Agilent Technologies N4000A Service manual

Smart Noise Sources
SNS Series
Operating and Service Guide
N4000A, N4001A, and N4002A
Manufacturing Part Number: N4000-90001
March 2001
© Copyright 2001 Agilent Technologies
Test Equipment Depot - 800.517.8431 - 99 Washington Street Melrose, MA 02176 - TestEquipmentDepot.com

ii
Notice
Information contained in this document is subject to change without
notice. Agilent Technologies makes no warranty of any kind with regard
to this material, including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose. Agilent
Technologies shall not be liable for errors contained herein or for
incidental or consequential damages in connection with the furnishings,
performance, or use of this material. No part of this document may be
photocopied, reproduced, or translated to another language without the
prior written consent of Agilent Technologies.
Certification
Agilent Technologies certifies that this product met its published
specifications at the time of shipment from the factory. Agilent
Technologies further certifies that its calibration measurements are
traceable to the United States National Institute of Standards and
Technology, to the extent allowed by the Institute’s calibration facility,
and to the calibration facilities of other International Standards
Organization members.
Warranty
This Agilent Technologies instrument product is warranted against
defects in material and workmanship for a period of one year from date
of shipment. During the warranty period, Agilent Technologies will at its
option, either repair or replace products which prove to be defective. For
warranty service or repair, this product must be returned to a service
facility designated by Agilent Technologies. Buyer shall prepay shipping
charges to Agilent Technologies and Agilent Technologies shall pay
shipping charges, duties, and taxes for products returned to Agilent
Technologies from another country. Agilent Technologies warrants that

iii
its software and firmware designated by Agilent Technologies for use
with an instrument will execute its programming instructions when
properly installed on that instrument. Agilent Technologies does not
warrant that the operation of the instrument, or firmware will be
uninterrupted or error free.
Limitation of Warranty
The foregoing warranty shall not apply to defects resulting from
improper or inadequate maintenance by Buyer, Buyer-supplied software
or interfacing, unauthorized modification or misuse, operation outside of
the environmental specifications for the product, or improper site
preparation or maintenance.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. AGILENT
TECHNOLOGIES SPECIFICALLY DISCLAIMS THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE.
Exclusive Remedies
THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND
EXCLUSIVE REMEDIES. AGILENT TECHNOLOGIES SHALL NOT
BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL,
OR CONSEQUENTIAL DAMAGES, WHETHER BASED ON
CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.
Safety Notices
This guide uses warnings and cautions to denote hazards.

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WARNING Warning denotes a hazard. It calls attention to a procedure
which, if not correctly performed or adhered to, could result in
injury or loss of life. Do not proceed beyond a warning note until
the indicated conditions are fully understood and met.
CAUTION Caution denotes a hazard. It calls attention to a procedure that, if not
correctly performed or adhered to, could result in damage to or
destruction of the instrument. Do not proceed beyond a caution sign until
the indicated conditions are fully understood and met.
NOTE Note calls out special information for the user’s attention. It provides
operational information or additional instructions of which the user
should be aware.
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.
Table 1 Safety Symbols
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.

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Electromagnetic Compatibility
This product conforms with the protection requirements of European
Council Directive 89/336/EEC for Electromagnetic Compatibility (EMC).
The conformity assessment requirements have been met using the
technical Construction file route to compliance, using EMC test
specifications EN 55011:1991 (Group 1, Class A) and EN 50082-1:1992.
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. See the Declaration of Conformity on page vi.
Radio-Frequency Electromagnetic Field
Immunity
When a 3 Vm-1 radio-frequency electromagnetic field is applied to the
Smart Noise Source according to IEC 61000-4-3:1995, 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.

