Most modern analyzers are LXI-C compliant. LAN eXtension for Instrumentation (LXI) is a standard that defines instrument connectivity over a LAN. The LXI-C standard allows for the instrument to be controlled over a LAN and contains a web server for remote operation. For example, in order to share measurement information across global teams, simply type the IP address for the analyzer into a web browser, and the analyzer’s display appears in the browser.

Most instruments, however, are still controlled through the GPIB interface. When choosing an analyzer, make sure that it has the connectivity for legacy test needs using GPIB and is set for the future with at least LXI class C compliance.

With the advent of LAN-enabled instruments, Internet security and safety are becoming key issues, especially across large enterprise systems. For example, if an instrument is based on Windows XP, it has all the characteristics of a PC. Putting it on the network makes it susceptible to viruses and attacks just like any other PC. Some instrument manufacturers have chosen Linux, although this can reduce the instrument connectivity to Microsoft-based tools.

Figure 4. Typical frequency spectrum for W-CDMA modulated signal.

Keithley’s RF vector signal analyzer (model 2810) is a good example that offers the features discussed above. Spanning a frequency range of 400 MHz to 2.5 GHz, it features fast frequency sweep times with narrow resolution bandwidths, fast-frequency tuning, rapid attenuator switching, and high-speed DSP that reduce test times significantly and cost of test, particularly in production testing applications. In addition, its compact, half-rack enclosure size conserves rack space, which is at a premium in most production test environments.

A spectrum or signal analyzer can be a large investment, and there are many analyzers in the marketplace from which to choose. To help evaluate individual analyzers, ask these questions:

• What is the available budget for purchasing an analyzer?
• What frequency range is required to be measured?
• What amplitude accuracy is required?
• What are the dynamic range requirements?
• What are the phase noise requirements?
• What type of signal is to be measured, CW or modulated?
• Is demodulation capability needed? What is the signal bandwidth?
• Will the instrument be manually or remotely controlled?

To ensure that you reap the best performance for your investment, it may benefit you to work with an instrument product manager to determine the type of analyzer that best fits your company’s needs and budget.

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