Spectrum analyzer textbook

I suppose there are texts, but I know for sure there are lots of very good applications notes available for free. Try Rohde and Schwarz, Agilent and Anritsu, for example. Obviously, these are written from the viewpoint of selling you equipment, but for sure they will tell you about the capabilities of the equipment to detect and demodulate modern communications signals. After all, that's a key reason for sales of such analyzers. These ap notes will tell you about the capabilities of real instruments, and how to get the most out of them.

Cheers, Tom

I tend to agree with Tom... app notes from Tek and Agilent/HP have a lot of really great information. Note that while newer app notes are readily available, older ones are often some of the most interesting/useful (ok, maybe not for those trying to look at, say, GSM signals, but in general...), and while some are available with some digging around the 'net, there are guys on eBay/their own web sites selling CDs of a bunch of them together for something like $20, which is quite worthwhile unless you're seriously strapped for cash and have a lot of free time.

(The problem with these old equipment manual/app note scans guys is that the prices are all over the place -- some want $10/article, some get $10/dozen articles --, the quality of the scans varies considerably, some of them are just copying the works of other guys -- and then some of them decide they'll start prominently adding their name/logo to the sheets to discourage this, which is annoying to the end user --, sometimes it's questionable whether or not they're infringing the original publisher's copyright, etc... I don't have that much experience with those guys, although I've bought a few things from Artek Media and have been happy with them.)

If you really want a book, Robert Witte's book is something of a classic here:

... and it's good, although if you've never touched a spectrum analyzer before in your life, it'll be missing some of the basic concepts that are often best understood just by playing around (as opposed to reading a book). He doesn't really cover digital signals as such, however... the book is more like a user's guide to traditional spectrum analyzers which weren't loaded up with complex protocol-specific diagnostic/measurement software routines like the fancy ones are today. (When Tom and I went to school, you felt lucky if your SA could demodulate AM and FM...)

---Joel

I think you are alluding to SIGINT.

Generally you analyze signals in their baseband. That is, modulation schemes can be done on any frequency. [Granted, some bands are not suitable for some modulation schemes, like FM where the AM broadcast band sits.]

Take a look at this program: