Cognitive Radio Project

Yea, I knew taking 5 courses instead of 4 was a bad idea… On top of that I’m preparing a number of documents required for graduate studies, attending job fairs…. I now have 2 Homeworks, 2 Seminars, a test and a project all due in the same week, oh goodie!

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There are a few things that I’ve noticed while setting up the workspace for the PXI:

• There arent really enough USB ports on the PXI, sure there are 4, but if you think about it, you need Keyboard + Mouse, which is either 1 USB or 2, depending on what splitter you are using. But either way, you are going to need 1 more for a External DVD  Drive, and that leaves only 1 remaining
• Lack optical drive, sure I can run setups through the network, but the box didnt come with the RF Spectral Measurement toolkit installed, and guess what, its on a DVD >.<
• No LNA, if you ever start to wonder why the signal is on -100dB when you have the transmiter right next to the antenna lol, check the Downconverter’s block diagram, its a 3 stage superhet receiver, minus the preamp
• KVM is very useful! We have a shinny computer as well as the PXI, and as the other post (FM one)’s gallery shows, we are running a dual screen setup, normally both screens can be used on the main computer, with the 2nd screen connected to a KVM which goes into the PXI, flip a switch you can start using the PXI!
• Remote desktop works, barely. If you are sitting right next to the machine, with 2 screens, and you are using RDC, the pain really hits you when you see highlighing an interactive help in labview takes like 10 seconds -.-… Having said that though, its awesome to be able to RDC into the PXI from half way across the campus, this allows for remote sensing as well
• The machine is sadly very loud, obviously not designed to be kept next to your table, rather than the humming you get this massive *VRUM* sound, kind of awesome in a way

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Right, so we are at the stage where everything is set up, there are a few pictures at the end of the post.

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This post is really just to summarize what impedance mismatch does. This is especially important when you connect a 75Ohm antenna to a 50Ohm VSA input

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Ok this is rather stupid, it took me like 4 days to realize that the VSA has no LNA or Preamp of any sort.. and all this time I was wondering why the signal received were all so weak.

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