A Portable 9 kHz to 2.7 GHz SpectrumAnalyzer
IFR Americas Inc.
Wichita, KS
A new lightweight, portable spectrum analyzer has been developed that covers the 9 kHz to 2.7 GHz frequency spectrum. The model 2398 spectrum analyzer is a fully synthesized instrument that combines ease of use and broad functionality with good value. The unit features a rugged 18 lb (8.2 kg), 13.75" x 7.15" x 14.75" frame with AC/DC operation, split-screen capability, low phase noise and a wide +20 to -108 dBm input range. The instrument is capable of AM and FM demodulation and electromagnetic compatibility precompliance measurements.
Performance Features
The 2398 spectrum analyzer is one of the lightest spectrum analyzers on the market today. As a result of its light weight and fully portable package, the instrument allows highly accurate measurements to be made both in the development laboratory and at a field location in a variety of wireless test, troubleshooting or installation applications. An optional AC/DC power supply and external batteries enable the analyzer to be used in remote locations where access to an AC power source is not available. The instrument also features a fully synthesized LO system that produces highly accurate frequency measurements. A standard 1 Hz frequency counter provides high resolution measurements of signals above -70 dBm.
A split-screen capability, shown in Figure 1 , offers the operator the ability to 
view two completely separate signals simultaneously with completely separate setup conditions. This capability permits interfering signals to be tracked (as in current CDMA and TDMA cellular system applications). The spectrum analyzer offers a standard AM and FM demodulator that allows testing and troubleshooting of a wide range of wireless radio system and repeater signals. An internal speaker and headphone connection are provided to aid in this analysis.
The spectrum analyzer features an AC-coupled input signal range of +20 to -108 dBm, permitting direct testing of RF amplifiers and providing a broad capability to identify interfering signals in modern wireless system applications. In addition, the instrument has user-selectable internal measurement features that perform measurements such as occupied bandwidth and relative power level. A full range of accurate marker capabilities, including peak, delta, marker noise and marker zoom, are provided that allow faster and more comprehensive signal measurement and identification. Figure 2 shows the marker function in use.
In addition, the analyzer provides a comprehensive limits capability that permits the user to set up pass/fail criteria on screen. A fail message appears when a signal exceeds the determined limit. The instrument is capable of simultaneously storing 20 traces and 10 setups in an internal memory. A Personal Computer Memory Card International Association memory card slot also is available for mass storage of traces and setups. An RS-232 interface and parallel printer port are standard and an optional IEEE-488 (general purpose interface bus (GPIB)) port offers additional capability for automated testing and data tracking. Hard copies for screen displays can be printed easily.
Applications
Its ability to cover 2.7 GHz and its weight of just 18 lb make the model 2398 
spectrum analyzer ideal for installation and maintenance of cellular and PCS radio equipment. Figure 3 shows a typical digital wireless signal display. The excellent phase noise makes the instrument a good tool for determining the spectral purity or spurious output of a wireless system. The split-screen function helps to locate and identify signal interference or simultaneously display the same signal at different times. The AM/FM demodulator permits the user to listen to modulated carriers and the light weight makes use in the field easy and effective.
The instrument is also well adapted for cable and broadcast television applications. The 2.7 GHz frequency range permits analysis of harmonics, and the demodulator function permits signals to be identified both visually and audibly.
The digitally synthesized analyzer can perform accurate tests on system transmitters, including operating frequency, carrier power, adjacent-channel power and intermodulation measurements. Using an optional tracking generator, the analyzer may be used for RF network tests, including filter alignment and cable fault location. The wide dynamic range permits RF amplifier testing and, when combined with a return loss bridge, the instrument also performs antenna return loss measurements.
In avionics applications, the analyzer provides a viable low cost solution for testing and troubleshooting transponders, distance measuring equipment and single-sideband communications equipment. An external triggering function and zero span allow easy characterization of pulsed signals.
In the laboratory, the analyzer's low noise floor and low distortion characteristics make it suitable for bench measurements for the design and development of RF and wireless components. The RS-232 interface, printer and optional GPIB ports are useful for providing hard copy design data outputs and for recording production data.
Conclusion
The model 2398 portable spectrum analyzer is one of the lightest full-featured instruments available in the 9 kHz to 2.7 GHz frequency range. Combining many of the standard features found only in higher priced full-sized analyzers with a price of $6495, the instrument offers the best price/performance ratio of any analyzer currently on the market. Additional information and the instrument's full specifications may be obtained via e-mail at info@ifrsys.com.
IFR Americas Inc.,
Wichita, KS
(800) 835-2352 or (316) 522-4981.