Keysight Technologies N4000A SNS Series, N4001A SNS Series, N4002A SNS Series Operating And Service Manual
Keysight N4000A, N4001A,
and N4002A SNS Series
Smart Noise Sources
Operating and
Service Manual
Notices
CAUTION
WARNING
Copyright Notice
© Keysight Technologies 2001 - 2017
No part of this manual may be repro-
duced 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.
Manual Part Number
N4000-90009
Edition
Edition 4, May 26, 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.
2 Keysight N4000/1/2A Operating and Service Manual
Safety Symbols
The following symbols on the instrument and in the manual indicate precautions
which must be taken to maintain safe operation of the instrument.
The Instruction Documentation
Symbol. The product is marked with
this symbol when it is necessary for the
user to refer to the instructions in the
supplied documentation.
This symbol indicates that a device, or
part of a device, may be susceptible to
electrostatic discharges (ESD) which
can result in damage to the product.
Observe ESD precautions given on the
product, or its user documentation,
when handling equipment bearing this
mark.
Keysight N4000/1/2A Operating and Service Manual 3
Regulatory Information
Electromagnetic compatibility
The N4000A, N4001A, and N4002A SNS Series Smart Noise Sources comply with
the following Electromagnetic Compatibility (EMC) compliances:
– IEC 61326-1/EN 61326-1
– Canada: ICES/NMB-001
– Australia/New Zealand: AS/NZS CISPR11
In order to preserve the EMC performance of the product, any cable which
becomes worn or damaged must be replaced with the same type and
specification.
Radio-frequency electromagnetic field immunity
When a 3 Vm-1 radio-frequency electromagnetic field is applied to the SNS series
smart noise source according to IEC 61000-4-3, degradation of performance may
be observed. When the frequency of the incident field falls within the bandwidth
of a measured noise figure or gain, the values displayed will deviate from those
expected. This phenomenon will only affect that specific frequency, and the SNS
will continue to perform to specification at all other frequency sample points.
The NFA may be unable to calibrate a chosen frequency sample point, if the
frequency matches that of an incident electromagnetic field.
4 Keysight N4000/1/2A Operating and Service Manual
Regulatory Markings
MSIP-REM-Kst-
xxxxxxxxxxxxxx
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.
The RCM mark is a registered trademark of the
Australian Communications and Media Authority.
This instrument is Class A suitable for professional
use and is for use in electromagnetic environments
outside of the home.
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.
ISM GRP.1 Class A indicates
that this is an Industrial
Scientific and Medical Group 1
Class A product.
This symbol indicates the time
period during which no
hazardous or toxic substance
elements are expected to leak
or deteriorate during normal
use. Forty years is the expected
useful life of the product.
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.
Keysight N4000/1/2A Operating and Service Manual 5
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/mta
(product-specific information and support, software and
documentation updates)
– www.keysight.com/find/assist
(worldwide contact information for repair and service)
6 Keysight N4000/1/2A Operating and Service Manual
Table of Contents
Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Regulatory Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Electromagnetic compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Radio-frequency electromagnetic field immunity . . . . . . . . . . . . . . . .4
Regulatory Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Waste Electrical and Electronic Equipment (WEEE) Directive 2002/96/
EC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Product category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Sales and Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
1Introduction
Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
2Installation
Handling Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Service and Recalibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Equipment Supplied with the NFA . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Equipment Available but not Supplied . . . . . . . . . . . . . . . . . . . . . . . . . .19
Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Mating connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3 Specifications
General Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Characteristic SWR at 23 °C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Excess Noise Ratio expanded uncertainty (U(Y)) . . . . . . . . . . . . . . .23
Supplemental characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Physical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Keysight N4000/1/2A Operating and Service Manual 7
4Operating Guide
Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Recommended test equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Operator’s check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Operator’s Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Performance Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Replaceable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Principles of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Repair of defective noise source . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Disassembly procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Reassembly procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Returning the SNS series smart noise source for calibration . . . . . 48
5 ENR File Format
Format Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Comment records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Header fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
ENR data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Viewing the Smart Noise Source ENR Data . . . . . . . . . . . . . . . . . . . . . 55
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Example 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Example 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
A Caring for Connectors
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Connector part numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Handling and storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
Visual Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Obvious defects and damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
8 Keysight N4000/1/2A Operating and Service Manual
Mating plane surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61
Precision 7 mm connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
Sexed connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
Compressed air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
Cleaning alcohol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
Precision 7 mm connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Cleaning interior surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Drying connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66
Mechanical Inspection: Connector Gages . . . . . . . . . . . . . . . . . . . . . . .67
Mechanical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Precision 7 mm connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
Sexed connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
50 Ω Type-N connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
75 Ω Type-N connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
Using Connector Gages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Inspecting and cleaning the gage . . . . . . . . . . . . . . . . . . . . . . . . . . .71
Zeroing the gage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71
Measuring connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
Making Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
Align connectors carefully . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74
To make a preliminary connection . . . . . . . . . . . . . . . . . . . . . . . . . .75
Final connection using a torque wrench . . . . . . . . . . . . . . . . . . . . . .75
Disconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78
Principles of Microwave Connector Care . . . . . . . . . . . . . . . . . . . . . . . .80
Keysight N4000/1/2A Operating and Service Manual 9
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10 Keysight N4000/1/2A Operating and Service Manual
List of Figures
Figure 1-1 Keysight SNS series smart noise source . . . . . . . . . . .16
Figure 3-1 Characteristic SWR at 23 °C . . . . . . . . . . . . . . . . . . . .23
Figure 3-2 Example ENR uncertainty versus frequency for the
Figure 3-3 Example ENR uncertainty versus frequency for the
Figure 4-1 Typical noise figure measurement test setup . . . . . . .30
Figure 4-2 Operator’s check test setup for data communication .32
Figure 4-3 A typical cleared ENR table . . . . . . . . . . . . . . . . . . . . .33
Figure 4-4 A typical ENR table after data entry . . . . . . . . . . . . . .34
Figure 4-5 Operator’s check test setup for T
Figure 4-6 Typical user value . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
Figure 4-7 Typical user value after uploading SNS value . . . . . . .36
Figure 4-8 Operator’s check for T
Figure 4-9 SNS connected to NFA graphic . . . . . . . . . . . . . . . . . .38
Figure 4-10 Typical example of power reading with Noise Source On
Figure 4-11 Typical example of power reading with Noise Source Off
Figure 4-12 Illustrated parts breakdown . . . . . . . . . . . . . . . . . . . . .44
Figure 4-13 SNS series smart noise source block diagram . . . . . .45
Figure 4-14 Removing the smart noise source plastic shell . . . . . . 47
Figure A-1 Precision 7 mm connector . . . . . . . . . . . . . . . . . . . . . .62
Figure A-2 Precision 3.5 mm connectors . . . . . . . . . . . . . . . . . . . .63
Figure A-3 SMA connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Figure A-4 Cleaning interior surfaces . . . . . . . . . . . . . . . . . . . . . .66
Figure A-5 Type-N connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
Figure A-6 Using the connector gage . . . . . . . . . . . . . . . . . . . . . .72
N4000A model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
N4001A and N4002A models . . . . . . . . . . . . . . . . .25
communication .35
cold
upload from SNS . . . . . . . .37
cold
39
40
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12 Keysight N4000/1/2A Operating and Service Manual
List of Tables
Table 2-1 Connectors that can be mated with the noise
sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Table 3-1 N4000/1/2A specifications . . . . . . . . . . . . . . . . . . . . .22
Table 3-2 Supplemental characteristics . . . . . . . . . . . . . . . . . . . 26
Table 3-3 Physical specifications . . . . . . . . . . . . . . . . . . . . . . . . .26
Table 4-1 Replaceable parts list for N4000A . . . . . . . . . . . . . . . .42
Table 4-2 Replaceable parts list for N4001A and N4002A . . . . .42
Table 4-3 Chassis parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Table 4-4 Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Table 5-1 Mandatory header fields . . . . . . . . . . . . . . . . . . . . . . .51
Table 5-2 Optional header fields . . . . . . . . . . . . . . . . . . . . . . . . . 52
Table A-1 Recommended connector gages . . . . . . . . . . . . . . . . .67
Table A-2 Recommended torque settings . . . . . . . . . . . . . . . . . .76
Table A-3 Adapters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Table A-4 Principles of microwave connector care . . . . . . . . . . .80
Keysight N4000/1/2A Operating and Service Manual 13
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14 Keysight N4000/1/2A Operating and Service Manual
Keysight N4000/1/2A SNS Series Smart Noise Sources
Operating and Service Manual
1 Introduction
Product Overview 16
This chapter provides an overview of the Keysight N4000/1/2A SNS Series Smart
Noise Sources.
15
1Introduction
Product Overview
This manual contains operating and service information for the Keysight SNS
series smart noise sources, consisting of models; N4000A, N4001A, and N4002A.
The SNS series smart noise source, when commanded “Off” produces RF noise
due to thermal agitation of its RF components at a level appropriate to its physical
temperature. When commanded “On” it still produces this noise and produces
additional noise component, referred to as EXCESS NOISE. These two noise levels
are used to measure the gain and added noise of the device under test, and
consequently, its noise figure.
