Agilent N4002A Product Overview

Agilent
N4000A, N4001A, N4002A
SNS Series Noise Sources
10 MHz to 26.5 GHz

Product Overview

Advances in Noise Figure Accuracy

N4000A

Used for low noise figure devices
or devices sensitive to mismatch
in the 10 MHz to 18 GHz range

N4001A

Used for general purpose measurements
in the 10 MHz to 18 GHz range

N4002A

Used for measurements in the
10 MHz to 26.5 GHz range

2

The Agilent SNS Series of noise sources work in conjunction with the
Agilent NFA Series of noise figure analyzers to simplify measurement
set-up and improve accuracy. When connected to the Agilent NFA
Series, the noise sources automatically download electronically
stored calibration data to the analyzers. The noise sources also have
the capability to automatically measure their own temperature so
that compensation can be applied to the calibration data. These
capabilities increase the overall reliability and accuracy of noise
figure measurements.

SNS Series key features and benefits

• Automatic download of ENR data to the NFA speeds overall
setup time

• Electronic storage of Excess Noise Ratio (ENR) calibration data
decreases the opportunity for user error.

• Temperature sensing improves measurement accuracy, leading to
tighter specification of device performance.

The N4000A and N4001A, which cover the 10 MHz to 18 GHz
frequency range, come with an APC 3.5 (m) connector as standard,
and offer the option of a Type-N (m) connector.

The N4002A, which covers the frequency range 10 MHz to 26.5 GHz,
has an APC 3.5 (m) connector as standard.

Noise sources designed to
meet specific needs

Automatically downloaded ENR data table in
the NFA Series of noise figure analyzers

3

N4000A for low noise
figure or mismatch
sensitive devices
up to 18 GHz

N4001A for general
purpose measurements
from 10 MHz to 18 GHz

N4002A for measurements
up to 26.5 GHz

The N4000A is designed to accurately measure devices with low
noise figure, or devices whose gain is especially sensitive to small
changes in source impedance. This includes most GaAs FET’s. The
N4000A maintains the same impedance whether turned on or off. By
maintaining the same impedance at the input to the device under
test (DUT) gain changes are reduced. These gain changes can often
masquerade as DUT noise and cause noise figure measurement
errors.

The ENR of this noise source is nominally 6 dB from 10 MHz to 18
GHz. DUTs with noise figures up to 20 dB can be accurately and
reliably measured with this device. The N4000A noise source has a
choice of connectors, with an APC 3.5 (m) as standard.

The N4001A noise source is ideal for general purpose use with a low
reflection coefficient and a nominal ENR of 15 dB from 10 MHz to
18 GHz. DUT’s with noise figures up to 30 dB can be measured
accurately and reliably with this device. The N4001A has a selection
of connectors, with an APC 3.5 (m) as standard.

The N4002A noise source was designed to measure DUT noise figures
reliably and accurately up to 30 dB from 10 MHz up to 26.5 GHz
accurately and reliably. This noise source comes with an APC 3.5
connector as standard.

4

The output of a noise source, usually given in terms of Excess Noise
Ratio (ENR), must be known in order to make accurate noise figure
measurements. Any uncertainty in the ENR transfers into
uncertainty of the measured noise figure, dB for dB. Agilent provides
accurate ENR calibration data with each noise source. ENR
uncertainty and reflection coefficients at each frequency point are
provided as well.

The following is an example of calibration data for an N4001A
noise source:

# ENR Data File
# Created by N8975A NFA Series Noise Figure Analyzer
# Serial Nmber 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 Ref l.Mag Unc (lin), On Refl.Phase Unc (deg),
# Off Refl.Mag Unc (lin), Off Ref l.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,
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,

Accurate noise power

5

The importance of
noise source reflection
coefficient

Two aspects of noise source reflection coefficient are important to
note:

• A non-zero reflection coefficient contributes to re-reflections

between the DUT and the source. The reflections cause
uncertainty in the noise power emerging from the source. The
measured noise figure, furthermore, refers to the actual noise
source impedance rather than the desired 50Ω value. The low
reflection coefficient of Agilent SNS Series noise sources can keep
this uncertainty under 0.1 dB.

• The change in ref lection coefficient between On and Off can

cause DUT Gain variations which, in turn, can cause noise figure
measurement errors. This problem is effectively eliminated by the
N4000A, whose complex reflection coefficient change is specified
to be less than 0.01.

6

Choosing between the
N4000A and the N4001A

The key difference between the N4000A and the N4001A noise
sources is the nominal 6 dB ENR of the N4000A whereas the N4001A
has a nominal 15 dB ENR.

