5120A / 5120A-01 / 5115A
Phase Noise Test Set
Operations and Maintenance Manual
For Software Revision 276 and Above
Part Number: DOC05120A, Rev M
5120A, 5120A-01, and 5115A Phase Noise Test Set (PNTS)
Operations and Maintenance Manual
Copyright © 2007-2009 Symmetricom Corporation.
Other product and company names may be trademarks of their respective owners.
DOC05120A Rev M
Revision History:
Revision Description Date Approved
A Initial Release 12/20/2004 GAR
B Updates for new software features. 1/13/2005 GAR
C Updates for hardware and software changes 3/25/2005 GAR
D Updates for software changes 9/26/2005 MSS
E Documents 5115A. Updates for software changes. 12/19/2005 PKS
F Software changes, noise floor specs, and DOCSIS. 01/19/2006 GAR
G Frequency counter precision and spur detection. 05/16/2006 GAR
H Documents 5120A-01, noise floor, and time constant 04/16/2007 GAR
J Correct number of Telnet sessions for data port 01/18/2008 GAR
K Revise 5120A-01 specifications, printer, update photos 03/17/2008 GAR
L Add power down note, upgrade via USB, fan filter 3/24/2009 GAR
M Add phaserate command, expand description for marker on
spur power level. Correct the maximum offset for 5115A to
match data sheet. Add text about front panel button usage
during data collection in chapter 6.
09/01/2009 GAR
Contents
1: Introduction 1
1.1 Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 About This Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 PNTS Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2: Setting Up a PNTS 7
2.1 Safety Information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Setting Up a PNTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2.1 Turning On the PNTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.2 Turning Off the PNTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3: The Screen and Basic Concepts 11
3.1 Softkey Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.1 Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.1.2 Manual Convention for Navigation Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2 Main Screen Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2.1 Collecting State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2.2 Input Signals’ Frequency and Power. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2.3 User in Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.2.4 User Specified Title . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.3 Types of Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3.1 Plots . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3.2 Tables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.3.3 Configuration Screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.4 Parameters, Input Components and Editors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.4.1 Numeric Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.4.1.1 The Number Pad Editor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.4.1.2 The + and - Integer Parameter Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.4.2 Mutually Exclusive Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
4: Global System Settings 21
4.1 The Settings Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
4.1.1 Setting Date and Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
4.1.2 Network Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1.2.1 Static Network Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1.2.2 DHCP Network Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.1.3 Printer Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.1.3.1 Printing to a USB Printer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.1.3.2 Printing to Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.1.3.3 Configuring Network Printers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1.4 Viewing Version Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
5120A/5115A Operations and Maintenance Manual i
4.1.5 Restoring Factory Default Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.1.6 Upgrading the software via USB flash drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
5: Configuring Data Displays 31
5.1 Configuring Phase Noise Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5.1.1 Scaling the Phase Noise Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.1.2 Setting Data Markers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5.1.3 Setting Up a Test Mask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
5.1.4 Display Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.1.4.1 Setting the Time Constant. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.1.5 The Spur Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
5.2 Configuring the Allan Deviation Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.2.1 Scaling the Allan Deviation Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
5.2.2 Selecting τ
5.2.3 Viewing the Allan Deviation Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.2.4 Setting Up Allan Deviation Test Masks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
5.3 Configuring the Phase Difference Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.3.1 Scaling the Phase Difference Plot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.3.2 Removing the Linear Trend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.3.3 Pausing or Resuming Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.4 Configuring the Frequency Difference Plot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
5.4.1 Scaling the Frequency Difference Plot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5.4.2 Pausing or Resuming Updates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5.5 Configuring the Frequency Counter. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5.5.1 Changing the Reference Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
5.5.1.1 Automatically Setting the Reference Frequency . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.5.1.2 Manually Setting the Reference Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
0
6: Collecting and Viewing Data Locally 53
6.1 Starting and Stopping Data Collection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
6.2 Printing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
6.3 Taking or Yielding Local Control.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
7: Collecting and Viewing Data Remotely 57
7.1 Accessing the PNTS Remotely and Exiting the Remote Session . . . . . . . . . . . . . . . . . . . . . . 58
7.2 The Network Command Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
7.2.1 Taking or Yielding Remote Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
7.2.2 Starting and Stopping Data Collection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
7.2.3 Retrieving Data from Command Port. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
7.2.4 Printing from the Command Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
7.2.5 Printer Configuration from the Command Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
7.2.6 Configuring Data Sets from the Command Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7.2.6.1 Pausing and Resuming Phase and Frequency Difference. . . . . . . . . . . . . . . . . . . 62
ii Contents
7.2.6.2 Removing the Linear Trend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7.2.6.3 Setting the Time Constant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
7.2.6.4 Setting the Allan Deviation τ
7.2.6.5 Setting Frequency Counter’s Reference Frequency. . . . . . . . . . . . . . . . . . . . . . . 63
7.2.7 Retrieving Status Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
7.2.8 Setting the User Specified Title. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
7.2.9 Showing the Software Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
7.2.10 Viewing Help for Remote Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
7.2.11 Setting Data Port Output Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
7.2.12 Other Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
7.2.13 Command Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
7.3 The Network Data Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
0
8: Optional Functionality 69
8.0.1 DOCSIS Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
8.0.2 Using the DOCSIS Option Locally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
8.0.3 Using the DOCSIS Option Remotely . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
8.1 5120A-01 Internal Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
8.1.1 5120A-01 Internal Reference Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
8.1.1.1 Calibrating 5120A-01 Internal Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
8.1.1.2 Calibrating 5120A-01 Internal Reference Remotely . . . . . . . . . . . . . . . . . . . . . . 73
9: Maintaining a PNTS 75
9.1 Calibrating the PNTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
9.2 Cleaning the PNTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
9.3 Cleaning the Fan Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
10:Troubleshooting 77
10.1 Troubleshooting Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
10.2 Replacing Fuses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Appendix A: Specifications 81
A.1 EC Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
A.2 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
A.3 Environmental Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
A.4 Physical Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Appendix B: Theory of Operation 87
B.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
B.2 Theory. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
B.3 Measurement Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Glossary 93
Symmetricom Customer Assistance 95
5120A/5115A Operations and Maintenance Manual iii
Index 97
iv Contents
Note
1: Introduction
FIRST READ THIS MANUAL THOROUGHLY!
This is especially true for the sections regarding Safety and Setup.
1.1 Symbols
These symbols appear throughout the manual and on the PNTS Phase Noise Test Set (PNTS).
Symbol Definition
This symbol means the following information is a note that gives you important
Note
information that may affect how you use the
Caution, refer to manual. Read all instructions in this manual before using this
product.
Caution - Risk of Electrical shock
Fuse symbol.
LAN port, network. DO NOT CONNECT TO TELECOM CONNECTIONS
THAT CARRY HAZARDOUS VOLTAGES.
Universal Serial Bus (USB) port.
Mains power on and off. Mains power is on when the button is in the depressed
position and off when the button is in the out position.
PNTS.
5120A/5115A Operations and Maintenance Manual 1
1.2 About This Manual
This manual describes how to set up, use, maintain, and troubleshoot a PNTS. The 5120A-01 is
equipped with two internal reference oscillators that automatically serve as the reference signal
when no external signal is connected to the Reference port. In this manual, the term “reference
signal” is inclusive of both reference signal sources.
“Chapter 1, Introduction” on page 1 explains symbols that appear in the manual and on the test set
as well as documentation conventions. The chapter also briefly describes the test set.
“Chapter 2, Setting Up a PNTS” on page 7 contains important safety information and describes
how to set up the test set for the first time.
“Chapter 3, The Screen and Basic Concepts” on page 11 describes the main components of the
graphical user interface, basic concepts related to navigating the user interface, and making
settings in general.
“Chapter 4, Global System Settings” on page 21 describes individual system settings such as
system time, network configuration and printer settings in detail.
“Chapter 5, Configuring Data Displays” on page 31 describes the various data displays for the
5120A, 5120A-01 and 5115A and how to manipulate and configure each data set.
“Chapter 6, Collecting and Viewing Data Locally” on page 53 describes how to start and stop data
collection and how to print using the front panel.
“Chapter 7, Collecting and Viewing Data Remotely” on page 57 describes how to view, print and
configure data sets using the Ethernet command port.
“Chapter 8, Optional Functionality” on page 69 describes optional functionality.
“Chapter 9, Maintaining a PNTS” on page 75 describes how to maintain the test set.
“Chapter 10, Troubleshooting” on page 77 describes how to troubleshoot using error messages.
“Appendix A, Specifications” on page 81 contains the detailed specifications for the test set.
“Appendix B, Theory of Operation” on page 87 contains the detailed information about the
algorithms and underlying theories for the test set.
2 1: Introduction
1.2.1 Conventions
This manual uses several typographical conventions to help explain how to use the test set.
Convention Definition
Bold Word s i n bold show:
Buttons and icons to click
Menu options to select
Commands to type
Non-variable information displayed in response to commands
Italics Wo rds i n italics show:
Names of windows and dialog boxes
Variable information displayed in response to commands
State information, label and button captions
5120A/5115A Operations and Maintenance Manual 3
Softkeys; press the
corresponding button to
access functions.
Test signal ports.Softkey labels; labels change
based on the current function.
Power.
Stop; use to stop
collecting data.
Print; use to print the
current screen to the
connected printer.
Start; use to start
collecting data.
Screen; automatically turns
off after one hour if no keys
are pressed. Press any
softkey to view the last
screen displayed.
1.3 PNTS Overview
The PNTS are instruments that combine sophisticated timing technologies into a single advanced
test set for the measurement of
the latest digital synthesizer, active mixer, and dual conversion techniques to capture precise,
accurate
of the digitized signal from both input paths to provide the lowest possible noise measurement.
The 5120A-01 features two built-in oscillators for applications where a reference signal is not
available or required.
The PNTS are designed for ease of use. Little configuration is required. Just connect signal sources
to the BNC (using supplied adapters) inputs and press Start.
(f) phase noise measurements. The 5120A and 5120A-01 also perform cross-correlation
(f) phase noise. The low-noise, bench-top instrument combines
The input impedance is 50 Ω, and the ideal nominal input level is near 1 V
. The test set
RMS
automatically initializes itself, measures the frequencies of the input signals, configures the signal
paths, and collects data.
All models measure phase noise, Allan deviation, frequency counter, frequency difference, and
phase difference.
An Ethernet port make remote control, measurement retrieval and printing to network printers
possible. Two USB ports on the rear panel provide connections for a printer, mouse and keyboard.
Figure 1 shows the test set’s front panel, and Figure 2 shows the test set’s rear panel.
Figure 1: Front Panel
4 1: Introduction
Power
connection
Ethernet
port
USB ports
Fuse
Cooling Fan
Filter
Figure 2: Rear Panel
All measurements are made between the Input and Reference ports. To ensure that measured
characteristics are those of the Input signal, a clean and stable signal must be supplied to the
Reference port of the PNTS. The 5120A-01 is equipped with two internal oscillators that can serve
this function, to use internal reference signal, simply do not attach a a signal to the reference port.
Consult “Appendix A, Electrical Specifications” on page 82 for internal oscillator performance
specifications.
The phase noise and phase spurs that are present on the Reference port are scaled by a factor of
20*log (Finput/Fref) when displayed. Consider the following example: A spur on a 10 MHz signal
is connected to the Input port with a clean 5 MHz connected to the Reference port. The spur
reading is -50 dBc. If the signal cables are swapped between the ports, the spur reading will be -56
dBc.
5120A/5115A Operations and Maintenance Manual 5
6 1: Introduction
Warning
2: Setting Up a PNTS
You should read the safety information below before setting up the test set. For more information,
see the following:
“2.2 Setting Up a 5120A or 5115A” on page 7
“3: The Screen and Basic Concepts” on page 11
“4.1.1 Setting Date and Time” on page 22
“4.1.2 Network Configuration” on page 23
“4.1.4 Viewing Version Information” on page 29
2.1 Safety Information
This unit is for indoor use only. It is not sealed to prevent moisture from entering the enclosure.
Do not set up or operate this equipment if you have not first received proper training.
Ensure that all cables are properly connected. The power cord must be located for easy removal.
Verify that input line voltage and current capacity from the supply circuit are within specifications
before turning on power to the test set.
Operating and maintenance personnel must receive proper training before setting up or
maintaining electrical equipment.
2.2 Setting Up a PNTS
The test set ships ready to set up on a desk, table, or other stable, flat surface.
Required for setup:
North American or European IEC power cord. One or the other will be supplied with the
instrument.
Two TNC male to BNC female adapters are supplied with the instrument.
Two customer-supplied 0.5-meter (approximately 19") coaxial cables terminated at one
end with male BNC connectors. The other end should have the appropriate connector as
determined by your application.
5120A/5115A Operations and Maintenance Manual 7
Caution
Optional components:
Customer-supplied USB A-type cables, one for each USB device.
Customer-supplied USB mouse. (recommended)
Customer-supplied USB keyboard.
Customer-supplied USB hub, if connecting more than two USB devices.
Customer-supplied USB printer from the list of compatible printers.
Customer-supplied CAT 5 LAN cable for network connection (RJ-45), if connecting to
the Ethernet port.
• If you need to connect the test set directly to your computer using the Ethernet port,
you must use a crossover cable instead of a standard LAN cable.
To set up the PNTS:
1. Carefully unpack and inspect the test set.
2. Check for physical damage.
If you observe physical damage, immediately contact Symmetricom Customer
Assistance (see page 95) and the carrier. We recommend saving the shipping
container for submitting any necessary claims to the carrier.
3. Verify that the front panel power button is turned off.
4. Plug the female end of the power cord into the male IEC-320 plug on the rear of the test
set.
5. Plug the male end of the power cord into a 100–240 V AC, 50/60 Hz power source.
Ensure that this power supply cord is connected to a properly grounded mains
receptacle.
6. Connect one coaxial cable from the Device Under Test (DUT) signal source to the Input
port of the test set.
7. Connect another coaxial cable between the signal reference and the Reference input port
of the test set. Skip this step if you intend to use internal reference available on the 5120A01
8. (Optional.) Connect a CAT 5 LAN cable to the Ethernet port on the rear panel of the test
set.
For information about configuring the network connection, see “4.1.2 Network
Configuration” on page 23.
9. (Optional.) Connect the USB A-type cables from a mouse, keyboard or printer to the USB
ports on the test set.
If you are connecting more than two USB devices, connect a USB hub to one port on
the test set, then connect the devices to the hub.
You can also use a USB-to-parallel adapter for a parallel-port printer.
You are now ready to turn the test set on.
8 2: Setting Up a PNTS
2.2.1 Turning On the PNTS
Once you have set up the test set, you are ready to turn it on.
To turn on the test set:
Press the Power button on the front panel.
• The logo screen displays.
• The main screen displays about 1 minute later. The main screen defaults to the phase
noise plot.
• When Ready displays in the status field (see Figure 3 on page 11 and “3.2.1 Collecting
State” on page 13) the instrument is ready for normal operation.
• If the “Self test has failed for the following item(s)…” message displays, call
Symmetricom Customer Assistance (see page 95).
Once Ready is displayed in the status field, data can be collected.
2.2.2 Turning Off the PNTS
There is a small chance that turning off the test set by removing the power cord could
cause the operating system files to be corrupted. Use the front panel button to turn off the
power, and take precautions to not turn off the power shortly after making changes to the
instrument Global System settings.
5120A/5115A Operations and Maintenance Manual 9
10 2: Setting Up a PNTS
Note
Current collecting state Frequency and power of input signals
Collection Duration
User specified title
Softkey labels
show the function
that will be
executed when the
physical button
next to them is
pressed.
Highlighting is
used to show state
information or
draw attention to
keys to aid in
navigation.
Main Mode Title User in Control
This Column holds what
are called softkey labels.
3: The Screen and Basic Concepts
The screen on the front panel of the PNTS displays data as plots or tables, status information, and
system configuration such as network settings. It defaults to the
test set is powered on.
Figure 3 depicts the default screen after the test set has been collecting data for several hours. It
names and describes the major components. These are described in section “3.2 Main Screen
Components” on page 13.
(f) phase noise data plot when the
Figure 3: Default Main Screen
When the 5120A-01 is used with internal references, the Reference field reads “Internal”, and
frequency and power are not shown.
5120A/5115A Operations and Maintenance Manual 11
The top softkey now reselects the phase noise plot. Its
original function was to configure the phase noise plot.
The second softkey now configures the Allan deviation
plot. It was just used to select the Allan deviation plot.
3.1 Softkey Interface
The column labeled “softkeys” in Figure 3 mirrors the set of buttons on the test set front panel
(Figure 1 on page 4 shows them side by side). The labels indicate the effect pressing the
corresponding button will have.
The function of a softkey changes depending on previous selections including navigation and
settings. Highlighting is used to represent state information, to invite navigation into a submenu, or
to return to a previous menu. The softkey interface can be used to configure all aspects of the test
set, except the User Specified Title. It is described in detail in the sections that follow.
A USB mouse can be used to press and release softkeys. To execute the function currently
assigned to a softkey, click on it. Some softkeys repeatedly execute their function while held
down. These keys are noted as they are described in this manual. Pressing (and holding) the mouse
button on a softkey repeatedly executes its function as well. Using the mouse to interact through
the softkey interface is also useful because it minimizes physical disturbance to the test set.