The Excess Noise Ratio (ENR) for each SNS has been measured at cardinal
frequencies and these frequency/ENR pair values are stored in the SNS’s internal
EEPROM. The ENR of the source relates the level of excess noise in dB to the noise
level appropriate to the standard temperature; 296 K. ENR does not include the
“Off” noise component.
Also included in the EEPROM calibration data is the measurement uncertainty and
the complex reflection coefficient in both the “On” and “Off” states for each SNS.
The SNS has a built in thermometer which monitors the ambient temperature.
This value can be transferred to the analyzer and control the setting of the T
value.
All models are provided with a twelve pin connector for power input and data
transfer. The output connector is a male APC-3.5 on the standard noise sources.
Type-N connectors are available as options for the Keysight SNS models N4000A
and N4001A.
cold
Figure 1-1 Keysight SNS series smart noise source
16 Keysight N4000/1/2A Operating and Service Manual
Keysight N4000/1/2A SNS Series Smart Noise Sources
Operating and Service Manual
2 Installation
Handling Precautions 18
Initial Inspection 18
Service and Recalibration 19
Equipment Supplied with the NFA 19
Equipment Available but not Supplied 19
This chapter provides you important information on how to check and prepare
your instrument for operation.
17
2Installation
CAUTION
CAUTION
CAUTION
Handling Precautions
The diode module is static sensitive and can be damaged or the calibration
can be altered.
Do not rotate the body of the SNS series smart noise source when
connecting to the noise figure analyzer, or internal damage may result.
Do not drop the SNS series smart noise source. Dropping can damage the
unit or alter the calibration.
Proper connector care is essential. See “Operator’s Maintenance” on page 41 for
more information.
Initial Inspection
1 Unpack and inspect the shipping container and its contents thoroughly to
ensure that nothing was damaged during shipment. If the shipping container
or cushioning material is damaged, the contents should be checked both
mechanically and electrically.
– Check for mechanical damage such as scratches or dents.
– Procedures for checking electrical performance are given under “Operator’s
check” on page 31.
2 If the contents are damaged or defective, contact your nearest Keysight
Technologies Service and Support Office. Refer to “Sales and Technical
Support” on page 6 of this manual. Keysight Technologies will arrange for
repair or replacement of the damaged or defective equipment. Keep the
shipping materials for the carrier’s inspection.
18 Keysight N4000/1/2A Operating and Service Manual
3 If you are returning the instrument under warranty or for service, repackaging
the instrument requires original shipping containers and material or their
equivalents. Keysight Technologies can provide packaging materials identical
to the original materials. Refer to “Sales and Technical Support” on page 6 of
this manual for the Keysight Technologies nearest to you. Attach a tag
indicating the type of service required, return address, model number, and
serial number. Mark the container FRAGILE to insure careful handling. In any
correspondence, refer to the instrument by model number and serial number.
Service and Recalibration
If your N4000/1/2A requires service or repair, contact the nearest Keysight office
for information on where to send it. The performance of the N4000/1/2A can only
be verified by specially-manufactured equipment and calibration standard from
Keysight. The recommended interval for recalibration is 12 months.
Equipment Supplied with the NFA
Installation 2
The following equipment is supplied from Keysight Technologies with the N8974A
and the N8975A Noise Figure Analyzer models for use with the Precision APC
3.5 mm smart noise sources:
– 8710-1761: 7.0 mm wrench
– 83059B: Precision 3.5 mm coaxial adapter
Equipment Available but not Supplied
The following equipment is available from Keysight Technologies for use with the
SNS series smart noise sources:
– 8710-1764: 20 mm 8 lb-in torque wrench
– 8710-1765: 5/16" 8 lb-in torque wrench
– 8710-1766: 3/4" 12 lb-in torque wrench (for use with Option 001)
Keysight N4000/1/2A Operating and Service Manual 19
2Installation
Options
The Keysight N4000A and N4001A noise sources are available with Option 001,
Type-N (male) output connector option.
Since the Type-N connectors are not suitable for use above 18.0 GHz, no output
connector option is available for the Keysight N4002A.
Mating connectors
The SNS series smart noise sources can be mated with other instrumentation
having the connectors listed in Tabl e 2-1.
Tab le 2-1 Connectors that can be mated with the noise
Configuration Mating connector
Input: all units
Output: standard APC-3.5 female
Option 001
sources
Multi-pin connector
Type-N female
[b]
[a]
[a] This is designed to operate with the NFA using the 11730 cable. A 11730A cable is supplied with the NFA.
[b] Must comply with U.S. Military Standard MII, C-39012.
20 Keysight N4000/1/2A Operating and Service Manual
Keysight N4000/1/2A SNS Series Smart Noise Sources
Operating and Service Manual
3 Specifications
General Specifications 22
Environmental Conditions 27
This chapter provides the specifications of the N4000/1/2A SNS Series Smart
Noise Sources.
21
3 Specifications
General Specifications
Specifications
The specifications in Table 3-1 are performance standards or limits against which
the SNS series smart noise source may be tested. These specifications for the
noise source are ONLY valid if the analyzer has been allowed to meet its specified
warm-up time.
The ENR expanded uncertainty analysis for noise source calibration is provided in
“Excess Noise Ratio expanded uncertainty (U(Y))” on page 23.
The “Supplemental characteristics” on page 26 are not specifications but are
typical characteristics included as additional information.
Tab le 3-1 N4000/1/2A specifications
Specification N4000A N4001A N4002A
Frequency range 10 MHz to 18 GHz 10 MHz to 18 GHz 10 MHz to 26.5 GHz
Excess Noise Ratio (ENR)
[a]
range
Impedance 50 Ω nominal 50 Ω nominal 50 Ω nominal
Operating temperature 0 to 55 °C 0 to 55 °C 0 to 55 °C
Maximum reverse power 1 watt 1 watt 1 watt
Maximum Standing Wave
Ratio (SWR)
[for source ON/OFF
states]
Reflection Coefficient
(Rho) (r)
[for source ON/OFF
[b]
states]
Connectors
[c]
4.5 to 6.5 dB 14 to 16 dB 12 to 17 dB
<1.06:1 (0.01 to 1.5 GHz)
<1.06:1 (1.5 to 3.0 GHz)
<1.13:1 (3.0 to 7.0 GHz)
<1.22:1 (7.0 to 18.0 GHz)
0.03 (0.01 to 1.5 GHz)
0.03 (1.5 to 3.0 GHz)
0.06 (3.0 to 7.0 GHz)
0.10 (7.0 to 18.0 GHz)
SNS output: APC-3.5 (male) standard or Type-N (male) Option 001
SNS input: Interconnect with 11730A/B/C cable
<1.15:1 (0.01 to 1.5 GHz)
<1.15:1 (1.5 to 3.0 GHz)
<1.20:1 (3.0 to 7.0 GHz)
<1.25:1 (7.0 to 18.0 GHz)
0.07 (0.01 to 1.5 GHz)
0.07 (1.5 to 3.0 GHz)
0.09 (3.0 to 7.0 GHz)
0.11 (7.0 to 18.0 GHz)
<1.22:1 (0.01 to 1.5 GHz)
<1.22:1 (1.5 to 3.0 GHz)
<1.22:1 (3.0 to 7.0 GHz)
<1.25:1 (7.0 to 18.0 GHz)
<1.35:1 (18.0 to 26.5 GHz)
0.10 (0.01 to 1.5 GHz)
0.10 (1.5 to 3.0 GHz)
0.10 (3.0 to 7.0 GHz)
0.11 (7.0 to 18.0 GHz)
0.15 (18.0 to 26.5 GHz)
[d]
22 Keysight N4000/1/2A Operating and Service Manual
Specifications 3
[a] ENR values are given at cardinal frequency points over the frequency range of each noise source. These values are stored within the noise
source’s internal EEPROM and documented on the calibration report.
[b] Maximum change in complex reflection coefficient between source ON and source OFF at all frequencies for N4000A only: 0.01.
[c] For correct connector usage, refer Tab le A- 2 for the torque settings.
[d] Type-N connector (Option 001) only available on the N4000A and N4001A models.
Characteristic
[1]
SWR at 23 °C
Figure 3-1 Characteristic SWR at 23 °C
Excess Noise Ratio expanded uncertainty (U(Y))
ENR values are given at cardinal frequency points over the frequency range of
each SNS series smart noise source. These values are stored within the noise
sources internal EEPROM and documented on the calibration report.
The uncertainty analysis for the calibration of the noise sources is in accordance
with the ISO/TAG4 Guide. The uncertainty data reported on the calibration report
is the expanded uncertainty (U(Y)) with 95% confidence level and a coverage
factor of 2. This uncertainty analysis is valid for APC 3.5 mm and Type-N
(Option 001) connector types.
[1] Characteristic values are met or bettered by 90% of instruments with 90% confidence.
Keysight N4000/1/2A Operating and Service Manual 23
3 Specifications
The uncertainty for each noise source can be unique to that noise source. The
uncertainty will typically vary by less than 0.01 dB at any frequency between
different noise sources produced in the same year when first produced.
Subsequent calibrations must be performed at suitably capable calibration
vendors in order to keep the uncertainties similar.
The standard level of calibration for the SNS series is Option A1R (calibration
against a 1-level removed reference standard). Another choice is Option APR
(calibration against a primary reference standard).
