual describes the vertical controls provided in the user
interface.
Figure 2-1 Soft front panel vertical system controls
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Scope Features and Functions 2
Channel Selection for Waveform Display
To display waveform from channel 1, click on or press F5.
To display waveform from channel 2, click on or press F6.
Toggle Channel On/Off
Click on the channel buttons on the vertical control panel or on the toolbar to
toggle the channel on or off.
– To toggle channel on, click on or (these images are in off mode).
– To toggle channel off, click on or (these images are in on mode).
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2 Scope Features and Functions
NOTE
Channel Options
Channel options provide four types of adjustment to the channel's waveform:
– AC Coupling
– Invert
–BW Limit and
– Attenuation (1X, 10X, 100X)
Channel Coupling Control
The AC coupling control is used to remove any DC offset voltage on a waveform.
By setting the coupling control to AC, the DC offset voltage is removed from the
input waveform.
To remove any DC offset voltage from channel 1, click on the button on the
soft front panel. Click on the Channel Options button and select AC
Coupling from the options list.
When AC coupling is not selected, the oscilloscope is always set to DC coupling
mode by default.
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Scope Features and Functions 2
Invert Control
The invert control inverts the displayed waveform with respect to the ground level.
When the oscilloscope is triggered on the inverted waveform, the trigger is also
inverted as well.
Click on the Stop button to stop the signal acquisition. To invert the waveform on
channel 1, click on the button on the soft front panel. Click on the
channel options button and select Invert from the options list.
Figure 2-2 and Figure 2-3 show the changes before and after conversion.
Figure 2-2 The waveform before inversion
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2 Scope Features and Functions
NOTE
Figure 2-3 The waveform after inversion
Bandwidth Limit Control
The bandwidth limit control can be used to removed high frequency components
on a waveform that are not important to the analysis of the waveform.
To remove high frequency components from the waveform on channel 1, click on
the button on the soft front panel. Click on the Channel Options button
and select BW Limit from the options list. The LowPass cutoff is at 25 MHz.
When the BW limit control is not selected, the oscilloscope is set to full
bandwidth.
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Scope Features and Functions 2
Drop-down list
Probe Attenuation Control
The probe attenuation control changes the attenuation factor for the probe. The
attenuation factor changes the vertical scaling of the oscilloscope so that the
measurement results will reflect the actual voltage levels at the probe tip.
To change the probe attenuation factor for channel 1, click on the button on
the soft front panel. Click on the channel options button and select
Attenuation from the options list. An option list containing the attenuation factors
in 1X, 10X, 100X will appear, select the desired factor.
Table 2-1 Probe attenuation factors and its corresponding settings.
Probe attenuation factors and corresponding settings
1:1 1X
10:1 10X
100:1 100X
Volt/Div Control
The Volt/Div control sets the sensitivity of the channel. You can select the channel
sensitivity from the drop-down list.
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2 Scope Features and Functions
You can also use the following buttons or shortcut keys to set the sensitivity of the
channel.
Channel 1
– Click on the or press Ctrl+Minus to increase the sensitivity of the
channel.
– Click on the or press Ctrl+Plus to decrease the sensitivity of the
channel.
Channel 2
– Click on the or press Alt+Minus to increase the sensitivity of the
channel.
– Click on the or press Alt+Plus to decrease the sensitivity of the
channel.
Offset
Offset is used to configure the position of the ground relative to the center of the
display.
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Horizontal Controls
The oscilloscope shows the time per division in the scale readout. As all
waveforms use the same time base, the oscilloscope only displays one value for
all channels, except for when Delayed Sweep is being used.
Horizontal controls allows you to adjust the horizontal scale and position of
waveforms. The horizontal center of the screen is the time reference for
waveforms. Changing the horizontal scale causes the waveform to expand or
contract around the screen center.
Scope Features and Functions 2
Figure 2-4 Soft front panel horizontal system controls
Horizontal control provides functions of time base, delay, and mode for the
horizontal scale adjustment.
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2 Scope Features and Functions
Trigger point
Time Base
Time base allows you to control how often the values are digitized.
To control the horizontal sweep speed,
– Click on or press Crtl+[ to increase sweep speed.
– Click on or press Crtl+] to decrease sweep speed.
– Select the time base from the drop-down list provided to adjust the
horizontal sweep speed.