Physical disturbance can affect the accuracy of sensitive measurements.
3.1.1 Navigation
Starting with the phase noise plot as shown in Figure 3, pressing the Allan Deviation Plot button
would:
Display the Allan deviation plot.
Change the softkey’s caption to Config Allan Deviation.
Highlight the softkey to show that Allan deviation is the active mode.
Pressing the same button at this time will enter a softkey menu (center in the figure below) that
allows for scale and test mask configuration, τ
format. This softkey menu has a highlighted Return softkey to return to the previous menu.
Figure 4 shows the flow from the Allan deviation plot, to its table format, and back to the plot.
.
selection, or viewing the Allan deviation in table
0
Figure 4: Softkey Navigation
12 3: The Screen and Basic Concepts
3.1.2 Manual Convention for Navigation Instructions
This manual uses the following convention to describe the softkey-based navigation flow shown in
in Figure 4 on page 12:
To view the Allan Deviation Table:
1. From the Allan deviation plot, press Config Allan Deviation.
2. Press View Table.
3. Press Return to go the previous screens.
3.2 Main Screen Components
This section provides a description of the main screen components shown in Figure 3 on page 11.
3.2.1 Collecting State
The collecting state shows the test set’s current mode of operation. The test set is in one of three
states at any given time: Ready, Initializing or Collecting.
In Ready state you may Start collecting provided that the Input and Reference signals’
frequency and amplitude are within operating range. Note that internal references
available on the 5120A-01 are within operating range unless the test set is damaged.
The Initializing state is a transition from Ready to Collecting state. In the Initializing state,
the test set takes a small set of measurements and uses it initialize the internal spur
detection algorithm. The Initializing state lasts up to 30 seconds.
Collecting state is entered once initialization is complete and the test set has begun
collecting and presenting data. When Collecting state is reached the test set starts
displaying measurements and tracking how long it has been collecting. See the top left
corner of Figure 3 for an example of the collection duration.
You can Stop collecting from either the Initializing or the Collecting state.
Note that updates to some data sets can be paused. The normal banner of asterisks displayed next
to the collecting state will change to Paused to indicate that the test set is presenting a paused data
set. The test set continues to make measurements and will present the most recent plot or table
when updates are resumed.
All measurements and calculations made in the Collecting state can be viewed, printed and
accessed on the network port even after you Stop collecting. They are cleared when data collection
is restarted.
3.2.2 Input Signals’ Frequency and Power
These fields display the frequency and power as measured by the PNTS. As frequency and/or
power fall outside of specification or operating range the color coding of the fields changes as
well. Frequency or power values displayed in red are outside of operating range. Values displayed
in orange are out of specification but fall within operating range.
When no reference signal is attached to the 5120A-01, the Reference field reads “Internal”, color
coded in blue, as internal reference signals are within operating range unless the test set is
damaged.
5120A/5115A Operations and Maintenance Manual 13
The screen always shows the currently connected signals’ frequency and power. When a data set is
printed, the frequency and power at the time the printed data set was collected is output. If data are
collected with 5 MHz signals on both ports, and the reference is replaced with a 10 MHz signal,
the screen shows 5 and 10 MHz, while a printout correctly shows 5 MHz for both signals.
3.2.3 User in Control
The phase noise test set can be controlled in two ways:
with front panel buttons, a mouse and/or a keyboard.
via a network connection on an Ethernet network.
This makes it possible for two different users to interfere with one another. A network user could
start a long term collection, only to have another user walk up to the front panel of the test set and
press the Stop button minutes later. These users are named from the test set’s perspective. The
network user is referred to as the Remote user, and the person using the front panel is called the
Local user.
To avoid interference between Local and Remote users, certain operations and configuration
settings require that the user wishing to perform them be in control of the test set (or willing to take
control). The user who is in control of the test set is identified in the top right corner of Figure 3.
The figure shows that the Local user has initiated data collection. If a Remote user were to issue
the stop command, they would receive a warning reminding them that they are not in control of the
test set. At this point the remote user can take control from the local user. See “7.2.1 Taking or
Yielding Remote Control” on page 58 for details on taking Remote control.
When the test set is powered on neither user is in control. The first user to execute a command or
make a setting which requires control of the test set implicitly takes control. If the Local user were
to press the Start button on the front panel, they would automatically take control of the test set.
When neither user is in control the label in the top right corner of the main screen is blank.
When the user who is controlling the test set is finished, they can relinquish control to reenter the
state described in the previous paragraph. See “6.3 Taking or Yielding Local Control.” on page 55
and “7.2.1 Taking or Yielding Remote Control” on page 58 for further instructions.
3.2.4 User Specified Title
A short string shown in the bottom right corner of Figure 3 can be entered using a USB keyboard
or set on the network interface. One title may be assigned at a time. The title appears on all
printouts and can thus be used to correlate data sets, identify the owner or input signal sources. The
title can be up to 34 characters long.
The title can be set by the Local user only if a keyboard is attached to the test set.
To set the user specified title:
1. Press the ‘T’ key on the keyboard.
2. Enter a title of up to 34 characters using the keyboard in the dialog box.
3. Press the ‘Enter’ key on the keyboard, or the Apply softkey to commit the new title.
The new title appears at the bottom right of the main screen and will be output at the
bottom of all future printouts.
The user specified title can also be set using a network command connection, see “7.2.8 Setting the
User Specified Title” on page 64.
14 3: The Screen and Basic Concepts
3.3 Types of Screens
The PNTS present three types of user interface main screens:
Plots
Tables
Input Components
Occasionally it will present a dialog with informational messages, error messages or request that
you take control (as described in “3.2.3 User in Control” on page 14) when you execute certain
functions.
3.3.1 Plots
Figure 3 on page 11 and Figure 4 on page 12 are examples of plots. Four of the five main screens
are plots. Plots can be configured in various ways described in detail in later chapters dedicated to
data set configuration.
The (f) Phase Noise plot also presents data subsets such as the Spur Table and meta
information such as Integrated Phase Noise in tables accessible through its configuration
softkey and mouse menus.
The Allan deviation plot can also be viewed in terms of a table.
3.3.2 Tables
There are two types of tables. The first is a read-only table such as the Allan deviation table. The
second type is an interactive table. Both types present softkeys which scroll the table up or down
as can be seen in the example table on the right side of Figure 4 on page 12. The scroll keys have
different effects depending on the type:
Read-only tables scroll the data set one page at a time.
Interactive tables select the row following or preceding the currently selected row.
Interactive tables move the selection a row at a time because they allow you to operate on the
selection. An example of this is the
marker at the selected spur’s frequency. See “Chapter 5, The Spur Table” on page 42 for details.
To perform operations upon a row in an interactive table, use the mouse pointer to select the row,
then right-click the selected row and choose one of the menu items that are generally available.
To vertically scroll up or down a table, use the scroll bar located on the right side of the table, or, if
available, the scroll wheel located on your mouse.
(f) phase noise plot’s spur table, which lets you place a
3.3.3 Configuration Screens
The test set can be configured in various ways. Configuring aspects of its function involves setting
parameters. Input components are used to interface with and make these settings. Components for
related parameters are often grouped, as multiple parameters affect a certain function. Examples of
such groups can be found in chapter “4: Global System Settings” on page 21 and its subsections.
5120A/5115A Operations and Maintenance Manual 15
Spin Button
Click to increase value
Click to decrease value
Mouse Interface
Right-click for menu of frequently used values.
(Not all parameters provide menus.)
Using a keyboard you can
type directly into the field to
avoid using the number pad
editor.
3.4 Parameters, Input Components and Editors
This section explains the possible parameter types and cross references an example of each. The
components which represent them, and how each type can be modified using the softkey interface,
a mouse or a keyboard, are detailed in the section referenced by each type.
Parameters fall into these categories:
“3.4.1 Numeric Parameters” on page 16 such as:
• Network interface port numbers
• The frequency counter’s user-specified reference frequency
“3.4.2 Mutually Exclusive Options” on page 18 such as:
• Print job destination
• TCP/IP address assignment method
3.4.1 Numeric Parameters
Numeric parameters fall into two categories:
Those confined to the integer domain.
Those in the real number domain such as the frequency counter’s reference frequency and
test mask points’ x and y coordinates.
All numeric parameters can be set as described in “3.4.1.1 The Number Pad Editor” on page 17.
Those in the integer domain can also be set as described in “3.4.1.2 The + and - Integer Parameter
Interface” on page 18. Numeric parameters are presented using the following components which
can be directly manipulated with the mouse or keyboard as described in Figure 5.
Figure 5: Spin Buttons
When a mouse or keyboard is not available, parameters presented by spin buttons must be set
using one of the editors described in the following sections. The editors can be used if you prefer
using them over the alternative input methods.
16 3: The Screen and Basic Concepts
Number pad buttons can be clicked with the mouse.
Note the white rectangle on
the button. It indicates
“focus”. The arrow softkeys
move the focus in the
direction they indicate,
wrapping to the first button
on the axis on which they
move focus.
Use the down and right
arrow keys to move the
focus to a different button.
Press the PUSH softkey to
push the focused button.
Softkey short cut for the
back space key. This key
repeats when held down.
To commit the new
parameter value you
entered, press Apply.
Press Cancel to discard
your edits and leave the
parameter unchanged.
With a keyboard you can directly enter a value.
Clear erases entire value.
Backspace erases the last digit.
3.4.1.1 The Number Pad Editor
The number pad editor is a small window that resembles the number pad on a keyboard. The
window’s title indicates the parameter being edited (the first octet of an IP address in the figure
below).
When the number pad editor is invoked, the softkey interface changes as shown on the
right side of the figure.
If a parameter already has a value when the editor is invoked, the number pad editor is
initialized with this value. Use the Clear button to erase the value entirely.
The <- button (the backspace button) erases the last digit.
The EXP button is used to enter numbers in scientific format.
The +/- button toggles the sign of the mantissa when it is pushed before the EXP button
and toggles the sign of the exponent when pushed after the EXP button.
5120A/5115A Operations and Maintenance Manual 17
Figure 6: The Number Pad Editor
When a spin button is selected, both The Number Pad Editor and the
+ and - Integer Parameter interface can be used to modify its value.
Press the Number Pad softkey to edit
the value using the number pad editor.
Press the +/- softkey to edit by increasing and decreasing
the current value using the interface shown on the right.
Use the small softkeys to increase
and decrease the value by 1. Press
and hold the keys to continually
increase or decrease the value
Use the large softkeys to increase
or decrease the value by 5 or 10
(actual value depends on the
parameter’s range)
Press the Return softkey when
you are finished editing the
number.
3.4.1.2 The + and - Integer Parameter Interface
Numeric parameters whose values are confined to the integer domain can be changed by
incrementing and decrementing their values. They are represented by spin buttons. See “Figure 5:
Spin Buttons” on page 16 for an example. When an interactive component that represents such a
value is selected, the softkey interface offers both the number pad and the + and - interface as an
editor:
Figure 7: The + and - Integer Parameter Interface
3.4.2 Mutually Exclusive Options
Mutually exclusive options on the settings screens are presented as a horizontal row of buttons
(similar to radio button controls in other graphical user interfaces). Figure 7 has the following
mutually exclusive options:
Bit Rate: which can be one of Auto, 10 Mbps, or 100 Mbps.
Address Assignment: which can be DHCP or Static Address.
The down and right arrow softkeys in Figure 7 move the focus just as they do in the number pad
editor. See Figure 6 on page 17 for an explanation of focus. As focus is changed on mutually
exclusive options the focused option is selected. The new setting takes effect when the Apply
softkey is pressed. The following is an example of how to toggle the Address Assignment option
assuming the state in Figure 7 as a starting point.
To change the Address Assignment method:
1. Press the down arrow softkey until focus reaches the DHCP button.
Focus is indicated with a white rectangle.
2. Press the right arrow softkey.
Focus and highlight move to the Static Address button - the new setting.
18 3: The Screen and Basic Concepts
Note that the buttons representing the options can be clicked directly with a mouse. Clicking an
interactive component moves the focus - it does not have to be moved with the arrow softkeys.
5120A/5115A Operations and Maintenance Manual 19
20 3: The Screen and Basic Concepts
Use these softkeys to
edit settings in their
corresponding group,
or execute related
functions such as print
job cancellation.
Accesses a screen which
can restore all settings to
factory default values.
4: Global System Settings
The PNTS have global configuration parameters. Many of these ship with acceptable defaults but
should be checked and modified as appropriate when the unit is received. The global configuration
settings persist when the test set is powered off.
Settings are grouped according to function and accessed through the Settings screen. Setting
screens include:
System date and time and time stamp format
Network options
Printing options
4.1 The Settings Screen
The Settings screen shows most current settings and serves as a submenu to the settings groups
listed above.
To access the Settings screen:
1. Press or click the Settings and Options softkey.
See “3.1 Softkey Interface” on page 12 for basic navigation instructions.
2. Press or click the Settings softkey.
Figure 8: Settings Screen
Note that the Settings screen displays the instrument’s current IP address. Use this address to
access the command and data ports, or to retrieve print jobs that were written to files.
5120A/5115A Operations and Maintenance Manual 21
Note
4.1.1 Setting Date and Time
All printouts produced by the test set show the test set date and time the print job was initiated. The
date and time is printed in the top left corner of the page. Date and time stamps on printouts can be
used to correlate printed data sets.
To set the system date and time:
1. Press Settings and Options.
2. Press Settings to access the Settings Screen (shown in Figure 8 on page 21).
3. Press Date and Time.
4. Use the arrow softkeys to access the date/time fields you wish to modify.
5. Adjust the numeric fields as described in section “3.4.1 Numeric Parameters” on page 16.
6. Select the preferred date/time format as described in section “3.4.2 Mutually Exclusive
Options” on page 18.
The field labeled Sample shows how time stamps will be printed.
7. Press Apply to save the new date and time and/or time stamp format.
The test set does not adjust for time changes due to daylight savings time.
22 4: Global System Settings
4.1.2 Network Configuration
In order to access the test set over a network, print to a network printer, or retrieve print jobs sent
to files, network settings must be configured. Skip this section if you do not intend to use these
features.
An example of the network settings screen can be found in Figure 7, on page 18. It groups the
following parameters:
Bit Rate: The bit rate setting is used to force the instrument’s network controller to a given
bit rate. The default of Auto should suffice on almost all networks. Contact a system
administrator if you feel this setting must be changed.
Address Assignment: Toggles between address assignment via Dynamic Host
Configuration Protocol (DHCP) and a Static Address.
IP Address, Network Mask and Default Route: These fields are only enabled when the
Address Assignment is set to Static Address.
Command Port and Data Port: These fields set the port numbers at which the test set will
answer command line interface and data connections.
Bit Rate and Address Assignment are mutually exclusive options, while the octets in IP Address
and Network Mask, and the Command and Data Port are all integers. See “3.4.2 Mutually
Exclusive Options” on page 18 and “3.4.1 Numeric Parameters” on page 16 for details on how to
set them.
The PNTS ship with the default network settings shown in Tab le 1 .
Table 1: Default network settings
Setting Default value
Bit Rate Auto
Address Assignment DHCP
IP address (set by DHCP)
Netmask (set by DHCP)
Default Route (set by DHCP)
Command port (TCP) 1299
Data port (TCP) 1298
If your network has a Dynamic Host Configuration Protocol (DHCP) server and the DHCP
assignment method is selected, the IP address does not have to be configured. Once the test set is
connected to the network, it should receive an IP address from the server. The address of the test
set must be determined in order to make a network connection from another computer. It can be
found in “Figure 8: Settings Screen” on page 21 (your system’s address will vary from that shown
in the figure).
4.1.2.1 Static Network Configuration
If your network does not have a DHCP server or a static IP address is preferred, you can set an IP
address, network mask and default route. The address and mask settings are required. The default
route is not strictly necessary, but enables network communication between the test set and
devices on a subnet other than that to which it is immediately attached. The network features can
be used on the local area network, even if no default route (specified as 0.0.0.0) is configured.
5120A/5115A Operations and Maintenance Manual 23
The command and data ports can also be changed if the default port numbers conflict with other
ports on the network. They are used to remotely control the test set and access collected data.
To configure the network connection with a static IP address:
1. Obtain the following information from your network administrator:
IP Address: ______ ______ ______ ______
Subnet Mask: ______ ______ ______ ______
Default Route: ______ ______ ______ ______
2. From the front panel, press Settings and Options (see “3.1.1 Navigation” on page 12).
3. Press Settings.
4. Press Network.
5. Use the down arrow softkey to focus (denoted by highlight on the input components) the
row labeled Address Assignment.
6. Press the right arrow softkey to toggle the setting to Static Address.
The spin buttons for the IP address, network mask and default route octets become
active (they are grayed out for the DHCP method).
7. Press the down arrow softkey to move to the row labeled IP Address. Press the right arrow
softkey to access and set the individual octets as described in “3.4.1 Numeric Parameters”
on page 16.