For Option A1R, performance can only be matched with a Standards Lab
Calibration, available from the Roseville Standards Lab at Keysight. For Option
APR, performance can only be matched by the National Physical Laboratory (NPL)
in the UK.
Using the appropriate calibration level should result in similar uncertainties to the
original production uncertainties. These will mostly be within 0.01 dB of the
original uncertainties, but they will vary with each calibration because they
include the repeatability observed on each device. Uncertainties for newly
produced devices include population repeatabilities instead of individual device
repeatabilities, and thus vary little between devices of the same model and option
configuration.
Figure 3-2 and Figure 3-3 show example uncertainties for standard (Option A1R)
production noise sources, as of the end of 2013. This time period is after
significant changes were made in the uncertainties from better understanding of
the error sources and improvements in the references from the National Metrology
Institute used, NPL. If NPL performance changes in the future, Keysight
uncertainties will follow those changes.
24 Keysight N4000/1/2A Operating and Service Manual
Specifications 3
Figure 3-2 Example ENR uncertainty versus frequency for the
N4000A model
Figure 3-3 Example ENR uncertainty versus frequency for the
N4001A and N4002A models
Keysight N4000/1/2A Operating and Service Manual 25
3 Specifications
Supplemental characteristics
Tab le 3-2 Supplemental characteristics
Physical specifications
Tab le 3-3 Physical specifications
Characteristic N4000/1/2A
ENR variation with temperature <0.01 dB/°C for 30 MHz to 26.5 GHz
Range 0 to 55 °C
Temperature sensing accuracy
Specifications N4000/1/2A
Net weight 0.160 kg (5.64 oz.)
Dimensions 112 × 38 × 30 mm (4.4 × 1.5 × 1.2 in)
Resolution 0.25 °C
Accuracy
– ±1° at 25 °C
– ±2° over 0 °C to 55 °C
26 Keysight N4000/1/2A Operating and Service Manual
Environmental Conditions
The 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
Temperature
Humidity <95% RH
Altitude
Specifications 3
Operating condition
– 0 °C to 55 °C
Storage/shipment condition
– –55 °C to 75 °C
Operating condition
– <4600 m (15000 ft)
Storage/shipment condition
– <15300 m (50000 ft)
Keysight N4000/1/2A Operating and Service Manual 27
3 Specifications
THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK.
28 Keysight N4000/1/2A Operating and Service Manual
Keysight N4000/1/2A SNS Series Smart Noise Sources
Operating and Service Manual
4 Operating Guide
Operating Instructions 30
Operator’s Maintenance 41
Performance Tests 41
Adjustments 41
Replaceable Parts 42
Service 46
This chapter provides simple quick-check instructions to verify the N4000/1/2A
SNS series smart noise source’s functionality prior to usage. It also provides
information on service and maintenance of the N4000/1/2A.
29
4 Operating Guide
CAUTION
Operating Instructions
This section refers to operation with the Keysight NFA Series Noise Figure
Analyzers. The Keysight SNS series smart noise sources work with these analyzers
as well as other Keysight analyzers. For more detailed operating instructions, refer
to the Keysight NFA Series Noise Figure Analyzers User’s Guide.
Use a DC blocking capacitor to protect the SNS series smart noise source
from damage when connected to any system where a DC voltage is present
on the output center conductor.
Noise figure measurements of devices (such as amplifiers, mixers, transistors, and
receivers) can be made using the SNS series smart noise source with a noise
figure analyzer. Figure 4-1 shows a simple test setup for a noise figure
measurement.
Figure 4-1 Typical noise figure measurement test setup
Recommended test equipment
30 Keysight N4000/1/2A Operating and Service Manual
All of the operator’s checks are performed using a Keysight Noise Figure Analyzer
NOTE
NOTE
with firmware version A.01.01 and above. This can be used to perform an
operational verification check.
Operator’s check
The operator’s checks in this section should be performed if failure of the SNS
series smart noise source is suspected. The checks can be used only to verify that
the SNS series smart noise sources are producing a broadband noise spectrum.
They cannot be used to check the units against specifications.
The operator’s checks are designed to find a fault in the SNS. However, the fault
could equally be with the cable and this should also be checked.
Operator’s check for data communication
The following procedure checks that the SNS can transfer the ENR data to the
NFA.
1 Remove any cables from the NFA input and SNS drive.
2 Press the Preset key. Wait until the preset routine is complete before
proceeding.
Operating Guide 4
The preset condition used is the NFA default of Preset (Factory).
3 Press the ENR key.
4 Press the SNS Setup menu key.
5 Press the Preference menu key and set it to Preference (SNS).
6 Press the Auto Load ENR menu key and set it to Auto Load ENR (Off).
7 Connect the SNS to the NFA Port using the multi-pin 11730 cable, as shown in
Figure 4-2 on page 32.
Keysight N4000/1/2A Operating and Service Manual 31
4 Operating Guide
Figure 4-2 Operator’s check test setup for data communication
8 Press the ENR key.
9 Press the ENR Mode menu key and set it to ENR Mode (Table).
10 Press the Common Table menu key and set it to Common Table (On).
11 Press the ENR Table menu key.
12 Press the Edit Table menu key and press the Clear Table menu key if there is
data in the ENR Table.
You are prompted to press this key again. This feature ensures you do not
accidentally clear a valid Frequency list table. Press the Clear Table menu key
again. Figure 4-3 on page 33 shows a typical cleared ENR table.
32 Keysight N4000/1/2A Operating and Service Manual
Operating Guide 4
Figure 4-3 A typical cleared ENR table
13 Press the Prev key.
14 Press the Fill Table From SNS menu key. Wait until the data is uploaded from
the SNS before proceeding.
15 Verify the data has been transferred from the SNS to the NFA. The data
transfer should be similar to Figure 4-4 on page 34. If it is not, return the SNS
to Keysight Technologies for repair.
Keysight N4000/1/2A Operating and Service Manual 33
4 Operating Guide
NOTE
Figure 4-4 A typical ENR table after data entry
Operator’s check for T
The following procedure checks that the SNS can transfer the T
NFA.
1 Remove any cables from the NFA input and SNS drive.
2 Press the Preset key. Wait until the preset routine is complete before
proceeding.
The preset condition used is the NFA default of Preset (Factory).
3 Press the ENR key.
4 Press the Tco ld menu key.
34 Keysight N4000/1/2A Operating and Service Manual
communication
cold
data to the
cold
Operating Guide 4
NOTE
5 Connect the SNS to the NFA Port using the multi-pin 11730 cable, as shown in
Figure 4-5 on page 35.
Figure 4-5 Operator’s check test setup for T
6 Press the SNS Tcold menu key and set it to SNS Tcold (Off).
7 Press the User Tcold menu key and set it to User Tcold (On).
The value displayed in the User Value menu key, typically 296.50 K. Figure 4-6
on page 36 shows a typical NFA menu map.
Keysight N4000/1/2A Operating and Service Manual 35
communication
cold
4 Operating Guide
Figure 4-6 Typical user value
8 Press the User Tcold From SNS menu key.
In the User Value menu key, the new ambient temperature value is displayed.
Figure 4-7 shows a typical NFA menu map.
Figure 4-7 Typical user value after uploading SNS value
36 Keysight N4000/1/2A Operating and Service Manual
Operating Guide 4
NOTE
9 If this value has not changed, warm the SNS by wrapping your hand around its
bulkhead as shown in Figure 4-8 for 20 seconds. This gives the SNS
thermometer time to change its ambient value. Then press the User Tcold
From SNS menu key again. The new ambient temperature value is displayed.
Figure 4-8 Operator’s check for T
10 If the value does not change, return the SNS to Keysight Technologies for
repair.
upload from SNS
cold
Operator’s check for switching noise source off and on
The following procedure checks that the SNS can switch the noise source off and
on. This ensures the excess noise switches.
1 Remove any cables from the NFA input and SNS drive.
2 Press the Preset key. Wait until the preset routine has completed before
proceeding.
The preset condition used is the NFA default of Preset (Factory).
Keysight N4000/1/2A Operating and Service Manual 37
4 Operating Guide
3 Connect the SNS to the NFA Port using the multi-pin 11730 cable, as shown in
Figure 4-9 SNS connected to NFA graphic
4 Press the Frequency/Points key.
5 Press the Frequency Mode menu key.
6 Press the Fixed menu key.
7 Press the Fixed Frequency menu key. Enter 1.0 GHz as a fixed frequency value,
Figure 4-9.
by pressing the 1 numeric key followed by pressing the GHz menu key.
8 Press the Sweep key.
9 Press the Manual Meas menu key.
10 Press the Manual State menu key and set it to Manual State (On).
11 Press the Noise Source menu key and set it to Noise Source (On).
12 Press the IF Att menu key and set it to IF Att (Hold).
13 Monitor the power value which appears in the manual measurement screen.
Figure 4-10 on page 39 shows a typical example of this.
38 Keysight N4000/1/2A Operating and Service Manual
Operating Guide 4
NOTE
Figure 4-10 Typical example of power reading with Noise Source On
14 Press the Noise Source menu key and set it to Noise Source (Off).
15 Monitor the power value which appears in the manual measurement screen.
Figure 4-11 on page 40 shows a typical example of this.
The monitored value is only to be used to indicate if the SNS is switching the
Excess Noise “On” and “Off” by showing a change in power value.