Delay
Delay setting allows you to set the specific location of the trigger event with
respect to the time reference position When the delay time knob is turned, the
trigger point will move to left or right of the waveform graph display.
To adjust the delay time,
– Click on or press Crtl+Left to increase the delay time.
– Click on or press Crtl+Right to decrease the delay time.
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Horizontal Mode Functions
NOTE
The oscilloscope offers three types of horizontal mode functions — Main mode,
Roll mode, and XY mode.
Main Mode
Main mode displays the normal viewing mode for the waveform graph display.
The oscilloscope is always set to Main mode by default.
Roll Mode
Scope Features and Functions 2
Roll mode causes the waveforms to move slowly across the oscilloscope’s display
from right to left. It allows dynamic changes (like adjusting a potentiometer) on a
low frequency waveforms to be seen by the user. When the oscilloscope is in Roll
mode, the waveforms are not triggered and run continuously. Measurements can
be made while in roll mode.
The Roll mode only operates on time base of 500 ms/div and slower. If the current
time base setting is faster than the 500 ms/div limit, it will be set to 500 ms/div
when the Roll mode is entered.
Use Roll mode on low-frequency waveforms to yield a display much like a strip
chart recorder. It allows the waveform to roll across the display.
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2 Scope Features and Functions
NOTE
NOTE
To enter Roll mode on channel 1,
1 Click on the button on the soft front panel. Click on the at the left of
the Mode option. Select Roll from the drop-down list.
2 To pause and display in Roll mode, click on the button.
In Roll mode, triggering and averaging functions are disabled.
XY Mode
In XY mode, voltage levels of two waveforms are compared point by point. The
display is changed from a volts-versus-time display to a volts-versus-volts
display. The time base is turned off. This mode only applies to channels 1 and 2.
Channel 1 amplitude is plotted on the X-axis and channel 2 amplitude is plotted
on the Y-axis. The cursors can be used to make measurements on XY mode
waveforms.
To use the XY horizontal mode
1 Connect a sine wave signal to channel 1, and a sine wave signal of the same
frequency but out of phase to channel 2.
2 Center the signal on the display using the channel 1 and 2 Offset knobs. To
expand the signal for convenient viewing, use the channel 1 and 2 volts/div
drop-down list.
In XY mode, the time base, delay and triggering functions are disabled. The
Normal trigger mode is enabled.
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Trigger Controls
The trigger determines when the oscilloscope starts to obtain data and display a
waveform. When the trigger is set up correctly, it can convert unstable displays or
blank screens into meaningful waveforms. The oscilloscope acquires data while
waiting for the trigger condition to occur. After it detects a trigger, the
oscilloscope continues to obtain enough data so it can draw the waveform on the
display.
Scope Features and Functions 2
Figure 2-5 Soft front panel of the Trigger Controls
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2 Scope Features and Functions
Trigger Modes
The oscilloscope provides two trigger modes: Auto Trigger Mode and Normal
Trigger Mode.
Auto Trigger Mode
In Auto trigger mode, the oscilloscope automatically triggers and captures
waveforms when you click on the Run button.
In many cases, a triggered display is not needed to check signal levels or activity.
For these applications, use Auto trigger mode (which is the default setting). Since
there are no edges on which to trigger, Auto trigger mode is used to display a DC
signal.
Normal Trigger Mode
If you only want to acquire specific events as specified by the trigger settings, use
Normal trigger mode. If you click on the Run button when the oscilloscope is in
Normal trigger mode, a trigger must be detected before an acquisition can be
completed.
Trigger Source
There are three types of trigger source: Channel 1, Channel 2 and External. The
external trigger source can be used as a source in several trigger types. The
trigger source will be the analog channel available on your oscilloscope.
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Trigger Settings
The oscilloscope provides three trigger modes: edge, pulse, and TV. Pulse width
trigger is used to find pulses with certain pulse widths. TV is used to trigger on
fields or lines for standard video waveforms.
Edge Trigger
Edge trigger can be used with analog and digital circuits. An edge trigger occurs
when the trigger input passes through a specified voltage level with the specified
slope.