8. Press the down arrow softkey to focus the row labeled Network Mask and repeat step 7 for
the network mask obtained in step 1.
9. Press the down arrow softkey to focus the row labeled Default Route and repeat step 7 for
the default route obtained in step 1. A default route value of 0.0.0.0 specifies that no
default route is required.
10. Press Apply to save the new settings.
The settings screen is reactivated. It reflects the new network configuration.
24 4: Global System Settings
Note
4.1.2.2 DHCP Network Configuration
When network parameters are configured using DHCP, the test set obtains address and routing
information from a server. The server reserves these parameter values for the test set for an amount
of time which depends on the server’s configuration. Near the end of this period, the DHCP client
application (on the test set) requests an extension, at which point the server renews this reservation
and this cycle repeats. The test set is said to “obtain a lease” from the server, and is said to “renew
the lease” shortly before it expires.
When the test set is powered on with DCHP configuration enabled, or is reconfigured from static
configuration to DHCP, it makes attempts to obtain a lease from a server. If a server cannot be
contacted, or a lease cannot be granted because no addresses are available, the test set will make
another request every few minutes.
Early versions of test sets cannot detect an Ethernet carrier. This can cause a noticeable delay in
initial lease acquisition when it is connected to a network after it has been powered on. The delay
results from a sequence of events similar to the following:
1. The test set requests a lease and fails because it is not connected to a network.
2. Another attempt is scheduled to run 3 minutes later.
3. 1 minute after the next attempt has been scheduled, the test set is attached to the network.
4. The test set does not request a lease for another 2 minutes - it scheduled the next request to
run 3 minutes after the failed attempt 1 minute ago.
The test set can be forced to request a lease by restarting the DHCP client application. A push
button on the network settings screen is used for this purpose.
To restart the DHCP client:
1. Navigate to the Settings screen (see “4.1 The Settings Screen” on page 21).
2. Press Network.
3. Press the down arrow softkey until focus (denoted by a white rectangle) reaches a push
button on the row labeled Operations.
The softkey interface displays a PUSH softkey.
4. Press the right arrow softkey until the Restart DHCP button is focused.
5. Press the PUSH softkey to push the focused button and restart the DHCP client.
A dialog confirms that the client application has been restarted and is requesting a new
lease.
6. Press Dismiss Dialog.
7. Press Apply or Cancel to return to the settings page.
The IP Address, Network Mask and Default Route fields on the Settings screen are
updated with the server provided values as soon as the test set is able to obtain a lease.
On test sets that can detect presence or absence of Ethernet carrier, the DHCP client is restarted
automatically when the test set is connected to the network. PNTS that can detect carrier, display
either “no carrier” or “active” in the Ethernet Carrier field on the Settings screen. PNTS which
cannot detect carrier always display “unknown” in the Ethernet Carrier field.
5120A/5115A Operations and Maintenance Manual 25
Note
4.1.3 Printer Configuration
Whenever the Print button on the front panel is pressed, or print commands arrive on the network
command interface, the 5120A or 5115A prints to the current print job destination in the current
format.
The test set can print plots, tables and the settings screen in two formats:
PCL5 - Printer Control Language 5 format which PCL5-capable printers will accept.
Printers of level PCL4 or below cannot use this format. Refer to the printer’s
documentation to determine its compatibility.
PostScript - Raw PostScript that only PostScript printers will accept.
Print jobs can be sent to one of three destinations:
Local - A USB printer attached to the test set. See “4.1.3.1 Printing to a USB Printer” on
page 26.
File - A file on the test set’s file system. These files are accessed via anonymous File
Transfer Protocol (FTP). See “4.1.3.2 Printing to Files” on page 28 for details.
Network - A network printer that supports direct transfer of information to a port such as
the HP JetDirect using port 9100. Other spooling protocols, such as the Internet Printing
Protocol (IPP), are not currently supported.
Note that section “4.1.2 Network Configuration” on page 23 must be completed before jobs can be
sent to a network printer or retrieved using FTP.
To configure printing:
1. Navigate to the Settings screen (see “4.1 The Settings Screen” on page 21).
2. Press Printing.
3. Use the arrow keys to select a destination for print jobs (see “3.4.2 Mutually Exclusive
Options” on page 18 for details).
If you selected the Network destination, the IP address and port number in the fields
labeled Remote Host and Remote Port became active.
4. Use the arrow keys to toggle the print format (a mutually exclusive option).
5. Press Apply to save the new configuration.
The settings screen is reactivated. It reflects the new configuration.
4.1.3.1 Printing to a USB Printer
To print to a USB Printer:
1. Attach a PCL5 or PostScript capable printer to one of the USB ports shown in Figure 2, on
page 5 or a USB hub connected to one of these ports.
A test set can print to an attached USB printer only if that printer natively supports either the
PostScript or PCL5 printer languages. Determining if a given USB printer supports PCL5 natively
in the printer firmware may require contacting the printer vendor's technical support.Most printers
which have an ethernet port are higher end printers which support either PostScript or PCL5
natively. These printers, if they also have a USB port, will generally work when directly attached
to a test set via USB. Several popular printers on the market use a non-conforming USB protocol
26 4: Global System Settings
which is handled by a proprietary Windows driver on a PC, but which is not available on a test set.
In general, you can tell if a USB printer will work on a test set if when plugged into a Windows
machine and configured as a PCL5 or PostScript printer, no proprietary software is required for it
to function. If you must install proprietary software on a PC for the printer to function, it will
usually not work when plugged directly into a test set via USB.Configure the test set to print to the
Local destination in the format the printer supports.
2. Print the data sets of interest using the methods described in sections “6.2 Printing” on
page 54 and “7.2.4 Printing from the Command Port” on page 60.
5120A/5115A Operations and Maintenance Manual 27
Note
4.1.3.2 Printing to Files
When the test set is configured to print to files, output that is normally sent to a USB or network
printer is stored on its file system instead. The test set will store up to fifteen print jobs. Jobs are
numbered starting at zero. Once all possible files are in use, the test set wraps around and starts
overwriting the oldest print job with the current one. Print job files are stored in the current print
format and compressed. The format and compression are indicated by file extensions:
print0.pcl.gz(.pcl denotes PCL5 format and .gz that the file is compressed)
print1.ps.gz(.ps denotes PostScript format and .gz that the file is compressed)
Print jobs written to files are stored in the printfiles directory. This directory is accessible via
anonymous FTP. Its contents (the print jobs) are erased when the test set is powered off.
To retrieve print jobs sent to files:
1. Access the test set with an ftp client using anonymous login (you will not need a
password).
See Figure 8, on page 21 to determine the test set’s IP address.
Be sure to configure the ftp client for binary file transfer. Most command line
based ftp clients accept the bin command for this purpose. See your ftp client
software documentation for details on how to set binary file transfer.
2. Download the files from the printfiles directory.
The following is a transcript of a sample command line ftp session. Input from you is shown in
bold text. Note that the test set will have a different IP address:
OS command prompt> ftp 206.168.13.249
Connected to 206.168.13.249.
220 ts FTP server (Version 6.00LS) ready.
User (206.168.13.249:(none)): anonymous
331 Guest login ok, send your email address as password.
Password: (no password required - just press enter here)
ftp> cd printfiles
ftp> bin
200 Type set to I.
ftp> get print0.ps.gz
150 Opening BINARY mode data connection for 'print0.ps.gz' (17358 bytes).
226 Transfer complete.
ftp> bye
The print0.ps.gz file is now on the computer from which the ftp session was initiated. The file can
now be decompressed and viewed or printed using third party software such as Ghostview.
28 4: Global System Settings
4.1.3.3 Configuring Network Printers
The network printing feature requires a network printer that supports direct transfer of information
to a port.
1. Configure the test set network connection, following section “4.1.2 Network
Configuration” on page 23.
2. Set the test set to print to the Network destination in the format the printer supports.
3. Enter the IP address and port number of the target printer.
4. Press Apply to save the new configuration.
4.1.4 Viewing Version Information
You can view the model number, software version and hardware CPLD revision numbers when
needed for troubleshooting.
To view the model number and software version:
1. Navigate to the Settings screen (see “4.1 The Settings Screen” on page 21).
2. Press Version Info to access version information.
3. Press Return to go back to previous screens.
4.1.5 Restoring Factory Default Settings
Parameters configured using the Settings submenus persist when the test set is power cycled.
Other settings such as the frequency counter’s user supplied reference frequency and test masks
also persist. All persisted settings can be reset to the values the 5120A or 5115A was shipped with,
using the following steps.
To restore all settings to factory default values:
1. Navigate to the Settings screen (see “4.1 The Settings Screen” on page 21).
2. Press Restore Factory Defaults.
A screen with information about the settings restoration operation is displayed.
3. Press Restore Factory Defaults.
A dialog requesting final confirmation that all settings are to be restored to default
values is shown.
4. Press Ye s .
The test set deletes the current parameter values from persistent storage and reboots.
After it restarts, a dialog confirming that default values have been restored is
displayed.
5120A/5115A Operations and Maintenance Manual 29
4.1.6 Upgrading the software via USB flash drive
Software versions TS-2-7-9-2 and above can be upgraded using a USB flash drive.
To perform the upgrade:
1. Install the new software image supplied by Symmetricom on a USB flash drive and install
it in one of the USB ports on the rear panel of the unit
2. Navigate to the Settings and Options screen (see “4.1 The Settings Screen” on page 21).
3. Press External USB Drive.
A screen with information about the upgrade process is displayed.
4. Press Check for Updates.
A dialog requesting confirmation that you would like to use this image for upgrade is
displayed.
5. Press Ye s .
The test set copies the new software image to a second disk partition, confirms that the new file
system is good and reboots.
30 4: Global System Settings
5: Configuring Data Displays
5.1 Configuring Phase Noise Plot
The 5120A and 5120A-01display (f) phase noise data out to 1 MHz, provided neither the input
nor reference signal is below 2 MHz. The 5115A displays data out to 100 kHz. This data shows the
(f) spectrum of the phase differences between the Input and Reference signals. All measurements
are referenced to the frequency of the Input signal.
Data first displays on the screen after collection starts, then the screen updates as often as a few
times per second. The first range of data displayed is from approximately 0.1 Hz to the maximum.
The longer the data collection period, the more data is available to display phase noise at lower
offset frequencies.
The test set detects spurs caused by its own operation. These spurs are referred to as internally
generated spurs. Internally generated spurs are removed from calculations. All spurs plotted on the
phase noise plot are part of the signals attached to Input or Reference port.
Figure 9 Example Phase Noise Plot shows an example phase noise plot.
5120A/5115A Operations and Maintenance Manual 31
New data display
in magenta.
Older data
display in green.
Spurs display in
red, even if part
of new data.
The region below the measurement
noise floor shaded gray.
Time constant shows the current
spectrum averaging interval.
Figure 9: Example Phase Noise Plot
The lower portion of the graph is shaded to the level of instrument noise that produces an
imaginary result from cross-correlation. This noise is caused by the test system, and recedes over
long averaging times. Its level constitutes a lower bound on the measurement noise floor. The
noise components that produce real results from cross correlation are indistinguishable from phase
noise present on the input signals. A separate measurement of the instrument noise floor at the
power and frequency of interest is recommended.
Typically, the actual noise floor of the instrument is above this level outside the flicker region. In
the case where phase noise measurements are less than 10 dB above the measurement noise floor,
a correction factor can be subtracted from the Phase Noise measurement to provide a best estimate
of the phase noise of the signals. Table 2 lists the suggested correction factors:
Table 2: Magnitude Difference and Noise Correction Factor
Magnitude difference (dB) 161063210
Noise correction factor (dB) 0.1 0.4 1.2 1.8 2.1 2.5 3
The 5115A does not perform cross-correlation, and cannot shade the measurement noise floor
region.
32 5: Configuring Data Displays
Note
The following phase noise settings can be configured:
Plot Scale (see page 33)
Data Markers (see page 35)
Test Mask (see page 38)
Display Tools, including Tim e Constant (see page 41)
5.1.1 Scaling the Phase Noise Plot
The phase noise plot can be scaled logarithmically or linearly in the following ways:
Automatically scale the y axis:
• Sets the dB/division to the closest values that allow display of all data.
• Sets the top grid line to a multiple of the selected dB/division value.
Manually scale the y axis:
• Allows for shifting the displayed values from a maximum of 60 dBc/Hz to a minimum
of -240 dBc/Hz.
• Lets you increase or decrease the dB/division allowing the following values: 0.5, 1,
1.5, 2, 5, 10, 15, 20, 25, and 30.
Automatically scale the x axis:
• Sets the x scale to logarithmic.
• Sets the minimum and maximum frequency to fit all data.
Fixed logarithmic scale x:
• Shows from 1 to 9 decades.
• Allows the following values (Hz): 10
6
and 10
Fixed linear scale x:
.
–4
, 10–3, 10–2, 10–1 100, 101, 102, 103, 104, 105,
• Forces minimum x value of 0 Hz.
• Allows the following maximum values (Hz): 10
5
, and 106.
10
The 5120A-01 cannot measure phase noise at offset frequencies greater than 100
kHz when either of the signals connected to the front panel signal input ports has
a frequency less than 2 MHz. When signals with lower frequencies are attached,
the plot can still be scaled to include the 1 MHz offset frequency, but no data will
be plotted from 100 kHz to 1 MHz. Both of the internal oscillators produce
frequencies greater than 2 MHz.
–3
,10–2, 10–1 100, 101, 102, 103, 104,
To scale the plot using softkeys:
1. Navigate to the Phase Noise Plot. See “3.1.1 Navigation” on page 12 for details.
5120A/5115A Operations and Maintenance Manual 33
2. Press Config Phase Noise.
3. Press Scale Plot.
The highlighted softkeys show whether each axis is auto scaled or in fixed scale mode.
To auto scale an axis, press Auto Scale X Axis or Auto Scale Y Axis.
To manually scale an axis, press one of the following:
• Fixed Scale Y Axis
- Use Shift Up 1 Div and Shift Down 1 Div to shift (scroll) the data up or down
one division on the screen.
- Use Increase dB/Div or Decrease dB/Div to increase or decrease the values
for each division on the plot.
• Scale X-log
- Use Inc Max or Dec Max to increase or decrease the maximum value on the
scale.
- Use Inc Min or Dec Min to increase or decrease the minimum value on the
scale.
• Scale X-linear
- Use Inc Max or Dec Max to increase or decrease the maximum value on the
scale.
If a USB mouse is attached to the test set, the plot can be manually scaled very effectively by
zooming in on a region of interest. This region is designated by dragging a rectangle around it.
To scale the phase noise plot using a mouse:
1. Right-click anywhere on the plot and select Scale > Zoom.
The mouse cursor changes to a cross hair.
Tip: Invoke this function by pressing the ‘Z’ key on a USB keyboard.
Tip: Cancel the zoom operation by clicking the right mouse button. Do so at any point
in this instruction set.
2. Move the mouse to one corner of the region of interest.
3. Press (and hold) the left mouse button.
4. Move the mouse to the opposite corner of the region of interest.
As the mouse is moved, a white rectangle from the original corner to the current
mouse position is continually drawn.
5. Release the left mouse button to zoom in on the selected region.
The phase noise plot is scaled to fit all data in the selected region.
Both the x and the y axis are switched to fixed scale mode.
The fixed scales produced by the zoom feature are subject to the same constraints described above.
The zoom feature cannot scale the x axis below a single decade in logarithmic mode.
34 5: Configuring Data Displays
If the mouse has a wheel, the equivalent of the Shift Up 1 Div and Shift Down 1 Div softkey
functions for the y axis can be performed by scrolling the wheel. Note that this operation puts the y
axis into fixed scale mode.
The mouse can quickly auto scale both the x axis and y axis. Right-click on the plot and select
Scale > Auto Scale. This function can be invoked by pressing the ‘A’ key on a USB keyboard.
5.1.2 Setting Data Markers
Data markers designate two specific frequencies, each with a diamond on the screen. These are
referred to as the marker and the delta marker. Once markers are positioned on a frequency, they
continue to display the measurement at that frequency until they are repositioned.
Both markers display their frequency and power spectral density values at the top of the phase
noise plot screen. This is useful because it provides more accurate coordinates than the plotted data
itself can indicate. The coordinates are updated as markers are repositioned or trace a new
measurement at their designated frequency.
When both markers are positioned, the difference between their coordinates is calculated and
displayed.
When either marker is tracing a measurement that is part of a spur, a small color coded window
pops up to indicate the spur’s frequency and power. The power displayed in the window should be
used to determine the power level of the spur, as the graphical display is displaying the spur on a
dBc/Hz scale. The spur information window moves to another quadrant if the plot is scaled so that
the marker indicator collides with the window.
A placed marker is considered visible even if the plot is scaled so that its indicator falls off the
screen. A visible marker’s spur information window remains visible as a result. When you Hide
Markers, their indicators and any extra window are hidden as well. Any extra windows visible at
the time the phase noise plot is printed will appear on the printout. Note that the marker
coordinates at the top of the screen overlap the title as a result of limited screen resolution.
Printouts have a much higher resolution and the marker coordinates are printed below the main
title instead of obscuring it.