Keysight N4000/1/2A Operating and Service Manual 39
4 Operating Guide
Figure 4-11 Typical example of power reading with Noise Source Off
16 If there is no change in value, return the SNS to Keysight Technologies for
repair.
40 Keysight N4000/1/2A Operating and Service Manual
Operator’s Maintenance
Proper connector care is a vital part of the maintenance which should be
performed by the user. The life of the connector can be greatly extended by
following the general connector care practices outlined in “Appendix A: Caring for
Connectors” on page 59.
Performance Tests
Due to the specialized test equipment involved, there are no recommended
performance tests for the user to perform. Return the noise sources to Keysight
Technologies when tests are required to verify its performance and for periodic
re-calibration. The calibration must be traceable to the national standards
laboratories. The suggested interval before initial re-calibration is one year.
Adjustments
Operating Guide 4
There are no adjustments that can be made to the SNS series smart noise
sources.
Keysight N4000/1/2A Operating and Service Manual 41
4 Operating Guide
NOTE
Replaceable Parts
Table 4-1, Tab le 4-2, and Tab le 4-3 list all replaceable parts available for the
Keysight N4000/1/2A SNS series smart noise source. Figure 4-12 shows a typical
SNS series smart noise source being prepared for parts replacement at the
assembly level by removing the four end screws (two at each end).
To order parts, contact your local Keysight Sales and Service Office. Refer to
“Sales and Technical Support” on page 6 of this manual.
If the N4000/1/2A is opened and parts replaced, it requires re-calibration.
Tab le 4-1 Replaceable parts list for N4000A
Model/Option
Bulkhead RF
N4000A N4000-60020 00346-60194 00346-60193 00346-60194 N4000-60016
N4000A Opt 001 N4000-60021 00346-60194 00346-60193 00346-60194 N4000-60016
[a] Only replace these parts if you have calibration facilities to verify the SNS.
Noise cartridge
kit (serial prefix
≤ MY/SG/US5322)
Tab le 4-2 Replaceable parts list for N4001A and N4002A
Model/Option
N4001A N4001-60003 00346-60154 00346-60027 N4000-60001
N4001A Opt 001 N4001-60004 00346-60154 00346-60027 N4000-60001
N4002A N4002-60004 00346-60155 00346-60027 N4002-60001
[a] Only replace these parts if you have calibration facilities to verify the SNS.
Replacement bulkhead
assembly
Replacement noise
cartridge
[a]
Keysight part number
Noise cartridge
(serial prefix
≥ MY/SG5323)
[a]
Keysight part number
Attenuator replacement
kit
Attenuator kit PC board
PC board assembly
42 Keysight N4000/1/2A Operating and Service Manual
Table 4-3 Chassis parts
Operating Guide 4
Model
N4000A, N4001A, N4002A E9321-20002 MP1, MP2 Machined casting
N4000A, N4001A, N4002A E9321-00001 MP3, MP4 Shield
N4000A, N4001A, N4002A E9321-40001 MP5, MP6 Plastic shell
N4000A, N4001A, N4002A 0460-1919 MP7, MP8 Copper roll shielding tape
N4000A, N4001A, N4002A N4000-80002 MP9 Label - Caution
N4000A, N4001A, N4002A N4000-80003 MP10, MP11 Label - SNS Series
N4000A N4000-80001 MP12 Label - N4000A
N4001A N4001-80001 MP12 Label - N4001A
N4002A N4002-80001 MP12 Label - N4002A
N4000A, N4001A, N4002A 00346-80011 MP13 Label - Caution
Keysight part
number
Reference
designator
Description
Table 4-4 Documentation
Model Keysight part number Description
N4000A, N4001A, N4002A N4000-90001 Operating and Service Manual
Keysight N4000/1/2A Operating and Service Manual 43
4 Operating Guide
Figure 4-12 Illustrated parts breakdown
44 Keysight N4000/1/2A Operating and Service Manual
Operating Guide 4
Figure 4-13 SNS series smart noise source block diagram
Keysight N4000/1/2A Operating and Service Manual 45
4 Operating Guide
Service
Principles of operation
Referring to the SNS block diagram in Figure 4-13 on page 45, a constant +28 V
is supplied from the NFA through the multi-pin “Connector” block when the SNS
is connected to the noise figure analyzer. A voltage inverter is used in the N4000A
and N4001A to input approximately –25 V to the current regulator.
The current regulator applies a negative bias current to the noise diode for the
N4000A and N4001A models. The N4002A utilizes a positive bias, so the voltage
inverter is not necessary. The current regulator block also provides the switching
necessary to produce the noise “On” and “Off” states.
The 2-wire bus interface allows for data transfer to and from the noise source. The
data stored in the EEPROM includes model, serial number, diode current setting,
and SNS calibration data.
The power supply provides +5 V to the 2-wire bus interface, EEPROM, and digital
temperature sensor.
The digital temperature sensor is a digital thermometer, thermally coupled to the
microwave assembly.
When the smart noise source is in its “On” state, the noise diode produces
broadband noise which is input to the attenuator.
The attenuator sets the final Excess Noise Ratio (ENR) and output impedance of
the smart noise source. A 16 dB attenuator is used in the N4000A to provide
nominal ENR values of 5 dB. A 6 dB attenuator is used in the N4001A and N4002A
models for nominal ENR values of 15 dB.
The standard output connector is a Precision 3.5 mm. A Type-N connector is
optional.
Troubleshooting
Check the connectors and perform the operator’s check described in the
Operating Instructions section of this manual. If the operator’s check results
indicate a problem, or if the connectors are damaged, please contact Keysight
Technologies. Our representatives can help isolate the problem and make
arrangements for repairs if necessary.
46 Keysight N4000/1/2A Operating and Service Manual
Repair of defective noise source
NOTE
NOTE
CAUTION
Repair by the user is not recommended because of the complex equipment
required for test and calibration. However, a number of replacement parts are
available for customers with repair and calibration capabilities. See “Replaceable
Parts” on page 42.
This manual does not include specific repair procedures covering the
replacement of parts listed in “Replaceable Parts” on page 42.
Disassembly procedure
If the Keysight SNS series smart noise source is opened and parts are replaced, it
requires re-calibration.
Disassemble the noise source only in a static-free work area. Electrostatic
discharge can damage the noise source.
Operating Guide 4
Figure 4-14 Removing the smart noise source plastic shell
Keysight N4000/1/2A Operating and Service Manual 47
4 Operating Guide
Disassemble the SNS series smart noise source by performing the following steps.
1 At the rear of the noise source, insert the blade of a screwdriver between the
2 Pry alternately at both sides of the connector until the plastic shells are apart.
Reassembly procedure
1 Replace the magnetic shields and plastic shells as shown in Figure 4-12 on
2 Snap the plastic shells together.
Returning the SNS series smart noise source for calibration
When returning the N4000/1/2A to Keysight Technologies for calibration, send it
to your nearest Keysight Sales and Service Office. Refer to “Sales and Technical
Support” on page 6 of this manual.
plastic shells (see Figure 4-14 on page 47). To prevent damage to the shells,
use a screwdriver blade as wide as the slot between the two shells.
Remove the shells and the magnetic shields.
page 44.
48 Keysight N4000/1/2A Operating and Service Manual
Keysight N4000/1/2A SNS Series Smart Noise Sources
Operating and Service Manual
5 ENR File Format
Format Details 50
Viewing the Smart Noise Source ENR Data 55
Examples 56
This chapter explains the format of an ENR file.
49
5 ENR File Format
Format Details
An SNS ENR file:
– includes all data currently supplied on the printed noise source calibration
– can be viewed and edited using a standard text editor (for example Wordpad).
– is simple to create and interpret.
– is easily printable.
– is easily imported into Microsoft Excel.
Format
The ENR file is read line by line. Each line is terminated by either a linefeed
character or a carriage-return, linefeed pair. Each line must be less than 100
characters long, excluding the terminator.
Lines containing only whitespace (tab or space character) are ignored. Each line is
interpreted as one of three types of record:
report.
–Comment
– Header Field
–ENR Data
Comment records
A comment record must have either a ‘#’ or ‘!’ as the first character in the line. The
entire line is ignored. Comment records can appear at any point within the file.
Header fields
General form
Header fields must have a ‘[’ as the first character in the line. Each header field
has the general form:
– [FieldName OptionalValue]
–The ‘[’ must be the first character on the line.
50 Keysight N4000/1/2A Operating and Service Manual
ENR File Format 5
NOTE
NOTE
– The FieldName and OptionalValue, if present, must be separated by
whitespace.
– Whitespace following the ‘]’ is ignored.
– The file must start with one or more header fields (ignoring comments and
blank lines).
All header fields must appear at the beginning of the file before the ENR data
records. Mixing header fields and ENR data is not permitted.
Mandatory header fields
Certain header fields must be present. These are:
Table 5-1 Mandatory header fields
FieldName Description OptionalValue Description Example
Filetype
Version
Indicates the type of
file
Indicates the version of
the file format which
applies to this file
ENR
versionnumber
(formatted as
major.minor)
Only ’ENR’ is allowed
for ENR data files
Allows for future
changes in the file
format
[Filetype ENR]
[Version 1.0]
All mandatory fields must appear in the file before any optional header fields.
Optional header fields
The following header fields are also allowed.
