discuss-gnuradio
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Discuss-gnuradio] GNU Radio flow graph for Spectrum sensing


From: Rodrigo Rozário
Subject: Re: [Discuss-gnuradio] GNU Radio flow graph for Spectrum sensing
Date: Fri, 15 Aug 2014 20:54:30 -0300

Hi Marcus,

Thanks for your reply. Now I understand the size of the file :D.
I really used 1MS/s for sample rate.

Folowing what you said, I take directly form the source. I tried as you can see in the attachment (before I will save the values in the file).

With the filter FIR and looking for FFT, the values of the power seen different.

Is there other implementation to get the value of the power?


2014-08-14 9:56 GMT-03:00 Marcus Müller <address@hidden>:
Hi Rodrigo (once again),

one of the wise elders reminded me that in the FFT, power is but
proportional to the input power in time domain, due to a factor of
fft_length occuring when forward-backward transforming.

Greetings,
Marcus

On 14.08.2014 11:29, Marcus Müller wrote:
> Hi Rodrigo,
>  both is right, due to Parseval's Theorem stating that energy of a
> signal in time and frequency domain is equivalent.
>
> Regarding "File is large": of course it is; I don't know what sampling
> rate you're using, but assume you have 1MS/s of complex float, that will be
> 2*32bit*10^6/s = 8MB/s of data.
>
> Regarding "it cannot be opened": Opened by what? Maybe you're not aware of:
> http://gnuradio.org/redmine/projects/gnuradio/wiki/FAQ#What-is-the-file-format-of-a-gr_file_sink-How-can-I-read-files-produced-by-a-file-sink
>
> Greetings,
> Marcus
> On 13.08.2014 23:29, Rodrigo Rozário wrote:
>> Hi Martin,
>>
>> I am generating by the following flowgraph:
>>
>> RTL2832 source -> FFT -> File Sink
>>
>> I tried too:
>>
>> RTL2832 -> File Sink
>>
>> Is it right?
>>
>>
>>
>>
>> 2014-08-13 9:00 GMT-03:00 Martin Braun <address@hidden>:
>>
>>> How are you generating those files?
>>>
>>>
>>> On 08/12/2014 01:30 AM, Rodrigo Rozário wrote:
>>>> Hi guys,
>>>>
>>>> I'm trying to configure a spectrum analyzer with GNU Radio and I had a
>>>> many problems. I tried a lot of ways to do it but all of them failed.
>>>>
>>>> More specifically, I need to get information about the FFT and store it.
>>>>
>>>> I tried the following:
>>>> - I get data from the block RTL2832 and store it: this is generates a
>>>> very big file data end a can't open. In a file of a few seconds of
>>>> storage (50Mb) I can't recognize the power values.
>>>>
>>>> - I try to store and after open it on a editor, but not work.
>>>>
>>>> I think that there is any problem in the format of the data stored. Can
>>>> you help? Anyone already can do it?
>>>>
>>>>
>>>> --
>>>> /*Rodrigo Rozário */
>>>> /CREA-DF - 21339/D-DF - Professional Registration/
>>>> /Engenheiro de Redes de Comunicação - //Network Engineering/
>>>> /Universidade de Brasília - //University of Brasília/
>>>> /
>>>> /
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Discuss-gnuradio mailing list
>>>> address@hidden
>>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>>
>>> _______________________________________________
>>> Discuss-gnuradio mailing list
>>> address@hidden
>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>>>
>>
>> _______________________________________________
>> Discuss-gnuradio mailing list
>> address@hidden
>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
>


_______________________________________________
Discuss-gnuradio mailing list
address@hidden
https://lists.gnu.org/mailman/listinfo/discuss-gnuradio



--
Rodrigo Rozário 
CREA-DF - 21339/D-DF
Engenheiro de Redes de Comunicação 
Universidade de Brasília

Attachment: Captura de Tela 2014-08-15 às 20.22.42.png
Description: PNG image


reply via email to

[Prev in Thread] Current Thread [Next in Thread]