5120A/5115A Operations and Maintenance Manual 35
Difference between
marker coordinates
Delta marker’s coordinates
display in orange color.
Normal marker’s coordinates
display in white color.
Delta marker and its
spur information
window display in
orange color.
Normal marker and
its spur information
window display in
white color.
Mouse cursor
Figure 10: Example Phase Noise Data with Data Markers
To place markers using the softkey interface:
1. Navigate to the Phase Noise Plot. See “3.1.1 Navigation” on page 12 for details.
2. Press Config Phase Noise.
3. Press Markers.
4. Press Normal Marker or Delta Marker.
A marker (diamond) displays at the center of the plot and its coordinates display at the
top of the screen.
5. Use the arrow softkeys to move the marker to the frequency of interest.
The left and right arrows move the marker to the next data point in the plot in the
direction of the arrow. These are repeating, accelerating softkeys. Pressing and
holding the key, the marker moves by a single point a few times, then in increments of
2 points a few times, then 4, increasing by a factor of 2, until 64 points at a time are
skipped - at this rate the entire data set can be traced in a reasonable amount of time.
Note that movement in terms of data points is not possible while no data set is plotted.
The and softkeys move the marker to the offset frequency at the
next vertical grid line.
The softkey moves the marker to the center of the x axis.
36 5: Configuring Data Displays
Note
To place a marker using the mouse:
1. Right-click anywhere on the phase noise plot and select Markers > Place Marker or
Markers > Place
Tip: These functions can be invoked by pressing the ‘M’ or ‘D’ key on a USB
Δ Marker.
keyboard.
The mouse cursor changes to a cross hair as shown above the delta marker in
Figure 10 Example Phase Noise Data with Data Markers.
2. Move the mouse.
The marker follows the x-coordinate of the mouse cursor.
Tip: Due to limitations imposed by screen resolution, multiple data points are plotted
at the same x-coordinate. Mouse-based marker placement also considers the ycoordinate when selecting the best matched measurement. The mouse was used to
place the delta marker in Figure 10 Example Phase Noise Data with Data Markers.
Note that the cross hair mouse cursor is above the actual measurement traced by the
marker. This ensures that the marker is placed on the highest data point at that offset
frequency. If the mouse cursor was at the same x coordinate but below the data set, the
lowest point at that x coordinate would have been selected.
3. Click the left mouse button to position the marker.
To remove all markers and related information windows:
1. From the front panel, press Phase Noise Plot.
2. Press Config Phase Noise.
3. Press Markers.
4. Press Hide Markers.
All markers and windows are removed from the screen.
Alternatively, right-click the phase noise plot at any time and select Markers > Hide. The marker
softkey interface need not be active.
Once a marker is placed at a frequency it will follow the measurement at the frequency closest to
it. This “best match measurement” is calculated every time new data becomes available. Consider
the following scenario to understand why this is relevant:
1. The test set has measured phase noise for 30 minutes and measurements at offset
-3
frequencies below 10
Hz are available.
2. A marker is placed at an offset frequency of 0.012 Hz.
3. Data collection is stopped and restarted. Phase noise data at 0.012 Hz will not be available
for some time. Until it becomes available, the measurement whose frequency most closely
matches that of the marker position is the measurement with the lowest offset frequency.
The marker follows this measurement. When a measurement at (or below) 0.012 Hz is
available the marker stops moving in frequency and begins to continually follow the 0.012
Hz measurement.
Markers can also be placed on a specific spur’s frequency using the Spur Table. For more
5120A/5115A Operations and Maintenance Manual 37
The red dotted line
is a test mask.
information on how to do so see “5.1.5 The Spur Table” on page 42.
5.1.3 Setting Up a Test Mask
Test masks display a visual fail level reference line for phase noise data. A test mask is a set of line
segment end points that are scaled as data points are. Line segments are drawn between the points
after scaling. Note that a test mask must contain at least two points before a line segment appears
on the plot.
38 5: Configuring Data Displays
Figure 11: Example Test Mask for Phase Noise
The PNTS can store five different phase noise test masks. One of them is considered to be the
current test mask. The current test mask changes as masks are loaded and saved. The current mask
is highlighted in the editor’s load and save softkey interfaces. It is marked with a dot in the mouse
popup menu. Loading, saving and editing of test masks is done with the test mask editor.
To access the test mask editor:
1. Select the Phase Noise Plot (see “3.1.1 Navigation” on page 12 for details).
2. Press Config Phase Noise.
3. Press Test Mask.
4. The Test Mask Editor is activated and displays the points in the current test mask. The
current test mask is empty when the phase noise test set is shipped. Figure 12 on page 39
shows the test mask editor for the test mask shown in Figure 11 Example Test Mask for
Phase Noise.
Current mask
is highlighted
Toggles visibility of the current
test mask. Displays Show Mask
when mask is hidden, or Hide
Mask when mask is visible.
The test mask editor provides the softkey
interface to edit, load, and save test masks.
Press Edit Mask to edit the
current test mask.
Adding or editing points requires inputting x and y coordinates. The number pad editor is executed
twice each time a point is added or edited. When adding new points, the number pad editor is
initialized with blank fields. When editing existing points, it is initialized with each coordinate’s
current value. This simplifies modification of only one of an existing point’s coordinates.
To edit a test mask:
1. Access the test mask editor as described in “ To access the test mask editor:” on page 38.
2. Press Edit Mask.
The softkey interface changes to provide an interface with the interactive table.
3. Press Add Point to add a new point to the test mask or go to Step 4 to edit existing points
or Step 6 to delete points.
Tip: Right-click the test mask table and select Add Point in the menu without entering
the Edit Mask interface.
“3.4.1.1 The Number Pad Editor” on page 17 is displayed for the first coordinate.
• Enter the Offset Frequency coordinate (in Hz) for the new point and press Apply,
If the first coordinate was applied, the number pad editor is displayed for the second
coordinate.
Figure 12: The Test Mask Editor
or press Cancel to cancel point addition.
• Enter the dBc/Hz coordinate for the new point and press Apply, or press Cancel
5120A/5115A Operations and Maintenance Manual 39
to cancel the addition.
If addition was not cancelled, the table lists the new point.
4. Use the arrow softkeys to highlight a point to edit.
5. Press Edit Point.
Tip: Steps 4 and 5 can be combined by double clicking the point to be edited with a
mouse. This can be done without entering the table’s interactive softkey interface as
stated in Step 2.
“3.4.1.1 The Number Pad Editor” on page 17 is displayed for the first coordinate.
• Edit the Offset Frequency coordinate (in Hz) and press Apply, or press Cancel to
cancel the edit.
The number pad editor is displayed for the second coordinate.
• Edit the dBc/Hz coordinate and press Apply, or press Cancel to cancel the edit.
When an edit is cancelled, both of the test mask point’s coordinates remain
unchanged.
If editing was not cancelled, the point’s row in the table is updated with the new
coordinates. The point may be moved, as test mask points are ordered according to
their x-coordinate.
6. Use the arrow softkeys to highlight a point to delete.
7. Press Delete Point.
With a mouse, points can be deleted by clicking their row, then right-clicking and
selecting Delete Point from the popup menu. This can be done without entering the
Edit Mask softkey interface as stated in Step 2.
Any added, edited or deleted points mark the test mask as changed. A warning is displayed upon
Return to the phase noise plot if a changed mask has not been saved. The message states that
modifications will be lost if the test set is powered off.
To save a test mask:
1. Access the test mask editor as described in “ To access the test mask editor:” on page 38.
2. Press Save Mask.
Note that the test mask that was last loaded or saved is highlighted.
3. Press one of the softkeys (shown on the right in Figure 12 The Test Mask Editor) to save
the mask to the corresponding slot.
If this will change an existing test mask, the system asks for confirmation before it
overwrites the existing mask. The screen displays the current and the original masks in
two tables. To overwrite the existing test mask, press Overwrite. To save the mask to
a different slot, press Cancel.
A message window confirms that the mask was saved.
To load a test mask:
1. Access the test mask editor as described in “ To access the test mask editor:” on page 38.
2. Press Load Mask.
3. Press one of the softkeys (shown on the right in Figure 12 The Test Mask Editor) to load
the test mask stored in the corresponding slot.
40 5: Configuring Data Displays
Note
The table on the left displays the loaded test mask.
The pressed softkey is highlighted. The loaded mask has become the current mask.
4. Press Return.
5. Make sure the mask will be plotted. The topmost softkey in the test mask editor will read
Hide Mask if the mask is to be plotted. If it will not be plotted, the softkey is labeled
Show Mask. Press the Show Mask key to enable plotting the mask.
Test masks can be loaded and saved by right-clicking the plot. Select Test Mask > Save > Mask 3
in the popup menu to save the current mask as the third mask, for example. Test masks can also be
shown and hidden using this menu.
5.1.4 Display Tools
The Display Tools softkey available through the Config Phase Noise menu accesses a menu with
the following softkeys:
Pause Updates stops update of the data display. This softkey toggles to Resume Updates.
Tak e S na ps h o t displays a snapshot of the data to compare to data as it is being collected.
Snapshot data is plotted in white.
Hide Snapshot toggles with Show Snapshot to disable/enable plotting of the snapshot.
Integrated Phase Noise accesses a read-only table that displays integrated phase noise
with and without spurs. Each row shows integrated phase noise for one lower limit. As the
phase noise data set grows, additional rows appear for even lower limits. See “3.3.2
Tables” on page 15 for more information about read-only tables. Integrated phase noise
includes phase noise out to 1 MHz.
Time Constant, described in detail in the following section.
5.1.4.1 Setting the Time Constant
The time constant determines the length of the running average used for (f) phase noise and Allan
deviation computations. Beginning with software revision 260 all test set models support
configuration of the time constant. One of four running averages can be selected: 1, 10, or 100
seconds, and infinite.
Before software revision 260, the PNTS always employed an infinite running average. The infinite
time constant is the factory default setting in new software revisions. The current time constant
setting is displayed in the phase noise plot. The field is labeled Time Constant and can be found
below plotted data, in the bottom right corner.
The time constant can be changed using the
be changed before or during data collection. When set in Collecting state, the following will be
observed:
(f) phase noise plot Display Tools sub-menu. It can
Allan deviation and (f) phase noise data set, its subsets and meta data such as integrated
phase noise, are cleared. They remain blank for a brief period - until measurements using
the new time constant become available.
Data sets in the phase and frequency difference plots and the frequency counter continue
to be maintained without interruption.
5120A/5115A Operations and Maintenance Manual 41
To set the time constant:
1. Select the Phase Noise Plot (see “3.1.1 Navigation” on page 12 for details).
2. Press Config Phase Noise.
3. Press Display Tools.
4. Press Time Constant to access a soft key menu that enumerates the valid settings.
• The current setting is denoted with highlight.
5. Press the soft key that corresponds to desired running average length.
To set the time constant using a mouse, right click the phase noise plot, select Display Tools >
Time Constant, and desired running average length from the sub-menu.
The time constant can also be set using a network command connection. See “7.2.6.3 Setting the
Time Constant” on page 62.
Complete display updates may take up to 2 minutes following a change in the time constant
setting.
For best Allan Deviation plot results, always set the time constant to infinity.
5.1.5 The Spur Table
The spur table is an interactive table that lists all the spurs in the plotted phase noise data. See
“3.3.2 Tables” on page 15 for more information on interactive tables.
The test set detects spurs caused by its own operation. These spurs are referred to as internally
generated spurs. Internally generated spurs are removed from calculations. All spurs listed in the
spur table are part of the signals attached to Input or Reference port.
Every spur’s frequency and power is listed regardless of how the phase noise plot is scaled. Spurs
that do not appear on the plot are listed as such.
To access the spur table:
1. From the phase noise plot, press Config Phase Noise.
2. Press View Spur Table.
Alternatively, one can right-click the plot and select View Spur Table.
One can Pause Updates and Resume Updates to the phase noise plot, and hence the spur table
itself, from the softkey interface provided by the table. This is equivalent to pausing and resuming
updates from the Display Tools softkey menu described in the previous section. Pausing Updates
makes reading the screen easier and simplifies marker placement.
The marker or delta marker can be placed on a spur’s frequency for easier identification on the
phase noise plot.
To place a marker at a spur’s frequency:
1. Use the arrow softkeys to highlight a spur.
Tip: Click the desired spur with a mouse.
2. Press Place Marker or Place
42 5: Configuring Data Displays
Δ Marker.
For general information about markers, see “5.1.2 Setting Data Markers” on page 35.
5.2 Configuring the Allan Deviation Plot
The PNTS can display the Allan deviation of the input signals. This data shows how much
deviation there is over time between the Input signal and the Reference signal. All measurements
are referenced to the Input signal.
The Allan deviation screen shows the following:
Allan deviation plot of the collected data.
Current τ
Noise Equivalent Bandwidth of the input filter, NEQBW, is displayed in the upper right
value displays in the upper-left corner.
0
corner. NEQBW describes the equivalent bandwidth of a filter for broadband (white)
noise and is the bandwidth of a rectangular characteristic filter having the same power
transfer function as the selection filter (same area under the curve).
The 5120A and 5120A-01 perform cross-correlation. They are able to compute the noise
floor and shade the region below the measurement noise floor in gray.
The 5115A does not perform cross-correlation, and cannot shade the measurement noise
floor region. Instead it computes error estimates and presents those estimates using red
vertical bars along with each measurement.
The following can be configured:
Plot scale (see page 43)
τ
setting (see page 44)
0
Test mask (see page 44)
5.2.1 Scaling the Allan Deviation Plot
The Allan deviation plot can be scaled automatically or manually.
To scale the plot:
1. Press Allan Deviation Plot (see “3.1.1 Navigation” on page 12 for details).
2. Press Config Allan Deviation.
3. Press Scale Plot.
The highlighted softkeys show the current settings.
Press Auto Scale X Axis or Auto Scale Y Axis to auto scale either axis.
To scale the plot manually, press one of the following:
• Fixed Scale Y Axis
- Use Inc Min or Dec Min to increase or decrease the minimum scale value.
- Use Inc Max or Dec Max to increase or decrease the maximum scale value.
• Fixed Scale X Axis
5120A/5115A Operations and Maintenance Manual 43
Note
- Use Inc Min or Dec Min to increase or decrease the minimum scale value.
- Use Inc Max or Dec Max to increase or decrease the maximum scale value.
The Allan deviation plot can be scaled using the zoom feature described for the phase noise plot.
See “ To scale the phase noise plot using a mouse:” on page 34 for details.
5.2.2 Selecting τ0
The τ0 value is the smallest sampling period used to calculate a set of Allan deviation values.
These values are computed at averaging times that are multiples of the base τ
values are: 1 ms, 10 ms, 100 ms, and 1 s.
. The available τ0
0
To select the τ
1. Navigate to the Allan Deviation Plot (see “3.1.1 Navigation” on page 12).
2. Press Config Allan Deviation.
3. Press Select τ
4. Increase or decrease the τ
To set τ
The current selection is indicated with a dot before the menu item.
with a mouse, right-click the plot and select the desired value from the Set τ0 submenu.
0
:
0
.
0
setting using the Inc τ0 or Dec τ0 softkeys.
0
5.2.3 Viewing the Allan Deviation Table
Allan deviation data can be viewed in tabular format by pressing the View Table softkey. The
table lists all Allan deviation values regardless of how the plot is scaled.
To access the table with a mouse, right-click the Allan deviation plot and select View Table from
the menu. The table provides both the softkey and mouse interfaces to change the τ
5.2.4 Setting Up Allan Deviation Test Masks
The Allan deviation test mask is configured in the same way the phase noise test mask is. The plot
maintains its own set of persistent test masks. Saving an Allan deviation test mask as Mask 3 does
not overwrite the corresponding phase noise test mask, for example.
value.
0
To set up the Allan deviation test mask:
1. Navigate to the Allan Deviation Plot (see “3.1.1 Navigation” on page 12).
2. Press Config Allan Deviation.
3. Press Test Mask.
The test mask editor has been invoked. Loading, editing, saving, showing and hiding
the Allan deviation test mask work just as described in section “5.1.3 Setting Up a
Test Mask” on page 38. The differences you will encounter are units in the test mask
tables and number pad editor, and the main screen title. Both help determine for which
plot the test mask editor has been invoked.
44 5: Configuring Data Displays
5.3 Configuring the Phase Difference Plot
The phase difference plot shows real-time measurements each second. After approximately nine
minutes, data pans to the right as new data becomes visible. All measurements are referenced to
the Input signal.
The phase difference plot shows the following:
Value of the center line, or its origin and slope when linear trend is removed. See “5.3.2
Removing the Linear Trend” on page 45 for details.
Value per division on the y axis in seconds.
Value per division of the x axis in seconds. This cannot be changed.
5.3.1 Scaling the Phase Difference Plot
The phase difference plot can do the following:
Automatically scale the y axis to fit all data.
Display the y axis in fixed-scale mode.
The x axis displays 60 seconds of data per division.
To scale the plot:
1. Press Phase Diff Plot (see “3.1.1 Navigation” on page 12).
2. Press Config Phase Diff.
To automatically scale the y axis, press Auto Scale Y Axis.
