Agilent X-Series Signal Analyzer This manual provides documentation for the following X-Series Analyzers: P XA Signal Analyzer N9030A M XA Signal Analyzer N9020A EXA Signal Analyzer N9010A CXA Signal Analyzer N9000A Spectrum Analyzer Mode Measurement Guide Notices © Agilent Technologies, Inc. 2008-2009 Manual Part Number licensed as “Commercial computer soft- ware” as defined in DFAR 252.227-7014 No part of this manual may be reproduced N9060-90032 (June 1995), or as a “commercial item” as in any form or by any means (including Supersedes: N9060-90030 defined in FAR 2.101(a) or as “Restricted electronic storage and retrieval or transla- computer software” as defined in FAR tion into a foreign language) without prior Print Date 52.227-19 (June 1987) or any equivalent agreement and written consent from Agi- agency regulation or contract clause. 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If software is for use in the performance of a U.S. Government prime contract or subcontract, Software is delivered and 2 Warranty This Agilent technologies instrument product is warranted against defects in material and workmanship for a period of one year from the date of shipment. During the warranty period, Agilent Technologies will, at its option, either repair or replace products that prove to be defective. For warranty service or repair, this product must be returned to a service facility designated by Agilent Technologies. Buyer shall prepay shipping charges to Agilent Technologies and Agilent Technologies shall pay shipping charges to return the product to Buyer. However, Buyer shall pay all shipping charges, duties, and taxes for products returned to Agilent Technologies from another country. Where to Find the Latest Information Documentation is updated periodically. For the latest information about this analyzer, including firmware upgrades, application information, and product information, see the following URLs: http://www.agilent.com/find/pxa http://www.agilent.com/find/mxa http://www.agilent.com/find/exa http://www.agilent.com/find/cxa To receive the latest updates by email, subscribe to Agilent Email Updates: http://www.agilent.com/find/emailupdates Information on preventing analyzer damage can be found at: http://www.agilent.com/find/tips 3 4 Contents 1 Getting Started with the Spectrum Analyzer Measurement Application Making a Basic Measurement 10 Using the Front Panel 10 Presetting the Signal Analyzer 11 Viewing a Signal 12 Recommended Test Equipment 15 Accessories Available 16 50 Ohm Load 16 50 Ohm/75 Ohm Minimum Loss Pad 16 75 Ohm Matching Transformer 16 AC Probe 16 AC Probe (Low Frequency) 16 Broadband Preamplifiers and Power Amplifiers 17 GPIB Cable 17 USB/GPIB Cable 17 RF and Transient Limiters 17 Power Splitters 18 Static Safety Accessories 18 2 Measuring Multiple Signals Comparing Signals on the Same Screen Using Marker Delta 20 Comparing Signals not on the Same Screen Using Marker Delta 23 Resolving Signals of Equal Amplitude 26 Resolving Small Signals Hidden by Large Signals 31 Decreasing the Frequency Span Around the Signal 35 Easily Measure Varying Levels of Modulated Power Compared to a Reference 37 3 Measuring a Low−Level Signal Reducing Input Attenuation 42 Decreasing the Resolution Bandwidth 45 Using the Average Detector and Increased Sweep Time 48 Trace Averaging 50 5 Contents 4 Improving Frequency Resolution and Accuracy Using a Frequency Counter to Improve Frequency Resolution and Accuracy 54 5 Tracking Drifting Signals Measuring a Source Frequency Drift 56 Tracking a Signal 59 6 Making Distortion Measurements Identifying Analyzer Generated Distortion 62 Third-Order Intermodulation Distortion 65 7 Measuring Noise Measuring Signal-to-Noise 70 Measuring Noise Using the Noise Marker 72 Measuring Noise-Like Signals Using Band/Interval Density Markers 76 Measuring Noise-Like Signals Using the Channel Power Measurement 79 Measuring Signal-to-Noise of a Modulated Carrier 81 Improving Phase Noise Measurements by Subtracting Signal Analyzer Noise 86 8 Making Time-Gated Measurements Generating a Pulsed-RF FM Signal 92 Signal source setup 92 Analyzer Setup 93 Digitizing oscilloscope setup 95 Connecting the Instruments to Make Time-Gated Measurements 97 Gated LO Measurement 98 Gated Video Measurement 102 Gated FFT Measurement 106 9 Measuring Digital Communications Signals Channel Power Measurements 110 Occupied Bandwidth Measurements 112 Troubleshooting Hints 113 6 Contents Making Adjacent Channel Power (ACP) Measurements 114 Making Statistical Power Measurements (CCDF) 119 Making Burst Power Measurements 