Table 2-2 Edge Trigger menu
Edge Trigger Panel Controls
Menu Settings Comments
Scope Features and Functions 2
Trigger
Mode
Source Channel 1 Sets Channel 1 as the trigger source
Settings Level Sets the voltage point on the waveform where trigger occurs
Trigger Settings Rising Trigger on rising edge
Coupling DC Sets the input coupling to DC
Auto Able to acquire waveform even when no trigger occurs
Normal Acquires waveform only when trigger occurs
Channel 2 Sets Channel 2 as the trigger source
External Sets External as the trigger source
Holdoff Sets the waiting period before starting a new trigger
Falling Trigger on falling edge
Alternate Trigger on alternate edge
Either Trigger on either edge
AC Sets the input coupling to AC
LF-Reject Sets the input coupling to low frequency reject
HF-Reject Sets the input coupling to high frequency reject
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2 Scope Features and Functions
NOTE
To configure edge triggering
1 Select the desired trigger source on the trigger source panel.
2 On the Trigger Settings panel, click on the Edge button.
3 Select the trigger level by adjusting the knob or by clicking on or .
4 Enter the desired holdoff time and unit, then click on Set to proceed.
5 Select the desired slope on the Edge Trigger Settings panel.
– To trigger both edges of a clock, use Alternating edge mode.
– To trigger on any activity of a selected source, use Either edge mode.
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Pulse Width Trigger
A pulse trigger occurs when a pulse is found in a waveform that matches the pulse
definition.
Table 2-3 Pulse Width Trigger menu
Pulse Width Trigger Panel Control s
Menu Settings Comments
Scope Features and Functions 2
Trigger
Mode
Source Channel 1 Sets Channel 1 as the trigger source
Settings Level Sets the voltage point on the waveform where trigger occurs
Polarity Trigger on the positive pulse
Mode > Greater than Pulse width greater than pulse width setting
Auto Able to acquire waveform even when no trigger occurs
Normal Acquires waveform only when trigger occurs
Channel 2 Sets Channel 2 as the trigger source
External Sets External as the trigger source
Holdoff Sets the waiting period before starting a new trigger
Trigger on the negative pulse
< Less than Pulse width less than pulse width setting
>< In range of Pulse width within the pulse width setting range
<> Out of range Pulse width out of the pulse width setting range
To configure pulse width triggering
1 Select the desired trigger source on the Trigger Source panel.
2 On the Trigger Settings panel, click on the Pulse Width button.
3 Select the trigger level by adjusting the knob or by clicking on or .
4 Select the desired polarity on the Pulse Width Trigger Settings panel.
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2 Scope Features and Functions
5 Select the preferred time qualifier by selecting the range from the Mode
drop-down list.
6 Enter the desired range value and unit then click on Set.
TV Trigger
TV triggering is used to trigger on fields or lines of NTSC, PAL, or SECAM standard
video waveforms. When TV is selected, the trigger coupling is set to AC.
Tab le 2-4 TV Trigger Menu
TV Trigger Panel Controls
Menu Settings Comments
Trigger Mode Auto Able to acquire waveform even when no trigger occurs
Normal Acquires waveform only when trigger occurs
Source Channel 1 Sets Channel 1 as the trigger source
Channel 2 Sets Channel 2 as the trigger source
Settings Holdoff Sets the waiting period before starting a new trigger
Standard NTSC/PAL/ SECAM/Generic Trigger on an NTSC, PAL, SECAM, or GENERIC TV waveform
Mode Odd Field Trigger on the rising edge of the first serration pulse of odd field.
Even Field Trigger on the rising edge of the first serration pulse of even field.
All Fields Trigger on the rising edge of the first pulse in the vertical sync interval (not
available in Generic Mode)
All Lines Trigger on all horizontal sync pulses
Custom Line Trigger on selected line number
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Scope Features and Functions 2
NOTE
To configure TV triggering
1 Select the desired trigger source on the Trigger Source panel.
2 On the Trigger Settings panel, click on the TV button.
3 Select the desired video standard on the TV Trigger Setting panel.
4 Select a mode to define the portion of the video signal to trigger on.
Table 2-5 Line (or count for Generic) numbers per field for each non-HDTV/EDTV video
standard
Video standard Field 1 Field 2
NTSC 1 to 263 1 to 262
PAL 1 to 313 314 to 625
SECAM 1 to 313 314 to 625
Generic 1 to 1024 1 to 1024
Line Number Represents Count
In Generic mode, the line number represents the number of a count instead of a
real line number. Line:Field 1 and Line:Field 2 are used to indicate where the
counting starts. For an interlaced video signal, the counting starts from the
rising edge of the first vertical serration pulse of Field 1 and/or Field 2.
