Tektronix TSG4102A, TSG4104A, TSG4106A User Manual

Download

TSG4100A Series

ZZZ

RF Signal Generators

User Manual

*P071315002*

071-3150-02

TSG4100A Series

ZZZ

RF Signal Generators

User Manual

Click the following link to protect your product.

► www.tektronix.com/register

www.tek.com

071-3150-02

Copyright © Tektronix. All rights reserved. Licensed software products are owned by Tektronix or its subsidiaries or suppliers, and are protected by national copyright laws and international treaty provisions.

Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supersedes that in all previously published material. Speciﬁcations and price change privileges reserved.

TEKTRONIX and TEK are registered trademarks of Tektronix, Inc.

Contacting Tektronix

Tektronix, Inc. 14150 SW Karl Braun Drive P.O. B o x 5 0 0 Beaverto USA

For product information, sales, service, and technical support:

n, OR 97077

In North America, call 1-800-833-9200. Worldwide, visit www.tek.com to ﬁnd contacts in your area.

Table of Contents

Important safety information......... ................................ ................................ ............. v

General safety summary ...................................................................................... v

Service safety summary............ ................................ .................................. ....... vii

Terms in this manual ................. ................................ .................................. ..... viii

Symbols and terms on the product......................................................................... viii

Preface .............................................................................................................. ix

Key features ......... ................................ .................................. ........................ ix

Documentation................................................................................................. x

Software upgrades ............................................................................................ xi

Conventions used in this manual.................................... .................................. ...... xi

Installation........................................................................................................... 1

Before installation ............................................................................................. 1

Standard accessories.............................. .................................. ........................... 1

Optional accessories.......... .................................. ................................ ............... 2

Instrument options ...................... ................................ ................................ ....... 2

Connect to a network......... ................................ .................................. ............... 3

Upgrade the ﬁrmware through the USB port ............................................................... 6

Powering on the instrument................................................................................... 7

Powering off the instrument .................................................................................. 7

Removing power from the instrument....................................................................... 7

Inspecting the instrument .. ................................ .................................. ................. 8

Instrument maintenance....................................................................................... 9

Operating basics ... .................................. ................................ .............................. 10

Front panel controls ........................ .................................. ................................ 10

Connectors..................................................................................................... 11

Display, navigation, and menus ............................................................................. 15

Quick start and functional check.... .................................. ................................ ...... 23

Settings. ..... . ..... . ..... . ..... . .... . . ...... . ..... . ..... . ..... . ..... . ..... . ..... . ..... . ..... . . .... . . .... . . ... . . . 27

Presets.................................... ................................ .................................. .... 28

Modulation sources....... ................................ ................................ .................... 30

Error log ....................................................................................................... 36

Digital communications........................................................................................... 37

Introduction.................................................................................................... 37

Vector modulation ............................................................................................ 38

Modulation techniques ..... .................................. ................................ ................ 45

Specialized PSK constellations.................... .................................. ........................ 52

Modulation functions......................................................................................... 55

User waveforms, constellations, and ﬁlters..................................................................... 57

Downloading binary data .................................................................................... 57

TSG4100A Series RF Signal Generators User Manual i

Table of Contents

Using the ﬁle As

Arbitrary user waveforms.................................................................................... 66

User constellations.................................... ................................ ........................ 67

User ﬁlters ..................................................................................................... 69

Reference ......................... ................................ ................................ .................. 71

Phase noise and offset diagrams ............................................................................ 71

Index

sistant utility software ..... . ..... . ..... . ..... . ..... . ..... . ... . . . .... . . .... . ..... . ..... . ... 58

ii TSG4100A Series RF Signal Generators User Manual

List of Figures

Figure 1: Error vector magnitude.... ................................ .................................. .......... 45

Figure 2: ASK constellations .. ................................ ................................ .................. 46

Figure 3: FSK constellations ..................................................................................... 46

Figure 4: Fo

Figure 5: Phase trellis diagram for binary CPM with a rectangular ﬁlter ... ................................ 49

Figure 6: Constellations for QAM 4 through QAM 256 .................. ................................ .... 50

Figure 7: VSB symbol constellations ........................................................................... 51

Figure 8: Decoding DQPSK transmissions....................... ................................ .............. 52

Figure 9: Offset modulation prevents transitions through the origin ..... . ..... . ..... . ... . . . .... . . .... . . .... 53

Figure 1

Figure 11: 3π/8 8 PSK follows standard 8 PSK, but the constellation rotates by 3π/8 after each symbol 54

Figure 12: Architecture for mapping digital symbols into IQ constellation points ........................ 67

Figure 13: QPSK,3.840Mcps, 1.85 GHz, 0dBm), RMS EVM: 1.7% ....................................... 72

Figure 14: Image 2, QPSK,3.840Mcps, 1.85 GHz, 0dBm), RMS EVM: 1.7% ............................ 73

Figure 15: Option VM03 W-CDMA, (QPSK,3.840Mcps, 2.1425GHz, 0dBm), RMS EVM: 1.7% . .... 74

re 16: Image 2, Option VM03 W-CDMA, (QPSK,3.840Mcps, 2.1425GHz, 0dBm), RMS EVM:

Figu

1.7% .......................... ................................ .................................. ................ 75

Figure 17: Option VM04 APCO-25, (4FSK-C4FM,4.8KS/s,850MHz, 0dBm), Freq Err: 0.5%. . ..... . . 76

Figure 18: Option VM05 DECT, (2FSK1.152Mbps,1.925GHz, 0dBm), RMS FSK Err: 1.5% . ..... . ... 77

Figure 19: Option VM06 NADC, (π/4 DQPSK,24.3KS/s,875MHz, 0dBm), RMS EVM: 0.3%......... 78

Figure 20: Option VM07 PDC, (π/4 DQPSK,21KS/s, 800MHz,0dBm), RMS EVM: 0.6% ............. 79

gure 21: Option VM08 TETRA, (π/4 DQPSK,18KS/s, 420MHz, 0dBm), RMS EVM: 0.7% . .... . ... 80

ur basic PSK constellations........................ ................................ ................ 48

0: π/4 DQPSK uses differential encoding and a rotating constellation. ........................... 54

TSG4100A Series RF Signal Generators User Manual iii

Table of Contents

List of Tables

Table 1: Front panel connectors.............. ................................ ................................ .... 12

Table 2: Rea

Table 3: Menus .............. ................................ .................................. .................... 16

Table 4: Preset default settings................................................................................... 24

Table 5: Modulation presets...................................................................................... 29

Table 6: TSG4102A and 4104A FM modulation vs. frequency ... .................................. ........ 34

Table 7: TSG4106A FM modulation vs. frequency ............... ................................ ............ 34

Table 8: V

Table 9: PSK constellations .......... ................................ .................................. .......... 47

Table 10: PRBS generating polynomials ..................... .................................. ................ 55

Table 11: Arbitrary waveform conﬁguration word ............................................................ 66

Table 12: QPSK constellation point computations ........................ ................................ .... 69

r panel connectors .................... ................................ .............................. 13

ector phase modulation waveforms ................................................................. 47

iv TSG4100A Series RF Signal Generators User Manual

Important safety information

This manual contains information and warnings that must be followed by the user for safe operation and to keep the product in a safe condition.

To safely perform service on this product, additional information is provided at the end of this section. (See page vii, Service safety summary.)

General safety summary

Use the product only as speciﬁed. Revie avoid injury and prevent damage to this product or any products connected to it. Carefully read all instructions. Retain these instructions for future reference.

Comply with local and national safety codes.

For correct and safe operation of the product, it is essential that you follow generally accepted safety procedures in addition to the safety precautions speciﬁed in this manual.

The product is designed to be used by trained personnel only.

Only qualiﬁed personnel who are aware of the hazards involved should remove the cover for repair, maintenance, or adjustment.

Before use, always check the product with a known source to be sure it is operating correctly.

This product is not intended for detection of hazardous voltages.

Use personal protective equipment to prevent shock and arc blast injury where hazardous live conductors are exposed.

While using this product, you may need to access other parts of a larger system. Read the safety sections of the other component manuals for warnings and cautions related to operating the system.

w the following safety precautions to

When incorporating this equipment into a system, the safety of that system is the responsibility of the assembler of the system.

To avoid ﬁre or personal

injury

TSG4100A Series RF Signal Generators User Manual v

Use proper power cord. Use only the power cord speciﬁed for this product and certiﬁed for the country of use.

Do not use the provided power cord for other products.

Ground the product. This product is grounded through the grounding conductor of the power cord. To avoid electric shock, the grounding conductor must be connected to earth ground. Before making connections to the input or output terminals of the product, make sure that the product is properly grounded.

Do not disable the power cord grounding connection.

Important safety information

Power disconne

source. See instructions for the location. Do not position the equipment so that it is difﬁcult to operate the power cord; it must remain accessible to the user at all times to allow for quick disconnection if needed.

Observe all terminal ratings. To avoid ﬁre or shock hazard, observe all ratings and markings on the product. Consult the product manual for further ratings information before making connections to the product. Do not exceed the Measurement Category (CAT) rating and voltage or current rating of the lowest rated individual component of a product, probe, or accessory. Use caution when using 1:1 test leads because the probe tip voltage is directly transmitted to the product.

Do not apply a potential to any terminal, including the common terminal, that exceeds the maximum rating of that terminal.

Do not ﬂoat the common terminal above the rated voltage for that terminal.

The measuring terminals on this product are not rated for connection to mains or Category II, III, or IV circuits.

Do not operate without covers. Do not operate this product with covers or panels removed, or with the case open. Hazardous voltage exposure is possible.

Avoid exposed circuitry. Do not touch exposed connections and components when power is present.

ct. The power cord disconnects the product from the power

Do not operate with suspected failures. If you suspect that there is damage to this

product, have it inspected by qualiﬁe

Disable the product if it is damaged. Do not use the product if it is damaged or operates incorrectly. If in doubt about safety of the product, turn it off and disconnect the power cord. Clearly mark the product to prevent its further operation.

Examine the exterior of the product before you use it. Look for cracks or missing pieces.

Use only speciﬁed replacement parts.

Use proper fuse. Useonlythefusetypeandratingspeciﬁed for this product.

Wear eye protection. Wear eye protection if exposure to high-intensity rays or

laser radiation exists.

Do not operate in wet/damp conditions. Be aware that condensation may occur if a unit is moved from a cold to a warm environment.

Do not operate in an explosive atmosphere.

Keep product surfaces clean and dry. Remove the input signals before you clean

the product.

d service personnel.

vi TSG4100A Series RF Signal Generators User Manual

Important safety information

Provide proper

details on installing the product so it has proper ventilation.

Slots and open otherwise obstructed. Do not push objects into any of the openings.

Provide a safe working environment. Always place the product in a location convenient for viewing the display and indicators.

Avoid improper or prolonged use of keyboards, pointers, and button pads. Improper or prolonged keyboard or pointer use may result in serious injury.

Be sure your work area meets applicable ergonomic standards. Consult with an ergonomics professional to avoid stress injuries.

Use only the Tektronix rackmount hardware speciﬁed for this product.

Servicesafetysummary

The Service safety summary section contains additional information required to safely perform service on the p roduct. Only qualiﬁed personnel should perform service procedures. Read this Service safety summary and the General safety

summa

ventilation. Refer to the installation instructions in the manual for

ings are provided for ventilation and should never be covered or

ry before performing any service procedures.

To avoid electric shock. Do not touch exposed connections.

Do not service alone. Do not perform internal service or adjustments of this

product unless another person capable of rendering ﬁrst aid and resuscitation is

sent.

pre

Disconnect power. To avoid electric shock, switch off the product power and disconnect the power cord from the mains power before removing any covers or panels, or opening the case for servicing.

se care when servicing with power on. Dangerous voltages or currents may exist

in this product. Disconnect power, remove battery (if applicable), and disconnect test leads before removing protective panels, soldering, or replacing components.

Verify safety after repair. Always recheck ground continuity and mains dielectric strength after performing a repair.

TSG4100A Series RF Signal Generators User Manual vii

Important safety information

Termsinthismanual

These terms may appear in this manual:

WARNING. Warning statements identify conditions or practices that could result

in injury or loss of life.

CAUTION. Caution statements identify conditions or practices that could result in

damage to this product or other property.

Symbols and terms on the product

These ter

The following symbol(s) may appear on the product:

ms may appear on the product:

DANGER indicates an injury hazard immediately accessible as you read the mark

WARNING indicates an injury hazard not immediately accessible as you read th

CAUTION indicates a hazard to property including the product.

ing.

e marking.

When this symbol is marked on the product, be sure to consult the manual to ﬁnd out the nature of the potential hazards and any actions which have to betakentoavoidthem. (Thissymbolmayalsobeusedtorefertheuserto ratings in the manual.)

viii TSG4100A Series RF Signal Generators User Manual

Preface

Key features

This manual d the TSG4100A Series RF Signal Generators. This manual supports the following instruments

TSG4102A

TSG4104A

TSG4106A

NOTE. Che

more information about your product. Visit www.tektronix.com/manuals.

For comp RF Signal Generators Installation and Safety Instructions that shipped with your instrument. The document can also found on the Tektronix Web site at www.tektronix.com/manuals.

The TSG4100A Series RF Signal Generators provide waveform generation and support both analog (standard) and vector/digital (optional) modulation. The instruments use a new technique to provide spurious free outputs with low phase

se (-113 dBc/Hz at20 KHz offset from 1 GHz carrier) and extraordinary

noi frequency resolution (1 μHz at any frequency). An ovenized SC-cut oscillator (M00 or E1 optioned m odels) timebase provides 100 times improvement in stability (and a 100 times reduction in the in-close phase noise) compared to instruments that use a TCXO time-base. Key features include:

escribes the installation, operation, and related signal concepts of

ck the Tektronix Web site for updates to this manual, which will include

liance, environmental, and safety information, see the TSG4100A Series

TrueDCto2GHz,4GHz,or6GHz

Typical ±0.30 dB amplitude accuracy (0 dBm CW signal at 22 ºC) from 100 MHz to 6 GHz

Dual baseband ARB generators

Analog modulation

Soft key to vector modulation upgrade

I/Q modulation inputs (400 MHz RF BW)

ASK, FSK, MSK, PSK, QAM, VSB, and custom I/Q

TSG4100A Series RF Signal Generators User Manual ix

Preface

Digital modula

tion applications for GSM, EDGE, W-CDMA, APCO-25,

DECT, NADC, PDC, and TETRA

USB, GPIB, RS-

232 and LAN interfaces

Documentation

The followi Signal Generator. The product documentation CD provided contains documents available at the time of publication. For the most current documentation, refer to the Tektronix Web site at www.tektronix.com/manuals.

To read about Use these documents

Basic installation, safety, and compliance Installation and Safety Instructions

Operation and installation User Manual (this manual)

Programming commands Programmer Manual

Speciﬁcations and performance veriﬁcation

User service

Data security

ng documentation is available for your Tektronix TSG4100A Series RF

This document contains basic information about instrument connectors, how to turn it on and off, compliance, environmental, and safety information. This manual is shipped as a printed book with your product and provides information in English and Russian. It is also available as a PDF ﬁle, downloadable from www.tektronix.com/manuals.

The user manual contains information about how to navigate the instrument UI, how to operate the instrument, and information about signals. This manual is available in printed form in English or Russian. Both are also available as PDF ﬁles.

