Samples are what comes out of your USRP, and what you process in GNU Radio.
What a tag is, how blocks work, and how you can write your own is all covered in the guided tutorials; I'd recommend reading those from first to 6, because that will cover all these topics, including dealing with Hardware like the USRP. Best regards, Marcus On 06/15/2015 10:49 PM, Ashraf Younis wrote: > I'm sorry but this is all too much. I need some help breaking this > process down. > What do you mean by samples, Is that the frequency list? > My first block is reading the data from the file, and has an input for > tx_tune? > What is a tag? > When I do all this I will run it in GRC, correct? > > On Mon, Jun 15, 2015 at 12:31 PM, Marcus Müller > <marcus.muel...@ettus.com <mailto:marcus.muel...@ettus.com>> wrote: > > Hi Ashraf, > > thanks for the nice words and the detailed problem description. > > Yes, I think there are ways to achieve what you want; you will > have to write a few GNU Radio blocks, but I think it's possible to > do after lecture of the GNU Radio guided tutorials [1]; if you > encounter any obstacles, the mailing list probably will have an > open ear for you :) > > You could write your own block that passes through samples, and > controls the USRP. For starters, that could be done in python, if > that feels more familiar to you than C++. It will have to be a > general block. > > As a first step, that block would simply wait for a tx_time tag > coming in. That tag value contains the time at which tuning happened. > Use that time to calculate the time at which the next tuning > should occur. > Give your block the ability to call your usrp_source's > set_command_time() with that time. > Use message passing to issue the tuning command [2]. > After each tag, pass a fixed amount of samples <= > (inter_tune_time*sampling rate), and just consume the rest, until > the next tag appears. Pass through the rx_freq tag to the first > passed sample. > > Connect your block's input to your usrp_source's output, and > message_connect your block's message output to the usrp_source's > message input. > > Connect the output of your block to a stream to vector; connect > that to whatever processing you want to do. For example, you can > do an FFT. > After the FFT, you could attach another block that you'd write > yourself, that would take the rx_freq tag again,and based on that, > would for example put the FFT vector into the right position in an > array of FFT vectors. > > Best regards, > Marcus > > [1] > https://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorials > [2] http://gnuradio.org/doc/doxygen/page_uhd.html#uhd_command_syntax > On 06/15/2015 06:10 PM, Ashraf Younis wrote: >> I have been trying to make my NI-B200 scan frequencies that I >> have in a text file for a couple days now. I was introduced to >> this mailing list through the GNU website and it has helped me >> alot these past few day, Thank you all, but I haven't completed >> my task yet so I'm going to be as specific as possible with what >> I need help with and with what I have been doing. >> >> I have a list of about 1000+ frequencies and I need to scan all >> of them with my NI-B200 and record their power(dB). I am >> currently using using usrp_spectrum_sense.py >> >> (https://github.com/gnuradio/gnuradio/blob/master/gr-uhd/examples/python/usrp_spectrum_sense.py) >> to scan the frequencies but it scans a range and not the specific >> frequencies I want so I made my own py file that simply loop the >> execution of usrp_spectrum_sense.py until the end of the list. It >> is a very crude way of going about things. Is there a better, >> much cleaner way I can accomplish my goal? >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> >> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org <mailto:Discuss-gnuradio@gnu.org> > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
