Re: Sending pre-saved OFDM file to USRP

GNU Radio
1

Well, I did it like that, it did not work with connecting the
file_source direct to USRP.
I thought then it might work when I do the ‘vector thing’ in the middle.
In either case, the receiver USRP does not detect anything.

----- Original Message ----
From: Tom R. [email protected]
To: Hoo-chang Shin [email protected]
Cc: [email protected]
Sent: Thursday, April 17, 2008 1:48:27 PM
Subject: Re: [Discuss-gnuradio] Sending pre-saved OFDM file to USRP

Hoo-chang Shin wrote:

gr.flow_graph.__init__(self)
self._tx_subdev_spec = usrp.pick_tx_subdevice(self.u)
self.connect(v_src, self.u)
self.run()

Why don’t you just do:

self.connect(src, self.u)

Instead of all the vector stuff in the middle?

Tom

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2

Hoo-chang Shin wrote:

Well, I did it like that, it did not work with connecting the file_source direct to USRP.
I thought then it might work when I do the ‘vector thing’ in the middle.
In either case, the receiver USRP does not detect anything.

Have you tried to run usrp_fft.py at the receiver to make sure you see
some energy?

Also, have you just tried using benchmark_ofdm_tx.py on one side and
benchmark_ofdm_rx.py on another?

There are a lot of parameters to tweak. The amplitude is one important
one (high enough to be seen at the receiver, low enough to avoid
clipping), and the decim/interp values depend on the speed of your
processor.

FWIW, just saying the receiver isn’t getting anything isn’t too useful
when asking for help with all of the possible issues.

Tom