Sep. 3rd, 2015

compilerbitch: That's me, that is! (Default)

I’ve been making a bit of an effort to get things-GPIB-related working a bit better around the lab. I have been hair-tearing a bit with my Prologix ethernet-GPIB interface recently. I seem to be able to get it to mostly work fine with single instruments, but it’s not happy with some of them in combination, particularly when my HP5342A microwave frequency counter is on the bus. This could of course be the counter, but anyway, I was fiddling with my HP8591A spectrum analyzer from LabVIEW via the Prologix with some level of success. I did, however, remember a bit of software I picked up some time ago — KE5FX’s HP7470 plotter emulator. This thing works great with the HP speccy!

Anyway, here is a plot from it:

GPIB_17 (5)

You can initiate the plot from within the plotter emulator by selecting the GPIB device from a pulldown menu. It takes about 2 or 3 seconds to pull the data down, then the plot appears. The trick to get it looking sexy like this one is to set the image size as big as possible, swap to a black background and the alternate colors, then save the image as a BMP, load it in Photoshop, scale it back down a bit and bring up the levels. OK, I know not everyone is as much of a Photoshop junkie as me, but Gimp will do this sort of thing just fine too. Then again, if you’re not too finicky, you might find the raw output in default mode just fine anyway.

So, KE5FX, if you’re Googling yourself and spot this post, many thanks and 73s de NQ6K. :-)

PS: The plot is a QPSK signal (just random data from a PRBS generator) at 250 MHz with a 5 MHz symbol rate, 100 averages.

Please note: this was cross-posted from my main blog at -- If you want me to definitely see your replies, please reply there rather than here.



compilerbitch: That's me, that is! (Default)

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