Oops, it's attached now

2009/8/7 Jonathan Coveney <[email protected]>

> So, the program will run, but instead of hearing anything, I just get oX
> over and over again.
> http://gnuradio.org/trac/wiki/UsrpFAQ/Gen#OUuainoutput
> It doesn't look like a normal error, and doing a search, I haven't seen it
> before.
>
> ./filesource_fmmod.py
> >>> gr_fir_ccf: using SSE
> >>> gr_fir_fff: using SSE
> oXoXoXoXoXoXoXoXoXoXoXoXoXoX ad infinitum
>
> Anyone know what's up? I'll keep taking a look (and try adding a throttle,
> for example). One possibility is that I had to manually set adc_rate, so I
> set it to 64000000 (since it should grab a value of 64MS/s from the usrp, at
> least according to the comment..and smaller values don't seem to work, so I
> don't know)
>
> I've attached the changes I made... to make it easy to traverse, I simply
> commented out existing code with a ##
>
> The code is usrp_wfm_rcv_nogui.py, modified to try and get a file source.
> If you have any idea what that error means, or maybe where the code goes
> wrong, your input would be appreciated (incidentally, what does the third
> value in gr.file_source modify? the boolean)
>
> And a final question, when reading from a source obviously you don't have
> to tune...but your samples were made over a given bandwidth, no? In my case,
> I'm using the TVRX, so about 6MHz. if I want to do FM demodulation, do I
> have to do it over the baseband? Or can I still "tune"? Is it just a matter
> of shifting the baseband mathematically/
>
> Thanks
>
> PS if I can get this all working easily, would it be instructive to include
> a basic nogui example that runs based on a file? It seems decidedly
> nontrivial.
>
>
> 2009/8/7 Johnathan Corgan <[email protected]>
>
> On Fri, Aug 7, 2009 at 12:49, Jonathan Coveney<[email protected]> wrote:
>>
>> > I can't find one. The _cfile.py files will save samples to a file of my
>> > specification, but I am trying to test using said samples, and not
>> > succeeding. If it does not exist, I tried this:
>> >
>> >         #self.u = usrp.source_c()                    # usrp is data
>> source
>> >         self.u = gr.file_source(gr.sizeof_gr_complex, "data.dat", False)
>> >
>> > but there are a lot of things that I'm not sure how to manipulate, such
>> as
>> > the various rates that are usually drawn off the USRP, but in this case
>> > don't necessarily apply because the samples are coming from a file?
>> Maybe
>> > they should just be set artificially to sort of trick the computer into
>> > thinking that the samples ARe coming from a USRP?
>>
>> You're on the right track--continue to use gr.file_source.  You'll
>> need to comment out all the lines that try to set frequency, gain,
>> etc.  You can put them in a Python 'if' block and either run all the
>> commands for the USRP, or just create the file source.
>>
>> The data is pulled from the file as fast as the computer can read the
>> disk.  If you want to play it back at a certain rate in wall clock
>> time, you can insert a gr.throttle(itemsize, sample_rate) block in the
>> pipeline.
>>
>> Johnathan
>>
>
>

Attachment: filesource_fmmod.py
Description: Binary data

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