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Declaration of Conformity

Contents
vii
1. General Information
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
Specifications - Table 1-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Excess Noise Ratio Expanded Uncertainty (U(Y)) - Table 1-2 . . . . . .6
Supplemental Characteristics - Table 1-3 . . . . . . . . . . . . . . . . . . . . . .8
Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Equipment Supplied with the NFA. . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Equipment Available But Not Supplied . . . . . . . . . . . . . . . . . . . . . . . .10
Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Recommended Test Equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Handling Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Initial Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Returning an SNS to Agilent for Repair. . . . . . . . . . . . . . . . . . . . . . . .12
Mating Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Connectors That Can Be Mated With the Noise Sources . . . . . . . . .12
Storage and Shipping Environment . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Operating Environment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Operator’s Maintenance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Operator’s Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Operator’s Check for Data Communication. . . . . . . . . . . . . . . . . . . .15
Operator’s Check for Tcold Communication . . . . . . . . . . . . . . . . . . .18
Operator’s Check for Switching Noise Source Off and On . . . . . . . .21
Performance Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Replaceable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

viii
Contents
Replaceable Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Replaceable Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Chassis Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Documentation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Principles of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Repair of Defective Noise Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Disassembly Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Reassembly Procedure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Returning a Noise Source for Calibration . . . . . . . . . . . . . . . . . . . . . . 31
Agilent Technologies Sales and Service Offices . . . . . . . . . . . . . . . . 32
2. ENR File Format
Format Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Comment Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Header Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
ENR Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Viewing the Smart Noise Source ENR Data. . . . . . . . . . . . . . . . . . . . . . 39
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
A. Caring for Connectors
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Connector Part Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Handling and Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Visual Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Obvious Defects and Damage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Mating Plane Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Precision 7 mm Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Contents
ix
Sexed Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Cleaning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
Compressed Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
Cleaning Alcohol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
Precision 7 mm Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50
Cleaning Interior Surfaces. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Drying Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Mechanical Inspection: Connector Gages. . . . . . . . . . . . . . . . . . . . . . . . .53
Mechanical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Precision 7mm Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Sexed Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
50 Ohm Type-N Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
75 Ohm Type-N Connectors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Using Connector Gages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Inspecting and Cleaning the Gage . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Zeroing the Gage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Measuring Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Making Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
Align Connectors Carefully . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60
To Make a Preliminary Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . .61
Final Connection Using a Torque Wrench . . . . . . . . . . . . . . . . . . . . . .62
Disconnection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
Adapters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Principles of Microwave Connector Care . . . . . . . . . . . . . . . . . . . . . . . . .67

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Contents

1
1 General Information

2Chapter 1
General Information
Introduction
Introduction
This manual contains operating and service information for the Agilent
SNS Series Smart Noise Sources, models; N4000A, N4001A, and
N4002A.
The Agilent SNS Series Smart Noise Sources have been designed to work
with the Agilent NFA Series Noise Figure Analyzers.
Figure 1-1 An Agilent SNS Smart Noise Source
Specifications
The “Specifications - Table 1-1” on page 3, page 4, and page 5 are
performance standards or limits against which the 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 of 60
minutes.
ENR expanded uncertainty analysis for noise source calibration in
“Excess Noise Ratio Expanded Uncertainty (U(Y)) - Table 1-2” on page 6
and page 7. The “Supplemental Characteristics - Table 1-3” on page 8
are not specifications but are typical characteristics included as
additional information for the user.

Chapter 1 3
General Information
Introduction
Specifications - Table 1-1
NOTE Specifications are valid at ambient temperature 23 oCelsius only (296 K).
Frequency Range
Excess Noise
Ratio (ENR)
Range1
Impedance
Operating
Temperature
Maximum reverse
power
N4000A and N4001A 10 MHz - 18 GHz
N4002A 10 MHz - 26.5 GHz
1. 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.
N4000A 4.5 - 6.5 dB
N4001A 14 - 16 dB
N4002A 12 - 17 dB
50 ohm nominal
0 oC to 55 oC
1 Watt

4Chapter 1
General Information
Introduction
Specifications - Table 1-1 Continued
Maximum
Standing Wave
Ratio (SWR) and
Reflection
Coefficient (ρ)
Source ON/OFF
States
Instrument model Frequency Range
(GHz)
Maximum
Standing Wave
Ratio (SWR)
Reflection
Coefficient
(Rho) (ρ)
N4000A10.01-1.5 <1.06:1 0.03
1.5 - 3.0 <1.06:1 0.03
3.0 - 7.0 <1.13:1 0.06
7.0 - 18.0 <1.22:1 0.10
N4001A 0.01-1.5 <1.15:1 0.07
1.5 - 3.0 <1.15:1 0.07
3.0 - 7.0 <1.20:1 0.09
7.0 - 18.0 <1.25:1 0.11
N4002A 0.01-1.5 <1.22:1 0.10
1.5 - 3.0 <1.22:1 0.10
3.0 - 7.0 <1.22:1 0.10
7.0 - 18.0 <1.25:1 0.11
18.0 - 26.5 <1.35:1 0.15
1. Maximum change in complex reflection coefficient between source ON
and source OFF at all frequencies for N4000A only: 0.01.

Chapter 1 5
General Information
Introduction
Specifications - Table 1-1 Continued
Figure 1-2 Characteristic1SWR at 23 oC
Connectors2
Dimensions
Net Weight
1. Characteristic values are met or bettered by 90% of instruments with 90% confidence.
2. For correct connector usage, refer Table A-2 for the torque settings.
SNS Output APC-3.5 (male) standard or Type-N (male) Option 0011
SNS Input Interconnect with 11730A/B/C cable to use with NFA.
1. Type-N connector (option 001) only available on the N4000A and
N4001A models.
112 x 38 x 30 mm (4.4 x 1.5 x 1.2 in)
0.160 kg (5.64 oz.)

6Chapter 1
General Information
Introduction
Excess Noise Ratio Expanded Uncertainty (U(Y)) - Table 1-2
ENR values are given at cardinal frequency points over the frequency
range of each 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 3.5mm and Type-N (option 001) connector types.
A significant proportion of the expanded uncertainty (U(Y)) is based on
the uncertainties provided by the National Standards Institutes. Agilent
therefore reserve the right to change the overall expanded uncertainties
based on changes in uncertainty values within the National Standards
Institutes.
Uncertainties are valid at ambient temperature 23°C ±1°C (296K) only.
A typical characteristic plot of ENR (U(Y)) versus each cardinal
frequency point is shown in Figure 1-3.
Figure 1-3 Characteristic1ENR Plot versus Cardinal Frequency Points
1. Characteristic values are met or bettered by 90% of instruments with 90% confidence.

Chapter 1 7
General Information
Introduction
Excess Noise Ratio Expanded Uncertainty (U(Y)) - Table 1-2
Continued
Characteristic
ENR (U(Y))
Specification
Instrument model Frequency
(GHz)
ENR Uncertainty (±dB)1
N4000A 0.01-1.5 0.16
1.5 - 3.0 0.15
3.0 - 7.0 0.15
7.0 - 18.0 0.16
N4001A 0.01-1.5 0.14
1.5 - 3.0 0.13
3.0 - 7.0 0.13
7.0 - 18.0 0.16
N4002A 0.01-1.5 0.15
1.5 - 3.0 0.13
3.0 - 7.0 0.13
7.0 - 18.0 0.15
18.0 - 26.5 0.22
1. Characteristic values are met or bettered by 90% of instruments with
90% confidence.

8Chapter 1
General Information
Introduction
Supplemental Characteristics - Table 1-3
Supplemental
Characteristics
ENR variation with
temperature:
<0.01 dB/°C for 30 MHz to 26.5 GHz
Temperature Sensing
Accuracy
Range 0 to 55 oC
Resolution 0.25 oC
Accuracy ± 1o at 25 oC
± 2o over 0 oC to 55 oC

Chapter 1 9
General Information
Description
Description
The 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 NFA and control the
calculation of the Tcold 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 Agilent
SNS models N4000A and N4001A.
Warranty
The noise sources are warranted and certified as indicated in this
manual. Connector damage resulting from improper use is not covered
under warranty.
Equipment Supplied with the NFA
The following equipment is supplied from Agilent 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 3.5mm Coaxial Adaptor

10 Chapter 1
General Information
Description
Equipment Available But Not Supplied
The following equipment is available from Agilent Technologies for use
with the noise sources:
• 8710-1764: 20mm 8lb-in Torque Wrench
• 8710-1765: 5/16" 8lb-in Torque Wrench
• 8710-1766: 3/4" 12lb-in Torque Wrench (for use with option 001)
Options
The Agilent N4000A and N4001A Noise Sources are available with the
following output connector options:
• Option 001, Type-N (male)
Since the Type-N connectors are not suitable for use above 18.0 GHz, no
output connector options are available for the Agilent N4002A.
Recommended Test Equipment
All of the operator’s checks are performed using an Agilent Noise Figure
Analyzer with firmware version A.01.01 and above. This can be used to
perform an operational verification check.