To use a fixed scale, press Fixed Scale Y Axis, then press one of the following:
• Use Shift Up 1 Div and Shift Down 1 Div to shift (scroll) the data up or down
one division on the screen.
• Use Increase Time/Div or Decrease Time/Div to increase or decrease the values
for each division on the plot.
• Use Center Median to center the data’s median vertical value.
5.3.2 Removing the Linear Trend
Phase difference measurements often exhibit a linear trend. This results in plots which appear as
diagonal "lines" when they are scaled in a way that fits all data. This is the result of a large units
per division selection on the y axis, which in turn results from accommodation of the oldest and
the most recent measurement which continually grow further apart. The large units per division
setting decreases resolution and makes it difficult to observe measurement details.
Consider the phase difference measurements plotted in Figure 13 Linear Trend in Phase
Difference Measurements. Over time they exhibit the trend discussed thus far. The white line
segment shows this trend, as it is measured by the Measure Linear softkey. The slope of this line
segment (from the first to the last available measurement) is taken into consideration when the
trend is measured.
5120A/5115A Operations and Maintenance Manual 45
Figure 13: Linear Trend in Phase Difference Measurements
Make the following observations about Figure 13 Linear Trend in Phase Difference
Measurements:
Region 1 contains measurements which fall below the trend line, and reach the trend line
towards the end of the region.
Region 2 contains measurements near or on the trend line segment.
Region 3 holds measurements which approach the trend line segment from above.
Once the trend has been measured, it can be removed from the plotted measurements, by pressing
the Remove Linear softkey shown in Figure 13 Linear Trend in Phase Difference Measurements.
Removing the linear trend from this data set results in the display shown in Figure 14 Linear Trend
Removed:
46 5: Configuring Data Displays
Figure 14: Linear Trend Removed
Make the following observations about Figure 14 Linear Trend Removed:
The y axis no longer lists the plot's center coordinate (in the top right corner) but refers to
Origin and the linear trend's Slope.
The origin is the center y-coordinate at the left most grid line.
Slope shows by how much the white line labeled Linear in Figure 14 Linear Trend
Removed was adjusted. It is the slope of the line through the oldest and most recent
measurement at the time the linear trend was measured using the Measure Linear
softkey.
Compare each of the rectangular regions with its counter part in Figure 13 Linear Trend in Phase
Difference Measurements.
The curves above and below the trend are better defined.
Trend line intersections which were barely noticeable in Figure 13 Linear Trend in Phase
Difference Measurements can readily be seen.
The Remove Linear softkey has changed to Don't Remove Linear. Pressing it at this time will
stop removing the trend from the data and display data set as seen in Figure 13 Linear Trend in
Phase Difference Measurements.
The linear trend can be measured whenever there are at least two phase difference measurements
available. Slope and origin are computed against the actual measurements even if the trend is
currently removed. There is no need to stop removing the trend before measuring it again.
If linear trend removal results in a plot that exhibits a linear trend of its own, the phase difference
measurements are following a curve rather than a line.
Pressing the Remove Linear softkey essentially plots the phase difference measurements' distance
from the trend last measured by the Measure Linear softkey. The top and bottom most grid lines
in Figure 14 Linear Trend Removed are parallel to the linear trend line segment in Figure 13
5120A/5115A Operations and Maintenance Manual 47
Linear Trend in Phase Difference Measurements, as depicted in Figure 15 Conceptual
Representation of Figure 14 Linear Trend Removed in terms of Figure 13 Linear Trend in Phase
Difference Measurements.:
Figure 15: Conceptual Representation of Figure 14 Linear Trend Removed in terms of Figure 13 Linear Trend in
Phase Difference Measurements.
5.3.3 Pausing or Resuming Updates
The phase difference measurement display can be paused by pressing the Pause Updates softkey.
To resume updates, press the Resume Updates softkey. As with all data sets that can be paused,
the test set continues to collect data while updates are paused and presents the latest data set when
they are resumed.
5.4 Configuring the Frequency Difference Plot
The PNTS can display the frequency difference between the Input and the Reference signals. The
measurements are plotted in real-time each second. All measurements are referenced to the Input
signal. After approximately nine minutes, data pans to the right so that new data becomes visible.
The frequency difference plot shows the following:
Value of the center line.
Value per division on the y axis.
Value per division of the x axis, in seconds. This cannot be changed.
48 5: Configuring Data Displays
5.4.1 Scaling the Frequency Difference Plot
The frequency difference plot can be scaled in the following ways:
Automatically scale the y axis to fit all data.
Display the y axis in fixed scale mode.
The x axis scale is 60 seconds per division and displays about nine minutes of data.
To scale the plot:
1. Press Freq Diff Plot (see “3.1.1 Navigation” on page 12).
2. Press Config Freq Diff.
To automatically scale the y axis, press Auto Scale Y Axis.
To manually scale it, press Fixed Scale Y Axis, then press one of the following:
• Use Shift Up 1 Div and Shift Down 1 Div to shift (scroll) the data up or down
one division on the screen.
• Use Increase Units/Div or Decrease Units/Div to increase or decrease the values
for each division on the plot.
• Use Center Median to center the data’s median value.
5.4.2 Pausing or Resuming Updates
The frequency difference measurement display can be paused by pressing the Pause Updates
softkey. To resume updates, press the Resume Updates softkey. As with all data sets that can be
paused, the test set continues to collect data while updates are paused and presents the latest data
set when they are resumed.
5.5 Configuring the Frequency Counter
The PNTS collect data that measures the frequency of the Input signal using the Reference signal
as a reference. The test set continually computes and displays frequency averages for the Input
signal port for the last 1, 10, 100, and 1000 seconds. When set automatically, the Reference
Frequency value may be displayed as “not yet set” until data collection begins, then the frequency
of the Reference port signal is displayed.
In the internal reference mode of the 5120A-01, the Reference Frequency displays as Internal
indicating that the internal oscillators are used. In this mode, a message about the accuracy of
absolute frequency averages is displayed (and printed) below the frequency counter table. In the
extremely unlikely event of corrupt internal reference calibration information, the Reference
Frequency displays as “UNCALIBRATED”. If this occurs, the internal reference oscillators
should be calibrated as soon as possible. See “8.1 5120A-01 Internal Reference” on page 72 for
information about calibration. For best frequency counter measurements with the 5120A-01, use
an external precision 10 MHz source connected to the Reference input.
The frequency counter table shows the following:
The average frequency of the Input signal.
Frequency averages which are continually updated. After 10 seconds, 1 and 10 second
averages are displayed, after 1000 seconds all four averages are available.
5120A/5115A Operations and Maintenance Manual 49
Frequency averages are output using variable precision. Two factors determine precision:
The sample time.
The lower of the frequencies of the signals attached to the Input and the Reference port at
the time data collection starts.
Table 3 shows the number of digits following the decimal point based on these factors:
Table 3: Variable Precision - Digits Following the Decimal Point
Averaging
Time (s)
Frequency <=
1.99 MHz
Frequency <=
4.99 MHz
Frequency >
4.99 MHz
113 13 13
10 14 14 14
100 14 14 15
1000 14 14 15
See Figure 16 on page 51 for a frequency counter screen example that shows all four frequency
averages at maximum precision.
5.5.1 Changing the Reference Frequency
The frequency used to compute frequency averages when an external reference signal (optional on
5120A-01 using the internal reference) is used can be set in one of two ways:
Automatically - The test set uses the Reference signal’s measured frequency.
Manually - The user specifies a more precise reference frequency.
The current reference frequency displays above the frequency table as shown in Figure 16
Frequency Counter Screen:
50 5: Configuring Data Displays
Current reference frequency shown with the
precision used to perform calculations.
How the reference frequency was
set. Displays auto or user.
Figure 16: Frequency Counter Screen
The reference frequency can be changed while the test set is in Collecting state on all models. New
settings are immediately used to recompute frequency averages.
On the 5120A-01, the automatic and manual reference frequency settings are applicable only when
an external reference is used. The reference frequency can be configured while in internal
reference mode. Any new setting will take effect during the next data collection that uses an
external reference signal.
5.5.1.1 Automatically Setting the Reference Frequency
The instrument can automatically set the frequency counter’s reference frequency when collecting
begins. The automatic reference frequency is the frequency of the Reference signal in MHz (to a
precision of one decimal digit) at the time collection starts. Automatic setting of the reference
frequency is the default setting.
To automatically set the reference frequency:
1. From the front panel, press Freq Counter (see “3.1.1 Navigation” on page 12).
2. Press Config Freq Counter.
3. Press Auto Reference Freq.
5.5.1.2 Manually Setting the Reference Frequency
Manually setting the reference frequency allows for much greater precision than that provided by
the automatic setting. A manually entered reference frequency may contain up to 15 decimal
digits.
To manually set the reference frequency:
1. From the front panel, press Freq Counter (see “3.1.1 Navigation” on page 12).
5120A/5115A Operations and Maintenance Manual 51
2. Press Config Freq Counter.
3. Press Enter Reference Freq.
The Reference Frequency number pad editor displays.
4. Enter the new reference frequency (in MHz).
See “3.4.1.1 The Number Pad Editor” on page 17 for help with entering numbers.
The table of frequencies updates with calculations using the new frequency.
The instrument retains the manually set reference frequency until a new one is entered
or automatic setting is selected. The frequency setting persists when the test set is
powered off.
52 5: Configuring Data Displays
Note
6: Collecting and Viewing Data Locally
6.1 Starting and Stopping Data Collection
After the PNTS is powered up, with Input and Reference signals connected, data collection can be
started. For information on configuring the display, see “Chapter 5, Configuring Data Displays” on
page 31. When the required data is available, collection can be stopped.
To start data collection:
1. Ensure that the reference signal source is connected to the Reference connector (optional
for 5120A-01) and the DUT (device under test) is connected to the Input connector on the
test set.
For more information, see “2.2 Setting Up a PNTS” on page 7.
2. Use one of the following methods:
Press Start on the front panel.
Right-click the current plot or table and select Control > Start from the menu.
Do not bump, vibrate, or otherwise disturb the test set or the signal cables during
operation, as this may influence the accuracy of data collection and results.
Pressing the front panel buttons other than STOP during collection could also
influence the measurement. Use of a mouse or control of the instrument via
Ethernet is recommended for best results if settings need to be changed during
collection.
• The action field displays Initializing and then transitions to Collecting. See “3.2.1
Collecting State” on page 13 for details.
• Data can be collected indefinitely. The Allan deviation plot and table display
values for averaging times up to 400,000 seconds.
• The instrument automatically turns off its LCD back-light if no buttons are
pressed within 1 hour. Press any softkey or move the mouse to view the last
displayed screen.
To stop data collection:
Use one of the following methods:
Press Stop on the front panel.
Right-click the current plot or table and select Control > Stop from the menu.
• The instrument stops collecting data, but continues to display the data it collected
on the screen. The collecting state returns to Ready.
5120A/5115A Operations and Maintenance Manual 53
Note
The most recent data is retained on all screens until a new data collection starts or
the instrument is powered off.
54 6: Collecting and Viewing Data Locally
Note
6.2 Printing
When the Print button on the front panel is pressed, the test set prints the visible plot or table to
the current print job destination. See “4.1.3 Printer Configuration” on page 26 for more
information about the print destinations and formats.
To print data:
1. Navigate to the data set to be printed (see “3.1.1 Navigation” on page 12).
2. Use one of the following methods:
Press Print on the front panel.
Right-click the current plot or table and select Control > Print from the menu.
The test set can queue up to 15 print jobs. All print jobs will go to the currently
selected printer (or file system). The number of pending print jobs is displayed in
the top left corner of screen.
To cancel pending print jobs:
1. Access the Settings page (see “4.1 The Settings Screen” on page 21 for details).
2. Press Printing.
3. Press the down arrow softkey until Cancel Print Jobs button is highlighted.
The softkey interface displays a PUSH softkey.
4. Press PUSH to push the Cancel Print Jobs button.
5. Press Return to return to the previous screens.
5120A/5115A Operations and Maintenance Manual 55
Note
6.3 Taking or Yielding Local Control.
Please see “3.2.3 User in Control” on page 14 for an introduction about the user in control of the
test set.
To t ak e Local control of the test set:
1. Perform an operation that requires control. Start or Stop data collection for example.
The reminder dialog stating that local control of the test set is required offers the
opportunity to take local control.
2. Press Ye s to take local control.
Now that the test set is under Local control, any function that requires control can be
executed using the softkey interface, mouse or keyboard.
To y ie ld Local control of the test set:
1. Access the Settings page (see “4.1 The Settings Screen” on page 21 for details).
2. Press Network.
3. Press the down arrow softkey until a push button on the row labeled Operations has focus
(denoted by a white rectangle).
The softkey interface displays a PUSH softkey.
4. Press the right arrow softkey until the Yield Control button is focused.
5. Press PUSH to push the Yield Control button.
6. Press Return to return to the previous screens.
Yielding control is not strictly necessary. A Remote user can take control.
56 6: Collecting and Viewing Data Locally
7: Collecting and Viewing Data Remotely
The PNTS can be controlled remotely using an Ethernet connection. Data can also be downloaded
over the Ethernet connection.
Two types of connections are accepted:
Data port connections
Command port connections
The data port continually publishes phase difference measurements in cycles while the test set is in
the Collecting state. See “7.3 The Network Data Port” on page 67 for additional details.
Command port connections are used to remotely control the test set to:
Take or yield remote control of the test set (see page 58).
Start and stop collecting data (see page 59).
Retrieve or print any other data set including:
• (f) Phase Noise
• Allan Deviation
• One Second Phase Difference
• One Second Frequency Difference
• Frequency Counter Data
• See “7.2.3 Retrieving Data from Command Port” on page 59 and “7.2.4 Printing from
the Command Port” on page 60 for details.
Configure Data Sets
• Pause and resume updates to phase and frequency difference (see page 62) and
removing the linear trend (see page 62).
• Set the Time Constant (see page 62).
• Set Allan deviation τ
value (see page 63).
0
• Configure the frequency counter’s reference frequency (see page 63).
Retrieve status information including: (see page 63)
• The input and reference signals’ frequency and power.
• The current collecting state.
Set the User Specified Title (see page 64).
Retrieve version information (see page 64).
Calibrate internal reference oscillators of a 5120A-01 (see page 73).
5120A/5115A Operations and Maintenance Manual 57
7.1 Accessing the PNTS Remotely and Exiting the Remote Session
Before Ethernet connections to either the command or the data port can be made, their port
numbers and the test set’s IP address must be known. See “4.1.2 Network Configuration” on
page 23 to learn how to configure them or check their current values.
Once the test set is configured and connected to the network, it can be accessed remotely using a
connection program, such as Telnet. The command and data ports each accept a single connection.
To access the test set remotely:
1. From a command prompt or your Telnet software, enter:
telnet <IP address> <1299>
telnet <IP address> <1298>
• This opens Telnet sessions to both ports so the instrument can be controlled and
phase difference data viewed.
• If data collection is in progress, the data port connection displays phase difference
data as described in section “7.3 The Network Data Port” on page 67. If data
collection must be started, see “7.2.2 Starting and Stopping Data Collection” on
page 59.
2. The command port outputs a short welcome message and displays a prompt with the test
set’s IP address. All commands described in the following sections are entered at this
prompt. Many commands produce output before re-displaying the prompt.
3. To close the command port connection, enter:
quit
If there are multiple test sets on your network, it may be beneficial to the system
administrator to know the MAC (hardware) address of each instrument. To obtain this
address send the show mac command. The test set will respond with its unique hardware
address. The settings screen shown in Figure 8 on page 21 can also be used to determine
the MAC address.
7.2 The Network Command Port
7.2.1 Taking or Yielding Remote Control
Please see “3.2.3 User in Control” on page 14 to understand the intent and effects of these
commands.
Some functions such as starting and stopping data collection require that the Remote user has (or
takes) control of the test set. When such commands are issued while the Local user has control,
they result in an error message asking the Remote user take control. Once control has been taken,
the command must be reissued.
To t ak e Remote control of the test set:
58 7: Collecting and Viewing Data Remotely
1. Enter:
control take
From now on the Local user will be told that a network user is in control when they attempt
operations that require it. The Local user will receive this message even after the Remote user
disconnects.
To y ie ld Remote control of the test set:
1. Enter:
control yield
7.2.2 Starting and Stopping Data Collection
Using the Ethernet port and a Telnet-capable program, data collection can be started and stopped
remotely.
To start and stop data collection remotely:
1. Access the Command port.
See “7.1 Accessing the PNTS Remotely and Exiting the Remote Session” on page 58
for more information.
2. From the Command port Telnet session, enter:
start
This command requires Remote control of the test set (see page 58).
When the test set reaches the Collecting state phase difference begins to arrive on any
open data port connections (see page 67).
3. To stop data collection, enter:
stop
This is a good time to permit either Local or Remote use by others using the control
yield command (though control can be yielded at any time - see page 58).
7.2.3 Retrieving Data from Command Port
All the data sets presented by the graphical user interface are available on the command port. To
retrieve a data set use the show command followed by the data set name of interest.