This manual contains descriptions of programming commands and their use. This manual is available as a PDF ﬁle.

Speciﬁcations and Performance Veriﬁcation Manual

This manual contains the instrument speciﬁcations and a procedure to check instrument performance against warranted characteristics. This manual is available as a PDF ﬁle.

Service Manual

This manual provides a list of replaceable parts, care and maintenance information, and information for servicing the instrument to the module level. This manual is available as a PDF ﬁle.

Declassiﬁcation and Security Instructions

This document helps customers with data security concerns to sanitize or remove memory devices. This document is available as a PDF ﬁle.

x TSG4100A Series RF Signal Generators User Manual

Preface

Software upgr

Conventi

onsusedinthismanual

ades

Software option upgrades are available. Software upgrades for options become operational only after you enter a valid option key for the speciﬁc generator model and serial nu

To check for upgrade s:

1. Use your Web browser to go to www.tektronix.com/software.

2. Enter the product name (for example TSG4104A) to ﬁnd available software

upgrades.

The following icons are used throughout this manual:

Sequence Step

mber.

Front panel power

Connect power

Network

PS2 SVGA USB

TSG4100A Series RF Signal Generators User Manual xi

Preface

xii TSG4100A Series RF Signal Generators User Manual

Installation

Before installation

Standard accessories

Unpack the instrument, and check that you received all items listed as Standard Accessories. Optional accessories and instrument options are also listed in this

section. Check the Tektronix Web site (www.tektronix.com) for the most current information.

Your instrument comes with the following accessories: installation and safety instructions (English and Russian languages), product software and documentation CD, and power cord.

Documents

Software

RF cable

Power cords

TSG4100A Series RF Signal Generators Installation and Safety Instructions

is a multi-language document (English and Russian). Tektronix part number 071-3390-XX.

TSG4100A Series RF Signal Generators Product SW and Documentation CD, Tektronix part number 063-4557-XX.

TSG File Assistant is a software application that allows you to convert raw data of custom waveforms, constellations, and ﬁlters (*.txt or *.csv ﬁles) to *.tsw, *.tsf, and *tsc ﬁles that are supported by the TSG. This software is available on the SW and Documentation CD that shipped with the instrument and for download from the Tektronix Web site at www.tektronix.com

NOTE. You can read more about how the TSG File Assistant works in this manual.

RF cable (Tektronix part number 012-1738-00): 1 meter, 50 Ω,N-typeto N-type

The TSG4100A Series RF Sig power cord options. Power cords for use in North America are UL listed and CSA certiﬁed. Cords for use in areas other than North Americ a are approved by at lea st one authority acceptable in the country to which the product is shipped.

nal Generators are shipped with one of the following

/downloads.

Opt. A0 - North America power

Opt. A1 - Universal EURO power

Opt. A2 - United Kingdom power

Opt. A3 - Australia power

TSG4100A Series RF Signal Generators User Manual 1

Installation

Optional accessories

Opt. A5 - Switze

Opt. A6 - Japan power

Opt. A10 - China power

Opt. A11 - India power

Opt. A12 - Brazil power

Opt. A99 - No power cord

Option TSG4100A-RM1; Single rackmount kit for all TSG4100A models

Option TS

Option TSG4100A-ATT: 30 dB, 5 Watt RF attenuator up to 6 GHz

Option GPIB: Adds GPIB interface

Option D1: A list of performance veriﬁcation test results

Option L0: Printed User manual (this manual). English. (You can always download an English or Russian User manual from the Tektronix Web site at www.tektronix.com/manuals.)

G4100A-RM2: Dual rackmount kit for all TSG4100A models

rland power

rument options

Inst

The following options must be speciﬁed at time of instrument order.

regions except North America. The following instrument conﬁguration options

All

are available in all regions except North America.

0: Instrument with oven-controlled crystal oscillator (OCXO).

M01: Instrument with voltage-controlled crystal oscillator (VCXO).

GPIB: Adds GPIB interface.

2 TSG4100A Series RF Signal Generators User Manual

Installation

Software options

North A merica o

only in North America.

E1: Instrumen and GPIB interface.

You can add the following software options to your generator:

Option VM00: Basic vector modulation package with internal 6M Hz modulation bandwidth

Option VM01: GSM modulation (requires Option VM00)

Option VM

Option VM03: W-CDMA modulation (requires Option VM00)

Option VM04: APCO-25 modulation (requires Option VM00)

Option VM05: DECT modulation (requires Option VM00)

Option VM06: NADC modulation (requires Option VM00)

Option VM07: PDC modulation (requires Option VM00)

Optio

nly. The following instrument conﬁguration option is available

t with oven-controlled crystal oscillator (OCXO) time-base

02: GSM EDGE modulation (requires Option VM00)

n VM08: TETRA modulation (requires Option VM00)

Connect to a network

LAN interface

Option VM10: Audio c lip (analog AM and FM) (requires Option VM00)

Option EIQ; External 200 MHz modulation bandwidth (requires Option VM00)

You can communicate with or remotely control your instrument through the LAN,

232, or GPIB interfaces. (GPIB requires Option GPIB.)

The LAN connector may be used to connect the instrument to a 10/100 Base-T Ethernet LAN. Before connecting the instrument to your LAN, check with your

etwork administrator for the proper method of conﬁguration of instruments

n on your network.

To set up the LAN interface:

1. Connect a LAN cable to the rear panel LAN port.

2. Press the Utility button from the main menu.

3. Select I/O Interface.

4. Select LAN to view the Ethernet network settings.

TSG4100A Series RF Signal Generators User Manual 3

Installation

5. Use the menu but other network information.

By selecting t automatically through DHCP. If you cannot establish communication using DHCP, you need to manually set up an IP address and a Subnet Mask, if necessary.

6. Press the Enter button.

7. Press the Return button three times to return to the main menu.

TCP/IP conﬁguration methods. InordertofunctionproperlyonanEthernet based local area network (LAN), the unit needs to obtain a valid IP address, a subnet mask, and a default gateway or router address. There are three methods for obta network administrator for the proper method of conﬁguration of instruments on your network.

TCP/IP based remote interfaces. Three TCP/IP based remote interfaces are supported: raw socket, telnet, and VXI-11 net instrument. Raw socket access is avail interface enables IEEE 488.2 GPIB-like access to the unit over TCP/IP. It enables controlled reads and writes and the ability to generate service requests. Most recent VISA instrument software libraries support this protocol.

ining these parameters: DHCP, Auto-IP, and Static IP. Check with your

able on port 5025. Telnet access is available on port 5024. The VXI-11

tons and number keys to enter the desired IP address and

he DHCP ON, the instrument can set its network address

Link speed. The physical Ethernet layer supports 10 Base-T and 100 Base-T link

eds. The default link speed is set to 100 Base-T, but it can be set to 10 Base-T.

spe

To reset the TCP/IP interface. When conﬁgured from the front panel, the TCP/IP is automatically reset. Otherwise, changes to the TCP/IP conﬁguration do not take effect until the TCP/IP interface is either reset or the instrument power is cycled. When reset is selected, any active connections will be aborted. The TCP/IP stack

ill be reinitialized and conﬁgured using the latest conﬁguration options.

CAUTION. Network security is an important consideration for all TCP/IP

networks. This instrument does not provide security controls, such as passwords or encryption, for controlling access. If such c ontrols are needed, you must provide it at the network level. For example, you can use an internet ﬁrewall.

4 TSG4100A Series RF Signal Generators User Manual

Installation

GPIB interface

The GPIB connec supports the required common commands of the IEEE-488.2 (1987) standard.

NOTE. Changes to the GPIB conﬁguration do not take effect until the interface is

reset or the instrument power is cycled.

To set up the GPIB interface:

1. Connect a GPIB cable to the rear panel GPIB port.

2. Press the U

3. Select I/O Interface.

4. Select GPIB.

5. Check that GPIB is set to ON. If it is not, highlight ON in the GPIB menu

to turn it on.

6. Press the Address button and use the number keys to assign a unique address to the instrument.

NOTE. Each device connected to the GPIB bus must have a unique GPIB address.

The GP

IB address must be from 0 to 30.

tor supports the IEEE-488.1 (1978) interface standard. It also

tility button from the main menu.

RS-232 interface

7. Press the Enter button.

8. Press the Return button three times to return to the main menu.

The RS-232 interface connector is a standard 9 pin, type D, female connector conﬁgured as a DCE (transmit on pin 2, receive on pin 3). In order to communicate properly over RS-232, the instrument and the host computer both m ust be set up tousethesameconﬁguration. The following baud rates are supported: 115200

default), 57600, 38400, 19200, 9600, and 4800. The rest of the communication

( parameters are ﬁ xed at 8 data bits, 1 stop bit, no parity, and RTS/CTS hardware ﬂow control.

To set up the RS-232 interface:

1. Connect a cable to the rear panel RS-232 port. Use a cable best suited for the desired baud rate (modulation rate).

2. Press the Utility button from the main menu.

3. Select I/O Interface.

4. Select RS232.

TSG4100A Series RF Signal Generators User Manual 5

Installation

5. Check that RS23 to turn it on.

6. Press the Baud rate.

7. Press the Re

2issettoON. If it is not, highlight ON in the RS-232 menu

Rate button and turn the general knob to set the desired baud

turn button three times to return to the main menu.

Upgrade the ﬁrmware through the USB port

The USB por memory device. To upgrade the ﬁrmware using the USB port, do the following:

1. From a com most recent instrument ﬁrmware from the Tektronix Web site at www.tektronix.com/downloads onto a USB memory device. Note the ﬁrmware version.

2. Press the Utility button from the instrument main menu.

3. Select System > About.

4. Look at

shown is older than the ﬁrmware version you downloaded from the Tektronix We b site.

t allows you to upgrade the instrument ﬁrmware using a USB

puter with an internet connection, download the

the instrument display screen and v erify that the ﬁrmware version

5. Insert the USB memory device into the USB port on the front panel of the instrument.

6. Check that the Firmware Update menu option becomes active a fter approximately 10 seconds as the instrument recognizes the USB memory device.

7. Press the Firmware Update button. A dialog box will appear asking if you want to update the ﬁrmware.

8. Use the arrow k eys to highlight Ye s if you want to start the update process, or No if you want to cancel the process.

9. Press the Enter button to start the update process (or cancel it if you selected

No).

6 TSG4100A Series RF Signal Generators User Manual

Powering on the instrument

Installation

Powering o

Remov

ing power from the instrument

ff the instrument

TSG4100A Series RF Signal Generators User Manual 7

Installation

Inspecting the instrument

Run the Self Test (Utility > System > Self Test) to run a series of tests to verify that the instrument is operating correctly. It tests communication to various peripherals on the main board, including the GPIB chips, the PLL chips, the DDS chips, the octal DACs, the FPGA, and the serial EEPROM. Errors will be reported on the front-pane error buffer and may be accessed through the e rror status menu after the self test completes. See section Error Codes on page 126 for a complete list of error codes.

If you want to check the accuracy speciﬁcations of your instrument, see the

TSG4100A Series RF Signal Generators Speciﬁcations and Performance Veriﬁcation Technical Reference PDF available on the Tektronix Web site at

www.tektronix.com/manuals.

l display when detected. The errors detected are stored in the instrument

8 TSG4100A Series RF Signal Generators User Manual

Instrument maintenance

Installation

Clean your in strument

Clean the exterior surfaces of the chassis with a dry lint-free cloth or a soft-bristle brush. If any dirt remains, use a cloth or swab dipped in a 75% isopropyl alcohol solution. Use a swab to clean narrow spaces around controls and connectors. Do not use abrasive compounds on any part of the instrument because they might damage the i

CAUTION. Avoid getting moisture inside the instrument during exterior cleaning;

use just enough moisture to dampen the cloth or swab. Do not wash the front-panel On/Off button. Cover the button while washing the instrument. U se only deionized or distilled water when cleaning. Use a 75% isopropyl alcohol solution as a cleanser and rinse with deionized or distilled water. Do not use chemica contain benzene, toluene, xylene, acetone, or similar solvents.

CAUTIO

cleaning agents or methods. Avoid using abrasive cleaners or commercial glass cleaners to clean the display surface. Avoid spraying liquids directly on the display surface. Avoid sc rubbing the display with excessive force.

Clean the display surface by gently rubbing the display with a clean-room wipe. If the display is very dirty, moisten the wipe with distilled water or a 75% isopropyl alcohol solution and gently rub the display surface. Avoid using excess force; this might damage the display surface.

nstrument.

l cleaning agents; they might damage the chassis. Avoid chemicals that

N. To prevent damage to the ﬂat panel display, do not use improper

rade your instrument

Upg

Return your in strument

Software upgrades are available from Tektronix. They can either be downloaded from the Tektronix Web site or they can be ordered from your local Tektronix representative. To add additional software options or features, you will need an

ption key from Tektronix. When you receive the software from Tektronix, you

o will also receive an option key. Follow the instructions you receive to install the software on your instrument. You will be prompted to enter the option key. See the About menu on the instrument to enter an option key. This information is in the Menus section of this manual. (See page 16 , Menus.)

If you return your instrument to Tektronix:

When repacking the instrument for shipment, use the original packaging. If the packaging is unavailable or unﬁt for use, contact your local Tektronix representative to obtain new packaging.

Seal the shipping carton with an industrial stapler or strapping tape.

TSG4100A Series RF Signal Generators User Manual 9

Operating basics

Operating bas

Front panel controls

ics

The followi the controls and elements noted in the illustration.

ng illustration shows the instrument front panel. The table describes

Front panel

10 TSG4100A Series RF Signal Generators User Manual

Operating basics

Item number

1 Power button

2RF

3 Adjustment

8Freq

9Ampt Presst

10 Mod Press to access modulation menu.

15 Numeric keypad

16 Menu selection

Control element or group Description

Press to turn power on or off. The power button has two modes: STANDBY and ON. In STANDBY mod consumption will not exceed 20 W once the instrument is warmed up. In ON mode, power is supplied to all circuitry and the instrument is on.

Press to turn R F signal output ON (LED light on) or OFF (LED light off). Only outputs that areactivef minimum value it will be disabled and the LED light will turn off.

knob

Select key

Preset

Setting

Mod On/Off Press to turn modulation function ON or OFF.

G/n ( dBμV) Press to select units (GHz, ns, nv, dBμv).

M/μ (μV) Press to select units (MHz, μs, μv).

K/m (mV) Press to select units (KHz, ms, mv)

Enter (dB(m)) Press to select units (Hz, s, dBm).

buttons

Turn knob to

Press to en underscore position when editing a parameter.

Press and hold to recall default setup.

Press to a

Press to adjust RF frequency.

o adjust amplitude.

Use these keys to enter numeric values for a variety of parameters.

Use these buttons to select menu items on the screen.

e, power is only supplied to the internal timebase and the power

or the current frequency setting will be accessible. If an output is set below its

navigate menus and adjust parameters.

ter submenu (right arrow), return to m ain menu (left arrow), or to adjust the

ccess the top menu.

Connectors

he following ﬁgures and tables show and describe various connectors located

T on the front panel and rear panel of the instrument.