Only the first two fields, Serialnumber and Model are currently used by the
noise figure analyzer.
Keysight N4000/1/2A Operating and Service Manual 51
5 ENR File Format
Tab le 5-2 Optional header fields
FieldName Description OptionalValue Description Example
Serialnumber
Model
Option
Caldate
Calduedate
Temperature
Humidity
Placeofcal
Trackingnum
Current
The serial number of
the SNS series smart
noise source
Identifies the SNS
series smart noise
source model
number
Identifies any model
code option
Date of calibration of
SNS series smart
noise source
Indicates date when
next calibration of
SNS series smart
noise source is due
Calibration
temperature
Calibration relative
humidity
Name of calibration
site
Tracking number
used during
manufacture
Calibrated value of
SNS current DAC
value
serialtext
modelcode Model code string [Model N4000A]
optioncode Option code string [Option 001]
date&time
date&time
value
value
placetext
value number [Trackingnum 100]
value number [Current 3000]
A string containing the
serial number
Formatted date and
optional time
Formatted date and
optional time
Number followed by unit.
Valid units are C, F, K
Number followed by
optional ‘%’
string containing the
place of calibration
[a]
[Serialnumber 3318A14223]
[Caldate 19991202.09:15:30]
[Calduedate 20001225]
[Temperature 24C]
[Humidity 40%]
[Placeofcal SouthQueensferry]
[a] If a unit is not specified, C will be used as the default unit.
The format of date&time parameters is YYYYMMDD[.hh:mm:ss], i.e. a 4-digit
year, 2-digit month, and 2-digit date, optionally followed by a ‘.’ then 2-digit
hour ‘:’ 2-digit minutes ‘:’ 2-digit seconds.
Unknown header fields are ignored by the noise figure analyzer. This allows for
future expansion.
52 Keysight N4000/1/2A Operating and Service Manual
ENR data
NOTE
ENR data records must be ordered from the lowest to the highest frequency.
General form
The noise figure analyzer attempts to interpret lines which are not comments or
header fields as ENR data. ENR data has the general form:
Freq [Funit] ENR [Eunit] [Euncert [on_mag on_phase off_mag
off_phase [on_mag_uncert [on_phase_uncert off_mag_uncert
off_phase_uncert]]]]
Square brackets signify optional fields.
Field separator
Each field is separated by whitespace. A single ‘,’ is allowed within or instead of
the whitespace.
ENR File Format 5
Numeric fields
With the exception of the two optional unit fields, the other fields are numeric.
Numbers are formatted as an optional sign, followed by a sequence of one or
more digits (which can include a single decimal point within the sequence),
followed by an optional exponent. The exponent consists of the ‘e’ or ‘E’ followed
by an optional sign followed by between one and three digits, for example, ‘10e6’
to represent 10 MHz.
Frequency fields
The frequency field (Freq) is the frequency at which the ENR amplitude was
measured.
The frequency unit field (Funit) is optional. The default unit is Hz.
Valid units are Hz, kHz, MHz, GHz, THz. Units are not case sensitive.
ENR fields
The ENR amplitude (ENR) is the measured ENR at the specified frequency.
Keysight N4000/1/2A Operating and Service Manual 53
5 ENR File Format
NOTE
The ENR unit field (Eunit) is optional. The default unit is dB. Currently, the only
allowed unit is dB. Note that units K, C, F (temperature) are reserved for possible
future use, but are not supported by the noise figure analyzer at this time.
The uncertainty field for the ENR amplitude (Euncert) is optional. However, this
field must be present if reflection coefficient data is supplied.
Reflection coefficient data
The reflection coefficient data is optional and is formatted as four fields
(on_mag, on_phase, off_mag, off_phase):
– reflection magnitude with SNS series smart noise source on
– reflection angle (in degrees) with SNS series smart noise source on
– reflection magnitude with SNS series smart noise source off
– reflection angle (in degrees) with SNS series smart noise source off
If any reflection coefficient data is supplied, then all four fields must be present.
The file format requires the ENR uncertainty field to be present before any
reflection data.
The reflection coefficient uncertainty (on_mag_uncert) is an optional parameter.
Either one or four reflection uncertainties are allowed. If one value is supplied, it is
assumed to apply to all reflection parameters. Alternatively, uncertainties can be
supplied for all four reflection parameters independently. Reflection coefficient
data must be present if this field is supplied.
54 Keysight N4000/1/2A Operating and Service Manual
Viewing the Smart Noise Source ENR Data
NOTE
NOTE
To view the ENR data you need a noise figure analyzer and a diskette.
For an explanation of saving a file to a diskette using the NFA, see the Noise
Figure Analyzer User’s Guide.
1 Connect the SNS to the NFA Port using the multi-pin 11730 cable, as shown in
Figure 4-2 on page 32.
Ensure the NFA is set to read the SNS data. See “Operator’s check for data
communication” on page 31 for further information.
2 Press the File key.
3 Press the Save menu key.
4 Press the ENR menu key.
5 Press the SNS menu key.
ENR File Format 5
6 Press the Tab key to highlight the Path: C:
Ensure ‘.’ ‘^UP^’ is highlighted.
7 Press the Select menu key.
Ensure the ‘[-A-]’ directory is highlighted.
8 Press the Select menu key.
9 Press the Enter key. Wait until the data is saved to the diskette.
10 You can now view the data on a PC using, for example, Wordpad as shown in
“Examples” on page 56.
The data is presented using Comma Separated Values (CSV). This allows you
to view it in a spreadsheet.
Keysight N4000/1/2A Operating and Service Manual 55
5 ENR File Format
Examples
Example 1
This first example shows a simple ENR file where the Frequency and ENR values
have been entered manually into the noise figure analyzer:
# ENR Data File
# Created by N8973A Keysight NFA Series Noise Figure Analyzer
# Serial Number GB40390000 Firmware Revision A.01.01
# 13:37:07 Mar 28, 2001
# Format is: Frequency (Hz), ENR (dB)
[Filetype ENR]
[Version 1.0]
10000000, 15.3500
100000000, 15.4230
1000000000, 15.2280
2000000000, 15.0900
3000000000, 14.9600
4000000000, 14.8400
5000000000, 14.7890
6000000000, 14.7500
7000000000, 14.7720
8000000000, 14.8570
9000000000, 14.9580
10000000000, 15.0600
11000000000, 15.0830
12000000000, 15.1950
13000000000, 15.2710
14000000000, 15.3430
15000000000, 15.4800
16000000000, 15.6750
17000000000, 15.8400
18000000000, 15.8940
56 Keysight N4000/1/2A Operating and Service Manual
Example 2
The second example is an SNS ENR file saved to a diskette:
# ENR Data File
# Created by N8975A NFA Series Noise Figure Analyzer
# Serial Number GB40390000 Firmware Revision A.01.01
# 13:37:07 Mar 28, 2001
# Format is: Frequency (Hz), ENR (dB), ENR Unc (dB),
# On Refl.Mag (lin), On Refl.Phase (deg),
# Off Refl.Mag (lin), Off Refl.Phase (deg),
# On Refl.Mag Unc (lin), On Refl.Phase Unc (deg),
# Off Refl.Mag Unc (lin), Off Refl.Phase Unc (deg)
[Filetype ENR]
[Version 1.1]
[Serialnumber US41240152]
[Model N4001A]
[Option 001]
[Caldate 20000727]
[Calduedate 20010727]
[Placeofcal EPSGQ]
[Trackingnum 10]
[Temperature 296.5K]
[Humidity 65%]
[Current 36272]
10000000,15.281,0.193,0.0450,-136.0,0.0450,-136.0,0.0030,-6.0,0.0070,
+6.0
100000000,15.291,0.190,0.0358,+168.0,0.0358,+168.0,0.0040,+4.6,0.0050,
-4.6
1000000000,15.118,0.151,0.0398,+39.6,0.0398,+39.6,0.0100,+4.5,0.0067,
+1.5
2000000000,14.999,0.168,0.0377,0.168,0.0377,-85.7,0.0056,+0.9,0.0086,
+1.9
3000000000,14.879,0.172,0.0267,+150.6,0.0267,+150.6,0.0080,-9.2,0.0090,
-1.2
4000000000,14.795,0.173,0.0130,-18.1,0.0130,-18.1,0.0013,+16.0,0.0063,
+10.0
5000000000,14.818,0.179,0.0359,+169.5,0.0359,+169.5,0.0024,-9.3,0.0035,
-0.3
6000000000,14.846,0.181,0.0556,+63.7,0.0556,+63.7,0.0041,+10.3,0.0067,
-4.3
ENR File Format 5
Keysight N4000/1/2A Operating and Service Manual 57
5 ENR File Format
NOTE
7000000000,14.895,0.180,0.0430,-37.0,0.0430,-27.0,0.0079,-2.3,0.0049,
-2.3
8000000000,15.016,0.198,0.0232,-160.3,0.0232,-160.3,0.0091,-3.8,0.0053,
-1.8
9000000000,15.134,0.201,0.0122,+71.4,0.0122,+71.4,0.0037,+17.3,0.0057,
+7.3
10000000000,15.253,0.194,0.0080,+116.2,0.0080,+116.2,0.0048,-1.4,0.0056
,-5.4
11000000000,15.249,0.243,0.0241,+65.7,0.0241,+65.7,0.0059,+1.5,0.0049,
+44.5
12000000000,15.349,0.240,0.0196,+8.8,0.0196,+8.8,0.0057,+3.2,0.0077,
+2.2
13000000000,15.383,0.188,0.0217,-5.4,0.0217,-5.4,0.0062,-6.9,0.0045,
-1.9
14000000000,15.355,0.178,0.0228,-66.6,0.0228,-66.6,0.0075,+11.2,0.0065,
+1.2
15000000000,15.367,0.187,0.0141,+141.6,0.0141,+141.6,0.0036,-3.2,0.0029
,-1.2
16000000000,15.421,0.182,0.0251,+6.4,0.0251,+6.4,0.0030,+7.2,0.0042,
-1.2
17000000000,15.418,0.174,0.0242,-100.5,0.0242,-100.5,0.0048,-2.7,0.0050
,+9.7
18000000000,15.464,0.179,0.0183,+124.4,0.0183,+124.4,0.0098,-1.1,0.0100
,+9.1
The values shown in Example 2 are representative of their position in the file.
