Software Defined Radio Transmitter Demo Board

Feb 06, 2006 5 Replies

Hello everyone.



We are a senior design group from Oregon State University. Our webpage is:

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(soon to be updated with Part Numbers and source code)



We've nearly ordered all of our parts: Spartan 3 (demo board), RF Oscillator, High Signal Level Upconverting Mixer, I/Q Modulator, Amplifier, Voltage Regulators, DACs, and Transmitters.



Our goal is to transmit signals using either 16QAM or BPSK Modulation.



Our plan is to * model functions using vhdl * build a prototype circuit * synthesize our code onto fpga * analyze results using various scopes



Currently working on a more accurate block diagram showing component connection. feel free to respond with questions/comments/concerns.



Why not use the GNU radio and USRP?

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All the tools are free, the usrp is only about $500, and it has two transmit and two receive.

-Clark

matlab first?

finish all sims first?

-- Mike Treseler

Yes you are so right, I forgot a lot of stuff. Don't worry we are using matlab, and we are going to finish sims.

we really should write some specs for it huh.

not so complete plan: * use matlab to design filters/model schemes * model functions using vhdl * simulate and debug * create testbenches * build a prototype circuit * synthesize our code onto fpga * analyze results using various scopes

working on block diagrams. sigh....

-Peter

Clark,

After you mentioned using GNU Radio, I looked it up and yes we are going to do something similiar. We are building this demo board ourselves as best we could as a senior design project. We dont know enough about USRP to decide to jump into using it yet.

-Peter

GNU Radio is a pain to install the first time, but once it's up it takes care of most of the nuissance/tedious stuff for you and you can focus directly on the signal processing. You can do signal processing in C code on the linux host or inside the cyclone fpga in vhdl (using free version of quartus).

One advantage for you is, if you do something simple like BFSK or BPSK you could do a loop back system and implement the receiver too. Truth is all the interesting stuff is in the receiver anyway: carrier recovery, synchronization, equalization, etc.

It's great for education tool. The board can stay with the school and each semester students can build on the previous groups work.

Just my opinion. I spent most of my senior design (years ago) wire wrapping my board (an FM receiver on an ISA card (years before you could buy commercially)). I would have learned a lot more if I'd had the GNU radio tool.

-Clark

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