Front panel connectors

TSG4100A Series RF Signal Generators User Manual 11

Operating basics

Table 1: Front p

anel connectors

Item number Connector Description

LF Output BNC output. Active for frequency s ettings between DC and 62.5 MHz. The amplitude may

be set independently for levels from 1 μV protected ag

RF Output Type N outpu

950 kHz and 4 GHz (TSG4104A), and 950kHz and 6 GHz (TSG4106A). The output power may be set from −110 dBm to 16.5 dBm (0.7 μV

USB A USB connector allows you to connect an external memory device to the instrument for

data stora

ge.

RMS

to1V

(–47 dBm to 13 dBm). This output is

RMS

ainst externally applied voltages of up to ±5 V.

t. Active for frequency settings between 950 kHz and 2 GHz (TSG4102A),

RMS

to 1.5 V

RMS

12 TSG4100A Series RF Signal Generators User Manual

Rear panel connectors

Table 2: Rear panel connectors

Item Connector Description

AC power (input) Connect the unit to a power source through the power cord provided with the instrument.

The center pin is connected to the chassis so that the entire box is earth grounded. The unit will operate with an AC input from 100 to 240 V Hz. The instrument requires 85 W and implements power factor correction. Connect only to a properly grounded outlet.

SYMBOL CLOCK (output)

This BNC provides a square wave synchronized to the symbol clock used in the modulation. The r ising edge of this clock triggers the programmed event markers associated with the arbitrary waveform.

EVENT (outputs) Three BNC outputs labeled #1, #2, and #3 are available for synchronizing external

instrumentation to programmable events within a generated arbitrary waveform. These may be programmed, for instance, to mark the start of a frame, or a slot within a frame, or the start of a synchronizing pattern in the waveform. One of the event markers may be further programmed to control the RF power of the front panel output for the generation of TDMA signals. Events are triggered on the rising edge of the symbol clock.

VECTORMODINI

VECTOR MOD IN Q

These BNC inputs enable external I/Q modulation. They accept signals of ±0.5 V, corresponding to full scale modulation, and have 50 Ω input impedances. Both inputs support signal bandwidths from DC to 100 MHz providing an RF modulation bandwidth of up to 200 MHz.

VECTOR MOD OUT I

VECTOR MOD OUT Q

These BNC outputs replicate the baseband I/Q modulation waveforms currently being used to modulate the RF. Both outputs have a source impedance of 50 Ω and when terminated into 50 Ω, will generate a full scale output of ±0.5 V.

ANALOG MOD OUT This output replicates the analog modulation waveform and has a 50 Ω reverse

termination. When using the internal source for AM, FM, and ΦM, it provides a waveform determined by the function and rate settings with an amplitude of 1 V impedance. During external analog modulation, this output mirrors the modulation input. For Pulse modulation, the output is a 3.3 V logic waveform that coincides with the gate signal.

Operating basics

, and with a frequency of 50/60

into a high

TSG4100A Series RF Signal Generators User Manual 13

Operating basics

Table 2: Rear panel connectors (cont.)

Item Connector Description

10 LAN

ANALOG M OD IN External analog modulation is applied to this input. The input impedance is 100 kΩ with

a selectable input coupling of either DC or AC (4 Hz roll off). For analog modulations (AM, FM, ΦM), a signal of ±1 V will produce a full scale modulation of the output (depth for AM or deviation for FM and ΦM). It supports bandwidths of 100 kHz and introduces distortions of less than –50 dB. For Pulse modulation types, this input is used as a discriminator that has a ﬁxed threshold of +1 V.

TIMEBASE OUT (10MHz2V

)

TIMEBASE IN (10 MHz

0.5 to 3.0 V

)

The instrument also provides a 10 MHz output for referencing other instrumentation to the internal timebase.

This input accepts an external 10 MHz reference. The external reference should be accurate to at least 2 ppm, and provide a signal of no less than 0.5 VPPwhile driving a50Ω impedance. The instrument automatically detects the presence of an external reference and locks to it, if possible. If the unit is able to lock to the reference, this is indicated on the front panel display.

The Ethernet uses a standard R J-45 connector to connect to a local area network (LAN) using standard Category-5 or Category-6 cable. It supports both 10 and 100 Base-T Ethernet connection and a variety of TCP/IP conﬁguration methods.

RS-232 The RS-232 port uses a standard 9 pin, female, subminiature-D connector. It is

conﬁgured as a DCE and supports baud rates from 4.8 kb/s to 115 kb/s. The remaining communication parameters are ﬁxed at 8 Data bits, 1 Stop bit, No Parity, with RTS/CTS conﬁgured to support H ardware Flow Control.

GPIB The GPIB (IEEE-488) communications port is for communications over a GPIB bus. T he

instruments support the IEEE-488.1 (1978) interface standard. It also supports the required common commands of the IEEE-488.2 (1987) standard.

E. When EXT is selected as the Source, the instrument will look for an

NOT

external 10 MHz reference at the timebase input BNC. If detected, the instrument will attempt to lock its internal clock to the external reference.

14 TSG4100A Series RF Signal Generators User Manual

Display, navigation, and menus

Controls and display elements are shown in the following illustrations and tables.

Operating basics

Ref number

4 Menus

Displayareafunction

Status

Quick

Settings Shows the parameters that can be modiﬁed for the currently selected item. You can

view

Display

The display s

Descrip

Indicates instrument status. When an item is highlighted yellow or is displayed with bold typeface, that feature is active. This area shows m odulation types, and if Modulation and RF are O

Shows on the front panel.

modify a parameter by pressing the corresponding menu button and then using the arrow keys

Menu such as LAN or GPIB setup, or setting a particular modulation type. Use the arrow k eys, general knob, and Enter key on the front panel to navigate the menus.

creen is divided into the following four sections:

tion

N or Off. Error messages, if applicable, show in the right corner of this area.

frequency and amplitude values. Units can be changed using the unit buttons

, general knob, and Enter key on the front panel.

buttons show items that you can select to access submenus for speciﬁc a ctions,

Saving display i mages

(screen shots)

You can save *.bmp ﬁles of the instrument display to a USB memory device as follows:

1. Insert a USB memory device into the USB port on the front of the instrument.

et the display as desired.

2.S

3. Simultaneously press and hold the < and > keys for 1 second.

4. Remove the memory device and download the saved *.bmp ﬁles to your PC

or other device.

TSG4100A Series RF Signal Generators User Manual 15

Operating basics

Navigation

Navigate the Me

nus and Settings areas of the display by using the arrow keys (left, right), general knob (up, down, and push in knob to select), and Enter key (select). When a parameter is selected in the Settings area, you can use the arrow keys to select a digit, the number keys to enter a value, and the Enter key to make a selection. When you are ﬁ nished, press the Enter key to set the parameter and then any menu item to deselect the parameter.

Menus

The following menus are available.

Table 3: Menus

Menu Description

Main menu

RF/LF menu and settings.

Mod m enu and settings.

Access modulation presets, constellation, source, rate, ﬁlter and other submenus.

The menu options in this menu change depending on the active modulation type.

16 TSG4100A Series RF Signal Generators User Manual

Table 3: Menus (cont.)

Menu Description

Mod Type submenus: Analog, Vector, Presets.

Operating basics

Constellation menu.

This is a Mod submenu. It is available when the appropriate modulation type is active. The items in this menu vary depending on the active modulation type.

TSG4100A Series RF Signal Generators User Manual 17

Operating basics

Table 3: Menus (cont.)

Menu Description

Source menu.

This is a Mod submenu. It is available when the appropriate modulation type is active. The items in this m enu vary depending on the active modulation type.

Filter menu.

This is a Mod submenu. It is available when the appr items in this m enu vary depending on the active modulation type.

opriate modulation type is active. The

AWGN/IMP menu: Noise submenu and AWGN/IMP settings.

Utility menu.

18 TSG4100A Series RF Signal Generators User Manual

Table 3: Menus (cont.)

Menu Description

I/O Interface menu.

This is a Utility submenu.

RS232 menu and settings.

This is an I/O Interface submenu.

Operating basics

GPIB me

This is an I/O Interface submenu.

This requires the instrument have the GP IB optio

nu and settings.

TSG4100A Series RF Signal Generators User Manual 19

Operating basics

Table 3: Menus (cont.)

Menu Description

LAN menu, submenus, and settings.

This is an I/O Interface submenu.

System menu.

This is a Utility submenu.

Allows you to set display backlight, date, time, run a self test, and remove private data (Secure).

Secure setting.

This is a System menu action that allows you to remove private data. Use the arrow keys to select Yes or No and then press the general knob or the Enter button on the front panel.

20 TSG4100A Series RF Signal Generators User Manual

Table 3: Menus (cont.)

Menu Description

File menu.

This is a Utility submenu. It allows you to access saved ﬁles such as waveform, constellation, ﬁlter, and setup ﬁles. Available ﬁles will show in the Settings area of the display when you select the ﬁle type.

You can load a ﬁle from the USB to location 0 on the instrument (USB), save a ﬁle (Save To) to location 1 through 9, delete a ﬁle (Delete), and delete all ﬁles (Erase All).

The Setup submenu allows you recall and save setups (Recall).

Operating basics

Status menu.

This is a Utility submenu. It shows the status of the instrument in the Settings area.

TSG4100A Series RF Signal Generators User Manual 21

Operating basics

Table 3: Menus (cont.)

Menu Description

About menu.

This is a Utility submenu. It shows the instrument ﬁrmware version, installed options, instrument serial number in the Settings area.

License M anage menu.

This is an About submenu. It allows you to enter option/software keys to activate options.

Firmware Update m enu.

This is an About submenu. It allows you to upgrade the ﬁrmware using the USB port.

NOTE. Upgrade procedures are available in

this manual. (See page 6, Upgrade the ﬁrmware through the USB port.)

22 TSG4100A Series RF Signal Generators User Manual

Table 3: Menus (cont.)

Menu Description

USB menu.

This is a Utility submenu. It allows you to access ﬁles from a USB memory device. Available ﬁles show in the Settings area of the display.

Error code menu.

This is a Utility submenu. It is an error log and allows you to view any error codes that have appeared.

Operating basics

Quick start and functional check

ectionisintendedtohelpﬁrst time users get started using a Tektronix

This s TSG4100A Series RF Signal Generator and to help verify that the instrument is functioning correctly.

Turn on the instrument

1. Con

2. Pu

3. Ch

NOTE. Your instrument will resume operating with the same settings that were

active when it was last turned off. You can preset the instrument to a default state without changing any of the stored settings or the communications conﬁguration. (See page 24, Set default settings (Preset button).)

nect the supplied power cord to the rear panel power input and then to the

AC mains power supply (100 to 240 V

sh the power button located on the left top corner of the front panel of the

instrument.

eck that the model number, ﬁrmware version, and instrument serial number

brieﬂydisplay.

±10%).

TSG4100A Series RF Signal Generators User Manual 23

Operating basics

Set default settings (Preset

button)

To set the instr presets, press and hold the Preset button on the front panel for three seconds. The

ument to the factory default settings without affecting saved

following table shows some of the default settings that will be loaded.

Table 4: Preset default settings

Setting Default value

Frequency 10 MHz

Amplitude (BNC) 0 dBm (1 mW into 50 Ω or 0.63 V

Amplitude (Type N) 0 dBm (1 mW into 50 Ω or 0.63 V

Modulation

Modulation Type FM

Source Sine

Rate 1 kHz

Deviation 1 kHz

Conne

ct outputs to

oscilloscope

1. Use appropriate cables to connect the front panel BNC and Type N outputs to

an oscilloscope.

OFF

2. Set the oscilloscope timebase to 50 ns/div and vertical sensitivity for

200 mV/div with DC coupling and 50 Ω input impedance.

Basic functional check

3. Check that the displayed cycle period is 100 ns (2 divisions).

4. Check that the displayed amplitude is 630 mV

NOTE. The displayed amplitude will be 630 mV if the oscilloscope input is not

set for 50 Ω.

Do the following after connecting to an oscilloscope to check that the information shows as expected on the display screen and that you can adjust the parameters and navigate the menus properly.

24 TSG4100A Series RF Signal Generators User Manual

Operating basics

1. Change the freq

a. Press the Freq button on the front panel to select the Frequency parameter

in the Quick View area.

b. Press the 5 number key.

c. Press the M/μ button to set the units to MHz.

d. Press the Setting button to exit the frequency setting.

Navigation quick tip. You can se units as follows: press the Freq button, use the general knob to increase/decrease the value, and then press the Setting button.

2. Change the amplitude for the Type N output by 1 dBm as follow

a. Press the Ampt button on the front panel to select the Type-N output

amplitude parameter in the Quick View area.

b. Press the Enter button to set the units to dBm.

c. Use the general knob to increase the amplitude by 1 dBm.

d. Press the Setting button to set and exit the amplitude setting.

Navigation quick tip. You can use the number keys and unit keys to set the amplitude parameter value and units as follows: press the Ampt button, press the desired number key, press the desired unit key, and then press the Setting button.

uencyto5MHzasfollows:

t the frequency parameter without changing the

Modulation presets

functional check

3. Change the amplitude for the BNC output by 0.001 V as follows:

a. Select RF/LF from the main menu.

b. Select LF Amplitude from the submenu.

c. Press the 5 number k ey.

d. Press a unit key to set the LF Amplitude to Vpp or Vrms.

e. Press the k/m button to set the units to mV.

f. Use the general knob to increase the amplitude by 1 mV.

g. Press the Setting button to set and exit the amplitude setting.

Your instrument includes a number of modulation presets that automatically conﬁgure the generator to produce modulation waveforms for a number of different communications protocols, such as GSM, DECT, and TETRA. Do the following to see how this preset type is enabled.

1. Press the Freq button and then set the frequency to 935.2 MHz.

2. Select Mod from the Main menu.

3. Select Mod Type from the Mod submenu.

TSG4100A Series RF Signal Generators User Manual 25

Operating basics

4. Use the general

NOTE. Turn the general knob to highlight your selection. Press the general

knob to select it.

5. Turn the general knob to highlight GSM andthenpresstheEnter button to

load the GSM preset.

6. Press the Mod On/Off button to enable modulation. The LED will be lit

and MODON will show in the Status area of the display when modulation is on. The i slot of random data.

7. Connect t

event ma rker #1.

8. Trigger

oscilloscope trace should look similar to that shown below.

the oscilloscope on event marker #1 and set the time/div to 10 μs. The

knob to select Preset from the Mod Type menu.

nstrument will generate a GSM frame consisting of one TDMA

he following to the oscilloscope: I/Q outputs, symbol clock, and

The oscilloscope traces above show that before the TDMA slot begins, the I and Q outputs are at ground, indicating that the RF power is off. Two symbols

efore the beginning of the time slot, the power is ramped up to full power. The

b beginning of data transmission for the time slot is indicated by event marker #1, whichistrace4intheﬁgure. The symbol clock shows the timing of symbol transmission relative to the I/Q outputs.

26 TSG4100A Series RF Signal Generators User Manual

Settings

Operating basics

Frequency

Phase

Amplitude

Pressing the Freq button allows you to adjust the carrier frequency of the front panel BNC (LF any of the following units: GHz, MHz, kHz, or Hz using the unit buttons on the front panel. The frequency resolution is 1 μHz at all frequencies. The frequency setting determines which outputs are active at any given time. Enabled outputs are noted in the front panel display and in the RF button light on the front panel. None of the outputs operate across the entire frequency range, but are dependant on the inst

The Phase setting is accessed through the main menu: RF/LF > Phase.This setting shows the relative phase of the output in degrees and is adjustable over ±360º. I The displayed phase is reset to 0° whenever the carrier frequency is changed. The phase resolution depends on the current setting of the frequency. For frequencies up to 100 MHz, the phase resolution is 0.01°, with reduced resolution for higher frequencies.