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2 Scope Features and Functions
Trigger Options
Coupling Modes
The oscilloscope offers four types of coupling modes — Direct Current (DC),
Alternating Current (AC), Low Frequency-Reject (LF-Reject), and High
Frequency-Reject (HF-Reject).
DC coupling allows DC and AC signals into the trigger path. When DC coupling is
selected, both DC and AC components of the input waveform are transferred to
the oscilloscope. DC coupling enables the triggering waveforms of as low as 0 Hz
without large DC offsets to be captured.
AC coupl ing enables the triggering waveforms with large DC offsets to be
captured.
LF-Reject coupling places a 35 kHz high-pass filter in series with the trigger
waveform. The LF-Reject coupling will remove any unwanted low frequency
components from a triggered waveform, such as power line frequencies that can
interfere with proper triggering.
HF-Reject coupling places a low-pass filter with the 3 dB point at 35 kHz.
HF-Reject removes high-frequency noise such as AM or FM broadcast stations
from the trigger path.
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Measurements and Cursors Controls
The Measurements & Cursors button is located on the toolbar of the soft front
panel. Click on the to activate the automatic
measurements and cursors system.
Scope Features and Functions 2
Figure 2-6 Soft front panel of the Measurements & Cursors Controls
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2 Scope Features and Functions
Markers
The oscilloscope provides three types of settings for marker property.
– Auto marker automatically places the cursors on the graph based on the
selected measurements.
– Manual marker allows the cursors to be placed manually on the graph for
customized measurements. This will enable the Cursors panel.
– Off will disable the graph markers from the graph display.
Cursors
Cursors are used to make custom voltage or time measurements on the scope
signals.
Source
Under cursors measurement, there are four available sources:
– Channel 1
– Channel 2
–Math Func.
–FFT
Math Func. and FFT sources are only available when the functions are activated
on the FFT & Math control panel.
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Scope Features and Functions 2
X and Y Cursors
To enable Cursors control, the Manual option on the Markers property must be
selected as shown below.
– X cursors places two cursors on the X-Axis of the waveforms to measure the
time difference between the two cursors (X2 minus X1). Delta X denotes the
time difference.
– Y cursors places two cursors on the Y-Axis of the waveforms to measure the
voltage difference between the two cursors (Y2 minus Y1). Delta Y denotes the
voltage difference.
To configure Auto marker
The Auto marker function will automatically place indicators on the waveforms
displayed on the graph to show the selected measurements.
1 Obtain and establish a stable signal on the waveform acquisition graph.
2 Click on the Measurements & Cursors button and select Auto at the Markers
property.
3 Proceed to select your desired measurements on the Measurements panel.
4 Markers will be automatically placed on the waveform to indicate the
measurements made.
5 Browse the measurement results on the Measurement Results panel to view
different markers for different measurements.
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2 Scope Features and Functions
Figure 2-7 shows the sample marker (horizontal line in orange color)
automatically marks the maximum value of the waveform displayed when
Maximum measurement type is selected.
Figure 2-7 Auto marker automatically marks the maximum value of the
waveform when Maximum measurement is selected
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Scope Features and Functions 2
To configure Manual marker
The Manual marker function allows you to manually place indicators on the
waveforms displayed on the graph to show the selected measurements.
1 Obtain and establish a stable signal on the waveform acquisition graph.
2 Click on the Measurements & Cursors button and select Manual at the Markers
property. The Cursors panel will be activated once Manual is selected.
3 Select Channel 1 or Channel 2 as desired. Then select X Cursors or Y Cursors
to define the measurements you would like to perform.
4 Use the navigation arrows to adjust the cursors position.
To adjust the first cursor (X1 or Y1), left-click and drag the cursor on the
graph.
To adjust the second cursor (X2 or Y2), right-click and drag the cursor on the
graph. Delta measurements of the Cursors can be obtained on the Cursors
panel.
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2 Scope Features and Functions
Measurements Controls
The U2701A/ U2702A modular oscilloscopes offers 26 types of automatic
measurements. You can select any of the following predefined measurements to
measure the waveforms.
