Hi:
Thank you so much for your kindly reply.
Sorry for my poor English.
The reason why i directly write the c++ code is that I want to use the uhd to control my two usrps send simultaneously.
The aim i want to reach is that read symbol from file and perform ifft and insert cp and then transmit.Just like you write:
[file source 1] --> [ (I)FFT ] --> [ cyclic prefixer ] --> [ USRP sink 1]
[file source 2] --> [ (I)FFT ] --> [ cyclic prefixer ] --> [ USRP sink 2]
I can control them simutanously.Use some class like uhd::usrp::multi_usrp.
Which is the best way to realize it?Use the c++ or write python flow graph?Thanks.
Thank you so much.
Best regards,
xianda
At 2014-05-31 08:25:53, "Marcus Müller" <address@hidden> wrote:
>Hi Xianda,
>
>some of your emails are really hard to read due to your email client
>writing non-standard-compliant HTML mail. Could you disable
>HTML/multimedia mail?
>
>> What I want to do is that read symbols from file and perform fft and insert cp and then transmit to the usrp.
>ok, thanks for clarifying that!
>
>>Just as the "fft" and "OFDM Cyclic Prefixer" do!
>
>Well, the fft block doesn't read from a file, and ofdm cyclic prefixer does not transmit, but I get your point.
>
>> The easy way is use the <gnuradio/fft/fft.h> and <gnuradio/digital/ofdm_cyclic_prefixer.h>;
>
>No!
>In GNU Radio, you build flow graphs out of existing blocks, whenever possible. So you want to use
>
>[file source] --> [ (I)FFT ] --> [ cyclic prefixer ] --> [ USRP sink ]
>
>by instantiating these blocks, and connecting them to a GNU Radio flow graph. Then you let GNU Radio run that flow graph.
>There's no need to write your own block, so far. Actually, you can do this without writing a single line of code just by constructing
>above flow graph in gnuradio-companion. That will generate the flowgraph setup and starting program in python.
>
>If you need to add more functionality, you usually just add another block to this chain, but from what you've said there will be no need to do this.
>
>
>> But as you said fft_complex_vcc is a block. But now how can i call it in my code?
>
>You don't, see my previous post on calling work().
>
>
>Greetings,
>Marcus
>
>
>
>On 31.05.2014 13:53, xianda wrote:
>> Hi:<br/> Thank you so much.<br/> What I want to do is that read symbols from file and perform fft and insert cp and then transmit to the usrp.Just as the "fft" and "OFDM Cyclic Prefixer" do!<br/> The easy way is use the<gnuradio/fft/fft.h> and <gnuradio/digital/ofdm_cyclic_prefixer.h>.But as you said fft_complex_vcc is a block.But now how can i call it in my code?(It's a block.It has work function.)Can i add it's work function in my code?Thank you.<br/>Best regards,<br/>xianda
>> At 2014-05-31 07:36:24, "Marcus Müller" <address@hidden> wrote:
>>> Hi Xianda,
>>>
>>>> I just want to write c++ code to realize ("fft" block+"OFDM Cyclic
>>> Prefixer").
>>>
>>> Sorry, I still did not understand. I only understand your C++, so here's
>>> my comments:
>>>
>>> The code you posted has really nothing to do with gr::block;
>>> gr::fft:fft_complex is *not* a gr::block, and has no work()!
>>> http://gnuradio.org/doc/doxygen/classgr_1_1fft_1_1fft__complex.html
>>>
>>> Also, I don't see the need to #include
>>> <gnuradio/digital/ofdm_cyclic_prefixer.h>. Is this a mistake or was it
>>> intentional?
>>>
>>> fft_complex really just a convenience wrapper around FFTW.
>>> I haven't tried to test your code, and you could read() directly into
>>> the get_inbuf() buffer, and write directly from your get_outbuf()
>>> buffer, but it looks ok.
>>>
>>> Again: gr::fft:fft_complex is not a block! it is used from within
>>> fft_complex_vcc (which is a block).
>>> All it does is use the FFTW library to perform FFTs, you can do that
>>> yourself without using GNU Radio at all. Only use it when you are
>>> developing a GNU Radio program!
>>>
>>> Greetings,
>>> Marcus
>>>
>>>
>>> On 31.05.2014 13:21, xianda wrote:
>>>> Hi:
>>>> Thank you so much.
>>>> I just want to write c++ code to realize ("fft" block+"OFDM Cyclic Prefixer").
>>>> And I attached my code which just realize ifft but the "OFDM Cyclic Prefixer" has it's work function.
>>>> #include <fstream>
>>>> #include <vector>
>>>> #include <gnuradio/gr_complex.h>
>>>> #include <gnuradio/fft/fft.h>
>>>> #include <gnuradio/digital/ofdm_cyclic_prefixer.h>
>>>>
>>>> std::vector<std::complex<float> *> buff1(64);//read data
>>>> std::vector<std::complex<float> *> buff2(64);//write data
>>>>
>>>> std::ifstream infile("a.dat",std::ifstream::binary);
>>>> std::ofstream outfile("b.dat",std::ofstream::binary);
>>>>
>>>> int main(){
>>>> while(not infile.eof())
>>>> {
>>>> infile.read((char*)&buff1.front(),buff1.size()*sizeof(std::complex<float>));
>>>>
>>>> gr::fft::fft_complex *buff=new gr::fft::fft_complex(64,0);
>>>> gr_complex *bu=buff->get_inbuf();
>>>> memcpy(bu,&buff1.front(),buff1.size()*sizeof(std::complex<float>));
>>>> buff->execute();
>>>> gr_complex *out=buff->get_outbuf();
>>>> memcpy(&buff2.front(),out,buff2.size()*sizeof(std::complex<float>));
>>>>
>>>> outfile.write((char*)&buff2.front(),buff2.size()*sizeof(std::complex<float>));
>>>> }
>>>>
>>>> infile.close();
>>>> outfile.close();
>>>> }
>>>>
>>>> Thank you.
>>>> Best regards,
>>>> xianda
>>>>
>>>> At 2014-05-31 06:33:35, "Martin Braun" <address@hidden> wrote:
>>>>
>>>>
>>>>
>>>> On 31 May 2014 11:57, "Marcus Müller" <address@hidden> wrote:
>>>>> Hi Xianda,
>>>>>
>>>>>
>>>>>> I know every block should have it's work or general_work function.And i know it's used by scheduler
>>>> For the record, a block that only uses message passing doesn't need a work function - not that that's what you're looking for here.
>>>>
>>>>
>>>> M
>>>>
>>>>
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