The frequency band ranges from 470MHz to 806MHz, each channel's frequency band is 8MHz, so we have 42 channels in total. Channel 1,3,5,7 are analog channels, others are digital channels.
I want to set the value of parameters in usrp_spectrum_sense.py as follows: fft-size: 2048 channel-bandwidth:8e6 samp-rate:12.5e6 freq_step: 8e6. dwell-delay:0.5 tune-delay:0.5 I experiment with ./usrp_spectrum_sense.py Then for each channel, we have 2048 bins, which can be used to calculate each channel's power(in dB). Am I right? On Mon, Apr 8, 2013 at 12:38 AM, Mike Jameson <m...@scanoo.com> wrote: > Hi, > > For your application, please experiment with the following command: > > ./usrp_spectrum_sense.py -A TX/RX --fft-size=25 --samp-rate=25e6 --gain=15 > --dwell-delay=0.25 --tune-delay=0.25 --channel-bandwidth=8e6 470e6 800e6 > > Note that 'freq_step' should remain unchanged at '0.75 * usrp_rate' in the > script to make sure signals at the edge of the incoming front-end signal > bandwidth (25MHz) are not missed. > > > Mike > > -- > Mike Jameson M0MIK BSc > Email: m...@scanoo.com > Web: http://scanoo.com > > > On 7 April 2013 17:22, Jincheng Zhang <perfume0...@gmail.com> wrote: > >> Thanks Mike. I'm a little confused. The parameters are listed as follows: >> >> sample-rate: >> channel-bandwidth: >> freq_step: >> fft_size: >> >> You mean that I should set sample-rate be 25e6, channel-bandwidth be 8e6, >> freq_step be 8e6 and fft_size be 25? >> >> If we set the fft-size be 25, then which 8 bins I should select to >> calculate the power? By the way, since the magnitude of FFT bin is decimal, >> maybe I should change the magnitude of FFT bin values to mw and add the 8 >> bins, and then transfer to decimal again? Since we cannot straightly add >> the FFT bin values in decimal. >> >> By the way, how about the "self.connect", should I add the log parameter >> to it? >> >> Thanks. Hope for your reply. >> >> >> >> On Mon, Apr 8, 2013 at 12:11 AM, Mike Jameson <m...@scanoo.com> wrote: >> >>> Hi Jincheng, >>> >>> Try setting the UHD sample rate to 25e6 and the number of fft bins to 25 >>> which will give you 1e6 Hz per bin. Adding up the magnitude of 8 bins >>> (1MHz * 8 = 8MHz) will therefore give you the wanted channel power in >>> decimal format (magnitude). >>> >>> In case you are confused, I recently updated usrp_spectrum_sense.py to >>> include a --channel-bandwidth setting which rounds up the frequency >>> displayed to the nearest frequency. I'm working on making it cleaner by >>> adjusting the fft size to match the wanted channel. In the meantime, set >>> '--channel-bandwidth=8e6' to make the frequency round to the nearest 8MHz >>> frequency. >>> >>> Hope that helps, >>> >>> Mike >>> >>> -- >>> Mike Jameson M0MIK BSc >>> Email: m...@scanoo.com >>> Web: http://scanoo.com >>> >>> >>> On 7 April 2013 16:23, Jincheng Zhang <perfume0...@gmail.com> wrote: >>> >>>> I want to use usrp_spectrum_sense.py to sweep the Hong Kong TV band >>>> which ranges from 470MHz to 806MHz and get every channel's power in dB. >>>> Each channel's frequency band is 8MHz. >>>> >>>> Now I'm using USRP2 with TVRX2 daughter board. I have installed the >>>> latest gnuraio and uhd. But when I use the usrp_spectrum_sense.py to get >>>> the power of each channel, some FFT bin values are extremely big. In >>>> particular, I'm not sure abou the self.connect(self.u, s2v, fft, >>>> c2mag, stats). It doesn't take "log" as the parameter, >>>> >>>> FFT size is 2048, sample-rate is 12.5MHz(to let the decimation be 8M), >>>> freq_step is 8MHz. Anyone has any ideas about how to use >>>> usrp_spectrum_sense.py to calculate each channel's power? >>>> >>>> >>>> On Sun, Apr 7, 2013 at 8:24 PM, Jincheng Zhang >>>> <perfume0...@gmail.com>wrote: >>>> >>>>> Hi, all, >>>>> >>>>> I use the usrp_spectrum_sense.py to sweep the TV band from 470MHz >>>>> to 806MHz. But when I use self.connect(self.u, s2v, fft, c2mag, log, >>>>> stats), the FFT bin values I got are all zero. >>>>> Also, what's the magnitude of FFT bin value? Thanks. >>>>> >>>>> -- >>>>> Best regards, >>>>> Jincheng Zhang >>>>> >>>> >>>> >>>> >>>> -- >>>> Best regards, >>>> Jincheng Zhang >>>> Department of Information Engineering >>>> The Chinese University of Hong Kong >>>> http://personal.ie.cuhk.edu.hk/~zj012/ <http://www.jxqc.org/> >>>> >>>> _______________________________________________ >>>> Discuss-gnuradio mailing list >>>> Discuss-gnuradio@gnu.org >>>> https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>>> >>>> >>> >> >> >> -- >> Best regards, >> Jincheng Zhang >> Department of Information Engineering >> The Chinese University of Hong Kong >> http://personal.ie.cuhk.edu.hk/~zj012/ <http://www.jxqc.org/> >> > > -- Best regards, Jincheng Zhang Department of Information Engineering The Chinese University of Hong Kong http://personal.ie.cuhk.edu.hk/~zj012/ <http://www.jxqc.org/>
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