124 Spurious Emissions Measurements 130 Troubleshooting Hints 132 Spectrum Emission Mask Measurements 133 Troubleshooting Hints 134 10 Demodulating AM Signals Measuring the Modulation Rate of an AM Signal 138 Measuring the Modulation Index of an AM Signal 142 11 IQ Analyzer Measurement Capturing wideband signals for further analysis 146 Complex Spectrum Measurement 147 IQ Waveform (Time Domain) Measurement 149 12 Using Option BBA Baseband I/Q Inputs Baseband I/Q Measurements Available for X-Series Signal Analyzers 154 Baseband I/Q Measurement Overview 155 13 Concepts Resolving Closely Spaced Signals 158 Resolving Signals of Equal Amplitude 158 Resolving Small Signals Hidden by Large Signals 158 Trigger Concepts 160 Selecting a Trigger 160 Time Gating Concepts 164 Introduction: Using Time Gating on a Simplified Digital Radio Signal 164 How Time Gating Works 166 Measuring a Complex/Unknown Signal 172 “Quick Rules” for Making Time-Gated Measurements 177 Using the Edge Mode or Level Mode for Triggering 180 7 Contents Noise Measurements Using Time Gating 181 AM and FM Demodulation Concepts 182 Demodulating an AM Signal Using the Analyzer as a Fixed Tuned Receiver (Time-Domain) 182 Demodulating an FM Signal Using the Analyzer as a Fixed Tuned Receiver (Time-Domain) 182 IQ Analysis Concepts 183 Purpose 183 Complex Spectrum Measurement 183 IQ Waveform Measurement 183 Spurious Emissions Measurement Concepts 185 Purpose 185 Measurement Method 185 Spectrum Emission Mask Measurement Concepts 186 Purpose 186 Measurement Method 186 Occupied Bandwidth Measurement Concepts 187 Purpose 187 Measurement Method 187 Baseband I/Q Inputs (Option BBA) Measurement Concepts 188 What are Baseband I/Q Inputs? 188 What are Baseband I/Q Signals? 188 Why Make Measurements at Baseband? 189 Selecting Input Probes for Baseband Measurements 190 Baseband I/Q Measurement Views 191 8 Getting Started with the Spectrum Analyzer Measurement Application 1 Getting Started with the Spectrum Analyzer Measurement Application This chapter provides some basic information about using the Spectrum Analyzer and IQ Analyzer Measurement Application Modes. It includes topics on: • “Making a Basic Measurement” on page 10 • “Recommended Test Equipment” on page 15 • “Accessories Available” on page 16 Technical Documentation Summary: Your Signal Analysis measurement platform: Getting Started Turn on process, Windows XP use/configuration, Front and rear panel Specifications Specifications for all available Measurement Applications and optional hardware (for example, Spectrum Analyzer and W-CDMA) Functional Testing Quick checks to verify overall instrument operation. Instrument Messages Descriptions of displayed messages of Information, Warnings and Errors Measurement Application specific documentation: (for example, Spectrum Analyzer Measurement Application or W-CDMA Measurement Application) Measurement Guide Examples of measurements made using the front panel keys or over a remote interface. User’s/Programmer’s Descriptions of front panel key functionality and the corresponding SCPI Reference commands. May also include some concept information. 9 Getting Started with the Spectrum Analyzer Measurement Application Making a Basic Measurement Making a Basic Measurement Refer to the description of the instrument front and rear panels to improve your understanding of the Agilent Signal Analyzer measurement platform. This knowledge will help you with the following measurement example. This section includes: • “Using the Front Panel” on page 10 • “Presetting the Signal Analyzer” on page 11 • “Viewing a Signal” on page 12 CAUTION Make sure that the total power of all signals at the analyzer input does not exceed +30 dBm (1 watt). Using the Front Panel Entering Data When setting measurement parameters, there are several ways to enter or modify the value of the active function: Knob Increments or decrements the current value. Arrow Keys Increments or decrements the current value. Numeric Keypad Enters a specific value. Then press the desired terminator (either a unit softkey, or the Enter key). Unit Softkeys Terminate a value that requires a unit-of-measurement. Enter Key Terminates an entry when either no unit of measure is needed, or you want to use the default unit. Using Menu Keys Menu Keys (which appear along the right side of the display) provide access to many analyzer functions. Here are examples of menu key types: Toggle Allows you to activate/deactivate states. Example: Toggles the selection (underlined choice) each time you press the key. Submenu Displays a new menu of softkeys. 10