Re: [Discuss-gnuradio] usrp_spectrum_sense.py raw iq samples

[Mallesham Dasari]

Hi Julian,

That's a lot of info. Thank you so much. Yeah, I have realized that flow graph is not sufficient. I am going through the first approach that you mentioned. Thanks a lot again. 

On Fri, Jan 6, 2017 at 4:18 AM, Julian Arnold <address@hidden> wrote:

Hi Mallesham,

I meant that with your B210 you can only capture up to 56 MHz of real
time bandwidth (in theory).
> By whole WiFi band, I mean from 2.401G to 2.473G,
However, you require over 70MHz at once. I didn't realize that you still
want to use the sweeping approach.
In that case, the flow graph I suggested is not sufficient.

You might want to take a look at [1] which is the block
usrp_spectrum_sense.py is using internally and modify it to your needs.
I guess you could just remove the FFT and Complex to Mag Square block
from usrp_spectrum_sense.py
(change self.connect(self.u, s2v, ffter, c2mag, stats) to
self.connect(self.u, s2v, stats)) and make sure
that [1] accepts a vector of complex float as input and stores it to a
file instead of sending a message to the top block.

Or you take a look at [2].
The USRP Source can be controlled via a message interface. Therefore,
you could create a block that writes N samples to a file and then sends
a tune command
back to the USRP Source.

If you need more help, let me know.

[1]
http://gnuradio.org/doc/doxygen/classgr_1_1blocks_1_1bin__statistics__f.html
[2] http://gnuradio.org/doc/doxygen/page_uhd.html#uhd_command_syntax

Cheers,
Julian

On 01/04/2017 10:42 PM, Mallesham Dasari wrote:
> Hi Julian,
>
> Thank you so much again. I am able to collect the raw IQ samples using
> USRP source and File sink with gnuradio-companion. But, I am confused
> why you said that I will run into additional problems.
>
> On Wed, Jan 4, 2017 at 12:22 PM, Mallesham Dasari
> <address@hidden <mailto:address@hiddenedu>> wrote:
>
>     Hi Julian,
>
>     Thank you so much for the response. By whole WiFi band, I mean
>     from 2.401G to 2.473G, which is complete WiFi band. Is it possible
>     to sweep entire band by using the approach you mentioned? I
>     thought using gnuradio-companion, we can scan only one or few
>     channels depending on the sample rate.
>
>     Regarding Hardware: I am using USRP B210 with a sample rate of 8Msps.
>
>     On Wed, Jan 4, 2017 at 4:00 AM, Julian Arnold

>     <address@hidden <mailto:address@hidden>> wrote:
>
>         Hi Mallesham,
>
>         the easiest way would probably be to create your own simple
>         flowgraph
>         using GRC like so:
>
>         |---------------------|                  |-----------------|
>         | USRP Source   | ----------> | File Sink       |
>         |---------------------|                  |-----------------|
>
>         However, remember that writing to a file can be slow. You
>         might want to
>         consider using a ramdisk.
>         Also, what whole Wifi band are you talking about? Depending on
>         your
>         hardware configuration you might run into additional problems.
>
>         Cheers,
>         Julian
>
>         On 01/03/2017 09:04 PM, Mallesham Dasari wrote:
>         > Hello,
>         >
>         > I am writing the raw IQ samples (m.raw_data) from
>         > usrp_spectrum_sense.py to a file. I would like to bypass the FFT
>         > overhead, which I will do later. I want to scan the whole
>         wide band of
>         > wifi as fast as possible. Can anyone throw some light on how
>         to take
>         > only raw samples without FFT?
>         >
>         > --
>         > Best Regards,
>         > *Mallesham Dasari*
>         > Department of Computer Science
>         > Stony Brook University
>         > USA - 11794
>         >
>         >
>         > _______________________________________________
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>         > address@hidden <mailto:address@hiddenorg>
>         > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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>
>
>
>
>
>     --
>     Best Regards,

>     *Mallesham Dasari*
>     Department of Computer Science
>     Stony Brook University
>     USA - 11794
>
>
>
>
> --
> Best Regards,
> *Mallesham Dasari*
> Department of Computer Science
> Stony Brook University
> USA - 11794

--

Best Regards,

Mallesham Dasari

Department of Computer Science

Stony Brook University

USA - 11794