Therefore, they may not be numerically accurate.
58 Keysight N4000/1/2A Operating and Service Manual
Keysight N4000/1/2A SNS Series Smart Noise Sources
Operating and Service Manual
A Caring for Connectors
Introduction 60
Visual Inspection 61
Cleaning 64
Mechanical Inspection: Connector Gages 67
Mechanical Specifications 68
Using Connector Gages 71
Making Connections 74
Adapters 78
Principles of Microwave Connector Care 80
The material contained in this appendix may not apply to the connector you are
using on the instrument.
59
A Caring for Connectors
Introduction
Recent advances in measurement capabilities have made connectors and
connection techniques more important than ever before. Damage to the
connectors on calibration and verification devices, test ports, cables, and other
devices represent an increasing burden in downtime and expense.
This Appendix will help you get the best performance from all coaxial microwave
connectors:
– To know what to look for when cleaning and inspecting them, in order to
preserve their precision and extend their life.
– To make the best possible microwave connections, improving the accuracy
and repeatability of all of your measurements, saving both time and money.
Connector part numbers
Refer to the latest edition of the Keysight RF & Microwave Test Accessories
Catalog for connector part numbers.
Handling and storage
Microwave connectors must be handled carefully, inspected before use and when
not in use, stored in a way that gives them maximum protection. Avoid touching
the connector mating plane surfaces and avoid setting the connectors
contact-end down, especially on a hard surface.
Never store connectors with the contact end exposed. Plastic end caps are
provided with all Keysight connectors and these should be retained after
unpacking and placed over the ends of the connectors whenever they are not in
use. Extend the threads of connectors that have a retractable sleeve or sliding
connector nut, then put the plastic end cap over the end of the connector.
Above all, never store any devices loose in a box or in a desk or a bench drawer.
Careless handling of this kind is the most common cause of connector damage
during storage.
60 Keysight N4000/1/2A Operating and Service Manual
Visual Inspection
Visual inspection and, if necessary, cleaning should be done every time a
connection is made.
Metal and metal by-product particles from the connector threads often find their
way onto the mating plane surfaces when a connection is disconnected and even
one connection made with a dirty or damaged connector can damage both
connectors beyond repair.
Magnification is helpful when inspecting connectors, but it is not required and
may actually be misleading. Defects and damage that cannot be seen without
magnification generally have no effect on electrical or mechanical performance.
Magnification is of great use in analyzing the nature and cause of damage and in
cleaning connectors, but it is not required for inspection.
Obvious defects and damage
Examine the connectors first for obvious defects or damage — badly worn plating,
deformed threads or bent, broken, or misaligned center conductors. Connector
nuts should move smoothly and be free of burrs, loose metal particles, and rough
spots.
Immediately discard, or mark for identification and send away for repair, any
connector that has obvious defects like these.
Caring for Connectors A
Mating plane surfaces
Flat contact between the connectors at all points on their mating plane surfaces is
required for a good connection. Therefore, particular attention should be paid to
deep scratches or dents and to dirt and metal or metal by-product particles on
the connector mating plane surfaces.
Also look for bent or rounded edges on the mating plane surfaces of the center
and outer conductors and for any signs of damage due to excessive or uneven
wear or misalignment.
Light burnishing of the mating plane surfaces is normal and is evident as light
scratches or shallow circular marks distributed more or less uniformly over the
mating plane surface. Other small defects and cosmetic imperfections are also
normal. None of these affect electrical or mechanical performance.
Keysight N4000/1/2A Operating and Service Manual 61
A Caring for Connectors
If a connector shows deep scratches or dents, particles clinging to the mating
plane surfaces, or uneven wear, clean it and inspect it again. Damage or defects
like dents or scratches, which are deep enough to displace metal on the mating
plane surface of the connector, may indicate that the connector itself is damaged
and should not be used. Try to determine the cause of the damage before making
further connections.
Precision 7 mm connectors
Precision 7 mm connectors, among them APC-7® connectors, should be
inspected visually with the center conductor collets in place, and whenever the
collet has been removed. See Figure A-1.
The collet itself should be inspected for edge or surface damage and for any signs
that the spring contacts are bent or twisted. If they are, replace the collet. When
the collet has been re-inserted, verify that it springs back immediately when
pressed with a blunt plastic rod or with the rounded plastic handle of the collet
removing tool. Never use a pencil or your finger for this purpose.
Figure A-1 Precision 7 mm connector
62 Keysight N4000/1/2A Operating and Service Manual
Sexed connectors
On sexed connectors, especially precision 3.5 mm and SMA connectors, pay
special attention to the female center conductor contact fingers (Figure A-2 and
Figure A-3). These are very easily bent or broken, and damage to them is not
always easy to see. Any connector with damaged contact fingers will not make
good electrical contact and must be replaced.
Caring for Connectors A
Figure A-2 Precision 3.5 mm connectors
Figure A-3 SMA connectors
Keysight N4000/1/2A Operating and Service Manual 63
A Caring for Connectors
NOTE
Cleaning
Careful cleaning of all connectors is essential to assure long, reliable connector
life, to prevent accidental damage to connectors, and to obtain maximum
measurement accuracy and repeatability. Yet it is the one step most often
neglected or done improperly. Supplies recommended for cleaning microwave
connectors are as follows:
– Compressed air
–Alcohol
– Cotton swabs
– Lint-free cleaning cloth
Compressed air
Loose particles on the connector mating plane surfaces can usually be removed
with a quick blast of compressed air. This is very easy to do and should always be
tried first using compressed air from a small pressurized can. The stream of air can
be directed exactly where it is wanted through a plastic (not metal) nozzle. No
hoses or other connections are needed. Hold the can upright, to avoid spraying
liquid along with the vapor.
Cleaning alcohol
Dirt and stubborn contaminants that cannot be removed with compressed air can
often be removed with a cotton swab or lint-free cleaning cloth moistened with
alcohol.
Use the least amount of alcohol possible, and avoid wetting any plastic parts in
the connectors with the alcohol.
Alcohol should be used in liquid rather than spray form. If a spray must be used,
always spray the alcohol onto a cloth or swab, never directly into a connector.
Very dirty connectors can be cleaned with pure alcohol. Other solutions that
contain additives should not be used.
64 Keysight N4000/1/2A Operating and Service Manual
Carefully avoid wetting the plastic support bead (which is easily damaged by
alcohol) inside the connector and blow the connector dry immediately with a
gentle stream of compressed air.
Precision 7 mm connectors
When precision 7 mm connectors have been cleaned with the center conductor
collet removed, insert the collet and clean the mating plane surfaces again.
When the connector is attached to a small component, or to a cable, calibration,
or verification standard, the easiest way to do this is to put a lint-free cleaning
cloth flat on a table and put a couple of drops of alcohol in the center of the cloth.
It should be noted that it is not necessary to remove the collet to use this cleaning
method.
Retract the connector sleeve threads so that the connector interface is exposed.
Gently press the contact end of the connector into the cloth moistened with
alcohol, then turn the connector.
Dirt on the connector interface will be scrubbed away by the cloth without
damaging the connector. Blow the connector dry with a gentle stream of
compressed air.
This cleaning method can be adapted even for fixed connectors such as those
attached to test ports. Simply fold the cloth into several layers of thickness,
moisten it, press it against the connector interface, and turn it to clean the
connector. Blow the connector dry with a gentle stream of compressed air.
Caring for Connectors A
Cleaning interior surfaces
Interior surfaces, especially on precision 3.5 mm connectors, are very difficult to
reach, and it is easy to damage connectors in trying to clean them. The openings
are very small, and generally the center conductor is supported only at the inner
end, by a plastic dielectric support bead. This makes it very easy to bend or break
the center conductor.
One suitable method (Figure A-4) is to cut off the sharp tip of a round wooden
toothpick, or a smaller diameter wooden rod, and then to wrap it with a single
layer of lint-free cleaning cloth.
Keysight N4000/1/2A Operating and Service Manual 65
A Caring for Connectors
NOTE
Figure A-4 Cleaning interior surfaces
Metal must never be used (it will scratch the plated surfaces), and in cleaning
precision 3.5 mm connectors the diameter must not exceed 0.070 in. (1.7 mm).
The wooden handle of a cotton swab, for example, is too large for this purpose.