Pressing the Ampt button allows y ou to adjust the output amplitude or power of the displayed output. If an output is set below its minimum value, it will be disabled. This is indicated on the display as RFOFF and the RF LED button on the f dBuV, or V

f the phase adjustment exceeds 360º, the phase is displayed modulo 360º.

ront panel being extinguished. Amplitude can be displayed in units of dBm,

Out) and Type N (RF Out) outputs. A frequency can be entered in

rument model.

. All stated values assume a load termination of 50 Ω.

RMS

LF Offset

I/Q Offset

RF On/Off

The Offset setting for the LF Out output is accessed through the main menu:

/LF > LF Offset. This setting shows the output offset voltages. Only the LF

Out (BNC) output has a settable DC offset. The Type N RF output is AC coupled and so has no DC offset setting. The DC offset for the LF Out is always accessible and active (independent of the frequency setting).

The O ffset setting for the I/Q outputs is accessed through the main menu: AWGN/IMP > I Offset or Q Offset. This setting shows the offset as %.

The front panel outputs can be turned on and off by pressing the RF button on the front panel. When the RF is off, the RF LED button on the front panel is extinguished and the RFON text on the display is grey. When RF is on, the RF LED button on the front panel is lit and RFON on the display is yellow.

TSG4100A Series RF Signal Generators User Manual 27

Operating basics

Presets

Mod On/Off

Noise (AWGN)

Power (AWGN)

Modulation can panel. When the modulation is off, the Mod LED button on the front panel is extinguished and the MODON text on the display is grey. When modulation is on, the Mod LED button on the front panel is lit and MODON on the display is yellow.

The Noise setting is accessed through the main menu: AW G N / I M P > Noise.This setting allows you to degrade a vector modulation waveform with additive white Gaussian noise (AWGN). You can select Add, Only, and Off in the Noise menu.

The Power setting is accessed through the main menu: AW G N / I M P > Power. This setting allows you to adjust the noise power for a vector modulation waveform with additive white Gaussian noise (AWGN). Use the general knob to adjust the power value in the Settings area of the display.

NOTE. M

Presets allow you to load preconﬁgured setups. The following presets types are available:

ore settings are available than are described in this manual.

be turned on and off by pressing the Mod buttononthefront

eset button (factory

default preset)

odulation presets

Preset button (factory defaults preset) (See page 28.)

Modulation presets (See page 28.)

r presets (See page 30.)

Use

Arbitrary waveform user presets (See page 30.)

To set the instrument to the factory default settings without affecting saved presets, press and hold the Preset button on the front panel for three seconds. Default settings will be loaded. (See Table 4 on page 24.)

The modulation presets shown in the following image and described in the following table are available.

The presets conﬁgure the instrument to perform the selected modulation, but the modulation is turned off. To turn on the modulation, press the Mod button until the LED is lit and MODON shows in the Status area of the display.

NOTE. Some presets may require speciﬁc options and may not be available on

all instrument models.

28 TSG4100A Series RF Signal Generators User Manual

Operating basics

Table 5: Modulation presets

Preset Description

AM Audio

FM Audio

NADC Vector modulation parameters used in North American Digital Cellular

PDC Vector modulation parameters used in Personal Digital Cellular (PDC)

DECT One TDMA slot within one frame of random data using the vector

P25

TETRA

GSM One TDMA slot within one frame of random data using the vector

GSM EDGE One TDMA slot within one frame of random data using the vector

W-CDMA One frame with one control channel and six data channels of random data

Analog AM modulation of an audio clip.

Analog FM modulation of an audio clip.

(NADC) communications.

communications.

modulation parameters of Digital Enhanced Cordless Telecommunications (DECT). The waveform transmits a P32 packet which includes the Z ﬁeld and is 424 symbols long.

Vector modulation parameters used in the APCO Project 25 communications system.

One TDMA slot within one frame of random data using the vector modulation parameters used in Terrestrial Trunked Radio (TETRA) communications. The waveform transmits a normal uplink burst, 231 symbols long, using normal training sequence 1.

modulation parameters of the Global System for Mobile communications (GSM). The packet is 148 symbols long and the midamble is ﬁlled with training sequence 0.

modulation parameters of the GSM with Enhanced Data rate for GSM Evolution (GSM-EDGE) communications. The packet is 148 symbols long and the midamble is ﬁlled with training sequence 0.

using the vector modulation parameters of Wideband Code Division Multiple Access (W-CDMA) communications for an uplink c hannel in a frequency division duplex (FDD) installation. The control channel uses a spreading factor of 256 while the data channels use a spreading factor of 4. The control and data channels are scrambled with long scrambling code 0.

TSG4100A Series RF Signal Generators User Manual 29

Operating basics

Arbitrary w aveform user

presets

Modulation user presets

(custom)

You can save arb to access the user setups menu. To recall a setup, navigate to the desired setup number in the menu and then press Recall. You can also selec t to access ﬁles from the USB device and to save to a speciﬁc location.

You can access modulation user presets by selecting Modulation > Source > Custom. then press the general knob.

To recall a preset, navigate to the desired user number in the menu and

itrary waveforms to the generator. Select Utility > File > Setup

Modulation sources

The instrument’s modulation capabilities include both internal and external modulation sources. The modulating waveform is replicated on the rear panel Analog Mod Out BNC.

Linear modulation

30 TSG4100A Series RF Signal Generators User Manual

The modulation source for AM / FM / ΦM, c an be either the internal generator or the rear panel external modulation input.

The internal modulation source is capable of generating sine, ramps, triangular, or square waves, at frequencies of up to 500 kHz. The instrument limits the modulation rate to 50 kHz for carrier frequencies above 62.5 MHz (93.75 MHz for the TSG4106A).

Operating basics

Pulse modulation

The rear panel e

xternal modulation input supports bandwidths of 500 kHz, but the modulation bandwidth is limited to 100 kHz for fc greater than 62.5 MHz (93.75 MHz for the TSG4106A). The sensitivity is set such that a 1 V signal results in a full scale deviation (depth) in the output. For example: in ΦM, if the deviation is set for 10°, applying –1 V produces a –10° shift; applying 0 V produces no shift; and applying +1 V produces a +10° shift.

When modulation is enabled using an internal source, the rear panel modulation output will provide a waveform of the selected function with a full scale range of ±1 V. When external modulation is s elected the modulation output tracks the applied signal.

In pulse modulation, the RF signal is turned on by the internally generated or externally applied signal.

The internal pulse modulation source is a digital waveform with period settable from 1 μs to 10 s with 5 ns of adjustability, and on time settable from 0.1 μsto

9999.9999 ms. The period of the digital waveform is set using the Period setting in the Mod menu. The on time (for pulse mode) is set using the Width setting in the Mod menu.

When an external input is selected the rear panel external modulation input is set for a threshold of 1 V. The resulting signal is used in place of the internal source. In pulse mode, the modulation output is a 3.3 V logic signal, which tracks the pulse waveform.

Linear Noise modulation

Example. The following image shows the front panel BNC and Type N outputs

for a pulse modulated carrier frequency of 50 MHz. The internal pulse modulator was set to 1 μs period with a 300 ns pulse width (or a 30% duty cycle). The output amplitudes were set to 2 V

into 50 Ω. The top trace is the rear panel

Modulation Output signal. The middle trace is the BNC output. The bottom trace is the Type N output. Both traces show about 50 ns latency in their response to the gating signal. The Type N output also shows some gate feedthrough at the leading edge of the signal.

For AM, FM and ΦM, the noise source is pseudo random additive white Gaussian noise (AWGN). The bandwidth of the noise and the RMS deviation are set using the Rate and Deviation settings in the Mod menu, respectively.

The peak d eviation will be about ﬁve times the set RMS deviation. This forces limits on the maximum allowed deviation corresponding to one ﬁfth of the non-noise counterparts. For example, at a carrier frequency of 500 MHz the maximum FM deviation for a sine wave function is limited to 4 MHz, and so the maximum deviation for noise modulation is limited to 800 kHz.

For linear modulation, the rear panel output will provide 200 mV

RMS

that will be band limited to the selected modulation rate. Again, the peak deviation will be ﬁve times this, or ±1 V

TSG4100A Series RF Signal Generators User Manual 31

Operating basics

Pulse Noise modulation

For pulse modul

ation, the noise source is a Pseudo Random Binary Sequence (PRBS). The bit period is set using the Period setting in the Mod menu. The PRBS supports bit lengths of 2n,for5≤ n ≤ 32whichcorrespondtoanoise periodicity from 31 to 4,294,967,295 periods. The bit length n is adjusted from the PRBS Len setting in the Mod menu.

During pulse PRBS modulation, the rear panel output will be a 3.3 V

waveform

with a duty factor equal to 2n/2 / 2n-1 (approximately 50 %).

Example. T

he following image shows the front panel BNC and Type N outputs for a pulse modulated carrier frequency of 50 MHz. The internal pulse modulator was set to 1 μs period with a 300 ns pulse width (or a 30% duty cycle).

The output amplitudes were set to 2 V

into 50 Ω. The top trace is

the rear panel Modulation Output signal. The middle trace is the BNC output. The bottom trace is the Type N output. Both traces show about 50 ns latency in their response to the gating signal. The Type N output also shows some gate feed-though at the leading edge if the

signal.

User Arbitrary Waveform

dulation

User arbitrary waveforms can be downloaded to the instrument over the remote

nterfaces into on board SRAM. Once downloaded, the waveform can be saved

i ontoaUSBmemorydevice. WaveformsstoredinSRAMorFLASHmaybe selected as possible modulation sources from the Mod > Source > Custom menu.

NOTE. You can read more about user waveforms and how to create them. (See

page 58, Using the ﬁle Assistant utility software.)

32 TSG4100A Series RF Signal Generators User Manual

Operating basics

Modulation outputs

Amplitu

de modulation

The rear panel A

nalog and Vector Mod Out BNCs provide a copy of the modulation function with ±1 V full scale range. This output will be a sine, ramp, triangle, square wave, pulse or noise depending on the selected internal modulation function.

When an external source is applied to the modulation input it will be bandwidth limited, digitized, and reproduced at the modulation output. The transfer function has a bandwidth of about 1 MHz and a latency of about 950 ns.

The modulation output has a 50 Ω source impedance (to reverse terminate reﬂections from the user’s load) but the output should not be terminated into 50 Ω.

Amplitude modulation can use either the internal modulation generator or an external source. The internal modulator can generate sine, ramp, triangle, square, noise, or user waveforms.

Example. The following image shows a 20 kHz carrier, with an amplitude of

into 50 Ω, amplitude modulated by an internally generated sine wave.

Themodulationrateis1kHzandthemodulation depth is 100%. Two traces are shown. The upper trace is the 1 kHz modulation waveform from the rear panel Analog Modulation Output BNC, offset up two divisions. The lower trace

he modulated carrier (from the front panel BNC output), offset down one

is t

division.

TSG4100A Series RF Signal Generators User Manual 33

Operating basics

Frequency modulation

The internal mo

dulation generator or an external source may be used to modulate the frequency outputs from the front panel BNC and Type N outputs. The internal modulator can generate sine, ramp, triangle, square, noise, or user waveforms.

During FM, the output frequency traverses fc ± MOD DEV at the speciﬁed MOD RATE. For example, if the frequency is set for 1000 MHz (1 GHz), and the modulation rate and deviation are set for 10 kHz and 1 MHz, respectively, then the output will traverse from 1000 MHz, up to 1001 MHz, down to 999 MHz, and back to 1000 MHz at a rate of 10 kHz (a period of 100 μs).

The FM modulation parameters are dependent on the frequency setting. The following tables list the FM parameters as a function of frequency. All frequency bands span octaves except for the ﬁrst b and. The internal FM rates correspond to the upper range that the internal function generator supports. The external bandwidth is deﬁned as the −3 dB response referenced to the external modulation source. For the bands 2 to 8, the rates and bandwidths are similar. However, the deviation increases by a factor o f two, from 1 to 64 MHz, for octaves 2 through 8.

Table 6: TSG4102A and 4104A FM modulation vs. frequency

Internal FM rate,

Frequency range

DC to 62.5 MHz

62.5 to 126.5625 MHz 50 100 1

126.5625 to 253.125 MHz 50 100 2

253.125 to 506.25 MHz 50 100 4

506.25 to 1.0125 GHz

1.0125 to 2.025 GHz

2.025 to 4.050 GHz

1 μHz to (kHz):

500 500

50 100 8

50 100 16

50 100 32

External FM bandwidth DC (or 4 Hz AC) to (kHz): FM deviation (MHz)

Smaller of fcor 64 MHz–fc(MH

Table 7: TSG4106A FM modulation vs. frequency

Internal FM rate,

Frequency range

DC to 93.75 MHz

93.75 to 189.84375 MHz 50 100 1

189.84375 to 379.6875 MHz 50 100 2

379.6875 to 759.375 MHz 50 100 4

759.375 to 1.51875 GHz

1.51875 to 3.0375 GHz

3.0375 to 6.075 GHz

1 μHz to (kHz):

500 500

50 100 8

50 100 16

50 100 32

External FM bandwidth DC (or 4 Hz AC) to (kHz): FM deviation (MHz)

Smaller of fcor 96 MHz–fc(MHz)

Example. The following image shows a 2 MHz carrier being frequency modulated by a 100 kHz square wave with a 1 MHz deviation. In this example of Frequency Shift Keying (FSK), the carrier frequency is being rapidly switched between 1 MHz and 3 MHz. The top trace is from the rear panel Modulation

34 TSG4100A Series RF Signal Generators User Manual

Operating basics

Output BNC whic is the front panel BNC output, whose amplitude was set to 1 V

h shows the 100 kHz modulating waveform. The m iddle trace

. The bottom

trace is from the front panel Type N output, whose amplitude was set to 2 V

Phase modulation

Phase modulation can use either the internal modulation generator or an external

. The internal modulator can generate sine, triangle, ramp, square, noise,

source or user waveforms. The phase of the output traverses the speciﬁed deviation at the modulation rate. For example, with a frequency of 1000 MHz (1 GHz), and modulation rate and deviation set to 10 kHz and 45°, respectively, the output will be a ﬁxed frequency with its phase traversing ±45 degrees at a 10 kHz rate.

ple. The following image shows the frequency spectrum of a 0 dBm,

Exam

50 MHz carrier being phase modulated by a 10 kHz sine wave with a deviation of 137.78°. Here, the modulation index, β = phase deviation =

137.78° × 2π / 360° = 2.40477 radians. For phase modulation by a sine, the carrier amplitude is proportional to the Bessel function J0(β), which

TSG4100A Series RF Signal Generators User Manual 35

Operating basics

Error log

has its ﬁrst zer

This instrument contains an error buffer that can store up to 20 error codes associated with errors encountered during p ower-on self t ests, command parsing, or command execution. Errors that occur will show in red colored font in the right corner of the Status area of the display. Theerrorsinthebuffercanbereadone by one by executing successive LERR? commands. You can also view the errors from th whichtheyoccurred.

emainmenubyselectErr Log. The errors are displayed in the order in

o at 2.40477, which suppresses the carrier to below -88 dB.

