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

[Julian Arnold]

Hey Mallesham,

I don't have the time right now to check your code but have you also
adjusted block [1] accordingly like I mentioned in my last mail?
It now needs to operate on complex float data.

[1]
http://gnuradio.org/doc/doxygen/classgr_1_1blocks_1_1bin__statistics__f.html

On 01/14/2017 11:48 PM, Mallesham Dasari wrote:
> Hi Julian,
> 
> Thanks again for your help. I have done some following changes in the
> usrp_spectrum_sense.py code. I Removed the FFT and Complex to Mag Square
> block and writing the m.raw_data into a file inside the while loop.
> However, I am getting very less data and the power values are not
> legitimate. Am I missing anything here?
> 
> I have attached my code. Please find the attachment. 
> 
> Can you help me in this? Thank you very much.
> 
> On Fri, Jan 6, 2017 at 4:18 AM, Julian Arnold <address@hidden
> <mailto: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
>     
> <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
>     <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@hidden>
>     <mailto:address@hidden
>     <mailto:address@hidden>>> 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>
>     <mailto: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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>     >
>     >
>     >
>     >
>     >
>     >     --
>     >     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

-- 
Julian Arnold, M.Sc.

Institute for Networked Systems
RWTH Aachen University

Kackertstrasse 9
52072 Aachen
Germany