Figure 2-8 Automatic measurements on the Measurements & Cursors panel
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Scope Features and Functions 2
Table 2-6 List of Time Measurements and Voltage Measurements
Measurements Selection List
Menu Settings Comments
Display Large Icon
Small Icon
List
Tile
Change how measurement icons are displayed
Source Ch 1
Ch 2
Math
Time Wid th (Negative) Measure the negative pulse width of a waveform (The time from the
Wid th (Positive) Measure the positive pulse width of a waveform (the time from the
Frequency Measure the frequency of a waveform
Period Measure the period of a waveform (the time between the mid-threshold
Rise Time Measure the rise time of a waveform (the time at the upper threshold minus
Fall Time Measure the fall time of a waveform (the time at the lower threshold minus
Duty Cycle (Positive)
Duty Cycle (Negative)
T Max The first time that the maximum voltage occurs on display
T Min The first time that the minimum voltage occurs on the display
Selects Channel 1, Channel 2, or Math as the waveform to be measured.
mid-threshold of the first falling edge to the mid-threshold of the next rising
edge)
mid-threshold of the first rising edge to the mid-threshold of the next falling
edge)
crossings of two consecutive, like-polarity edge)
the time at the lower threshold of the edge)
the time at the upper threshold on the edge)
Measure the positive and negative duty cycle of a waveform
Duty Cycle is defined as (Pwidth / Period) * (100) which is the percentage of
the period that the waveform is high
Delay Measures the time difference from the selected edge on Channel 1 and the
selected edge on Channel 2 closest to the trigger reference point at the
middle threshold points on the waveforms
Phase Shift The calculated phase shift from Channel 1 to Channel 2 (in degrees)
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2 Scope Features and Functions
Tab le 2-6 List of Time Measurements and Voltage Measurements (continued)
Measurements Selection List
Voltage Amplitude Measure voltage between Vtop and Vbase of a waveform
Average Measure average voltage of a waveform
Base Measure a flat base voltage of a waveform
Maximum Measure the absolute maximum voltage of a waveform
Minimum Measure the absolute minimum voltage of a waveform
Overshoot Measure the overshoot voltage in percentage of a waveform
Overshoot is a waveform distortion which follows a major edge transition
Peak to Peak Measure peak-to-peak voltage of a waveform
(V
- V
Min
)
Max
Preshoot Measure the preshoot voltage in percentage of a waveform
Preshoot is a waveform distortion which precedes an edge transition
VRMS (AC) The AC VRMS (Root Mean Square Voltage) is a modified RMS measurement
and removes the DC component of the waveform from the calculation of the
RMS voltage
VRMS (DC) The DC VRMS (Root Mean Square Voltage) measurement is the classic way
of making an RMS voltage measurement
Cycle Mean Takes VRMS (DC) for one cycle
CREST Defined as Peak/RMS (Maximum/VRMS (DC))
Top Measure a flat top voltage of a waveform
Std Deviation Standard Deviation is an RMS measurement across the full screen with the
DC component removed.
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Scope Features and Functions 2
NOTE
Table 2-7 List of Time Measurements and Voltage Measurements for FFT
Measurements Selection list
Menu Settings Comments
Time X at Max The first time that the maximum magnitude occurs on display
X at Min The first time that the minimum magnitude occurs on the display
Voltage Average Measure average magnitude of a waveform
Maximum Measure the absolute maximum magnitude of a waveform
Minimum Measure the absolute minimum magnitude of a waveform
Peak to Peak Measure peak-to-peak magnitude of a waveform
FFT Measurements
When you make an X at Max or X at Min measurement on a math FFT function,
the resultant units will be in Hertz. No other time related automatic
measurement can be made on the FFT math function. Use the cursors to make
other measurements on FFT
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Automatic Measurement Procedures
Automatic measurements can be used on any channel source or any running math
function. Cursors are turned on to focus on the most recently selected
measurement.
1 Select the markers for your measurement.
Markers enable you to expand the time base around the start and stop events
of the time interval to be measured, thus achieving more time resolution than
the automatic measurements.
2 Select either Channel 1 or Channel 2 according to the waveform you want to
measure. Math function and FFT channel can be selected if they are enabled.
3 Select the desired measurement from the Measurements panel. The
Measurements Results panel is displayed at bottom of the graph.