Consider the 6 dB ENR noise source when

• The DUT is especially sensitive to source impedance changes
at its input

• There is a need to measure very low noise figures

• The noise figure does not exceed 20 dB

The N40001A is well suited to general-purpose measurements up to
18 GHz, whereas the N4000A is better suited to making measure­ments on lower noise devices or devices which are sensitive to
changes in input impedance. The N4000A contains additional
internal attenuation, which provides greater isolation at its output.
It is less affected by the ON/OFF condition that is the output
impedance of the N4001A. There is a benefit of using a N4000A
rather than a N40001A with an added attenuator. The extra atten­uaton in the N4000A is included in its calibration and is fully
traceable.

7

SNS Series noise source
specifications

Supplemental
characteristics

Specifications

The specifications 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. Specifications are valid at
ambient temperature 23°Celsius only (296 K).

Instrument model Frequency range ENR range

N4000A 10 MHz to 18 GHz 4.5 - 6.5 dB
N4001A 10 MHz to 18 GHz 14 - 16 dB
N4002A 10 MHz to 12 GHz 12 - 16 dB

12 MHz to 26.5 GHz 14 - 17 dB

Figure 1. Characteristic SWR at 23°C

Instrument Frequency Max standing Reflection
model range (GHz) wave ratio (SWR) coefficient (Rho) (p)

N4000A 0.01 - 1.5 < 1.04:1 0.02

1.5 - 3.0 < 1.04:1 0.02

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

Maximum change in complex reflection coefficient between noise
source ON and OFF states: 0.01

Supplemental characteristics are not specifications but are typical
characteristics included as additional information for the user.

ENR variation with temperature: < 0.01 dB/°C for 30 MHz to 26.5
GHz

Range: 0 to 55°C
Resolution: 0.25°C
Accuracy: ±1° at 25°C

±2° over 0°C to 55°C

Termperature sensing
accuracy

8

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 in 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.

ENR uncertainty

Instrument model Frequency (GHz) (± 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 betterd by 90% of instruments with 90% confidence.

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 2.

Figure 2. Characteristic ENR plot versus cardinal frequency points

Characteristic ENR (U(Y))
specification

9

Connector care for the
APC-3.5 (m) connector

The APC-3.5 (m) connector is designed for instrumentation
applications requiring long life, low reflection coefficient, and good
mating capabilities with SMA connectors.

The APC-3.5 (m) can achieve a life expectancy of over 1000
connections if precautions as listed below are taken:

1. Use a torque wrench set to the recommended torque.

2. Tighten the nut only, to prevent the connectors rotating with

respect to each other. Friction causes rapid wear of the conducting
surfaces.

3. Clean connectors after every 10 connections.

4. Mate with APC-3.5 connectors in good condition.

Casual use of the connector can reduce the life expectancy of
APC-3.5 (m) connectors to fewer than 200 connections. Below is a
list of several actions that may also reduce the life expectancy of the
APC-3.5 (m).

1. Estimating the torque with an ordinary wrench.

2. Twisting the noise source body (accidentally or otherwise) during

final tightening or when loosening.

3. Frequent mating with worn-out SMA connectors. This can be a

problem with frequently used accessories.

The APC-3.5 (m) connector used on the SNS Series of noise sources
has an extra-large nut to make it easier to tighten without applying
torque to the noise source body. A 20 mm torque wrench is also
available from Agilent for this application. Please contact your local
Agilent representative for ordering information.

Agilent 20mm torque wrench 8710-1764

10

Ordering information

Products

N4000A SNS Series noise source, 10 MHz to 18 GHz, nominal ENR 6 dB
N4001A SNS Series noise source, 10 MHz to 18 GHz, nominal ENR 15 dB
N4002A SNS Series noise source, 10 MHz to 26.5 GHz, nominal ENR 15 dB

All of these noise sources are provided with an APC 3.5 (m)
connector as standard

Options

The following option is available with the N4000A and the N4001A:

Connector

N400xA-001 Type-N (m) connector

Service options

Warranty and service

For 3 years, order 36 months of R-51B. For 5 years, order 60 months.
Standard warranty is 12 months.

R-51B Return to Agilent warranty and service plan

Calibration1

For 3 years, order 36 months of the appropriate calibration plan shown
below. For 5 years, specify 60 months.

R-50C-001 Standard calibration plan
R-50C-002 Standard compliant calibration plan

Recommended accessories

The new SNS Series of noise sources requires a compatible cable and
adaptor to enable their use. The cables are supplied with the NFA
Series noise figure analyzers and are also available as separate items.

11730A: 5-foot (1.5 m) power sensor and SNS noise source cable
(supplied with NFA)
11730B: 10-foot (3.0m) power sensor and SNS noise source cable
11730C: 20-foot (6.1m) power sensor and SNS noise source cable

A good quality adaptor must be used to connect the SNS series noise
source to the input of the NFA series noise figure analyzer. Agilent
provides a suitable connector upon purchasing an NFA. These adaptors
are also available separately.