Even though the handle can sometimes be inserted into the connector, even
when wrapped in lint-free cloth, movement of the handle against the center
conductor can exert enough force on the center conductor to damage it
severely.
Moisten the cloth with a small amount of alcohol and carefully insert it into the
connector to clean the interior surfaces. Use an illuminated magnifying glass or
microscope to see clearly the areas you wish to clean.
Drying connectors
When you have cleaned a connector, always be sure that it is completely dry
before reassembling or using it. Blow the connector dry with a gentle stream of
clean compressed air and inspect it again under a magnifying glass to be sure that
no particles or alcohol residues remain.
66 Keysight N4000/1/2A Operating and Service Manual
Mechanical Inspection: Connector Gages
Even a perfectly clean, unused connector can cause problems if it is mechanically
out of specification. Since the critical tolerances in microwave connectors are on
the order of a few ten-thousandths of an inch, using a connector gage is essential.
Before using any connector for the first time, inspect it mechanically using a
connector gage. How often connectors should be gaged after that depends upon
usage.
In general, connectors should be gaged whenever visual inspection or electrical
performance suggests that the connector interface may be out of specification,
for example due to wear or damage. Connectors on calibration and verification
devices should also be gaged whenever they have been used by someone else or
on another system or piece of equipment.
Precision 3.5 mm and SMA connectors should be gaged relatively more often than
other connectors, owing to the ease with which the center pins can be pulled out
of specification during disconnection.
Connectors should also be gaged as a matter of routine — after every 100
connections and disconnections initially, more or less often after that as
experience suggests.
Caring for Connectors A
Connector gage kits containing all of the items required are included in many
Keysight calibration kits. They are also available separately. Part numbers are as
follows:
Table A-1 Recommended connector gages
Type Part number/ordering information
Precision 7 mm (APC-7) 85050-80012
Precision 3.5 mm 11752D
Precision 2.4 mm 11752E
Type-N 85054-60047
Keysight N4000/1/2A Operating and Service Manual 67
A Caring for Connectors
Mechanical Specifications
The critical dimension to be measured, regardless of connector type, is the
position (generally, the recession or setback) of the center conductor relative to
the outer conductor mating plane.
Mechanical specifications for connectors specify a maximum distance and a
minimum distance that the center conductor can be positioned behind (or, in
female Type-N connectors, in front of) the outer conductor mating plane. Nominal
specifications for each connector type exist, but the allowable tolerances (and
sometimes the dimensions themselves) differ from manufacturer to manufacturer
and from device to device. Therefore, before gaging any connector, consult the
mechanical specifications provided with the connector or the device itself.
Precision 7 mm connectors
In precision 7 mm connectors, contact between the center conductors is made by
spring-loaded contacts called collets. These protrude slightly in front of the outer
conductor mating plane when the connectors are apart. When the connection is
tightened, the collets are compressed into the same plane as the outer
conductors.
For this reason, two mechanical specifications are generally given for precision
7 mm connectors — the maximum recession of the center conductor behind the
outer conductor mating plane with the center conductor collet removed; and a
minimum and maximum allowable protrusion of the center conductor collet in
front of the outer conductor mating plane with the collet in place.
The center conductor collet should also spring back immediately when pressed
with a blunt plastic rod or with the rounded plastic handle of the collet removing
tool. Never use a pencil or your finger for this purpose.
With the center conductor collet removed, no protrusion of the center conductor
in front of the outer conductor mating plane is allowable, and sometimes a
minimum recession is required. Consult the mechanical specifications provided
with the connector or the device itself.
68 Keysight N4000/1/2A Operating and Service Manual
Sexed connectors
NOTE
In Type-N and precision 3.5 mm connectors, the position of the center conductor
in the male connector is defined as the position of the shoulder of the male
contact pin — not the position of the tip. The male contact pin slides into the
female contact fingers and electrical contact is made by the inside surfaces of the
tip of the female contact fingers on the sides of the male contact pin.
50 Ω Type-N connectors
No Type-N connector should ever be used when there is any possibility of
interference between the shoulder of the male contact pin and the tip of the
female contact fingers when the connectors are mated. In practice this means
that no Type-N connector pair should be mated when the separation between
the tip of the female contact fingers and the shoulder of the male contact pin
could be less than zero when the connectors are mated. Gage Type-N
connectors carefully to avoid damage.
Type-N connectors differ from other connector types in that the outer conductor
mating plane is offset from the mating plane of the center conductors. The outer
conductor sleeve in the male connector extends in front of the shoulder of the
male contact pin. When the connection is made, this outer conductor sleeve fits
into a recess in the female outer conductor behind the tip of the female contact
fingers (Figure A-5).
Caring for Connectors A
Figure A-5 Type-N connectors
Keysight N4000/1/2A Operating and Service Manual 69
A Caring for Connectors
NOTE
Therefore the mechanical specifications of Type-N connectors give a maximum
protrusion of the female contact fingers in front of the outer conductor mating
plane and a minimum recession of the shoulder of the male contact pin behind the
outer conductor mating plane.
As Type-N connectors wear, the protrusion of the female contact fingers generally
increases, due to wear of the outer conductor mating plane inside the female
connector. This decreases the total center conductor contact separation and
should be monitored carefully.
75 Ω Type-N connectors
75 Ω Type-N connectors differ from 50 Ω Type-N connectors most significantly in
that the center conductor, male contact pin, and female contact hole are smaller.
Therefore, mating a male 50 Ω Type-N connector with a female 75 Ω Type-N
connector will destroy the female 75 Ω connector by spreading the female
contact fingers apart permanently or even breaking them.
If both 75 Ω and 50 Ω Type-N connectors are among those on the devices you
are using, identify the 75 Ω Type-N connectors to be sure that they are never
mated with any 50 Ω Type-N connectors.
70 Keysight N4000/1/2A Operating and Service Manual
Using Connector Gages
Before a connector gage is used, it must be inspected, cleaned, and zeroed.
Inspecting and cleaning the gage
Inspect the connector gage and the gage calibration block carefully, exactly as
you have inspected the connector itself. Clean or replace the gage or the block if
necessary (dirt on the gage or block will make the gage measurements of the
connectors inaccurate and can transfer dirt to the connectors themselves,
damaging them during gaging or when the connection is made).
Zeroing the gage
Zero the gage by following the steps described below. Be sure that you are using
the correct connector gage and correct end of the gage calibration block for the
connector being measured.
– Hold the gage by the plunger barrel (not the dial housing or cap) and, for male
connectors, slip the protruding end of the calibration block into the circular
bushing on the connector gage. For precision 7 mm, female precision 3.5 mm
use the flat end of the gage calibration block. For female Type-N connectors,
use the recessed end of calibration block.
– Hold the gage by the plunger barrel only (Figure A-6). Doing so will prevent
errors in gage readings due to the application of stresses to the gage plunger
mechanism through the dial indicator housing.
Caring for Connectors A
– Carefully bring the gage and gage block together, applying only enough
pressure to the gage and gage block to result in the dial indicator pointer
settling at a reading.
– Gently rock the two surfaces together, to make sure that they have come
together flatly. The gage pointer should now line up exactly with the zero mark
on the gage. If it does not, inspect and clean the gage and gage calibration
block again and repeat this process. If the gage pointer still does not line up
with the zero mark on the gage, loosen the dial lock screw and turn the
graduated dial until the gage pointer exactly lines up with zero. Then
re-tighten the lock screw.
Keysight N4000/1/2A Operating and Service Manual 71
A Caring for Connectors
NOTE
Figure A-6 Using the connector gage
Gages should be checked often, to make sure that the zero setting has not
changed. Generally, when the gage pointer on a gage that has been zeroed
recently does not line up exactly with the zero mark, the gage or calibration
block needs cleaning. Clean carefully and check the zero setting again.
Measuring connectors
Measuring the recession of the center conductor behind the outer conductor
mating plane in a connector is done in exactly the same way as zeroing the gage,
except of course that the graduated dial is not re-set when the measurement is
made.
If the connector has a retractable sleeve or sliding connector nut — precision
7 mm connectors, for example — extend the sleeve or nut fully. This makes it
easier to keep the gage centered in the connector.
Hold the gage by the plunger barrel and slip the gage into the connector so that
the gage plunger rests against the center conductor. Carefully bring the gage into
firm contact with the outer conductor mating plane.
72 Keysight N4000/1/2A Operating and Service Manual
Caring for Connectors A
Apply only enough pressure to the gage so that the gage pointer settles at a
reading.
Gently rock the connector gage within the connector, to make sure that the gage
and the outer conductor have come together flatly. Read the recession (or
protrusion) from the gage dial. (For maximum accuracy, measure the connector
several times and take an average of the readings.)
Rotate the gage relative to the connector between each measurement. To monitor
connector wear, record the readings for each connector over time.
Keysight N4000/1/2A Operating and Service Manual 73
A Caring for Connectors
Making Connections
Making good connections is easy if a few simple principles are kept in mind:
– All connectors must be undamaged, clean, and within mechanical
specification.
– The connectors must be precisely aligned with one another and in flat physical
contact at all points on the mating plane surfaces.
– The connection must not be too tight or too loose.
– Lateral or horizontal (bending) force must not be applied to the connection,
nor should any connection ever be twisted.