To select single or multiple measurements,
1 Drag and drop a measurement
Click on the desired measurement icon, while holding the selected
measurement, drag it over to the Measurements Results panel. Drop the
selection on the panel.
2 Drag and drop multiple measurements
On the Measurements panel, hold down the mouse button, drag and select
multiple measurements. Drag all the selected measurements and drop the
selections on the Measurement Results panel.
3 Double-click on a measurement
Go to your desired measurement and double click on the icon.
4 Select the measurement and press Enter
Click on the desired measurement icon and press Enter. To select more than
one measurement, press Ctrl and click on the desired measurements icons
then press Enter.
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Scope Features and Functions 2
Figure 2-9 Measurements panel and Measurements Results panel
To reset the selected measurements on the Measurements Results panel, select
the measurement that you would like to reset and click on the button. To
reset all measurements, click on the header of the reset column, Reset.
To delete a measurement, select the measurement that you would like to remove
from the Measurements Results panel and click on the button. To delete
all measurements, click on the header of the delete column, Remove.
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FFT & Math Controls
The FFT & Math button is located on the toolbar of the soft front panel.
Figure 2-10 Soft front panel of the FFT & Math controls.
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Fast Fourier Transform Function
NOTE
FFT is used to compute the fast Fourier transform using analog input channels or
math functions. FFT takes the digitized time record of the specified source and
transforms it to the frequency domain. When the FFT function is selected, the FFT
spectrum is plotted on the graph display as magnitude in dBV versus frequency.
The readout for the horizontal axis changes from time to frequency (Hertz) and the
vertical readout changes from volts to dB.
Scope Features and Functions 2
Figure 2-11 FFT controls
When the FFT source is channel 1 or channel 2, FFT units will be displayed in
dBV.
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FFT Settings
Selecting an FFT Window
There are four FFT windows. Each window has trade-offs between frequency
resolution and amplitude accuracy. Use the following guidelines to select the best
window.
Tab le 2-8 Comparison between the four FFT windows
Window Characteristics Best for measuring
Rectangular Best frequency resolution, worst magnitude
resolution. This is essentially the same as no
window.
Hanning
Hamming
Blackman Harris Best magnitude, worst frequency resolution. Single frequency waveforms, to find higher order
Flattop Best amplitude accuracy, poor frequency
Better frequency, poorer magnitude
accuracy than Rectangular. Hamming has
slightly better frequency resolution than
Hanning.
resolution when compared with the Hanning
window.
Transients or bursts, the waveform levels before and
after the event are nearly equal. Equal-amplitude sine
waves with fixed frequencies. Broadband random noise
with a relatively slow varying spectrum.
Sine, periodic, and narrow-band random noise.
Transients or bursts where the waveform levels before
and after the events are significantly different.
harmonics.
Amplitude of single frequency components with little
nearby spectral energy in the signal.
The Random Dither option enables the reduction of noise floor. To enable this
option, click on the Random Dither checkbox.
Horizontal scaling is automatically calculated. It will span the entire range of
spectrum horizontally for best-fit display.
Vertical Scale option allows you to scale your spectrum vertically. Vertical Offset
allows you to adjust the vertical offset of your spectrum.
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Scope Features and Functions 2
To make FFT measurements
1 On the FFT & Math control panel, click Activate FFT checkbox to enable the
FFT function.
2 On the FFT Settings panel, select the desired channel source or Math function
that you would like to perform FFT on.
3 On the Settings tab, select the desired Window (Rectangular, Hanning,
Hamming, BlackmanHarris, Flattop).
4 To reduce the noise floor of the waveform, click on the Random Dither
checkbox. The horizontal scale (span), which is the entire range of the
spectrum, will be automatically calculated, as shown in the image above.
5 Set the vertical scale factors for the spectrum in the Scale property box. Then,
set the offset of the spectrum by using the knob or the arrow keys to adjust the
offset value.
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Figure 2-12 Waveform obtained with Hanning window selected
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Scope Features and Functions 2
NOTE
Peak Scan
After performing FFT measurements, you can obtain the peak information of your
spectrum by following the steps below.
To use the Peak Scan function, the oscilloscope signal acquisition must be
stopped. This is because in Run mode, you will not see proper subsequent peaks
as the spectrum is being refreshed.
