CODEWITHSUNDEEP
fpgalabviewusrpsoftware-defined-radio
dimme
dimme

Reputation: 4424

Forwarding a signal from RX to TX using a USRP with FPGA

This is a LabVIEW (Software) FPGA (Hardware) question so I don't know whether I should post here or on the electronics Stack Exchange.

I have a USRP-2953R and I want to achieve a very simple project. I want to read a signal from RF0/RX1 and output it to RF1/TX1 using the FPGA (not forwarding anything to the host). The signal is centered at 5.9GHz with 10MHz of bandwidth. Is that feasible? What should my approach be?

I have tried different modifications to the "Simple NI-USRP Streaming" project that comes with LabVIEW 2013, but I haven't successfully outputted anything. I'm using LabVIEW 2013 SP1 and I am able to compile and execute code successfully on the USRP FPGA. It simply doesn't do what I want it to do.

Any help would be greatly appreciated.

Upvotes: 2

Views: 1255

Answers (1)

nalyd88
nalyd88

Reputation: 5148

The "Simple NI-USRP Streaming" project's starting FPGA code starts on the receive side with the ADCs being sampled. These values are then mixed down, and decimated before piping it to the Target-Host RX FIFO. The transmitter code starts by reading the Host-Target TX FIFO. Try replacing the RX and TX FIFOs with one Target scoped FIFO. Then as samples get placed in the FIFO they will also get pulled out for transmit (note you may need to put the TX code in a separate SCTL). Also, you may want to leave the original RX FIFO in place for debugging and just add the target scoped one in parallel.

Also, make sure the Host is setting up the USRP correctly. You will probably have to make some modifications to the TX-RX Host vi before it will configure the FPGA code (described above) to run properly. For instance, you will have to remove the target scoped FIFOs (if you removed them from the FPGA).

I'm not sure what you've already tried but hopefully this was of some help!

Upvotes: 1

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