Align connectors carefully
Careful alignment of the connectors is critical in making a good connection, both
to avoid damaging connectors and devices and to assure accurate measurements.
As you bring one connector up to the other and as you make the actual
connection, be alert for any sign that the two connectors are not aligned perfectly.
If you suspect that misalignment has occurred, stop and begin again.
Alignment is especially important in the case of sexed connectors, such as
precision 3.5 mm and SMA connectors, to avoid bending or breaking the contact
pins. The center pin on the male connector must slip concentrically into the
contact fingers of the female connector. This requires great care in aligning the
two connectors before and as they are mated.
When they have been aligned, the center conductors must be pushed straight
together, not twisted or screwed together, and only the connector nut (not the
device itself) should then be rotated to make the connection. (slight resistance is
generally felt as the center conductors mate).
Alignment of precision 7 mm connectors is made easier by the fact that the
connector sleeve on one of the connectors must be extended fully (and the sleeve
on the other connector retracted fully) in order to make the connection. Extending
the sleeve creates a cylinder into which the other connector fits.
If one of the connectors is fixed, as on a test port, extend that connector sleeve
and spin its knurled connector nut to make sure that the threads are fully
extended, while on the other connector, fully retract the connector sleeve.
74 Keysight N4000/1/2A Operating and Service Manual
To make a preliminary connection
NOTE
Align the two connectors carefully and engage the connector nut over the
exposed connector sleeve threads on the other connector.
Gently turn the connector nut until a preliminary connection is made. Let the
connector nut pull the two connectors straight together. Do not twist one
connector body into the other (as you might drive a screw or insert a light bulb) as
this is extremely harmful and can damage the connectors.
When the mating plane surfaces make uniform, light contact, the preliminary
connection is tight enough. Do not overtighten this connection.
At this stage all you want is a connection in which the outer conductors make
gentle contact at all points on both mating surfaces. Very light finger pressure
(no more than 2 inch-ounces of torque) is enough.
Final connection using a torque wrench
When the preliminary connection has been made, use a torque wrench to make
the final connection. Tighten the connection only until the “break” point of the
wrench is reached, when the wrench handle gives way at its internal pivot point.
Do not tighten the connection further.
Also make sure that torque actually is being applied to the connection through the
torque wrench, not only to the wrench handle or in any way that prevents the
break point of the wrench from controlling the torque applied to the connection.
Suggestions to ensure that torque is actually being applied are given in Table A-2.
Caring for Connectors A
Using a torque wrench guarantees that the connection will not be too tight, thus
preventing possible damage to the connectors and impaired electrical
performance. It also guarantees that all connections will be made with the same
degree of tightness every time they are made.
Torque wrenches pre-set to the correct value for each connector type are included
in many Keysight calibration kits, and they are also available separately. Torque
settings are detailed in Table A -2.
When using a torque wrench, prevent rotation of anything other than the
connector nut that is being tightened with the torque wrench. Generally this is
easy to do by hand (all the more so if one of the connectors is fixed) as on a test
port. In other situations, an open-end wrench can be used to keep the bodies of
the connectors from turning.
Keysight N4000/1/2A Operating and Service Manual 75
A Caring for Connectors
Hold the torque wrench lightly by the knurled end of the handle only. Apply force
at the end of the torque wrench only, perpendicular to the wrench and always in a
plane parallel to the outer conductor mating planes. This will result in torque
being applied to the connection through the wrench until the break point of the
wrench is reached.
Avoid pivoting the wrench handle on the thumb or other fingers. This results in an
unknown amount of torque being applied to the connection when the break point
of the wrench is reached. Avoid twisting the head of the wrench relative to the
outer conductor mating plane. This results in applying more than the
recommended torque.
Tab le A-2 Recommended torque settings
Type Description
Precision 7 mm 12 lb-in (136 N-cm)
Precision 3.5 mm 8 lb-in (90 N-cm)
SMA
Type-N
5 lb-in (56 N-cm)
Use the SMA wrench to connect male SMA connectors to female precision
3.5 mm connectors.
Connections of male precision 3.5 mm connectors to female SMA connectors
can be made with the precision 3.5 mm torque wrench (8 lb-in).
Type-N connectors may be connected finger tight. If a torque wrench is used,
12 lb-in (136 N-cm) is recommended.
To reiterate the main do’s and do not’s detailed previously:
– Avoid holding the wrench tightly, in such a way that the handle is not pivoted
but simply pushed downward the same amount throughout its length. If this is
done, an unlimited amount of torque can be applied.
– Hold the wrench at the same point near the end of the handle every time, and
always in the same orientation. Whenever possible, begin tightening the
connection with the wrench held horizontally.
76 Keysight N4000/1/2A Operating and Service Manual
Disconnection
NOTE
Disconnect connectors by first loosening the connector nut that was tightened in
order to make the connection. If necessary, use the torque wrench or an open-end
wrench to start the process, but leave the connection finger tight. At all times
support the devices and the connection to avoid putting lateral (bending) force on
the connectors.
Complete the disconnection by disconnecting the connector nut completely.
Never disconnect connectors by twisting one connector or device out of the
other as one might remove a screw or a light bulb. This is extremely harmful and
connector damage can occur whenever the device body rather than the nut
alone is being turned.
If the connection is between sexed connectors, pull the connectors straight apart
and be especially careful not to twist the body of any device as you do so. Twisting
the connection can damage the connector by damaging the center conductors or
the interior component parts to which the connectors themselves are attached. It
can also scrape the plating from the male contact pin or even (in rare instances)
unscrew the male or female contact pin slightly from its interior mounting,
bringing it out of specification (this can also occur if the female contact fingers are
unusually tight).
Caring for Connectors A
Keysight N4000/1/2A Operating and Service Manual 77
A Caring for Connectors
CAUTION
Adapters
Adapters are used to connect a device with one connector interface to a device or
to test equipment that has another interface, or to reduce wear on connectors
that may be difficult or expensive to replace. Reducing wear is possibly the most
important use of adapters, especially when devices that have SMA connectors are
being used.
SMA connectors are low-cost connectors generally used up to about 23 GHz.
They are not precision mechanical devices and are not designed for repeated
connections and disconnections as they wear out quickly and are very often
found, upon assembly, to be out of specification, even before they have been
used. This makes them potentially destructive to any precision 3.5 mm connectors
with which they might be mated.
Worn, damaged, or out-of-specification SMA connectors can destroy a
precision 3.5 mm connector even on the very first connection. For this reason
it is recommended that you use high-quality precision adapters, sometimes
called “connector savers”, whenever more than a few connections are to be
made between SMA and precision 3.5 mm connectors.
In most applications two adapters will be required, one each at the input and the
output of the device. Male-female adapters cause no change in the sex of the
interface. The same interface is presented when the adapter is in place as is
presented in the original setup.
Same-sex adapters (male-male, female-female) change the sex of the interface.
For example, if the original interface presents a male connector, attaching a
female-female adapter will result in a female interface to which devices or cables
that have male SMA (or male precision 3.5 mm) connectors can be connected.
Adapters are included in many Keysight calibration kits and with many Keysight
devices, or they may be ordered separately.
78 Keysight N4000/1/2A Operating and Service Manual
Table A-3 Adapters
Type Description
– Precision 7 mm/male 3.5 mm
Precision 7 mm and Type-N
Precision 3.5 mm and SMA
– Precision 7 mm/female 3.5 mm
– Precision 7 mm/male 50 Ω Type-N
– Precision 7 mm/female 50 Ω Type-N
– Male 3.5 mm/female 3.5 mm
– Male 3.5 mm/male 3.5 mm
– Female 3.5 mm/female 3.5 mm
– Precision 7 mm/male 3.5 mm
– Precision 7 mm/female 3.5 mm
– “Connector saver” male 3.5 mm/female 3.5 mm
– “Connector saver” male 3.5 mm/male 3.5 mm
Caring for Connectors A
Keysight N4000/1/2A Operating and Service Manual 79
A Caring for Connectors
Principles of Microwave Connector Care
Tab le A-4 Principles of microwave connector care
Handling and storage
DO DO NOT
– Keep connectors clean. – Touch mating plane surfaces.
– Extend sleeve or connector nut. – Set connectors contact-end down.
– Use plastic end caps during storage.
Visual inspection
DO DO NOT
– Inspect each connector carefully before every
connection.
– Look for metal particles, scratches, and dents.
Cleaning
DO DO NOT
– Try compressed air first. – Use any abrasives.
– Clean connector threads. – Get liquid onto plastic support beads.
Gaging
– Use a damaged connector - EVER.
DO DO NOT
– Clean and zero the gage before using. – Use an out-of-spec connector.
– Use correct gage type.
– Use correct end of calibration block.
– Gage all connectors before first use.
Making connections
DO DO NOT
– Align connectors carefully. – Apply bending force to connection.
– Make preliminary connection lightly. – Overtighten preliminary connection.
– Turn connector nut only to tighten. – Twist or screw in connectors.
– Use a torque wrench for final connection. – Tighten past “break” point of torque wrench.
80 Keysight N4000/1/2A Operating and Service Manual
This information is subject to change
without notice. Always refer to the
Keysight website for the latest
revision.
© Keysight Technologies 2001 - 2017
Edition 4, May 26, 2017
Printed in Malaysia
*N4000-90009*
N4000-90009
www.keysight.com
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