36 TSG4100A Series RF Signal Generators User Manual

Digital communications

The TSG4100A Series generators support two types of modulation: analog and vector. Analog modulation refers to the modulation of a scalar parameter of the carrier signal, such as amplitude, frequency, or phase. Vector modulation refers to the modulation of t he vector characteristics (amplitude and phase) of the carrier (I/Q) modulation techniques.

Introduction

Prior to the industrial revolution, communications over long distances took long periods of time using written words or images. Today, long distance communication is most frequently accomplished by encoding information onto an electrical signal that can be transmitted over very long distances at close to the speed of light. The electrical signal is usually an RF carrier and the information is encoded usually one o f three types: amplitude, frequency, or phase.

signal. Vector modulation is implemented using In-phase/Quadrature

by modulating or altering the carrier in some way. The modulations are

In most acoustic vibrations from a person’s voice, for instance, can be converted into an electrical signal with the use of a microphone. The resulting electrical signal is an analog signal, which may be easily converted back into voice with an ampliﬁer and a speaker. In traditional analog communications, the analog signal itself is used to modulate the RF directly. In FM radio, for example, the ampliﬁed anal the RF carrier directly. The primary advantage of such a scheme is its simplicity and affordability. Receivers were fairly easy to design and cheap to produce. The disadvanta ge of analog communicationisthatitiswastefulofpowerand bandwidth, and susceptible to degradation by noise.

Digital communications refers to the transmission of digital data or numbers, instead of analog signals. Analog signals can be converted into digital data with the use of an analog to digital converter (ADC). The ADC measures the analog

ignal at an instant in time and assigns a number to it. Big signals are assigned big

s numbers and small signals are assigned small numbers. The ADC samples the size of the analog signal every few microseconds and assigns a number proportional to the size of the signal at each instant. In this way, an analog signal is ultimately converted into a sequence of numbers.

Digital data may then be converted back into analog signals with the use of a digital to analog converter (DAC). A DAC takes a number and converts it into a voltage proportional to the number—small numbers produce small voltages, and large numbers produce large voltages. By updating the number in the DAC every few microseconds with the sequence of numbers produced by the ADC, the original analog signal may be reproduced.

cases, the information being transmitted is an analog signal. The

og voice signal from the microphone is used to modulate the frequency of

TSG4100A Series RF Signal Generators User Manual 37

Digital communications

Vector modulation

All TSG4100A Series generators include standard support for I/Q modulation on RF carriers between 400 MHz and 6.075 GHz. In addition, they feature a dual, arbitrary waveform g enerator operating at 125 MHz for baseband signal generation. The generator has built-in support for the most common vector modulation QAM (4 to 256), 8VSB, and 16VSB. It also includes built-in support for all the standard pulse shaping ﬁlters used in digital communications: raised cosine, root-raised cosine, Gaussian, rectangular, triangular, and more. Lastly, it provides direct support for the controlled injection of Additive White Gaussian Noise (AWGN) into the signal path.

The baseband generator supports the playback of pure digital data. It automatically maps digital symbols into a selected IQ constellation at symbol rates of up to 6MHzand ﬁnal waveform updated in real time at 125 MHz. This baseband signal is then modulatedontoanRFcarrierusingstandard IQ modulation techniques.

This architecture provides a simpliﬁed and productive user experience. PRBS data and simple patterns can be played back directly from the front panel. Trade-offs in ﬁlter bandwidth versus power efﬁciency can be explored from the front panel in real time without the need to download complex new waveforms each time. Likewise, the degradation o f a signal by AWGN can be easily manipulated from

ront panel.

the f

schemes: ASK, QPSK, DQPSK, π/4 DQPSK, 8PSK, FSK, CPM.

passes the result through the selected pulse shaping ﬁlter to generate a

Constellations

Your instrument comes with a number of modulation presets for demonstrating

ious modulation capabilities. Sample modulation waveforms and setups are

var included for communications standards such as NADC, PDC, DECT, APCO Project 25, TETRA, GSM, GSM-EDGE, and W-CDMA.

Finally, the rear panel BNC I-Q modulation inputs and outputs enable arbitrary vector modulation through an external source. The external signal path supports 300 MHz of RF bandwidth with a full scale range of ±0.5 V a nd a 50 Ω input impedance.

One important characteristic of digital signals that distinguishes them from analog signals is that they are quantized and bounded. Normally, digital signals are represented as binary sequences of ﬁnite length. A 1-bit (binary) signal has only two states: 0 or 1. A 2-bit signal is represented with two binary digits in sequence and, thus, has 4 states: 00, 01, 10, and 11. A 3-bit signal will have 8 states. An N-bit signal will have 2

states.

38 TSG4100A Series RF Signal Generators User Manual

Digital communications

Gray co

The transmissi information is encoded in a modulation of the amplitude, frequency, or phase of an RF carrier. However, unlike analog communications, only a ﬁnite number of modulated states are allowed. In binary phase shift key (BPSK) modulation, for example, only two phases are allowed. These are usually chosen to be 0 and 180°. One phase represents a 0 and the other represents a 1. Similarly, in quadrature phase shift chosen to be ±45° and ±135°. Each of the four phases is associated with a unique 2-bit binary sequence: 00, 01, 10 or 11.

The set of allowed phases and their mapping to binary sequences constitutes a digital constellation. The constellation may be succinctly represented in a polar diagram of the I/Q plane identifying the allowed states and their mapping.

A vector signal generator can modulate both the amplitude and the phase of an RF carrier, simultaneously. This enables many more options for deﬁning symbol constellations. In quadrature amplitude modulation (QAM), both the amplitude and phase of the allowed states are deﬁned, usually in a rectangular array.

It is important to recognize that the mapping from symbol to constellation point

is completely arbitrary and at the discretion of the communications protocol designer. Usually, some form of Gray coding is utilized in order to minimize the

ible transmission of multi-bit errors. A Gray code mapping has the property

poss that all nearest neighbor constellation points differ in code by at most 1 bit. The example QPSK constellation in Figure 39 satisﬁes this property, but the example QAM 16 constellation in Figure 40 does not. For the QPSK constellation, the nearest neighbors to 00 are 01 and 10. Both of these transitions involve a single bit transition. This property holds true for all the QPSK constellation points.

contrast, point 0001 in the QAM 16 constellation, of Figure 40 includes the

In nearest neighbor point 0010, which involves two simultaneous bit transitions, violating the basic property of Gray c odes.

on of digital data is straight forward. Like analog communication,

key (QPSK) modulation, only 4 phases are allowed. These are usually

Gray code helps to reduce the accidental transmission of multi-bit errors, thereby increasing the effectiveness of any error correction measures included in the communications protocol. Unfortunately, Gray code mappings are not unique. Nor is there any agreement on a standard mapping. Each protocol includes its own unique Gray code mapping. As such the SG390 series generators use the simple mapping scheme s hown in the examples and leave it to the user to encode their data to match the mapping scheme of the protocol they are using.

TSG4100A Series RF Signal Generators User Manual 39

Digital communications

Susceptibility to noise

Intersymbol interference

As mentioned pr states. A BPSK constellation, for instance, has only two allowed states: 0° and 180°. This property greatly enhances the robustness of digital communications in the face of noise. Since a BPSK constellation contains only two allowed states, any transmission which includes a deviation from these two states must be the result of noise. If the noise deviations are small, the receiver can recover the actual transmissi point was the intended transmission. This is in stark contrast to analog communications, where any noise in the bandwidth of the channel will degrade the ﬁdelity of the transmitted signal. Digital transmissions suffer no degradation until the noise becomes so great that the nearest neighbor principle is not always true. Even then, errors can often be corrected by the receiver if the protocol makes use of Gra

Pulse shaping ﬁlters ﬁx the frequency domain problems by ﬁltering out the high frequency components that would interfere with neighboring users. Unfortunately, they introduce a new problem in the time domain, intersymbol interference (ISI). The problem can be understood by observing the impulse response of the pulse shaping ﬁlter as a function of time. Generally speaking, pulse shaping ﬁlters with low bandwidth have long response times. Conversely, ﬁlters with relatively high bandwidth have short response times. Low bandwidth is good, but long response times cre ate a problem.

eviously, digital constellations have a ﬁnite number of allowed

on with 100% accuracy by assuming the nearest allowed constellation

ycodeandsufﬁcient redundancy has been built into the transmission.

A digital communications receiver must make a decision about which symbol was transmitted after every symbol period. The decision is usually made when the impulse response for that symbol is at its peak. Intersymbol interference occurs when the response of adjacent symbols interferes with the response of the current symbol at the moment the decision is made.

The following ﬁgure shows the impulse responses of three symbols superimposed on each other. At time t = 0, the receiver must decide which symbol was transmitted. Notice that the responses from both the previous symbol and succeeding symbols are nonzero. The full response at time t = 0 is the superposition of all three responses. The residual responses of the adjacent symbols will add or subtract to the symbol under question, thus, interfering with the decision about what was transmitted.

40 TSG4100A Series RF Signal Generators User Manual

Digital communications

Pulse shaping ﬁlt ers

Up to now, we hav number of allowed states, but we have not discussed how the signal transitions from one allowed state to the next. The simplest method would be to jump as quickly as possible from state to state. Although simple, this method turns out to be undesirable in most cases, because it creates spurious energy at large offsets from carrier. This is important because the RF spectrum is a limited resource that has to b people are trying to transmit data simultaneously. Without cooperation, all of these transmissions would interfere with one another and nobody would be able to communicate.

One of the most common means of sharing the RF spectrum is with frequency division multiple access (FDMA). In this scheme the RF spectrum is divided into many small frequency bands. Each user is assigned one band and may transmit at will as long as his transmission is conﬁned to his assigned b and. If this basic rule is obeyed, everyone can communicate simultaneously without interference. Unfortunately, transmissions that jump from symbol to symbol as quickly as possible invariably violate this rule. Thus, almost all communication protocols stipulate pulse shaping ﬁlters to overcome this problem.

Pulse shaping ﬁlters limit the bandwidth of a digital transmission by converting the sharp transitions into gradual transitions with much lower bandwidth. They are essentially low pass ﬁlters, which ﬁlter out all the high frequency components of the sharp transitions.

e emphasized the fact that digital constellations have a ﬁnite

esharedbymanypeoplecooperativelyatthesametime.Lotsof

Three different pulse shaping ﬁ lters are commonly used in digital communications: the raised cosine ﬁlter, the root-raised cosine ﬁlter, and the Gaussian ﬁlter. Each addresses the problem of ISI differently.

Raised cosine. The ﬁrst strategy for dealing with ISI is to remove it with a cleverly designed ﬁlter that has zero intersymbol interference. The raised cosine ﬁlter meets this criterion. It is deﬁned by the following frequency response:

where f is the frequency, T is the symbol period and α is a dimensionless parameter controlling the excess bandwidth of the ﬁlter. When α =0,theﬁlter approximates a b rick wall. When α =1.0theﬁlter has 100 % excess bandwidth over the brick wall ﬁlter, i.e. it is twice as wide.

The impulse response of the raised cosine ﬁlter is

given by

TSG4100A Series RF Signal Generators User Manual 41

Digital communications

where sinc(x) = the raised cosine ﬁlter for α =1.0,α =0.5,andα = 0.3. Notice that as α is reduced the impulse response lasts longer and extends over many symbols. Normally, this behavior would cause intersymbol interference. However, the sinc(x) function in the impulse response of the raised cosine ﬁlter has the important property that it goes to zero at all integer values of x except 0 where it is 1.0. This is what leads to zer adjacent symbols should make this clear.

sin(πx)/(πx). The following ﬁgure shows the impulse response of

o intersymbol interference. A plot showing the impulse response of

The previous graphs show the impulse responses of adjacent symbols for a raised cosine ﬁlter with α = 0 .3. Notice that the impulse responses of all adjacent symbols goes to zero at t = 0 when the receiver makes its decision. Thus, even though the full response lasts for about 8 symbol periods, the response of neighboring symbols is always zero at the moment a decision is being made.

Root-raised cosine. This ﬁlter is perhaps the most common pulse shaping ﬁlter. Its frequency response is given by the square root of the raised cosine ﬁlter:

The impulse response of the root-raised cosine ﬁlter is given by

42 TSG4100A Series RF Signal Generators User Manual

Digital communications

where all par

The previous graph shows the impulse response of the root-raised cosine ﬁlter for α =1.0,α =0.5,andα = 0.3. The response is qualitatively similar to the raised cosine response, but it does not generally have zero ISI. However, cascading two such ﬁlters together creates a raised cosine ﬁlter which does have zero ISI. Thus, many communication protocols stipulate that both the transmitter and the receiver use root-raised cosine ﬁlters. The transmitter’s ﬁlter limits the bandwidth of the transmitted waveform to prevent adjacent channel interference. The receiver’s ﬁlter improves signal recovery by further ﬁltering out noise in the communication’s channel. Finally, the two ﬁlters in combination p roduce a raised cosine response which does have zero ISI.

ameters have the same deﬁnitions as in the raised cosine ﬁlter.

Gaussian. The last strategy for dealing with intersymbol interference is to accept it, but limit its reach to just the nearest neighboring symbols in time. The Gaussian ﬁlter is a common choice here because it has no ringing, a short duration, and relatively compact bandwidth. It is created by convolving a rectangular ﬁlter with a Gaussian:

where T is the symbol period, g(t) is a Gaussian, and rect(t/T) is deﬁned by

The Gaussian g(t) is given by

TSG4100A Series RF Signal Generators User Manual 43

Digital communications

with

BT is the 3 dB bandwidth-symbol time product, a dimensionless factor similar to α in raised cosine ﬁlters that controls the bandwidth of the ﬁlter. The following graph shows the impulse response of the Gaussian ﬁlter for BT = 1.0, BT = 0.5, and BT = 0.3. Intersymbol interference is limited to the nearest neighbor symbols which simpliﬁes receiver design.

scussed previously, digital communication protocols often stipulate both a

Error vector magnitude

44 TSG4100A Series RF Signal Generators User Manual

As di symbol constellation and a pulse shaping ﬁlter. Given a constellation, a pulse shaping ﬁlter, and a set of symbols to transmit, you can map out the expected trajectory of the modulated RF carrier as a function of time as each symbol is transmitted. The trajectory can be characterized by a vector quantity which identiﬁes the amplitude and phase of the RF at a given moment in time. You can

en evaluate the quality of a d igital transmission by comparing the received

th trajectory with the expected reference trajectory. The deviation b etween the two is a vector quantity indicating the error of the received signal at a given moment in time. The magnitude of the error is called the error vector magnitude (EVM).

The following ﬁgure diagrams the relationship on the IQ plane. The measured signal is compared to the reference signal and the difference is given by the error vector. The length of the error vector is the error vector magnitude. The error vector magnitude is often reported as a percentage relative to some standard signal, such as the magnitude of a constellation point.

Digital communications

Figure 1: Error vector magnitude

Error vectors are helpful in characterizing the quality of a transmitted signal. They are a natural measure of the noise in a communications channel, but they can also h elp identify defects of a transmitter, such as ampliﬁer compression or an IQ gain imbalance.