1 Click on the Stop button on the oscilloscope toolbar to stop the signal
acquisition, then click on the FFT & Math button.
2 On the FFT Settings panel, click on the Peak Scan tab, then select the Peak
Scan checkbox to enable peak scan.
3 Once the Peak Scan is enabled, you will see an indicator on your spectrum
pointing at the first peak of your spectrum as shown Figure 2-13.
4 To find the subsequent peaks (in descending order) of your spectrum, click on
the Find Next Peak button. You will see an indicator on your spectrum pointing
at the next highest peak of your spectrum as shown Figure 2-14.
5 To get the first peak once again, click on the Find First Peak button.
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Figure 2-13 First Peak
Figure 2-14 Next Peak
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Math Function
The math functions control allows the selection of the math functions add,
subtract, multiply, divide, and FFT for CH1 and CH2. The mathematical result can
also be measured using the grid and cursor control.
Math Function Settings
Scope Features and Functions 2
Reverse Function allows you to toggle the orientation of the channel math
computation when selected.
By default the orientation is Channel 1 <Math operation> Channel 2. When this
option is enabled, the orientation will be reversed to Channel 2 <Math operation>
Channel 1, whereby Math operation is based on your choice of selection.
Math Functions
Math Functions Comments
+ (Add) Adds Channel 1 and Channel 2 voltage values, point by point (CH1 + CH2)
- (Subtract) Subtracts Channel 1 with Channel 2 voltage values, point by point (CH1 – CH2, CH2 – CH1)
x (Multiply) Multiplies Channel 1 and Channel 2 voltage values, point by point (CH1 * CH2)
/ (Divide) Divides Channel 1 and Channel 2 voltage values, point by point (CH1 / CH2, CH2 / CH1). If zero
divide by zero, the result will be 1. If either Channel 1 or Channel 2 is positive and it is divided by
zero, the result will be in positive infinity. If either Channel 1 or Channel 2 is negative and it is
divided by zero, the result will be in negative infinity.
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2 Scope Features and Functions
The Scale options allows you to scale the computed waveform.
The Offset option allows you to set the offset on the computed waveform.
To perform math computation of acquired waveform
1 On the FFT & Math control panel, click on the Activate Math Function
checkbox to enable the Math function.
2 On the Math Function Settings panel, select the function (Add, Subtract,
Multiply, Divide) as desired.
3 Set the vertical scale factors for the selected Math function in the Scale
property box. Then, set the offset of the computed waveform by using the knob
or the arrow keys to adjust the offset value.
4 Click on the Active Reverse Function checkbox to reverse the channels'
computation if desired. This allows you to flip the order of operation for the
channels.
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Scope Features and Functions 2
Figure 2-15 Acquired waveform using Subtract function
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2 Scope Features and Functions
Options Controls
To display the Acquisition Mode menu and Display Options menu, click on the
button on the toolbar on the soft front panel.
Figure 2-16 Soft front panel of the Options Controls
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Scope Features and Functions 2
Acquisition Mode
The figure below shows the Acquisition Mode on the soft front panel.
The U2701A/U2702A scopes have the following acquisition modes.
Table 2-9 List of Acquisition Modes
Menu Settings Comments
Mode Normal Normal acquisition mode is for most waveforms with normal decimating at
slower sweep speeds, no averaging.
Peak Detect
Average Average acquisition mode is for reducing noise and increasing resolution (at all
Peak Detect acquisition mode is
infrequently (at slower sweep speeds).
sweep speeds without bandwidth or rise time degradation).
for displaying narrow pulses that occur
To reduce the displayed random noise, select Average acquisition. This mode will
decrease the screen refresh rate.
To avoid waveform aliasing, select Peak Detect acquisition. Peak Detect mode
captures the maximum and minimum values of a waveform over multiple
acquisitions.
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Display Options
The figure below shows the Display Options menu on the soft front panel.
The three types of display options offered are:
– Vector connects the sample points by using digital interpolation.
– Sin x/x interpolation is used to expand the horizontal signal resolution when
the horizontal scale is set to 100 ns or faster.
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To perform interpolation using sin(x)/x filter to maintain the linearity of the
waveform, enable the Sin x/x interpolation option. Once enabled, a smoother
waveform will be displayed.
