Re: [Discuss-gnuradio] Sending pre-saved OFDM file to USRP

[Hoo-chang Shin]

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 Rondeau <address@hidden>
To: Hoo-chang Shin <address@hidden>
Cc: address@hidden
Sent: Thursday, April 17, 2008 1:48:27 PM
Subject: Re: [Discuss-gnuradio] Sending pre-saved OFDM file to USRP

Hoo-chang Shin wrote:
> Hi,
>
> I'm trying to send a pre-saved OFDM file to a transmitter USRP, and to 
> receive the signal from a receiver USRP.
> >From the 'benchmark_ofdm_tx.py' I've saved the OFDM signal to a file using 
> >'gr.file_sink', instead of sending it to 'usrp.sink_c'.
> And then I want to read the data from the saved file and send it though the 
> transmitter USRP, and receive it from the other USRP, but does not work.
>
> Could anyone give tip, why it does not work? Or give help how to make it work?
>
>
> This is my code:
>
> #!/usr/bin/env python
>
> from gnuradio import gr
> from gnuradio import usrp
>
> from numpy import *
>
> class send_from_file_graph (gr.flow_graph):
>
>     def __init__(self):
>     gr.flow_graph.__init__(self)
>     
>     filename = 'tx_usrp_data.dat'
>     # which I had saved from 'benchmark_ofdm_tx.py' using 
> 'gr.file_sink(gr.sizeof_gr_complex, filename)'
>     src = gr.file_source ( gr.sizeof_gr_complex, filename, False)
>     
>     self.v_snk = gr.vector_sink_c()
>     
>     # setup usrp
>     self.u = usrp.sink_c(fusb_block_size=0, fusb_nblocks=0)
>     self.u.set_interp_rate(512)
>     self._tx_subdev_spec = usrp.pick_tx_subdevice(self.u)
>     self.subdev = usrp.selected_subdev(self.u, self._tx_subdev_spec)
>     
>     self.u.tune(self.subdev._which, self.subdev, 2.45e9)
>     self.subdev.set_gain(200)
>     self.subdev.set_auto_tr(True)
>     # ##
>     
>     self.connect(src, self.v_snk)
>     self.run()
>     v_src = gr.vector_source_c(self.v_snk.data())
>     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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