To retrieve any data set on the command port:
1. Access the Command port (see page 58).
2. Start data collection if necessary (see page 59).
3. At the command prompt enter:
show <datasetname>
Where <datasetname> is one of those listed below.
The data sets returned contain the most recent data (unless they are paused). Running
the same show <datasetname> command at a later time will return the most recent
data set at that point in time.
5120A/5115A Operations and Maintenance Manual 59
Use the show spectrum command to retrieve the
(f) phase noise data collected thus far. The
command returns the current time constant followed by a header labeling the first column as the
offset frequency coordinate and second as its power spectral density. It then returns the same
measurements that are plotted, one per line, with frequency in Hz followed by the power spectral
density in dBc/Hz. The 5120A and 5120A-01 then output the noise floor.
Use the show spurs command to retrieve the spur table. The command returns a header labeling
the following columns, then the spurs, one per line. Each line includes the spur’s index and its
frequency and power.
Use the show ipn command to retrieve the current time constant and integrated phase noise table.
Use the show adev command to retrieve the Allan deviation. The test set outputs the current time
constant followed by an Allan deviation table for each τ
prefixed with the τ
value and the input filter’s noise equivalent bandwidth. On the 5120A and
0
for which it is computed. Each table is
0
5120A-01, the corresponding noise floor is returned after each table. When all tables have been
returned, the command prompt is displayed again.
Use the show phasediff command to retrieve the one second phase difference strip chart data. The
test set outputs a header. The header indicates if the phase difference data set is paused. If the
linear trend is removed, the header states so and includes the trend’s slope and y-intercept. All
phase difference measurements are output with their corresponding x-coordinate so the
measurement can be related to the linear trend’s y-intercept. For more information about linear
trend removal see “Chapter 5, Removing the Linear Trend” on page 45.
Use the show freqdiff command to retrieve the one second frequency difference strip chart data.
The test set outputs a header showing that frequency difference data follows. If the frequency
difference data set is paused, the header will indicate this.
Use the show fcounter command to retrieve frequency counter data. The command outputs a
header showing the Reference frequency (and how it was set), followed by labels for the averaging
interval and average frequency columns. One line per averaging interval available at this time is
returned.
7.2.4 Printing from the Command Port
All data collected by the PNTS can be printed from the command port.
The print command can be used as a standalone command. When used without a parameter the
screen currently displayed by the graphical user interface is printed. The command is more useful
when used with parameters that specify what to print.
To retrieve a list of the data sets and screens that can be printed, issue the show screens command.
The test set returns a list of print command parameters, one per line each followed by a short
description of what will be printed. The following is a summary of these parameters:
spectplot - Phase Noise Plot
ipn - Integrated Phase Noise Table
spurtable - Spur Table
adevplot - Allan Deviation Plot (please see note at the end of this section)
adevtable - Allan Deviation Table (please see note at the end of this section)
phasediff - Phase Difference Plot
freqdiff - Frequency Difference Plot
60 7: Collecting and Viewing Data Remotely
Note
fcounter - Frequency Counter Table
settings - The Settings Screen
all - All of the above except settings screen (please see the note at end of this section)
The following commands would print the phase noise plot and the spur table:
print spectplot
print spurtable
Both data sets can be printed with this command:
print spectplot spurtable
Both variations ultimately print the same data sets. Issuing the print command once for each set
results in two print jobs with one page each, while listing both sets in a single command produces
a single print job with two pages. The second variation is more efficient because fonts must be sent
to the printer (or stored in a file) only once instead of twice. When printing to a file the second
variation also has the benefit of bundling the related data sets in a single file that can be viewed
with third party software. The print all command creates a single job with all data sets.
Data sets can only be printed once per print command:
print spectplot spectplot spurtable
Does not result in a print job that prints the phase noise plot twice. Neither does the following:
print all spectplot
The print command is also used to cancel all pending print jobs. To cancel print jobs, enter:
print cancel
The Allan deviation data printed corresponds to the current τ0 value. See “7.2.6.4 Setting the Allan
Deviation t0 Value” on page 63 for information on setting τ0 on a command connection.
7.2.5 Printer Configuration from the Command Port
Current printing options can be examined and modified from the command port. This section
explains how to make the settings with little regard to their effects. For more information about
printer setup in general see “4.1.3 Printer Configuration” on page 26.
You can retrieve the current printer configuration using the show printoptions command. The
command returns the current print job destination and selected print format.
The print format is changed using the set command as follows:
set print format <formatname>
Where <formatname> is one of the possible formats returned by the show printformats
command. The valid <formatname> values are: pcl5 and postscript. To print in postscript format
enter:
set print format postscript
5120A/5115A Operations and Maintenance Manual 61
To change where print jobs are sent, use the following variations of the set print command:
set print local
set print file
set print remote <hostaddr> <port>
These commands change print job destination to that indicated by their last parameter.
The last variation requires IP address and port number of a network printer that supports direct
transfer of information to the port, such as the HP JetDirect using port 9100. Other spooling
protocols such as the Internet Printing Protocol (IPP) are not supported at this time.
7.2.6 Configuring Data Sets from the Command Port
7.2.6.1 Pausing and Resuming Phase and Frequency Difference
The phase and frequency difference display can be paused using the command port connection.
When a data set is paused new measurements are recorded but not returned by the corresponding
show command or plotted by the user interface.
Use the pause command as follows:
pause phasediff (to pause updates to the one second phase difference data set)
pause freqdiff (to pause updates to the one second frequency difference data set)
To resume updates, issue the resume command with the same parameter value passed with pause
command. The show command will now return the current data set, and the user interface will plot
it.
7.2.6.2 Removing the Linear Trend
The phase difference cache supports measuring and removal of its linear trend. See “Chapter 5,
Removing the Linear Trend” on page 45 for conceptual details.
You can perform both functions on a command connection using the following commands:
measurelinear (to measure the current linear trend)
removelinear <on|off>
The on or off parameters to the removelinear command are equivalent to the Remove Linear and
Don’t Remove Linear softkeys in the graphical user interface. Note that this command affects the
plot in the graphical user interface.
The measurelinear command can be run regardless of whether the trend is currently removed or
not. The command may result in a message stating that there is no data to measure a trend with, if
the one second phase difference strip chart cache is empty at the time you issue the command.
7.2.6.3 Setting the Time Constant
You can set the Time Constant which controls the length of running average used to compute (f)
phase noise and Allan deviation using the following command:
set timeconstant <value>
Where the <value> parameter is set to:
0 (sets an infinite running average)
1, 10, or 100 (seconds)
62 7: Collecting and Viewing Data Remotely
For more general information about the time constant see “Chapter 5, Setting the Time Constant”
on page 41.
7.2.6.4 Setting the Allan Deviation τ0 Value
You can set the τ0 value using the following command:
set tau0 <value>
Where the <value> parameter is set to:
A fixed floating point number
0.001, 0.01, 0.1, or 1 (seconds)
The Allan deviation plot or table can be printed for a single τ
deviation plot for a τ
of 10 ms, issue the following commands:
0
value only. To print the Allan
0
set tau0 0.01
print adevplot
For more information about printing from the network, see “7.2.4 Printing from the Command
Port” on page 60.
To determine the current τ
value, use the show tau0 command. The test set will return the current
0
value in the format used by the set tau0 command.
7.2.6.5 Setting Frequency Counter’s Reference Frequency
See “Chapter 5, Configuring the Frequency Counter” on page 49 for general information about the
frequency counter.
To automatically set the reference frequency each time data collection starts, enter:
set referencefreq auto
To manually set it to a more precise value, provide the frequency in MHz as the last parameter to
the set referencefreq command. To set it to 5.0000003 MHz enter:
set referencefreq 5.0000003
Future show fcounter commands return the averages calculated using the new reference
frequency. The user interface table is also updated immediately. Note that show fcounter can be
used to determine what the current reference frequency is.
The reference frequency is applicable only to external signals connected to the Reference port, it
does not affect the reference frequency used in the internal reference mode featured by the 5120A-
01. The set referencefreq command can be sent while a 5120A-01 is operating in internal
reference mode, it will take effect the next time data is collected using an external reference signal.
7.2.7 Retrieving Status Information
To determine the current data collection state, enter show state. The command outputs the current
state and time constant. If the test set is in the Collecting state when the command is issued, the
duration of data collection is also output. For general information see “3.2.1 Collecting State” on
page 13.
5120A/5115A Operations and Maintenance Manual 63
To see the input frequency and power of the signals attached to the test set, enter show inputs. The
test set responds with two sets of frequency and amplitude values for the signals connected to input
and reference port:
Frequency and amplitude of the currently connected signals.
Frequency and amplitude of the signals against which the most recent (or current) data
collection was run.
7.2.8 Setting the User Specified Title
For general information about the user specified title see “3.2.4 User Specified Title” on page 14.
To retrieve the current user specified title, access the command port and run the show title
command.
To set the title that appears at the bottom of all printouts, use the set title command with a quoted
string of up to 34 characters. The title common to many of the screen shots in this manual is set as
follows:
set title “Quartz Oscillator vs Self”
The test set will return a confirmation message showing what the title has been set to. This
provides immediate feedback in case the string you provided is truncated because it exceeds the
maximum length.
7.2.9 Showing the Software Version
Version information, useful for troubleshooting, can be accessed on the command port.
To remotely show the software version:
1. Access the Command port (see page 58).
2. At the command prompt enter:
show version
The commands returns information such as the following:
• Model: 5115A
• DSP CPLD Revs: 03 00 00 00
• ADC CPLD Revs: 01 01 00 00
• ISA CPLD Rev: 0015
• Software: Revision 252
• Options:
• DOCSIS ATP
7.2.10 Viewing Help for Remote Commands
The test set continues to be under development and new commands may have been added to the
command line interface. The help command provides a list of all available commands.
To view a list of all available commands:
1. Access the Command port.
64 7: Collecting and Viewing Data Remotely
Note
For more information, see “7.1 Accessing the PNTS Remotely and Exiting the
Remote Session” on page 58.
2. From the Command port Telnet session, enter:
help
A list of all the available commands displays.
To view help for a specific command:
1. Access the Command port.
For more information, see “7.1 Accessing the PNTS Remotely and Exiting the
Remote Session” on page 58.
2. From the Command port Telnet session, enter:
help <command_name>
The usage of the command displays.
This variation of the help command also lists various abbreviations for some
verbose commands. Issuing help measurelinear reveals that ml is a valid
shorthand for the command.
Commands validate their parameters and in most cases provide a list of valid parameters if
arguments are found to be invalid. This too can serve as a source of help using a command.
7.2.11 Setting Data Port Output Rate
The output rate of the data port can be set in samples per second using the set phaserate <rate>
command, where the output rate <rate> can be either 1,10,100, or 1000. The show phaserate
command can be used to determine what the current value of phase rate is.
7.2.12 Other Commands
The following lists some commands that were not documented in detail. Please use the help
network command as the authoritative source for all commands. See “7.2.10 Viewing Help for
Remote Commands” on page 64 for details.
reset
Reset the test set.
restorefactorydefaults
Restores all persistent settings to factory default values and reboots the test set. See “4.1.5
Restoring Factory Default Settings” on page 29 for more information about persistent
settings.
set <option> <args>
date options:
set date YYYYMMDDhhmmss
5120A/5115A Operations and Maintenance Manual 65
set dateformat <1|2|3> - sets date format for printouts.
1 = verbose (three letter month name)
2 = numeric date, month first (mm/dd/yyyy)
3 = numeric date, day first (dd/mm/yyyy)
set timeformat <24/12> - sets time format for printouts.
24 = 24 hour format
12 = 12 hour format with AM/PM specifier
show <option>
date - returns the current date in the configured format.
dateformat - current date and time format.
timeformat - current date and time format.
7.2.13 Command Summary
Table 4: Command Summary
Command Synopsis
beep Beeps the pc speaker.
button Simulates a front panel button press.
calibrate Calibrates 5120A-01 internal reference oscillators.
calinfo Returns current 5120A-01 internal reference calibration data.
control Takes or yields remote control of the test set.
help Display help for a command, or list all commands.
history Lists previously entered commands.
measurelinear Measures linear trend in ‘show phasediff’ data set.
pause Pauses updates on phase or frequency difference cache.
print Prints a plot or table.
prompt Turns command prompt on or off.
quit Closes the command connection.
removelinear Enables/Disables phase difference linear trend removal.
reset Resets the test set.
restorefactorydefaults Restores all configuration settings to factor default settings.
resume Resumes updates to phase or frequency difference cache.
set date <YYYYMMDDhhmmss> Sets system date and time.
set dateformat <1|2|3> Selects format for printout date stamps.
set phaserate <rate> Sets data port output rate in samples per second: 1, 10, 100 or
1000.
set print file Print new jobs to the file system (fetch print jobs using FTP).
set print format <format> Print new jobs in the specified format.
66 7: Collecting and Viewing Data Remotely
Table 4: Command Summary
Command Synopsis
set print local Print new jobs to local (USB) printer.
set print remote <host> <port> Print new jobs to network printer.
set referencefreq <auto|freq> Selects automatic, or specified manual reference frequency used
by frequency counter.
set tau0 <tau0value> Sets tau0 value in seconds: 0.001, 0.01, 0.1 or 1
set timeconstant <value> Sets length of running average time constant for spectrum and
Allan deviation
set timeformat <24/12> Selects time format for printout time stamps.
set title <title> Sets user specified title (quoted string up to 34 characters)
show adev Returns snapshot of Allan deviation tables.
show date Returns current date and time in selected format.
show dateformat Returns selected printout date stamp format.
show fcounter Returns snapshot of frequency counter table.
show freqdiff Returns snapshot of frequency difference strip chart.
show inputs Returns input frequency and amplitude on input signal ports.
show ipn Returns integrated phase noise table.
show mac Returns MAC (ethernet) address of the test set.
show phasediff Returns snapshot of phase difference strip chart.
show phaserate Returns current phaserate value.
show printformats Returns acceptable values for set print format command.
show printoptions Returns current printer settings.
show screens Returns name of screens that can be printed.
show spectrum Returns snapshot of spectrum table.
show spurs Returns snapshot of spur table.
show state Returns current collecting state.
show tau0 Returns current tau0 value.
show timeformat Returns selected printout time stamp format.
show title Returns current user specified title.
show version Returns model, software and hardware version information.
start Begin data collection
stop Stop data collection.
7.3 The Network Data Port
The network data port outputs phase difference data while the test set is in the Collecting state. The
phase differences are in units of cycles of the Input signal. Phase differences are output as floating
point numbers, one number per line, either 1, 10, 100, or 1000 samples each second. The default
rate is 1000 samples per second, to change the rate use the set phaserate command. See “Chapter
7, Setting Data Port Output Rate” on page 65.
5120A/5115A Operations and Maintenance Manual 67
The data port accepts no input, all input to data port connections is discarded by the PNTS.
Phase difference measurements are published while the test set is in the Collecting state. See
“3.2.1 Collecting State” on page 13. When data collection is stopped or the test set is in the
Initializing state, no data is published. Once collection is restarted, phase differences are output
again. This means that a data port connection can be kept open while collection is stopped, input or
reference signal sources are changed, and collection is restarted.
To retrieve phase difference data remotely:
1. Access the Data port.
For more information, see “7.1 Accessing the PNTS Remotely and Exiting the
Remote Session” on page 58.
If you want to store the data in a file, tell your Telnet software to capture the data.
If no phase difference data is published on the command port, the test set is not in the
Collecting state - connect to the command port and start data collection. See “7.2.2
Starting and Stopping Data Collection” on page 59 for details.
68 7: Collecting and Viewing Data Remotely
8: Optional Functionality
The PNTS include optional DOCSIS functionality.
8.0.1 DOCSIS Overview
DOCSIS stands for “Data Over Cable Service Interface Specification”. PNTS with the DOCSIS
option enabled can be used to easily test jitter for cable modems and supporting equipment. The
goal of these tests is to ensure that the master clock and symbol clock are properly locked via the
M/N ratios as per the DRFI Specification Section 6.3.6. The DOCSIS option is included with the
PNTS.
The test works on the assumption that locking between the master clock and the symbol clock may
be verified by comparing the master clock from a DTI server test port to that of the symbol clock
from the EQAM RF output in alternating binary sequence mode. All measurements must be
performed with worst case common mode noise on the DTI client input from the DTI server. The
test run by the option covers 100% of the locking parameters on a single channel or the single test
port. Other channels are assumed to behave in the same manner.
The jitter calculation uses frequency counter’s reference frequency, 100 second frequency
average, integrated phase noise with a low limit of 1 mHz and the user supplied DRFI ratio as
inputs. It computes jitter resulting from frequency error (J1) and jitter resulting from random
variations (J2), and finally combines those values to compute Total Jitter. Table 5 explains in
detail how Total Jitter is calculated.
