[time-nuts] Software defined spectrum analyzer

k6rtm at comcast.net k6rtm at comcast.net
Sun Dec 12 02:01:45 UTC 2010


The Signal Hound is an interesting gadget. It's far more "portable" than my HP 8594E! And yes, the 10 MHz ref input on the back does help; without an external reference it does tend to wander around. 

Their website says they've replaced the original model with a rev "B" which adds a preamp and also temperature compensation. They were saying over the summer they'd have a tracking gen option as well, but I don't see it. 

The tricks they use (sorry, "advanced digital signal processing techniques"), such as shifting the LO around and watching what a signal of interest does to determine if it's real or not makes some fundamental assumptions about the signal of interest, such as that it's more or less the same during the multiple passes with different LO values. If the signal of interest doesn't play by those assumptions, all bets are off. 

The website says that, if you're trying to measure wide bw signals, 20 MHz or wider (such as 802.11g, 802.11n), or hoppers (bluetooth?) you have to throw it into a mode where it only does high-side mixing. 

73 bob k6rtm 




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