83059B precision 35 mm coaxial adaptor

Agilent recommends a torque wrench for use with the large sized (20
mm) APC 3.5 (m) connectored nut found on the Agilent SNS Series
noise sources. Agilent also recommends a torque wrench for use with
the 5/16” connector on the female to female adaptor when used in
conjunction with the NFA Series noise figure analyzers.

8710-1764: 20 mm torque wrench
8710-1765: 5/16” torque wrench

11

The SNS Series of noise sources is designed specifically for use with
the Agilent NFA Series of noise figure analyzers. The NFA Series are
recognized as the industry standard for making noise figure
measurements. The NFA Series of noise figure analyzers increases
speed and accuracy, and offers improved usability. When used in
conjunction with the new SNS Series, the NFA Series delivers
increased measurement accuracy and convenience to the operator.

Agilent instruments are backed up with a full spectrum of literature
and support offerings. A detailed listing follows.

NFA Series - Noise Figure Analyzers - Brochure,
Literature number 5980-0166E

NFA Series - Noise Figure Analyzers - Configuration guide,
Literature number 5980-0163E

NFA Series - Noise Figure Analyzers - NFA Series - Data Sheet
Literature number 5980-0164E

NFA Series - Noise Figure Analyzer - Programming Examples,
Literature number 5968-9498E

Fundamentals of RF and Microwave Noise Figure Measurements,
Application Note 57-1, Literature number 5952-8255

Noise Figure Measurement Accuracy, Application Note 57-2,
Literature number 5968-4545E

10 Hints for Making Successful Noise Figure Measurements,
Application Note 57-3, Literature number 5980-0288E

Key web resources

For the latest information on Agilent noise figure solutions,
visit our web page at:

www.agilent.com/find/nf

For the latest news on the component test industry,
visit our web page at:

www.agilent.com/find/component_test

Noise Figure Literature
from Agilent

Microsoft®is a U.S. registered trademark
of Microsoft Corp.

Windows®and MS Windows®are U.S.
registered trademarks of Microsoft Corp.

www.agilent.com/find/emailupdates

Get the latest information on the
products and applications you select.

Agilent Email Updates

Agilent Technologies’ Test and
Measurement Support, Services, and
Assistance

Agilent Technologies aims to maximize the
value you receive, while minimizing your risk
and problems. We strive to ensure that you
get the test and measurement capabilities
you paid for and obtain the support you
need. Our extensive support resources and
services can help you choose the right
Agilent products for your applications and
apply them successfully. Every instrument
and system we sell has a global warranty.
Support is available for at least five years
beyond the production life of the product.
Two concepts underlie Agilent’s overall
support policy: “Our Promise” and “Your
Advantage.”

Our Promise

Our Promise means your Agilent test and
measurement equipment will meet its
advertised performance and functionality.
When you are choosing new equipment, we
will help you with product information,
including realistic performance
specifications and practical
recommendations from experienced test
engineers. When you use Agilent equipment,
we can verify that it works properly, help
with product operation, and provide basic
measurement assistance for the use of
specified capabilities, at no extra cost upon
request. Many self-help tools are available.

Your Advantage

Your Advantage means that Agilent offers a
wide range of additional expert test and
measurement services, which you can
purchase according to your unique
technical and business needs. Solve
problems efficiently and gain a competitive
edge by contracting with us for calibration,
extra-cost upgrades, out-of-warranty
repairs, and on-site education and training,
as well as design, system integration,
project management, and other professional
engineering services. Experienced Agilent
engineers and technicians worldwide can
help you maximize your productivity,
optimize the return on investment of your
Agilent instruments and systems, and
obtain dependable measurement accuracy
for the life of those products.

By internet, phone, or fax, get assistance
with all your test and measurement needs.

Online assistance:
www.agilent.com/find/assist

Phone or Fax

United States:
(tel) 1 800 452 4844

Canada:
(tel) 1 877 894 4414
(fax) [phone]

China:
(tel) 800 810 0189
(fax) 1 0800 650 0121

Europe:
(tel) (31 20) 547 2323
(fax) (31 20) 547 2390

Latin America:
(tel) [phone]
(fax) [phone]

Japan:
(tel) (81) 426 56 7832
(fax) (81) 426 56 7840

Korea:
(tel) (82 2) 2004 5004
(fax) (82 2) 2004 5115

Taiwan:
(tel) 080 004 7866
(fax) (886 2) 2545 6723

Other Asia Pacific Countries:
(tel) (65) 375 8100
(fax) (65) 836 0252
Email: [e-mail]

Product specifications and descriptions in
this document subject to change without
notice.

© Agilent Technologies, Inc. 2002
Printed in USA, May 13, 2002

5988-0081EN