Table 5: Calculating Total Jitter
Value Units Definition or Calculation Notes
M DRFI specification ratio numerator see step 3 below
N DRFI specification ratio denominator see step 3 below
reference_frequency Hz reference frequency see step 4 below
desired_freq Hz
meas_freq Hz measured input frequency 100 s frequency average
meas_random_jitter_RMS radians
con s 50 / SQRT(3) constant
J1 ns con * | meas_freq - desired_freq | / desired_freq jitter from frequency error
J2 ns meas_random_jitter_RMS / (2 * Π * desired_freq) jitter from random variations
Total Jitter ns
M / N * reference_frequency
Φ
RMS(1 mHz)
SQRT(J1
2
+ J22)
integrated phase noise
pass/fail criterion
5120A/5115A Operations and Maintenance Manual 69
Note
Use these softkeys to
enter the M and N values
for the M/N ratio used
for the test.
Use this softkey to
calculate jitter and pass or
fail the signal.
8.0.2 Using the DOCSIS Option Locally
Figure 17 shows the DOCSIS option screen after it has calculated total jitter for a set of input
signals. The signals PA S S E D because total jitter was less than 1.5 ns.
Figure 17: DOCSIS Option Screen
To r un a D OC S I S t e s t :
1. Connect the master clock to the Reference port and the bit clock to the Input port.
Verify that the Reference frequency displays as 10.2 MHz and the Input frequency
displays as 5.x MHz.
2. Press Settings and Options, then Options and finally DOCSIS ATP to navigate to the
DOCSIS option screen.
3. Press Enter M to enter the numerator and Enter N for the denominator.
See “3.4.1.1 The Number Pad Editor” on page 17 for help with entering numbers.
Both M and N must be positive integers representable as an unsigned 16 bit value.
These values persist when the test set is powered off.
4. Press Enter Reference Freq and enter the frequency counter’s reference frequency.
5. Press Start and collect data for at least 45 minutes.
6. Press Calculate Jitter.
If a dialog stating that more data must be collected is displayed, press Dismiss Dialog,
wait a few minutes, then press Calculate Jitter again.
The J1, J2 and Total Jitter values are calculated and displayed, the Overall Result
shows PA S S E D when jitter is less than 1.5 ns or FA I L E D otherwise.
The DOCSIS and frequency counter reference frequency are the same value. Changing the
reference frequency in either screen changes the setting for both screens.
70 8: Optional Functionality
Note
8.0.3 Using the DOCSIS Option Remotely
The DOCSIS option can utilized on the network command port. See “7: Collecting and
Viewing Data Remotely” on page 57 for details about controlling the test set using a
network connection.
To run a DOCSIS test remotely:
1. Connect the master clock to the Reference port and the bit clock to the Input port.
2. Access the Command port. See “7.1 Accessing the PNTS Remotely and Exiting the
Remote Session” on page 58.
3. Use the show inputs command to verify that the reference frequency is at 10.2 MHz and
the input frequency is at 5.x MHz.
4. Issue the start command and collect data for at least 45 minutes.
The start command requires remote control of the test set. See “7.2.1 Taking or
Yielding Remote Control” on page 58 for more information.
5. Use the set referencefreq command to the set reference frequency if necessary.
See “7.2.6.5 Setting Frequency Counter’s Reference Frequency” on page 63 for
details.
Once the reference frequency has been set it persists until it changed by the user.
6. Use the docsis command to calculate jitter.
The docsis command has two variations, they are explained in the example below.
The command returns the J1, J2, Total Jitter and Overall Result values. The user
interface reports the same values.
If the command returns an error message stating that more data must be collected
before the test can be run, wait for more data to be collected and reissue the docsis
command.
The docsis network command has two variations. One variation accepts the M and N parameters to
be used for jitter calculation. The other variation reuses the M and N values from the most recent
DOCSIS test. To run the test depicted in Figure 17 on page 70, enter the following commands
once enough data has been collected:
set referencefreq 10.24
docsis 78 149
Once M and N values have been set as parameters to the docsis network command or in the user
interface, they can be reused by omitting the parameters from the command. To use current M, N
and reference frequency values for the test simply enter:
docsis
5120A/5115A Operations and Maintenance Manual 71
Calibration data from
previous, active calibration
Press to calibrate internal
references, once Pending
Calibration frame indicates
internal reference frequencies
can be calculated.
Displays calibration data to
be stored when Calibrate soft
key is pressed, or reason why
internal reference frequencies
cannot be calibrated at this
time.
8.1 5120A-01 Internal Reference
The 5120A-01 features two internal reference oscillators that can be used instead of an external
reference signal when such a signal is not available or required for accuracy. The 5120A-01
automatically switches to internal reference mode when an external reference signal is absent.
8.1.1 5120A-01 Internal Reference Calibration
The 5120A-01 is calibrated before it is shipped from the factory. The frequency of the internal
oscillators must be measured and calibration values entered annually. See section 8.2.1.1 for
details on performing the calibration.
Internal reference calibration must also be performed in the unlikely event of calibration data
corruption. Corrupt calibration data is reflected as an UNCALIBRATED reference frequency on
the frequency counter screen (when internal reference mode is used), and not calibrated in the
Current Calibration frame of the Internal Reference (Figure 18).
Internal reference calibration can be done on-site provided a calibration lab quality 10 MHz signal
is available. To perform calibration, this signal is attached to Input port on the front panel. Data is
collected in internal reference mode until the 1000 second frequency average has been computed
by the frequency counter. The frequency average is then used to calculate the internal oscillators'
frequencies. For calibration purposes the function of the Input port is thus reversed - it actually
serves as a reference signal used to measure the internal reference oscillators' frequencies.
Upon calibration, the newly determined frequencies are used immediately, even during the data
collection used to perform calibration in the first place. Frequency averages presented by the
frequency counter can be re-examined (without stopping data collection) to study the impact of
calibration.
8.1.1.1 Calibrating 5120A-01 Internal Reference
Internal reference calibration is performed using the Internal Reference screen shown in Figure 18.
Figure 18: Example Internal Reference Option Screen
72 8: Optional Functionality
Note
To calibrate the internal reference oscillators:
1. Set the test set's system date and time if necessary, as calibration information is time
stamped.
To check current system time see “4.1 The Settings Screen” on page 21, to set system
time see “4.1.1 Setting Date and Time” on page 22 for details.
2. Detach any signal connected to the Reference port.
3. Attach a calibration lab quality 10 MHz signal to the Input port.
4. Press Settings and Options, then Options, and finally Internal Reference to access the
calibration screen.
This screen can be accessed to retrieve current calibration information regardless
of attached signals or collecting state.
5. Start data collection and wait at least 17 minutes for the 1000 second frequency average
used to calculate the internal oscillators' frequencies.
While the internal reference screen is active, the 5120A-01 periodically attempts
calibration data calculation. Calculation results or conditions that prevented the
calculation are reported in the Pending Calibration frame. When the Pending
Calibration frame presents the measured frequencies, the test set is ready to store the
oscillator calibration values (proceed to the next step)
6. Press Calibrate to store frequency calibration data.
Calibration frequencies are calculated, and stored. The Previous Calibration frame
updates to reflect newly calibrated frequencies and time of calibration.
8.1.1.2 Calibrating 5120A-01 Internal Reference Remotely
To retrieve current internal reference calibration data remotely:
1. Access the Command port. See “7.1 Accessing the PNTS Remotely and Exiting the
Remote Session” on page 58.
2. Issue the calinfo command.
The 5120A-01 returns date and time of calibration and the calibrated frequencies of
both internal reference oscillators.
To calibrate the internal reference oscillators remotely:
1. Detach any signal connected to the Reference port.
2. Attach a calibration lab quality 10 MHz signal to the Input port.
3. Access the Command port. See “7.1 Accessing the PNTS Remotely and Exiting the
Remote Session” on page 58.
4. Set the test set's system date and time if necessary, as calibration information is time
stamped.
Run the show date command to check, and set date command to set the system time.
5120A/5115A Operations and Maintenance Manual 73
5. Issue the start command and collect data for at least 17 minutes for the 1000 second
frequency average used to calculate internal oscillators' frequencies.
6. Issue the calibrate command.
If calibrated frequencies cannot be calculated at the time the calibrate command is
issued the 5120A-01 responds with the reason for the failure.
If the command does not cause a response, calibration was successful.
7. Use the calinfo command to verify the newly calibrated frequencies.
74 8: Optional Functionality
Warning
9: Maintaining a PNTS
9.1 Calibrating the PNTS
Symmetricom can provide a manufacturer’s calibration.
A performance verification procedure is available from Symmetricom to enable a customer or
calibration lab to perform the calibration.
Contact Symmetricom Customer Assistance (see page 95) for pricing or to obtain the performance
verification procedure.
For information about calibrating the 5120A-01 internal reference oscillators see “8.1 5120A-01
Internal Reference” on page 72.
9.2 Cleaning the PNTS
Do not spray or use too much liquid when cleaning the test set. Liquid can enter the test set and
damage sensitive electronic components.
Clean the main chassis with a soft cloth dampened with a mild soap and water solution.
9.3 Cleaning the Fan Filter
Units that started shipping in March 2009 include a small fan on the rear cover for commonality
with the 5125A chassis and to improve cooling. The fan filter can be removed from the outside of
the instrument. You can use a small flat screwdriver to gently pry the black fan grating from one
corner of the fan cover. After removing one corner, pull the fan grating straight away from the rear
of the instrument to remove it. The foam fan filter can them be removed. Clean the filter with low
pressure compressed air. Re-install the foam filter and grating.
5120A/5115A Operations and Maintenance Manual 75
76 9: Maintaining a PNTS
Caution
10: Troubleshooting
Perform all of the following procedures before returning the test set for service. If the test set still
appears to have a problem, call Symmetricom Customer Assistance (see page 95) to obtain
technical support. Please be prepared to provide the representative with the
number of your instrument.
Do not remove the top cover of the instrument. It does not contain any user-serviceable parts. The
3 V lithium battery and memory card on the single board computer PCB must be replaced only by
trained and authorized personnel.
The only user-serviceable parts are the fuses. For more information, see “10.2 Replacing Fuses”
on page 80.
If the test set does not appear to be operating properly, check the following first:
1. If the test set is turned on, press Power to turn it off.
2. Check for visible damage on the test set, cables, and connectors.
3. Ensure that all cables are firmly connected.
4. Determine if any input power circuit breakers have been tripped.
5. Ensure that your power source is within specification.
6. Press Power to turn the instrument on.
7. Check that the green LED on the front panel near the Power button is lit.
If it does not come on and your power source has been thoroughly checked, unplug the
instrument from its power source and check both fuses mounted in the power entry
module located on the rear of the chassis. Replace if necessary with 250-volt, 1-amp,
time delay, 5 x 20 mm fuses. For more information, see “10.2 Replacing Fuses” on
page 80. Check your power source prior to reconnecting the power cord after
replacing fuses.
The logo screen is displayed.
If the “Self test has failed for the following item(s)…” message displays during start-
up, contact Symmetricom Customer Assistance (see page 95).
8. Connect signals to the Input and Reference ports.
Verify that both signals are within operating range. See “3.2.2 Input Signals’
Frequency and Power” on page 13 for more information.
9. Press Start.
The test set should begin collecting data, as described in “2.2.1 Turning On the PNTS”
on page 9, and should update the data display.
5120A/5115A Operations and Maintenance Manual 77
10.1 Troubleshooting Error Messages
Table 6 lists the error messages that display in the action field, their meaning, and what to do.
Table 6: Error Messages
Error message What it means What to do
Cannot start collecting
while input signals’
frequency or amplitude are
out of operable range.
Input/Reference frequency/
amplitude changed
significantly. Stopped
Collecting.
Data collection cannot start if the
input signals fall below 1 MHz or 3
dBm, or go above 30.0 MHz or 17
dBm.
The specified signal’s frequency or
amplitude changed significantly from
the values at the time data collection
was started.
Collection was stopped automatically
as not to corrupt data sets computed
thus far.
Check the frequency and amplitude
of the highlighted input
1. Check the signal connections on
the input and reference ports.
2. Do not bump or otherwise disturb
the test set or the connected
signals.
3. Do not change the input or
reference port signals’ frequency
during data collection.
4. If the problem persists, contact
Symmetricom Customer
Assistance
(see page 95).
Input/Reference ADC
clipping error. Stopped
Collecting.
Failed to connect to printer
<ip address>.
(where <ip address>
denotes the address of the
target network printer)
The test set did not properly set
attenuators to correctly limit input
voltage to the range the ADC can
measure.
A connection could not be established
to the specified remote printer due to a
network discontinuity or the printer
not being powered on.
1. Check the signal connections on
the input and reference ports. If
they are within operating range,
cycle power.
2. Do not bump or otherwise disturb
the test set or the connected
signals.
3. Do not change the input or
reference port signals’ amplitude
during data collection.
4. Contact Symmetricom Customer
Assistance
problem persists.
1. Check the connection from the
(see page 95) if the
test set to the network.
2. Check the connection from the
printer to the network.
3. Make sure the printer is powered
on.
4. Make sure that you used the
correct IP address and port.
• For more information, see
“4.1.3 Printer Configuration”
on page 26.
78 10: Troubleshooting
Table 6: Error Messages
Error message What it means What to do
Failed to connect to USB
printer.
Tried to print to a local USB printer,
but could not find a printer connected
to the USB port. Or the printer is not
powered on.
Failed to print entire file. Printing stopped in the middle of
transferring the information to the
remote or USB printer. This is
probably due to the printer being
powered off or a connection
discontinuity.
Maximum number queued
print jobs reached.
Print jobs were queued faster than
they can written to the printer or file
system. Up to 15 print jobs can be
queued before this message is
displayed.
File system integrity check
failed. All settings have
been set to factory defaults.
The part of the file system where
configuration and preferences are
stored failed integrity check when the
test set was powered on. It was
restored to factory defaults.
Process <processname> has
failed. Please cycle power
on the test set.
One of the applications has failed at a
level indicative of a programming
error.
(where <processname> is
one of a2dReader, netd or
ui)
Failed to open keypad
device.
The user interface was unable to
communicate with front panel keypad
device. This indicates a corrupt file
system (driver cannot be loaded), or a
broken keypad.
Make sure the local USB printer is
connected to the USB port and
powered on.
1. Check the connection from the
test set to the network or USB
printer.
2. Check the connection from the
printer to the network.
3. Make sure printer is powered on.
Do not queue print jobs so quickly or
attach a faster printer.
1. Reconfigure the test set.
If this problem persists, contact
Symmetricom Customer Assistance
(see page 95).
1. Power cycle the
If this problem persists, contact
Symmetricom Customer Assistance
test set.
(see page 95).
1. Power cycle the
If this problem persists, contact
Symmetricom Customer Assistance
test set.
(see page 95).
Detailed programming error
exception error message
such as:
UI Initialization
File: sourcecode.cc
Line: 150
Errno 2: ENOENT
Msg: Example error.
Retaddrs: 0x80ff490
0x80ddb60 0x80dc0b0
The user interface was initialized
enough to display dialogs. An
unhandled exception reached the main
event loop. Information in this dialog
is useful to the software developers.
Please contact Symmetricom
Customer Assistance
(see page 95)
with all information in the error
message.
5120A/5115A Operations and Maintenance Manual 79
10.2 Replacing Fuses
If you know that a local event caused blown fuses, you can replace the fuses in the test set power
entry module on the rear panel. See “Figure 2: Rear Panel” on page 5.
Required for this procedure:
Small flat-head screwdriver
Replacement fuse for a standard IEC 320 power entry module with fuse (250-volt, 1-amp,
time delay, 5 x 20 mm fuse, T)
To replace a fuse:
1. Disconnect the power cable from the back of the test set.
2. Using a small screwdriver, open the fuse cover on the back of the test set.
3. Replace the old fuses as necessary.
4. Close the fuse cover.
5. Reconnect the power cable to the back of the test set.
80 10: Troubleshooting
Appendix A: Specifications
A.1 EC Declaration of Conformity
In accordance with EN 45014:1998
We Symmetricom, Inc.
Of 4775 Walnut Drive Suite 1B
Boulder, CO 80301
USA
declare that:
Equipment Phase Noise Test Set
Model Number 5120A, 5120A-01, and 5115A
Product Options None
in accordance with the following Directives:
73/23/EEC The Low Voltage Directive
and its amending directives
89/336/EEC The Electromagnetic Compatibility Directive
and its amending directives
has been designed and manufactured to the following specifications:
Safety: EN61010-1: 2001
Safety Requirements for Electrical Equipment for Measurement, Control and
Laboratory Use - Part 1: General Requirements
EMC EN61326-1: 2001
Electrical Requirements for Electrical Equipment for Measurement, Control and
Laboratory Use - Part 1: General Requirements
EN 55011 Class A
Radiated Emissions
I hereby declare that the equipment named above has been designed to comply with the relevant
sections of the above referenced specifications. The unit complies with all essential requirements
of the Directives.
Signed by: S.R. Stein
Position: Vice President of Engineering, TTM Division
Done at Boulder, Colorado U.S.A on 02 February 2008
5120A/5115A Operations and Maintenance Manual 81
A.2 Electrical Specifications
Table A-1 lists the electrical specifications for the 5120A, 5120A-01, and 5115A.
