By Paul Holes, Field Application Engineer, RFuWave Group

When looking for signal behaviour using test equipment, there is some information regarding these signals that we must know, namely:

• When and where does the signal occur, and for how long?
• What are the centre frequency and bandwidth?
• Is there any modulation and, if so, what’s its form?

It is possible to search in either frequency and/or time domain; however, the following should be borne in mind when deciding how best to analyse the signal of interest:

The frequency domain is best for identifying signals in the frequency spectrum, i.e. is the signal dynamic or static, is it burst-y or modulated, or is it just a continuous wave.

The time domain is best for identifying the occurrence of events, perhaps at a specific time or at a time relevant to other events.

In the frequency domain, a spectrum analyser must possess the following criteria to be able to see the signal being analysed or hunted:

• It must have a higher frequency with an adequate dynamic range and a bandwidth wider than the signal of interest.
• Ideally it should be capable of vector signal analysis and have a signal capture memory to repeatedly replay that signal, as well as enabling analysis of other device behaviour when subjected to the said signal of interest.