Modulat

ASK (am

ion techniques

plitude shift

keying)

There are a number of modulation techniques used by the generator. They are described below.

ASK is a modulation technique in which digital symbols are encoded in the amplitude of the RF. The phase is ignored. ASK is implemented by only modulating the I channel and forcing the Q channel to zero.

Digital c onstellations. The generators provide four default constellations for use with 1-bit, 2-bit, 3-bit, and 4-bit digital modulation. Custom user constellations can also be downloaded, if desired. The default constellations are summarized in the following image. Waveforms for digital modulations include PRBS data, simple patterns, and user data. Frequency deviations of up to 6 MHz are supported.

econﬁgured deviation applies to symbol 0 in each of the constellations.

TSG4100A Series RF Signal Generators User Manual 45

Digital communications

Figure 2: ASK constellations

FSK (freq

uency shift

keying)

FSK is a modulation technique in which digital symbols are encoded in the frequency of the RF. The amplitude of the carrier is held constant. In t he SG390 series generators FSK is implemented using an internal rate generator followed by cosine/

Simple waveforms. As with analog modulation, the RF m ay be vector modulated in frequency with simple waveforms: sine, ramp, triangle, square, noise, and user waveforms.

Digit

with 1-bit, 2-bit, 3-bit, and 4-bit digital modulation. Custom user constellations can also be downloaded, if desired. The default constellations are summarized in the following image. Waveforms for digital modulations include PRBS data, simple patterns, and user data. Frequency deviations of up to 6 MHz are supported. The conﬁgured deviation applies to symbol 0 in each of the constellations.

sine tables to convert a phase into its respective I and Q components.

al constellations. The generators provide four default constellations for use

Figure 3: FSK constellations

46 TSG4100A Series RF Signal Generators User Manual

Digital communications

PSK (phase shift keying)

PSK is a modulat

ion technique in which digital symbols are encoded in the phase of the RF. The amplitude of each constellation point is the same. In spite of this, the modulation is not constant amplitude as it is for FSK. The pulse shaping ﬁlters create amplitude variations as the modulation traverses from symbol to symbol, creating waveforms very similar to QAM. In fact, vector PSK modulation may be considered a subset of QAM modulation.

Simple waveforms. Vector phase modulation with some simple waveforms is supported. The supported waveforms are summarized in the following table.

Table 8: Vector phase modulation waveforms

Waveform Description

Sin cos Channel I is a sine wave and channel Q is a cosine wave. This combination moves the R

down in frequency by the modulation rate.

Cos sin Channel I is a cosine wave and channel Q is a sine wave. This combination moves the RF carrier

up in frequency by the modulation rate.

Phase noise Degrades the RF output with pure phase noise. The amplitude is held constant. The bandwidth and

RMS deviation of the noise may be conﬁgured.

IQ noise Degrades the RF output with IQ noise. The bandwidth of the noise may be conﬁgured. The noise

power is equal to the RF carrier power when modulation is off.

F carrier

Digital constellations. The generators provide four basic constellations and four specialized constellations. Custom user constellations desired. The constellations are summarized in the following table. Waveforms for digital modulations include PRBS data, simple patterns, and user data. Frequency deviations of up to 6 MHz are supported.

NOTE. More information about basic and specialized constellations is available

here. (See page 48, Basic PSK constellations.) (See page 52, Specialized PSK constellations.)

Table 9: PSK constellations

Display Standard acronym

PM binary

PM quadrature

PM Quad offset OQPSK

PM diff quad DQPSK

PM π4 diff quad π/4 DQPSK

PM 3π83bit

PM 3 bit

PM 4 bit

BPSK

QPSK

3π/8 8 PSK

8PSK

16 PSK

Bits / symbol Comments

Normal binary shift keying

Normal quadrature shift keying

Offset quadrature shift keying

Differential quadrature shift keying

DQPSK with π/4 rotation

8PSKwith3π/8 rotation

Normal 8 PSK

Normal 16 PSK

can also be downloaded, if

TSG4100A Series RF Signal Generators User Manual 47

Digital communications

Basic PSK const

the following image. Note that the QPSK constellation follows a different mapping pattern than the 8 PSK and 16 PSK conste llations. Since this constellation is identical to the QAM constellation of the same size, i t uses the same mapping.

Figure 4: Four basic PSK constellations

ellations. The four basic PSK constellations are summarized in

CPM (continuous phase

modulation)

CPM is a form of FSK modulation. Like FSK modulation, the RF carrier maintains a constant amplitude at all times. Only the phase is modulated. However, the general deﬁnition of FSK modulation allows for the phase to hop when the frequency is shifted. Such an allowance enables the creation of simple FSK modulators consisting of two independent oscillators and a multiplexer, driven by the data, switching between the two frequencies. When the multiplexer switches between the oscillators, both the frequency and the phase of the output change.

Continuous phase modulation, in contrast, guarantees that the phase will not suffer a discontinuous jump when switching to a new frequency. As the name implies, the phase will be continuous. The implementation of FSK in the SG390 series generators happens to be continuous phase, so in this respect, the two modulations are almost the same. Internally, however, the implementations have one distinct difference: the FSK implementation tracks frequency while the CPM implementation tracks phase. The FSK implementation allows arbitrary frequency deviations, but will, in general, slip phase relative to a ﬁxed carrier. The CPM implementation, on the other hand, requires a rational modulation index, but will never slip phase. Aside from this, the two modulations are identical.

The following equation d escribes the correspondence between an FSK peak

frequency deviation, Fdev, and a CPM modulation index, h:

48 TSG4100A Series RF Signal Generators User Manual

Digital communications

whereTisthesy

Phase trellis diagram. As mentioned previously, CPM modulation is a form of continuous phase FSK. However, it can also be viewed as a special form of offset phase shift keying, OPSK, with sinusoidal symbol weighting. Ultimately, this means that CPM transmissions may be decoded by demodulating the frequency or, alterna symbol transition. Thus, one can map out a trellis diagram o f allowed transitions and phases over time. (See Figure 5.)

tively, the phase. For binary CPM the phase will traverse hπ for e very

mbol period and N denotes the number of bits per symbol.

QAM (quadrature

amplitude modulation)

Figure 5: Phase trellis diagram for binary CPM with a rectangular ﬁlter

Note that if h is a simple rational fraction, the allowed phases will map onto

te number of allowed phases. For h = 1/2, for instance, there are only 4

a ﬁni allowed phases: 0, π/2, π,and3π/2. Only 2 of the 4 phases are allowed at each transition, however.

quadrature amplitude modulation (QAM), both the amplitude and phase of the

In constellation points are varied, usually in a rectangular array. In all other respects, it is identical to phase shift keying.

QAM constellations. The generators provide default constellations for QAM 4, QAM 16, QAM 3 2, QAM 64, and QAM 256. The constellations are all arranged as rectangular arrays with a simple right to left and top to bottom naming pattern. The front panel displayed power corresponds to the constellation points in the corners of the array. For QAM 32, it indicates the power of the “missing” point in each corner. (See Figure 6.)

TSG4100A Series RF Signal Generators User Manual 49

Digital communications

MSK and GMSK

Figure 6: Constellations for QAM 4 through QAM 256

Minimum shift keying (MSK) and Gaussian minimum shift keying (GMSK) are perhaps the two most well known examples of CPM modulation. MSK is binary CPM with a modulation index, h = 1/2, and a rectangular ﬁlter. It derives its name from the fact that the two frequencies of the modulation have the minimum frequency separation allowed for orthogonal detection. The frequency separation

ust ¼ of the symbol rate. Thus, it is one of the most bandwidth efﬁcient types

is j of modulation.

K further improves the bandwidth efﬁciency of MSK, by replacing the

GMS rectangular ﬁlter with a Gaussian ﬁlter. GMSK with a b andwidth symbol time product of BT = 0.3 is used in the GSM mobile communications protocol.

Modulation index. Modulation indices for CPM modulation may be speciﬁed to 3 decimal digits, but internally the value is rounded to the nearest rational factor,

/512, where n is an integer. For example, if you want to obtain a modulation

n index of 7/16 = 0.4375, you would enter 0.438. Internally, the instrument will round the result to 224/512 = 7/16.

50 TSG4100A Series RF Signal Generators User Manual

Digital communications

VSB (vestigial sid eband)

Vestigial side the over-the-air transmission of digital television (DTV) in the United States. Amplitude modulation normally creates two sidebands: an upper sideband and a lower sideband. However, the information content in the upper sideband is identical to that of the lower sideband. Thus, one can increase the bandwidth efﬁciency of the modulation by nearly a factor of two, without loss of information by ﬁltering modulation (SSB AM). In practice, however, it is very difﬁcult to completely ﬁlter out the lower sideband. A vestigial portion of the lower sideband is often still present, hence the name vestigial sideband modulation.

Receivers required to demodulate VSB need to lock onto a clean reference frequency. To facilitate this, the ATSC digital television standard stipulates the addition of a pilot tone to the modulation at the carrier frequency. The pilot tone is located at the lower edge of the VSB spectrum. The standard describes 2versio and 16 VSB. Both modulation types are supported by the generator at modulation ratesofupto12MHz. Thetransmissionrate required by the DTV standard is 4.5 × 684 / 286

VSB constellations. The generators provide two constellations for use with 8 VSB

6 VSB modulation. Unlike the other modulation modes, these constellations

and 1 are ﬁxed and cannot be changed. (See Figure 7.)

band modulation (VSB) is a form of amplitude modulation used in

out the lower sideband. This is referred to as single sideband amplitude

ns of the modulation to be used for over-the-air transmissions: 8 VSB,

10.762 MHz.

Figure 7: VSB symbol constellations

Notice that the constellations are not symmetric about the origin. They have been shifted to the right. This bias in the constellation is what creates the pilot tone required by the standard.

AWGN (additive white

Gaussian noise)

TSG4100A Series RF Signal Generators User Manual 51

All digital modulations may be optionally degraded by additive white Gaussian noise (AWGN). The noise is inserted just before the pulse shaping ﬁlters. The noise may range in power from –10 dB to –70 dB relative to the maximum power of a constellation.

Digital communications

External IQ modulation

The instrument above 100 MHz. Rear panel BNC inputs are available as I and Q signal inputs. The inputs are terminated into 50 Ω with full-scale amplitude of 0.5 V. Note that an external vector modulation option is available for ASK, PSK, and QAM modulation modes. The options are identical in all modes and are available merely as a convenience to the user.

Specialized PSK constellations

The generators provide built-in support for four specialized PSK constellations

See Table 9.): OQPSK, DQPSK, π/4 DQPSK, and 3π/8 8 PSK. All of

edifﬁculties in receiving and decoding the basic PSK constellations

liﬁed because the receiver can use the phase of the last symbol as a reference

Differential encoding of

symbols

listed in ( these constellations are variations of the basic PSK constellations intended to address speciﬁc problems in receiver design.

One of th is that the d emodulation requires a coherent detector. The receiver must lock onto and track phase of the RF carrier for the entire transmission in order to successfully decode the transmitted message. Differential encoding of digital symbols enables the use of noncoherent receivers which are simpler and more cost effective to produce.

In differential encoding the information is encoded in the difference in phase from one symbol to the next, rather than in the phase itself. Receiver design is simp for decoding the next symbol. It does not need to lock onto a stable reference over the entire transmission. Rather, it only needs a reference that is stable from one symbol to the next, which a much easier goal to meet. In fact, for DQPSK, the reference may simply be a delayed version of the signal itself.

can be modulated through an external source with bandwidths

The DQPSK constellation looks identical to the QPSK constellation but the interpretation is different. Data is differentially encoded, and so what matters is how the phase changes from one symbol to the next, not the current phase. (See

igure 8.)

Figure 8: Decoding DQPSK transmissions

52 TSG4100A Series RF Signal Generators User Manual

Digital communications

Offset or staggered

modulation

This type of mod design. RF ampliﬁers can be made to operate more efﬁciently if the signals they are amplifying are nearly constant in amplitude. This is especially important for satellites deployed in space. The difﬁculty is that the ampliﬁers have a nonlinear response in this regime. The nonlinearities are often not problematic as long as the amplitude variations are contained within a small band. Unfortunately, normal QPSK modula constellation points are deﬁned with constant amplitude, the RF amplitude varies as it transitions from one point to the next. For transitions of 180°, the signal power will momentarily go all the way down to zero. Nonlinear ampliﬁers forced to make such a transition will create out-of-band interference, thus, defeating the whole purpose of the pulse shaping ﬁlters.

Offset modulation addresses this problem by modifying the modulation to prevent a transition through the origin. (See Figure 9.)

ulation addresses transmitter problems in the communication

tion does not meet this criterion. Remember that even though the

otating constellations

Figure 9: Offset modulation prevents transitions through the origin

In normal QPSK modulation, I and Q data are shifted into the pulse shaping ﬁlters simultaneously. With offset or staggered modulation, the shifting of data for the

channels is offset by half a symbol period. First I is shifted in. One half a

two symbol period later, Q is shifted in. One half a symbol period later, the next I is shifted in, and so on. On the IQ plane, I transitions are strictly horizontal, and Q transitions are strictly vertical. However, since both transitions cannot happen simultaneously, the trajectory must follow the outside edges between constellation points. It can never go through the origin, thus, solving the problem.

Offset modulation is not the only method of preventing transitions through the origin. The second commonly employed technique is to rotate the constellation after each symbol. This strategy is exempliﬁed by the π/4 DQPSK and the 3π/8 8 PSK constellations. (See Figure 10.)

TSG4100A Series RF Signal Generators User Manual 53

Digital communications

Figure 10: π/4 DQPSK uses differential encoding and a rotating constellation.

Like DQPSK, π/4 DQPSK employs differential encoding, which means information is encoded in the change in phase, rather than the phase itself. However, symbol transmission. See Figure 56. Unprimed constellation points may only transition to primed constellation points and vice versa. The allowed transitions are indicated in the ﬁgure. Notice that none o f the transitions pass through the origin, thus, solving the problem.

The 3π/8 8 PSK constellation is similar in design to the π/4 DQPSK. In this case, data is not differentially encoded, but the constellation rotates to prevent transitions through the origin. In this case, the basic constellation is that of 8 PSK, excep transmission. A version of this constellation with a Gray code mapping is used in the GSM EDGE mobile communication protocol. (See Figure 11.)

the constellation for π/4 DQPSK rotates by 45° or π/4 radians after each

t that the constellation rotates by 67.5° or 3π/8 radians after each symbol

Figure 11: 3π/8 8 PSK follows standard 8 PSK, but the constellation rotates by

/8 after each symbol

3π

ue to the rotation of the constellation, unprimed constellation points may only

D transition to primed constellation points and vice versa. The allowed transitions are indicated in the ﬁgure. Notice that none o f the transitions pass through the origin, again solving the problem. The exclusion from the origin is smaller than for the π/4 DQPSK constellation, however. This constellation, therefore, places more stringent demands on the linearity of the transmitter.

54 TSG4100A Series RF Signal Generators User Manual

Digital communications

Modulation fu

nctions

The modulation functions available for the vector function subtype are similar to those offered for analog modulation: sine, ramp, triangle, square, noise, user, and external. Fo

r the digital modulation subtypes, the available waveforms include:

PRBS data, pattern data, and user data.