Table A-1: Electrical Specifications
Item Specification
Protection Class Class I (Grounded Type)
Power Input Voltage 100–240 V AC
Note: Fluctuations not to exceed ± 10% of nominal supply
voltage.
Power Input Frequency
–60 Hz
50
Power consumption 5120A - 60 W maximum
5120A-01 - 65 W maximum
5115A - 40 W maximum
Power Inlet Type IEC 60320 sheet C14
Power Supply Cord Set
18 AWG (0.75 mm
2
minimum)
Power Mains Fuse Two 250 V ~ 1A T (Time delay) 5 x 20 mm.
Signal Inputs
Connectors
Battery
Frequency: 1–30 MHz
Impedance: 50 Ω ±5 Ω
Input level: 3–17dBm
Input: Two TNC (supplied with BNC adapters)
Output: Two USB 1.1, Type A
Network: RJ-45 (10 or 100 baseT)
Lithium on single board computer printed circuit board: 3V, type
BR2032.
Dispose of the battery in accordance with local regulations.
Table A-2:
(f) Noise Floor Specifications
1
Input Signal 5115A 5120A and 5120A-01 using
external reference
1 MHz 1 Hz offset, < -131 dBc/Hz
10 Hz offset, < -140 dBc/Hz
100 Hz offset, < -142 dBc/Hz
1,000 Hz offset, < -142 dBc/Hz
10,000 Hz offset, < -142 dBc/Hz
100,000 Hz offset, < -142 dBc/Hz
1 Hz offset, < -131 dBc/Hz
10 Hz offset, < -140 dBc/Hz
100 Hz offset, < -148 dBc/Hz
1,000 Hz offset, < -156 dBc/Hz
10,000 Hz offset, < -160 dBc/Hz
100,000 Hz offset, < -163 dBc/Hz
82 Appendix A: Specifications
Table A-2:
(f) Noise Floor Specifications
2-5 MHz 1 Hz offset, < -133 dBc/Hz
10 Hz offset, < -143 dBc/Hz
100 Hz offset, < -147 dBc/Hz
1,000 Hz offset, < -147 dBc/Hz
10,000 Hz offset, < -147 dBc/Hz
100,000 Hz offset, < -147 dBc/Hz
10 MHz 1 Hz offset, < -133 dBc/Hz
10 Hz offset, < -143 dBc/Hz
100 Hz offset, < -147 dBc/Hz
1,000 Hz offset, < -147 dBc/Hz
10,000 Hz offset, < -147 dBc/Hz
100,000 Hz offset, < -147 dBc/Hz
20 MHz 1 Hz offset, < -123 dBc/Hz
10 Hz offset, < -136 dBc/Hz
100 Hz offset, < -146 dBc/Hz
1,000 Hz offset, < -147 dBc/Hz
10,000 Hz offset, < -147 dBc/Hz
100,000 Hz offset, < -147 dBc/Hz
30 MHz 1 Hz offset, < -127 dBc/Hz
10 Hz offset, < -137 dBc/Hz
100 Hz offset, < -145 dBc/Hz
1,000 Hz offset, < -146 dBc/Hz
10,000 Hz offset, < -146 dBc/Hz
100,000 Hz offset, < -147 dBc/Hz
1
1 Hz offset, < -140 dBc/Hz
10 Hz offset, < -152 dBc/Hz
100 Hz offset, < -164 dBc/Hz
1,000 Hz offset, < -169 dBc/Hz
10,000 Hz offset, < -169 dBc/Hz
100,000 Hz offset, < -169 dBc/Hz
1 Hz offset, < -145 dBc/Hz
10 Hz offset, < -155 dBc/Hz
100 Hz offset, < -165 dBc/Hz
1,000 Hz offset, < -170 dBc/Hz
10,000 Hz offset, < -175 dBc/Hz
100,000 Hz offset, < -175 dBc/Hz
1 Hz offset, < -137 dBc/Hz
10 Hz offset, < -150 dBc/Hz
100 Hz offset, < -160 dBc/Hz
1,000 Hz offset, < -170 dBc/Hz
10,000 Hz offset, < -172 dBc/Hz
100,000 Hz offset, < -172 dBc/Hz
1 Hz offset, < -127 dBc/Hz
10 Hz offset, < -138 dBc/Hz
100 Hz offset, < -151 dBc/Hz
1,000 Hz offset, < -162 dBc/Hz
10,000 Hz offset, < -165 dBc/Hz
100,000 Hz offset, < -165 dBc/Hz
Note 1: For each 1dB decrease in input amplitude below 8 dBm, the noise floor will increase approximately 1dBc/Hz.
Table A-3: Allan Deviation Specifications
Model Specification
5115A less than 1E-14 at 1 second, 0.5 Hz bandwidth
5120A
less than 3E-15 at 1 second, 0.5 Hz bandwidth
5120A-01 External Ref.
5120A-01 Typical, using Internal Reference:
less than 9E-13 at 1 second, 0.5 Hz bandwidth
less than 4E-13 at 10 seconds, 0.5 Hz bandwidth
less than 1E-12 at 100 seconds, 0.5 Hz bandwidth
less than 1E-11 at 1,000 seconds, 0.5 Hz bandwidth
Table A-4: 5120A-01 Phase Noise Specifications (Internal Reference)
Offset 10 MHz Input 5 MHz Input
1 Hz -120 dBc/Hz -126 dBc/Hz
10 kHz -170 dBc/Hz -168 dBc/Hz
5120A/5115A Operations and Maintenance Manual 83
Warning
A.3 Environmental Specifications
Ordinary protection: This test set is for INDOOR USE ONLY. It is not sealed to prevent moisture
from entering the enclosure.
Pollution Degree 2 per EN61010-1EN 61010-1
Installation (Over-Voltage) Category II for transient over-voltages per EN 61010-1EN
61326-1, Class A
Equipment suitable for continuous operation
Table A-5 lists the environmental specifications for the 5120A, 5120A-01, and 5115A.
Table A-5: Environment Specifications
Item Temperature Relative Humidity Altitude
In Use 15°C to 40°C 5% to 95%
(non-condensing)
3,000 meters
(9,843 feet)
Storage –25°C to 70°C 5% to 95%
(non-condensing)
Transportation –25°C to 70°C 5% to 95%
(non-condensing)
84 Appendix A: Specifications
A.4 Physical Specifications
Table A-6 lists the physical specifications for the 5120A, 5120A-01, and 5115A.
Table A-6: Physical Specifications
Item Specification
Size 33.8 cm x 17.4 cm x 43.7 cm (13.31" x 6.84" x 17.21")
Weight 5120A: Approximately 9.1 kg (20 pounds)
5115A: Approximately 8.4 kg (18.5 pounds)
Figure A-1 shows the dimensions of the 5120A, 5120A-01, and 5115A.
Figure A-1: 5120A, 5120A-01, and 5115A dimensions
5120A/5115A Operations and Maintenance Manual 85
86 Appendix A: Specifications
Appendix B: Theory of Operation
B.1 Introduction
Traditionally, phase noise measurements are made by analog techniques. A transducer is used to
convert the phase fluctuations to a voltage that is sampled and Fourier analyzed. The transducer is
almost always a double-balanced mixer that, along with the following low noise amplifiers, must
be calibrated at all Fourier frequencies of interest. The double balanced mixer operates as a phase
detector only when the signals at the local oscillator (LO) and signal ports are approximately in
phase quadrature. Thus analog phase noise measurements of two sources require that the unit
under test be phase locked to the reference. Using digital techniques, it is possible to eliminate
both of these restrictions making it much simpler to make high quality phase noise measurements.
Figure B-1 shows the analog approach to source phase noise measurements.
Figure B-1: Analog source phase noise measurements require both calibration and a phase-lock loop.
The digital method samples the RF waveforms rather than the output of the phase detector. The
phase detection is performed by digital signal processing, which results in several advantages: the
phase detector has 2Nπ range, eliminating the need for a phase-lock loop (PLL), and all digital
filters are sufficiently flat to eliminate the need to calibrate individual measurements. It is possible
to make the signal processing errors fall below the noise of the analog-to-digital converters
(ADCs), which then determine the noise floor of the direct-digital, phase-noise measurement
system. As seen below, this noise is rather high, but can be reduced to useful levels through the
1
application of cross-correlation.
1.F. L. Walls, S. R. Stein, James E. Gray, and David J. Glaze, “Design Considerations in State-of-the-Art Signal Processing and Phase Noise Measurement Systems,” Proceedings of the 30th Annual Frequency Control
Symposium, 1976, pp 269-274.
5120A/5115A Operations and Maintenance Manual 87
The concept for direct-digital phase-noise measurements is shown in Figure B-2.
Input
Reference
Figure B-2: The RF signals are immediately converted to digital samples in order to perform direct-digital phase-noise
Analog/Digital
Converter
Digital Signal Processing
Analog/Digital
Converter
measurements.
B.2 Theory
The analog-to-digital converters have 14 bits of precision and maximum sampling rates of
80 MHz. In order to prevent harmonics, spurs, and noise from aliasing into the measured
spectrum, a 30 MHz analog anti-alias filter is employed before the RF signals are sampled. The
heart of the approach is the down converter that immediately follows the sampler. In-phase
samples of each input signal are multiplied by the sine and cosine of a synthesized local oscillator
and low-pass filtered. When the LO frequency is approximately equal to the input frequency, the
output of the filters are in-phase (I) and quadrature (Q) base-band samples. The phase difference
between the input signal and the synthesized LO is computed using the arctangent function as
shown in Figure B-3.
Figure B-3: A local oscillator synthesized from the internal clock down-converts the input to base-band where the
samples are used to compute the phase difference between the LO and the input.
This step is the heart of the direct-digital technique. It is not necessary to down-convert to DC
before computing the phase difference. A small DC offset causes the phase to accumulate nearly
linearly. Although the arctangent function repeats every π radians, it is possible to unwrap the
phase and recover the correct linear function. This should be contrasted with the analog approach.
The double balanced mixer produces a distorted sine function of the phase difference. As the two
inputs approach the in-phase condition, the output of the mixer is insensitive to the phase
difference between the signals, and the distortion makes it impossible to accurately compute the
88 Appendix B: Theory of Operation
Φ1Φ
CLKΦADC1
+–
Sample and
Down Convert
Input 1
Input 2
Subtract
Scale
DFT
Φ
∗
2
Φ
∗
CLK
Φ
∗
ADC2
+–
Φ1Φ2Φ
ADC1ΦADC2
–+–
Sample and
Down-convert
Φ1Φ2Φ
ADC1ΦADC
–+–
Φ
2
Φ
∗
2
ω
1
ω
------
2
=
Sample,
Down-convert,
& Transform
Input 1
Reference 2
Complex
Conjugate
Φ
∗
1
Φ
∗
2
Φ
∗
ADC1
Φ
∗
ADC2
–+–
S
Φ1Φ2–
f() 2L f()=
Multiply and
Average
Φ1Φ2Φ
ADC1ΦADC2
–+–
phase even if quadrature mixers were employed. Thus analog test sets must be maintained near
quadrature where the sine of the phase is nearly linear and equal to the phase angle. When
measuring sources, the quadrature condition is achieved by a long time constant, phase-lock loop.
Down-conversion is performed on the second input channel, and the two are subtracted to obtain
the phase difference between the two sources. However, if the two input signals have different
nominal frequencies, then the phase of the second channel must be scaled to the same nominal
frequency as the first channel. For example, if we were calculating the phase difference between a
10 MHz signal and a 5 MHz signal, then the phase difference between the 5 MHz source and the
LO must be multiplied by 2 before subtraction from the phase difference of the 10 MHz signal and
its LO. The subtraction process causes the phase noise of the instrument’s clock oscillator to
cancel, just as it does in a dual-mixer, phase-difference, measurement system.
The frequency content of the measured phase difference is analyzed by computing the Discrete
Fourier Transform (DFT) of the phase difference. The computation to this point is shown in
Figure B-4. However, if the Power Spectral Density (PSD) of the phase were computed from the
DFT, the broadband noise floor would be limited by the white noise of the ADCs at a level of –150
dBc/Hz or worse with today’s best converters. This is the price that has been paid for the
convenience of operation without a PLL or need for calibration and would make the direct-digital
approach uninteresting for measuring precision oscillators, except for the fact that convenient
methods exist to overcome the limitation.
Figure B-4: Sample, Down-convert and Transform: After down-conversion, the phase differences are scaled,
subtracted, and Fourier analyzed to determine the frequency content.
The power spectral density of phase, Sφ(f,) is the squared magnitude of the Fourier transform. This
computation is performed by the 5115A as shown in Figure 5. The instrument displays
(f), which
is defined to be equal to half the spectral density.
Figure B-5: 5115A: The power spectral density of the phase is computed by multiplying the phase by its complex
5120A/5115A Operations and Maintenance Manual 89
conjugate and averaging
Sample,
Down-convert,
& Transform A
Input 1
Reference 2
S
Φ1Φ
2
–
Multiply
Φ
1A
Φ
2AΦADC1AΦADC2A
–+–
Sample,
Down-convert,
& Transform B
Σ
Σ
Φ
∗
1B
Φ
∗
2B
Φ
∗
ADC1B
Φ
∗
ADC2B
–+–
Uncorrelated
Sample,
Down-convert,
& Transform A
Input
S
Φ
1
Φ
1AΦ2A
Φ
ADC1AΦADC2A
–+–
Sample,
Down-convert,
& Transform B
Σ
Φ
∗
1B
Φ
∗
2B
Φ
∗
ADC1B
Φ
∗
ADC2B
–+–
Uncorrelated
Internal
Reference 2
2
3
1
Multiply
Internal
Reference 1
Instead of computing the magnitude-squared of the DFT to obtain an estimate of the PSD, the
5120A computes the cross-spectrum of two identical measurement systems as shown in Figure B-
6. The ADC noise is highly uncorrelated and averages down, allowing improvement of the
broadband noise floor to better than –170 dBc/Hz.
Figure B-6: 5120A and 5120A-01 with external reference: The PSD is computed as the cross-spectrum of the DFTs
from two identical processing front ends.
The 5120A-01 computes the cross-spectrum of two identical measurement systems as shown in
Figure B-7. The ADC noise and the internal reference oscillator noise are highly uncorrelated and
average down, allowing improvement of the broadband noise floor to fall below –170 dBc/Hz with
only one instrument input.
Figure B-7: 5120A-01 with internal references: The PSD is computed as the cross-spectrum of the DFTs from two
identical processing front ends.
90 Appendix B: Theory of Operation
In order to produce a useful PSD estimate, the spectrum estimation process is broken into a series
of spans that have appropriate frequency resolution (DFT length). The process as performed by the
5120A and 5120A-01 with cross-correlation is shown in Figure B-8. A similar process is used in
the 5115A. This process allows more rapid estimation of the higher frequency portions of the
spectrum. Data for each lower frequency span is obtained by low-pass (anti-alias) filtering the
higher sample rate data, then decimating it appropriately.
Figure B-8: 5120A: Successive Filter-decimate-transform Signal Processing Stages
The spectrum estimation process for all unit types is broken into a series of spans that have
appropriate frequency resolution (DFT length). The process, as performed in the 5120A and
5120A-01 with cross-correlation, is shown in Figure B-8. The process allows more rapid
estimation of the higher frequency portions of the spectrum. Data for each lower frequency span is
obtained by low-pass (anitalias) filtering the higher sample rate data, then decimating it
appropriately.
B.3 Measurement Methodology
All phase noise measurements are referenced to the frequency of the Input port. This has an effect
on how you connect the instrument for different measurements. One example is listed below.
Example: You have a noisy synthesizer tuned to 12 MHz and a very clean 5 MHz reference. You
want to know the phase noise of the synthesizer.
Test Method 1—You connect the 12 MHz signal to Input and the 5 MHz signal to
Reference. The phase noise of the synthesizer under test will be measured and displayed
relative to 12 MHz.
Test Method 2—You connect the 5 MHz signal to Input and the 12 MHz signal to
Reference. The phase noise of the synthesizer will be measured and displayed referenced
to the 5 MHz signal. To make the phase noise measurements referenced to 12 MHz, you
will need to add a frequency scaling term of 20*log10(f(INPUT)/f(REFERENCE) =
20*log10(12MHz/5MHz) = 7.60 dB to all phase noise measurements displayed. You will
do this scaling with a separate tool.
5120A/5115A Operations and Maintenance Manual 91
92 Appendix B: Theory of Operation
Glossary
\n Line feed
\r Carriage return
dB decibels
dBc Decibels referred to the carrier
dBc/Hz Decibels per Hz referenced to the carrier
CPLD Complex Programmable Logic Device
DHCP Dynamic Host Configuration Protocol
DOCSIS Data Over Cable Service Interface Specification
DRFI Downstream RF Interface
DSP Digital Signal Processor
DTI DOCSIS Timing Interface
DUT device under test
EQAM Edge Quadrature Amplitude Modulation
ESD electrostatic discharge
FTP File Transfer Protocol
IPP Internet Printing Protocol
NEQBW Noise equivalent bandwidth
PCL Printer Control Language
SSB single side band
USB Universal Bus
5120A/5115A Operations and Maintenance Manual 93
94
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