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SP-09-460: NTIA Seminar Series on Spectrum Measurement Theory and Techniques

Have you ever wondered how a spectrum analyzer works, how to properly adjust all of the analyzer's parameters, or why a stair-step pattern initially appears on a spectrum analyzer screen when you turn it on? Do you know how to precisely calculate the analyzer's sensitivity in your head, merely by glancing at the screen display without any signal present? Are you uncertain about how much gain, and how low a noise figure, you ought to specify when you are ordering a low-noise amplifier (LNA) for a radio receiver? Do you want to know the difference between noise figure and noise factor? Do you wonder how to diagnose and solve radio interference problems?

If you have questions about how to make good radio spectrum measurements or how to diagnose interference problems, you will find the answers in the NTIA Seminar Series on Spectrum Measurement Theory and Techniques. In this series of talks, an NTIA engineer at the Institute for Telecommunication Sciences (ITS) laboratory in Boulder, CO, discusses the fundamentals of radio spectrum measurements. Frank Sanders, an ITS Senior Technical Fellow with thirty years of experience in this field, recognizes that even for many engineers who routinely use spectrum analyzers, the fundamentals of how they work and how to use them may be a bit murky; even in university lab classes the instructors do not always understand these machines very well themselves.

Most of the talks, which are 80-100 minutes long, are divided into two parts. In the first portion of each video, Sanders explores a particular aspect of radio spectrum measurement technique or theory with a whiteboard lecture. In the second part, the lessons of the whiteboard discussion are implemented with actual measurement hardware and radio signals. A few of the talks, which for example involve large numbers of photographs of radar systems, are videos of his Microsoft Powerpoint presentations.

In this series, Sanders explains spectrum analyzer functionality in terms of convolution bandwidth and shows how, when convolution is understood along with the mechanics of analyzer design, spectrum analyzer operations and outputs become easy to understand and use. Other topics include (1) what you need to know to use spectrum analyzers to examine all types of radio signals, including mobile radios, radars, and digital data links; (2) the use of low noise amplifiers and how to specify the right gain and noise figure for your receiver and measurement applications; (3) how radar systems work, and how to understand and interpret the signals that you see coming from radars; (4) the ways that radio interference can occur; (5) a methodical approach for diagnosing and solving radio interference problems; (6) the math needed to convert spectrum analyzer measurements into field strengths of radio signals; and (7) the proper conversions for radiation hazard calculations.

The titles in this series are listed below. They are made available through YouTube and you can access the full series as a playlist here.

Talk 1: Thermal Noise Limits in Radio Measurements
This talk explains the most fundamental limits on all radio receivers and measurement systems.

Talk 2: Fundamentals of Spectrum Analyzer Design
This talk explains how spectrum analyzers work, describing them as convolution machines.

Talk 3: Spectrum Analyzer Detection Modes
This talk explains how to select the best type of detection for any given type of received signal.

Talk 4: Measuring Signal Power and Field Strength Conversions
This talk explains what field strength is, and how to get the field strength of a signal from spectrum analyzer readings.

Talk 5: The Riis Equation: Optimizing Noise Filter and Dynamic Range
This talk explains how to design a receiver with the proper amount of gain and noise figure in its RF front end.

Talk 6: The Radar Equation: How to Build Your Own Radar
This talk explains how radars are built and how they work.

Talk 7: The Difficulty of Measuring Radar Emission Spectra
This talk explains why it is difficult to measure radar emissions.

Talk 8: A Radar Spectrum Measurement System Design
This talk explains how to overcome the difficulties of measuring radar emissions.

Talk 9: Measuring Radar Emissions
This talk explains how to intercept and analyze radar signals.

Talk 10: Noise Diode Calibration of a Measurement System
This talk explains what noise diodes are and how they should be used to calibrate the gain and noise figure (sensitivity) of radio measurement systems.

Talk 11: Reviewing Radar Systems
This talk reviews all types of radar systems (currently in existence) in terms of their functions and designs.

Talk 12: Additional Specialized Spectrum Measurement Techniques
This talk explains how to jam radars, including methods that make it impossible for operators to know that jamming is occurring.

Talk 13: Methodologies and Results of NTIA Broadband Spectrum Surveys
This talk describes the techniques and results of broadband spectrum surveys between 108 MHz to 19.7 GHz, with specially tailored algorithms for each spectrum band.

Talk 14: Resolving RF Interference: Co channel Interference
This talk explains one of the major types of RF radio interference.

Talk 15: Resolving RF Interference: RF Front-end Overload Problems
This talk explains a second major type of RF radio interference.

Talk 16: Resolving RF Interference: Miscellaneous Problems
This talk explains all the other types of radio interference, and how to diagnose and resolve any RF interference problem.

Talk 17: Identifying Radar Signal Interference in Geostationary Satellites
This talk explains how to identify radar interference in satellite links, and how to identify and find the radars involved.

Talk 18: RF Radiation Hazard Calculations & Measurements
This talk explains the difference between ionizing and non-ionizing radiation, the basis of RF hazards, and how to calculate & measure against radiation hazard (radhaz) limits.

Talk 19: Additional Spectrum Measurement Techniques
This talk explains how to observe specialized types of radio signals, such as point-topoint microwave links.

Talk 20: Spectrum Efficiency Studies of Radars
This talk explains why radars need a lot of spectrum, and why they don't share well with other systems.

NTIA Special Publication SP-09-460, "Seminar Series on Spectrum Measurement Theory and Techniques," was developed and is owned by NTIA/ITS, an agency of the Federal Government. It was created under Project 9340012-000 "ITS-T Support" between September 2007 to January 2009. Pursuant to Title 15 United States Code section 105, works of Federal employees are not subject to copyright protection in the United States.

This NTIA Special Publication is provided by NTIA/ITS as a service and is expressly provided "AS IS." Neither ITS nor NTIA makes any warranty of any kind, express, implied or statutory, including, without limitation, the implied warranty of merchantability, fitness for a particular purpose, non-infringement and data accuracy. ITS/NTIA does not warrant or make any representations regarding the information contained in this video, including but not limited to its correctness, accuracy, reliability or usefulness. This video is free. You can use, copy, modify and redistribute it upon your acceptance of these terms and conditions and upon your express agreement to provide appropriate acknowledgments of NTIA/ITS's ownership of and development of this video by keeping this exact text present in any copied or derivative works.

Certain commercial equipment is shown in this video to illustrate the points discussed. In no case does such use imply recommendation or endorsement by NTIA, nor does it imply that the equipment shown is necessarily the best available for the purpose.

For technical information concerning this series, contact:
Frank Sanders, Senior Technical Fellow
Institute for Telecommunication Sciences
Voice: (303) 497-7600