Figure 2-17 The waveform before interpolation
Figure 2-18 The waveform after interpolation
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2 Scope Features and Functions
– Waveform persistence (infinite) enables the oscilloscope to update the
display with new acquisitions, but does not erase the results of previous
acquisitions. Waveform persistence is not kept beyond the display area
boundary. Use infinite persistence to measure noise and jitter, to see the
worst-case extremes of varying waveforms, to look for timing violations, or to
capture events that occur infrequently.
Clear Display clears the previous acquisitions on the graph display. Then, the
oscilloscope will again start to accumulate acquisitions. Turn off infinite
persistence, then press the Clear Display key to return the oscilloscope to the
normal display mode.
Miscellaneous menu contains an option to display tooltips with keyboard
shortcuts. When this option is enabled, by hovering the mouse cursor over most
of the controls, a tooltip with the appropriate keyboard shortcut to access the
particular function will appear.
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AutoScale and Run/Stop buttons
AutoScale
AutoScale automatically configures the oscilloscope to best display the input
signal by analyzing any waveforms connected to the channel and external trigger
inputs.
If AutoScale fails, your current setup will remain unchanged. The following steps
will teach you how to perform auto scaling on your acquired signals.
1 Once you have obtained a running signal, click on on the
oscilloscope toolbar or via Tools menu.
2 The auto scaling may take awhile for the application to analyze and adjust the
waveform.
3 Once the auto scaling has completed, you will see a best-fit waveform
displayed on your graph.
Run/Stop Button
Scope Features and Functions 2
The Run/Stop button is used to manually start or stop the oscilloscope’s
acquisition system from acquiring waveform data.
– Click on to start acquiring waveform.
– Click on to stop acquiring waveform.
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Pan and Zoom
The ability to pan (move horizontally) and zoom (expand or compress horizontally)
an acquired waveform is important because of the additional insight it can reveal
about the captured waveform. This additional insight is often gained from seeing
the waveform at different levels of abstraction. You may want to view both the big
picture and the specific little picture details.
The ability to examine waveform detail after the waveform has been acquired is a
benefit generally associated with digital oscilloscopes. Often this is simply the
ability to freeze the display for the purpose of measuring with cursors or printing
the screen.
To zoom an acquired waveform
1 Click on the Stop button to stop the signal acquisition.
2 Go to Analog panel by clicking the Analog button on the toolbar or press Ctrl + 1.
3 On the Horizontal panel, click on to zoom in or to zoom out. You
may also use the drop-down list to select the zoom value.
4 Alternatively, you can use the zoom reference panel above the waveform graph
display to zoom in and out of the graph.
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Scope Features and Functions 2
zoom reference panel
Figure 2-19 Zoom reference panel
5 To zoom in, right-click on the zoom reference panel and select Zoom In from
the menu. Repeat the same action to further increase the zoom level.
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Figure 2-20 Zoom In
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2 Scope Features and Functions
6 To zoom out, right-click on the zoom reference panel and select Zoom Out
from the menu. Repeat the same action to further decrease the zoom level.
Figure 2-21 Zoom Out
7 Select Restore Default from the menu to reset the zoom level to default.
To pan an acquired waveform
1 Click on the Stop button to stop the signal acquisition.
2 Go to Analog panel by clicking the Analog button on the toolbar or press Ctrl + 1.
3 On Delay panel, use the or arrow key to pan your graph right or left.
You may also turn the knob to control the panning.
4 Alternatively, you can use the zoom reference panel above the waveform graph
display to pan the graph. Click and hold the area in the zoom area selection
bar, then drag left or right to pan the graph. The analog trigger point will move
in respond to the panning of the graph.
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Figure 2-22 Panning a waveform
zoom area selection bar
trigger point
Scope Features and Functions 2
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Keysight U2701A/U2702A USB Modular Oscilloscopes
User’s Guide
3 Characteristics and
Specifications
For the characteristics and specifications of the U2701A/U2702A USB Modular
Oscilloscopes, refer to the datasheet at
http://literature.cdn.keysight.com/litweb/pdf/5990-9537EN.pdf.
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3 Characteristics and Specifications
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This information is subject to change
without notice. Always refer to the
Keysight website for the latest
revision.
© Keysight Technologies 2009 - 2017
Edition 10, June 1, 2017
Printed in Malaysia
*U2702-90013*
U2702-90013
www.keysight.com
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