ADVANCED SPECTRUM MANAGEMENT is currently evolving in terms of how it is being accomplished. Both spectrum-management and RF signal-monitoring applications have special equipment requirements, which tend to go beyond the typical radio receiver or spectrum analyzer. An application note from Tektronix, Inc. (Beaverton, OR) details how new spectrum analyzers may manage to change the face of such spectrum management. The 16-page paper is titled, "Advanced Spectrum Management with the RSA6100A Series RealTime Spectrum Analyzer."
The RSA6100A spectrum analyzer, which is at the heart of the application note, covers frequencies through 14 GHz. It provides up to 110 MHz of instantaneous intermediate-frequency (IF) bandwidth and a minimum of 73 dB of dynamic range. In addition, its DPX spectrum-display system can process more than 48,000 spectrum measurements per second. This capability lends itself to the discovery of short-duration events. The DPX display also is color-graded. It can therefore show both infrequent and more frequent events. Because the DPX processing rate is much faster than the human eye can perceive, the display must be slowed down to view live signals. When it comes to the crowded spectrum, DPX promises to help the engineer see varying RF that previously could not be separated or even seen.
The note explains how the spectrum analyzer can be used to capture low-probability-of-detection (LPD) transmission bursts, hunt for bugs (eavesdropping devices), and clear a frequency band (i.e., to search and locate users of a former band to notify them that they need to move to a different frequency). Examples also are provided for pinpointing the sources of spurious interference, radar-system interference, and crowded-band intermodulation.
In addition, the paper delves into software-defined-radio (SDR) verification. During operation, this radio may switch between several different modulation formats. The wideband nature of such RF switching may spread over an entire communications band. Aside from displaying the spectrum, it is helpful if the analyzer shows the time-domain display of the RF as it changes. The note concludes by examining the RSA6100A's two forms of signal output: analog IF and digitized time samples. Although the paper is largely devoted to the company's spectrum-analyzer series, it serves as a good primer on the capabilities of next-generation spectrum analyzers and how they may be used in spectrum management.
Tektronix, Inc., 14200 SW Karl Braun Dr., P.O. Box 500, Beaverton, OR 97077; (800) 835-9433, Internet: www.tektronix.com