Re: [Discuss-gnuradio] How to process file sink from UHD Source USRP

[Marcus Müller]

So, this is a bit of a bigger question. The center frequency is something that *you* configure, so errr... you might just as well save it as part of the file name, or so.

A precise reception time requires setting the precise time in the USRP. But, as soon as you've done that, you can use the time tags that the USRP source emits, e.g. to save the tags as metadata along with the samples (or separately). "Power" is not anything the USRP measures. You need to estimate that from the samples, so you seem to be asking the wrong questions.

Maybe you'd want to make sure that you both understand what you're trying to build, and how you can even get the data you want at all, before considering how to safe it. I'd encourage you to both discuss that with your peers and supervisors, as well as with the mailing list – but the latter really requires that you write down a concise, clear, unambigous, as-mathematically-precise-as-possible system purpose.

Best regards,

Marcus

On 07/12/2017 11:52 AM, Sinta Novtafiani wrote:

So, how can i get the information of frequency, power, time that usrp received? Is there any tools in gnuradio companion which can get those data? If you have any reference it may be helpfull for me. Thankyou.

Besr Regard,

Sinta.

On Jul 11, 2017 4:24 PM, "Marcus Müller" <address@hidden> wrote:

You're just saving samples from the USRP – there's no info like "frequency" or "time" attached to those. It's just a very long row of complex numbers.

Best regards,

Marcus

On 07/11/2017 01:23 AM, Sinta Novtafiani wrote:

Hello Marcus,

Thankyou for your advice. I just want to know data actual of my program like frequency, time and power then save as file txt so i can read the data anytime. But i have problem, when i read the raw binary file use those source code above, its appears float data in one coloumn and i don't know which one frequency, time, or power because i didn't got header of the data. I have to convert .dat file into format that can read anywhere or convert to numerical data in matrix because the data will process furthermore 

On Jul 10, 2017 2:09 PM, "Marcus Müller" <address@hidden> wrote:

Dear Sinta,

I've had this discussion several times before, so let me please shortly mention that you've signed up to the mailing list via Nabble, which is a very suboptimal thing for you (you might miss answers posted by us). Please sign out of nabble, and sign up directly to https://lists.gnu.org/mailman/listinfo/discuss-gnuradio; enough of that :)

This is more of a collection of thoughts for future readers than direct criticism on your approach:

Well, I really don't know why you would want a text file containing float samples. It doesn't make sense from a precision point of view, it doesn't make sense from a storage size point of view, and it doesn't even make sense from a usability point of view – I don't really believe you'll get a "feeling" for data if you scroll around in a 1mio lines text file :)

That being said, there's probably very legitimate reason you'd want a CSV file (for example, get a couple data points only to import them into a spreadsheet software). You probably want to look into the "Head" block that limits the number of items going through.

Also, you could just as well in your Python code not save all of `data`, but only let's say `data[:100]`.

Best regards,

Marcus

On 07/10/2017 08:54 AM, Sinta Novtafiani wrote:

Hello Nicholas,

Thankyou for your reply. I've try that way and its work. I have a problem, my file that generate from file sink is big. And it cause text edtior become not reponding when i open file that have converted to txt. Did you know how to control file size from file sink?

I use this code below to convert binary file into txt

data="">name'), dtype=scipy.float32)

scipy.savetxt('filename.txt', data)

On Mon, Jul 10, 2017 at 1:52 AM, Nicolas Cuervo <address@hidden> wrote:

Hello Sinta,

This specific question is handled in the GNURadio FAQ [1]. Please try to use the scipy.fromfile() method and check if the output agrees with your expectations.

Regards,

- Nicolas

[1] https://wiki.gnuradio.org/index.php/FAQ#What_is_the_file_format_of_a_file_sink.3F_How_can_I_read_files_produced_by_a_file_sink.3F

On Mon, Jul 10, 2017 at 5:25 AM, Sinta Novtafiani <address@hidden> wrote:

I got UHD Source receiver with frequency sweeper, its working fine but i need
to read and actually process the data to make graph out of it without using
QT GUI, i try to open with hex editor but dont seem to understand the
pattern of the file that i need to process, im making python program to
convert it to numbers but the number that comes up doesnt seem relevant with
the one i see at QT GUI.
<http://gnuradio.4.n7.nabble.com/file/n64518/receiver.png>
<http://gnuradio.4.n7.nabble.com/file/n64518/46_AM.png>



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