What kind of modulation is used in this waveform?

[bravehamid]

In the XBEE module datasheet, it is mentioned that the Moore modulation used in it is FSK, but the spectrum observed is as follows. Which modulation is related to this shape?

 

[majoco]

Looks to me like the amplitude spectrum of an FM signal..... Google "Bessel Function" but don't beat yourself up about if you get bogged down with the maths of it all!

 

[slicerwizard]

DSSS (direct sequence spread spectrum), perhaps?

 

[royldean]

Is a single screen shot of bandwidth really enough to conclusively determine modulation? Wouldn't you need some amount of time based data?

 

[slicerwizard]

It's enough for some signals. I can easily recognize 2 FSK Motorola 3600 bps control channel carriers, for example. The OP's signal definitely looks like spread spectrum to me. Of course, he doesn't show how much bandwidth it's using, so the image is of limited value. I'd prefer a raw I/Q stream sample.