PRBS data

This instrument can generate pseudo random binary sequences (PRBS) for use with digit

al modulation subtypes. The length of the PRBS waveform can be adjusted from 5 to 32. The default PRBS length is 9. The PRBS patterns are generated with linear feedback shift registers. The following table shows the generating polynomials for each PRBS pattern. The output of the PRBS generator is inverted so that the all-ones state is excluded, rather than the all-zeros state. All PRBS waveforms start in the all-zeros state.

Table 1

Length Polyno

10 x10+

11 x11+x9+1

12 x12+x11+x8+x6+1

13 x

14 x14+x13+x8+x2+1

15 x15+x14+1

16 x

17 x17+x14+1

18 x18+x11+1

20 x20+x17+1

21 x21+x19+1

22 x22+x21+1

23 x23+x18+1

24 x24+x23+x18+x14+1

25 x25+x22+1

26 x24+x25+x16+x5+1

27 x27+x26+x16+x2+1

28 x28+x25+1

0: PRBS generating polynomials

mial

5+x3

6+x5

7+x6

8+x7+x5+x3

9+x5

13+x12+x8+x2

16+x15+x9+x6

19+x18+x10+x2

TSG4100A Series RF Signal Generators User Manual 55

Digital communications

Table 10: PRBS generating polynomials (cont.)

Length Polynomial

29 x29+x27+1

30 x30+x29+x16+x4+1

31 x31+x28+1

32 x32+x31+x18+x10+1

Pattern data

User da

Modulation rate

Modulation deviation

cale factor)

Digital modulation subtypes can also be modulated with 16-bit patterns. The current pattern is shown as hexadecimal digits. Once selected, the pattern may be edited from the front panel by modifying each hexadecimal digit. The default pattern is the binary sequence 01010101 01010101, which corresponds to the hexadecimal value 0x5555.

User data can be downloaded into on-board SRAM and subsequently saved into FLASH. If user waveforms are available for the selected modulation subtype, they can be selected as a modulation function. You can read more about user

orms. (See page 30, Arbitrary waveform user presets.) and (See p age 57,

wavef User waveforms, constellations, and ﬁlters.)

The modulation rate is associated with the current modulation type. For digital

ulation subtypes, this is the symbol rate; otherwise, it is the frequency or

mod bandwidth of the selected waveform.

For FSK or CPM modulations, the modulation deviation identiﬁes either the peak

eviation or the modulation index of the modulation as indicated. For all other

d types of vector modulation, the power of the modulated waveform is deﬁned by the constellation, the ﬁltering, and the carrier power. However, in order to prevent clipping when waveforms are passed through the pulse shaping ﬁlters, the constellations are reduced by a factor of 7/16. The resulting scale is deﬁned to have a scale factor of 1.0. Output power calibration assumes a scale factor of 1.0. Normally, this scale factor need not be changed, because the carrier power is set with the Amplitude button. However, you can alter this scale factor, if desired. Larger scale factors will use more of the available digital phase space and reduce the quantization noise of the ﬁnal waveform. This might also be desirable if the amplitude is already at m ax power and you still need a bit more power. The risk is that the pulse shaping ﬁlters will occasionally clip the waveform to the rail during large excursions.

56 TSG4100A Series RF Signal Generators User Manual

User waveforms, constellations, and ﬁlters

User waveform

s, constellations, and ﬁlters

This generat digital modulation formats, constellations, and ﬁlters. However, you may choose to download custom waveforms, constellations, and ﬁlters over the remote interface if the built-in support does not match your needs.

NOTE. See the TSG4100A Series RF Signal Generator Programmer Manual for

detailed information about remote programming commands.

Downloading binary data

User waveforms, constellations, and ﬁlters can contain a considerable amount of data. In order to improve the efﬁciency of transfer, the data is sent in binary format. This can be done using remote commands that accept binary data follow the syntax for an IEEE 488.2 deﬁnite length <ARBITRARY BLOCK PROGRAM DATA>. You can also use the TGS File Assistant utility software to download suppor LAN connection. (See page 58, Using the ﬁle Assistant utility software.)

The <A following format:

or provides a broad array of built-in support for the most common

ted ﬁle types to the generator when it is connected to the Ethernet through a

RBITRARY BLOCK PROGRAM DATA> message element has the

data> =#[ASCII digit 1 to 9][ASCII digit 0 to 9]+[Binary data]

<arb

The message element has 4 parts to it:

1. The ASCII character #.

2. An ASCII digit from 1 to 9. This digit identiﬁes the number, M, of ASCII

digits that follow.

3. M bytes containing ASCII digits from ‘0’ to ‘9’ that identify the number, N,

of binary bytes that follow.

4. N bytes of binary data.

The following example may help clarify. The following block transmits the 26 ASCII bytes from A to Z:

#3026ABCDEFGHIJKLMNOPQRSTUVWXYZ

The ﬁrst two characters indicate that an arbitrary block of data follows and that the length of the block is given by the following 3 digits, ‘026’. These digits indicate that the binary message is 26 bytes long. The actual data follows. For clarity, only printable characters were used in this example, but arbitrary 8-bit binary data may be transmitted as part of an <arb data> block.

TSG4100A Series RF Signal Generators User Manual 57

User waveforms, constellations, and ﬁlters

Big-endian byte order

SRAM versus ﬂash storage

In many cases, 1 The native encoding for numbers in computers follows one of two common formats: little-endian a nd big-endian. The generators expect data in a big-endian format. Most Intel based computers natively store numbers in a little-endian format. For these machines, all binary numbers will have to be converted into a big-endian format before being transmitted.

As an example, the decimal number 43,891 is represented by the hexadecimal value 0xABCD. Storage of this number within the memory of a computer, however, d number is stored as the bytes AB CD. In the little-endian format, however, the number is stored as the bytes CD AB (the bytes are swapped). Numbers stored in this format will need to be swapped back into big-endian format before being transmitted over the remote interface.

The generators include 2 MB of SRAM and ﬂash for storage of arbitrary waveforms, constellations, and ﬁlters. SRAM is volatile memory that is lost when power is removed from the instrument. Flash is nonvolatile memory that is retained even when power is cycled. User data is always downloaded into SRAM ﬁ desired with one of the commands SAVW, SAVC, or SAVF. Waveforms may be played directly out of SRAM or ﬂash.

rst. Once downloaded, you can optionally copy the data into ﬂash if

6-bit or 32-bit numbers must be encoded in a binary transmission.

epends on the native storage format. In the big-endian format the

Using the ﬁle Assistant utility software

The TSG File Assistant is a utility software application that runs on Windows 7 and that allows you to convert custom user data ﬁles (waveforms, constellations, and ﬁlters) from *.txt or *.csv ﬁles to ﬁles types supported by the generator (*.tsw, *.tsc, or *.tsf). This utility also allows you to download supported ﬁle types to the

nerator when it is connected to the Ethernet through a LAN connection.

NOTE. Raw Socket Interface is not currently supported in the March 31, 2015

software version.

Download TSG File

Assistant

The TSG File Assistant utility software is available for download at www.tek.com/downloads. To download the software, do the following:

1. Go to www.tektronix.com/downloads.

2. Select Software.

58 TSG4100A Series RF Signal Generators User Manual

User waveforms, constellations, and ﬁlters

3. Enter TSG File Assistant in the search ﬁeld.

4. Whe

n the search results appear, select TSG4k File Assistant and follow the

instructions to download and install the software.

TSG4100A Series RF Signal Generators User Manual 59

User waveforms, constellations, and ﬁlters

Load or convert an existing

ﬁle to the instrument

The following p *.tsc) or convert an unsupported ﬁle and send it to the instrument.

1. Launch the TSG

2. Select the desired interface.

3. To check the ID of the instrument you are going to connect to, click the IDN? button. The instrument name will appear in the Message ﬁeld.

4. Do one of the following:

If you selected the GPIB interface, e nter the GPIB address in the GPIB

Address ﬁeld and then click Connect.

rocedure shows you how to load a supported ﬁle (*.tsw, *.tsf, and

File Assistant.

If you selected the VISA interface, select the instrument from the

Resource List drop down menu and then click Connect.

If you do not see the instrument you want in the Resource List, select IP

Address, enter the IP address, and then click Connect.

5. Select Instrument > Send File from the TSG File Assistant menu bar.

60 TSG4100A Series RF Signal Generators User Manual

User waveforms, constellations, and ﬁlters

6. A dialog box wil drop down menu.

This number will determine where the ﬁle will be saved in the generator. For example, if you select 0, then the new ﬁle will be saved to the location in the generator that is associated with that User Number. In the image of the generator display below, the <Empty> ﬁeldnexttothe0woulddisappear.

l appear. In this box, select a number from the User Number

Createanewﬁle

7. Click the Load File and Send button.

8. Select the *.tsw, *.tsf, or *.tsc ﬁle you want to save to the instrument. It will

be saved to the instrument.

The following procedure shows you how to create a new ﬁle (*.tsw, *.tsf, and *.tsc) from raw data or a *.txt ﬁle and send it to the instrument.

1. Launch the TSG File Assistant.

2. Select the desired interface.

TSG4100A Series RF Signal Generators User Manual 61

User waveforms, constellations, and ﬁlters

3. To check the ID o button. The instrument name will appear in the Message ﬁeld.

4. Do one of the fo

If you selected the GPIB interface, e nter the GPIB address in the GPIB

Address ﬁel

If you selected the VISA interface, select the instrument from the

Resource Li

If you do not see the instrument you want in the Resource List, select IP

Address,e

5. Select File from the TSG File Assistant menu bar.

f the instrument you are going to connect to, click the IDN?

llowing:

d and then click Connect.

st drop down menu and then click Connect.

nter the IP address, and then click Connect.

6. Do the following depending on the type of data you have:

Filter. To create a new ﬁlter ﬁle, do the following:

a. Select New Filter from the File menu.

b. Click the Load Raw Data From File button to open the *.txt ﬁle

containing the ﬁlter data.

NOTE. The raw data format should be a number and then a comma and then a

number, as shown in the following image. O nce the data is loaded, you can

so add or edit the data in the new ﬁlter window.

62 TSG4100A Series RF Signal Generators User Manual

User waveforms, constellations, and ﬁlters

c. Enter the o

Constellation. To create a new constellation ﬁle, do the following:

a. Select New Constellation from the File menu.

b. Click the

containing the constellation d ata.

NOTE. The raw data format should include number pairs that deﬁne a point.

Points should be listed one per line, as shown in the image below. Once the data is loaded, you can also add or edit the data in the new constellation window.

ffset value in the Offset ﬁeld.

Load Raw Data From File button to open the *.txt ﬁle

NOTE. There is a 520192 row maximum. More than 520192 rows will cause

an error to occur.

TSG4100A Series RF Signal Generators User Manual 63

User waveforms, constellations, and ﬁlters

Analog wavefor

a. Select New Analog Waveform from the File menu.

b. Click the Load Raw Data From File button to open the *.txt ﬁle

containing the waveform data.

NOTE. The ra

number, as shown in the following image. O nce the data is loaded, you can also add or edit the data in the new ﬁlter window.

m. To create a new analog waveform ﬁle, do the following.

w data format should be a number and then a comma and then a

Vector waveform. To create a new vector waveform ﬁle, do the following.

a. Select New Vector Waveform from the File menu.

b. Selec

c. Click the Load Raw Data From File button to open the *.txt ﬁle

d. If you selected Symbol, then enter the Bits/Symbol v alue after the data

NOTE. The raw data format should be a number and then a comma and then a

number, as shown in the following image. O nce the data is loaded, you can also add or edit the data in the new waveform window.

t Symbol or IQ Data.

aining the waveform data.

cont

loaded.

has

64 TSG4100A Series RF Signal Generators User Manual

User waveforms, constellations, and ﬁlters

e. If you selec

has loaded.

NOTE. The raw data format should include number pairs that deﬁne a point.

Points should be listed one per line, as shown in the following image. Once the data is loaded, you can also add or edit the data in the new waveform window.

7. To send or save the new ﬁle, do one of the following:

To send the new ﬁle to the generator, select Instrument > Send To and select the desired User number.

ted IQ Data, you do not need to enter anything after the data

This number will determine where the ﬁle will be saved in the generator. For example, if you select 0, then the new ﬁle will be saved to the location

the generator that is associated with that User Number. In the image

in of the generator display below, the <Empty> ﬁeldnexttothe0would disappear.

TSG4100A Series RF Signal Generators User Manual 65

User waveforms, constellations, and ﬁlters

To s ave t he ﬁle, select File > Save (or Save As) and save the ﬁle to

location 1 through 9 in the generator.

Arbitrary

user waveforms

NOTE. See the TSG4100A Series RF Signal Generator Programmer Manual for

detailed information about remote programming commands. It is available for download at www.tektronix.com/manuals.

NOTE. You can use the TGS F ile Assistant utility software to download supported

ﬁle typ the Ethernet through a LAN connection. (See page 58, Using the ﬁle Assistant utility software.)

The generators support two different formats for arbitrary user waveforms: as a stream of digital bits, or as a series of 16-bit I/Q values. The former is much more efﬁcient than the latter and is the preferred choice, if possible. In both cases, data is transmitted in 16-bit chunks with the following command:

Parameter i is a 32-bit value indicating the conﬁguration format of the user data. The conﬁguration bits are described in the following table.

es of arbitrary user waveforms to the generator when it is connected to

WRTW i, j, <arb data>

Table 11: Arbitrary waveform conﬁguration word

Bit 31-9 8 7-6 5-0

Meaning reserved analog reserved

Bits/symbol may be one of the values 1 to 9, 16, or 32. Use 32 for vector waveforms consisting of 16-bit, IQ value pairs that bypasses the symbol reader and constellation mapping. Use 16 for analog and vector waveforms that bypass the symbol reader and constellation mapping. Bit 8 should be set if the waveform is intended for analog modulation. All other bits should be cleared.

Parameter j is a 32-bit value indicating the total number of bits in the waveform.

66 TSG4100A Series RF Signal Generators User Manual

bits/symbol

User waveforms, constellations, and ﬁlters

User constellations

<arb data> cont even integer number of bytes. Waveforms have a minimum size of 16 bits and are played back from MSB to LSB. If a waveform does not end on a 16-bit boundary, the least signiﬁcant bits of the last word in the waveform will be ignored. For example:

WRTW 4, 28, #14XXXX

The ﬁrst parameter indicates that the waveform consists o f 4-bit symbols for vector modulation. The second parameter indicates that there are 28 bits in the total waveform. The third parameter indicates that 4 bytes, or 32-bits, of binary data are transmitted. Since the full waveform consists of 28 bits, the 4 least signiﬁca are transmitted because this is the minimum even integer of bytes which fully contains the waveform.

NOTE. You can use the TGS File Assistant utility software to download supported

ﬁle typ Ethernet through a LAN connection. (See page 58, Using the ﬁle Assistant utility software.)

nt bits of the last 16-bits of transmitted data will be ignored. 4 bytes

es of user constellations to the generator when it is connected to the

ains the b inary data representing the data and it must contain an

The generators have the ability to process pure digital data by dynamically mapping digital symbols into IQ constellation points in real time. The symbol mapping is quite versatile and can easily accommodate differential e ncoding and rotating coordinate systems. The mapping is performed with the data from two tables stored in RAM: a symbol table, and a symbol set table. The basic

chitecture is diagrammed here. (See Figure 12.)

Figure 12: Architecture for mapping digital symbols into IQ constellation points

The constellation RAM is 1kW in size which provides space to deﬁne up to 512, 32-bit, IQ constellation points with each point allocating 16 bits for I and 16 bits for Q. Associated with each symbol is a symbol set. Thus, the constellation RAM is accompanied by 512 bytes of symbol set RAM which deﬁnes the symbol set to associate with the following symbol.

TSG4100A Series RF Signal Generators User Manual 67

User waveforms, constellations, and ﬁlters

The constellat of a (9 – N)-bit s ymbol set and an N-bit symbol. The address is computed from the current symbol and set with the equation:

constellation address = (symbol + set × 2N) mod 512

where N is th reader is reading in 2-bit symbols and that the current symbol is 3 and that the current symbol set is 5. The symbol will be mapped to the constellation point stored at address 3 + 5 × 22 = 23. At startup the ﬁrst symbol set is initialized to zero.

For simple constellations, symbol set RAM is cleared and the symbol maps directly to a constellation point. For a constellation that rotates by π/4 after each symbol, we will have 8 different constellations before the constellation has rotated by exact set RAM with 2N 1s, followed by 2N 2s, followed by 2N 3s, etc until we reach 2N 7s, followed by 2N 0s. For differential encoding, the encoding of the next symbol is determined by the previous symbol. In this case, each symbol gets mapped to a different constellation, and so we have 2N different constellations.

For each user constellation, two parameters must be declared: bits/symbol and whether the I and Q points in the constellation are to be staggered or not. Most constellations do not operate in staggered mode; both I and Q points enter their

ective pulse shaping ﬁlters simultaneously. Staggered mode is required for

resp offset modulation in which the Q values shift into their ﬁlter half a symbol after the I values have shifted.

ion RAM is accessed with a 9-bit address that is the concatenation

e number of bits per symbol. As an example, suppose the symbol

ly 2π. For N-bit symbols, the rotation is accomplished by ﬁlling symbol

Constellation example

User constellations are downloaded into SRAM with the following command: WRTC i, j, <arb data>. Parameter i indicates the number of bits/symbol, N. It will normally range from 1 to 9. A value of 16 or 32 is accepted to enable staggered modulation when constellation mapping is bypassed. Parameter j indicates whether staggered operation is desired. Set j = 1 for staggered operation,

therwise set j = 0. <arb data> should be a deﬁnite arbitrary block with 2560 bytes

o of binary data. The <arb data> block is organized as 512 32-bit IQ pairs followed by 512 bytes of symbol set data. Each 32-bit IQ pair consists of a 16-bit I value followed by a 16-bit Q value in a big-endian format.

NOTE. You can read more about big-endian byte order and downloading binary

data here. (See page 58.)

As an example, we will compute the constellation for QPSK with the symbol mapping deﬁned in the following ﬁgure.

68 TSG4100A Series RF Signal Generators User Manual

User waveforms, constellations, and ﬁlters

The points lie on a circle of constant amplitude. The radius of the circle is 32767. Thus, we can compute the IQ coordinates as shown in the following table.

Table 12: QPSK constellation point computations

Symbol Formula Value Hex values

32767 (cos(π/4), sin(π/4)) (23170, 23170) (5A82, 5A82)

32767 (cos(3π/4), sin(3π/4)) (–23170,23170) (A57E, 5A82)

32767 (cos(7π/4), sin(7π/4)) (23170,–23170) (5A82, A57E)

32767 (cos(5π/4), sin(5π/4)) (–23170,–23170) (A57E, A57E)

User ﬁlters

Note th

at we need only deﬁne 4 constellation points. All others may be set to zero, since they will not occur for 2-bit waveforms. Furthermore, since the constellation does not change from symbol to symbol, we should zero out all symbol set RAM as well.

Combining all this information together we can synthesize the following command to download the constellation:

WRTC 2, 0, #42560<5A 82 5A 82 A5 7E 5A 82 5A 82 A5 7E A5 7E A5 7E…><NL>

The ﬁrst parameter indicates this is a 2-bit constellation. The second parameter indicates that the IQ values are not staggered. The third parameter indicates that we are transmitting 2560 binary bytes. The portion inside the brackets shows the ﬁrst 16 bytes of the transmission. These bytes represent our 4 constellation

oints. The following 2544 bytes are all zero. The brackets are not part of the

p transmission. Finally, all commands must be terminated with a semicolon, a carriage return <CR>, or a new-line <NL>. This command is no exception. Thus, a <NL>, which h as the hexadecimal value 0x0A, follows the 2560 binary bytes.

NOTE. You can use the TGS File Assistant utility software to download supported

ﬁle types of user constellations to the generator when it is connected to the Ethernet through a LAN connection. (See page 58, Using the ﬁle Assistant utility software.)

TSG4100A Series RF Signal Generators User Manual 69

User waveforms, constellations, and ﬁlters

This instrumen You also have the option to download custom ﬁlters. The ﬁlters have 24 symbols of memory and are deﬁned with an oversampling ratio of 128, which means they are composed of 24 × 128 = 3072 coefﬁcients. The large oversampling ratio is a consequence of the fact that the ﬁlters also play an integral part in the re-sampling of waveforms being played back at an arbitrary rate. Large oversampling ratios enable accu structure.

Internall with 16 bits of precision along with a global 16-bit offset. T his helps facilitate the binary transfer without compromising overall precision. Coefﬁcients should be scaled so that the 17-bit value +32768 is equivalent to 1.000.

Most ﬁlters are symmetric and peak at the center, but these are not requirements. However, the event markers and TDMA control engine within the FPGA assume a 12 symbol latency for the ﬁlter. Filters shorter than 24 symbols are easily accommodated by padding the ﬁlter with zeros at the beginning and the end.

t provides built-in support for several commonly used digital ﬁlters.

rate re-sampling with simple, linear interpolation in a Farrow ﬁlter

y, ﬁlter coefﬁcients are stored with 17 bits of precision, b ut transmitted

70 TSG4100A Series RF Signal Generators User Manual

Reference

Phase noise and offset diagrams

Reference

TSG4100A Series RF Signal Generators User Manual 71

Reference

Figure 13: QPSK,3.840Mcps, 1.85 GHz, 0dBm), RMS EVM: 1.7%

72 TSG4100A Series RF Signal Generators User Manual

Reference

Figure 14: Image 2, QPSK,3.840Mcps,1.85GHz,0dBm),RMSEVM:1.7%

TSG4100A Series RF Signal Generators User Manual 73

Reference

Figure 15: Option VM03 W-CDMA, (QPSK,3.840Mcps, 2.1425GHz, 0dBm), RMS EVM: 1.7%

74 TSG4100A Series RF Signal Generators User Manual

Reference

Figure 16: Image 2, Option VM03 W-CDMA, (QPSK,3.840Mcps, 2.1425GHz, 0dBm), RMS EVM: 1.7%

TSG4100A Series RF Signal Generators User Manual 75

Reference

Figure 17: Option VM04 APCO-25, (4FSK-C4FM,4.8KS/s,850MHz, 0dBm), Freq Err: 0.5%

76 TSG4100A Series RF Signal Generators User Manual

Reference

Figure 18: Option VM05 DECT, (2FSK1.152Mbps,1.925GHz, 0dBm), RMS FSK Err: 1.5%

TSG4100A Series RF Signal Generators User Manual 77

Reference

Figure 19: Option VM06 NADC, (π/4 DQPSK,24.3KS/s,875MHz, 0dBm), RMS EVM: 0.3%

78 TSG4100A Series RF Signal Generators User Manual

Reference

Figure 20: Option VM07 PDC, (π/4 DQPSK,21KS/s, 800MHz,0dBm), RMS EVM: 0.6%

TSG4100A Series RF Signal Generators User Manual 79

Reference

Figure 21: Option VM08 TETRA, (π/4 DQPSK,18KS/s, 420MHz, 0dBm), RMS EVM: 0.7%

80 TSG4100A Series RF Signal Generators User Manual

Index

Accessories

documents, 1 optional, 2 power cords, 1 standard, 1

Amplitude, 27

modulation, 33

to change Analog mod in, 14 Analog mod out, 13 Arbitrary user waveforms, 30, 66 Arbitrary waveform

modulation, 32

ary waveforms

Arbitr

user, 66 ASK

digital constellations, 45 ASK (amplitude shift keying), 45 AWGN (additive white Gaussian

nois

,25

e), 51

Backlight, 20 Basic constellations

PSK, 48 Big-endian byte order, 58 Binary data, 57

MP ﬁle

save image of display as, 15 BNC, 15

Cable, 1 Cleaning procedures, 9 Connector

Analog mod in, 14

Analog mod out, 13

symbol clock, 13

Vector mod in I, 13

VectormodinQ, 13

Vector mod out I, 13

Vector mod out Q, 13

Connectors

front panel, 11 rear panel, 13

Constellation ﬁles

accessing,

Constellations, 38

QAM, 49 user, 67 VSB, 51

Controls, 10

interfac

CPM

Phase trellis diagram, 49

CPM (continuous phase

modulation), 48

Custom modulation presets, 30

m modulation setups, 30

Custo

e, 15

Date

setting, 20

Differential encoding of

symbols, 52

Digital communication, 37

gital constellations

ASK, 45 FSK, 46 PSK, 47

Display, 15

save a screen shot of, 15

Documentation, x

Tektronix part numbers, 1

Downloading ﬁles

TSG File Assistant, 58

Error codes, 23 Error log, 36 Error messages, 15 Error vector magnitude, 44 Ethernet, 3, 20 Event outputs, 13 EXT, 15

External IQ modulation, 52

Factory default settings

preset, 24, 28 File Assistant, 58 Filter ﬁle

Filters, 40, 41

Firewall

Firmware

Firmware upgrade, 6, 22 Flash, 58 Frequency, 27

ont panel

FSK, 34

FSK (frequency shift keying), 46 Functional check, 24

accessing, 21

common pulse shaping, 41

Gaussian, 43

pulse shaping, 41

raised c

root-raised cosine, 42

user, 69

internet network security, 4

upgra

modulation, 34

to change, 25

buttons, 10

connectors, 11

controls, 10

digital constellations, 46

osine, 41

de, 22

Gaussian

ﬁlter, 43 General knob

press to select, 26 GMSK (Gaussian minimum shift

keying), 50 GPIB, 5, 14

TSG4100A Series RF Signal Generators User Manual 81

Index

Help, x

Incoming inspection, 8 Index

modulation Inputs, 12, 13 Installation, 1 Instrument

options, 2 Internet, 20 Intersym

,50

bol interference, 40

Key

install option, 22

LAN, 3, 14 LF Out, 27 License

ge, 22

mana Linear

modulation, 30 Linear noise

modulation, 31

Maintenance

leaning procedures, 9

repackaging, 9 Manuals, x Menu

accessing, 15

Menus, 15, 16

About, 22 analog, modulation type, 17 AWGN /IMP, 18 Constellation, 17 Customized ﬁlters, 18 Customized Error code, 23 File, 21 Filter, 18 Firmware upgrade, 22 GPIB, 19 I/O Inter LAN, 20 Main, 16 Mod (modulation), 16 Mod (modulation) Type, 17 navigating, 15 Noise presets, modulation type, 17 RF/LF, 16 RS232, 19 Self Test, 20 Source, 18

tus, 21

Sta System, 20 USB, 23 Utility, 18 vector, modulation type, 17

Mod button, 28

odulation

amplitude, 33 arbitrary user waveforms, 30 available presets, 17 custom user presets, 30 frequency, 34 linear, 30 linear noise, 31 outputs, 33 Phase, 35 presets functional check, 25 pulse, 31 pulse noise, 32 sources, 30 user arbitrary waveform, 32 user presets, 30 vector, 38

source, 18

face, 19

submenu, 18

Modulation dev Modulation index, 50 Modulation presets, 28 Modulation rate, 56 Modulation technique

ASK, 45 AWGN , 51 CPM, 48 External IQ, 52 FSK, 46 GMSK, 50 MSK, 50 PSK, 47 QAM, 49 VSB, 51

MSK (minimum shift keying), 50

iation, 56

Navigation, 25

general knob, 26

rk connections, 3

Netwo Noise (AWGN), 28

Offset

I/Q, 27 LF, 27

Offset or staggered

dulation, 53

mo Optional accessories, 2 Options

GPIB, 19

install key, 22

instrument, 2

Power cords, 1

software, 3 Outputs, 13

Event, 13

LF, 12

modulation, 33

RF, 12

Part numbers, m anuals, 1 Part numbers, media (CD), 1 Pattern data, 56

82 TSG4100A Series RF Signal Generators User Manual

Index

Phase, 27

modulation, 35

Phase trellis diagram

CPM, 49

Power

AC, 13

removing, 7 Power (AWGN), 28 Power cord options, 1 Power off, 7 Power on, 7 PRBS (pseudo random binary

sequence Preset

factory default settings, 24,

Preset button, 24, 28 Presets

custo

custom user setups, 30

modulation, 25, 28 PSK

basic constellations, 48

digital constellations, 47

spe PSK (phase shift keying), 47 Pulse

modulation, 31 Pulse noise

modulation, 32

s) data, 55

muser, 30

cialized constellations, 52

QAM

constellations, 49 QAM (quadrature amplitude

modulation), 49 Quick view, 15

Raised cosine

ﬁlter, 41 Real-Time spectrum analyzer, 23 Rear panel

connectors, 13 Repackaging, 9 Returning the instrument, 9

RF button, 27 RF Out, 27 Root-raised cosine

ﬁlter, 42 Rotating constellations, 53 RS-232, 5, 14

Save

screen shot of display, 15 Saved ﬁles

accessing, 21 Saving ﬁles

accessing, 21 Scale fa Screen shots

Secure

Security

Self test, 8 Self Test, 20 Serial number, 22 Settings, 15 Setup ﬁles

Software

Software key

Software upgrades, xi

Specialized constellations

Spectrum analyzer

SRAM, 58 Staggered or offset

Standard accessories, 1

Status, 15

ctor, 56

how to save, 15

removing private data, 20

rk, 4

netwo

cessing, 21

options, 3

TSG File Assistant, 1, 58

install, 22

installing, 9

PSK, 52

real-time concepts, 23

modulation, 53

documents, 1

power cord, 1

RF cable, 1

software, 1

Symbol clock, 1

Time

setting, 20 Timebase, 14 TSG File Assistant software, 1,

58 Turn instr Turn instrument on, 7

ument off, 7

Unit buttons, 15 Upgrade, 6

ﬁrmware, 22 Upgrades

re, xi, 9

softwa USB, 12, 23 User

modulation presets, 30

modulation setups, 30 User arbitrary waveform

lation, 32

modu User constellations, 67 User data, 56 User ﬁlters, 69 Utility

TSG File Assistant, 58

ector

modulation, 38 VectormodinI, 13 VectormodinQ, 13 Vector mod out I, 13 Vector mod out Q, 13 VSB

constellations, 51 VSB (vestigial sideband), 51

Waveform ﬁles

accessing, 21

TSG4100A Series RF Signal Generators User Manual 83

Tektronix TSG4102A, TSG4104A, TSG4106A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual