---------- Forwarded message ---------- From: Soumaya el barrak <elbarrak.soum...@gmail.com> Date: 2017-01-16 10:32 GMT+01:00 Subject: Re: [Discuss-gnuradio] usrp_spectrum_sense.py input parameters in USRP B200 To: Marcus Müller <marcus.muel...@ettus.com>
Hi Marcus, Thank you so much for your reply, I followed your recommendations, I used a sample-rate of 8MS/s and FFT-size 1024 and I kept the tune-delay and dwell-delay at 0.25 s. But I still receive some strange power values while scanning the 2.4 GHz band. I also obtained high power picks while tuning from one center frequency to another. Could you please explain for me where I am mistaken? And what is the explanation of those power picks? Best.. Soumaya 2017-01-13 14:46 GMT+01:00 Marcus Müller <marcus.muel...@ettus.com>: > Hi Soumaya, > > the B200 tunes slower and might need up to half a second when tuning > further. > > You should hence minimize the amount of tuning, and instead of 4MS/s use a > higher rate, a larger FFT size, and tune less often. > > The power normalization is truly, 100%, arbitrary. Since these dB are all > "relative to digital 1", they only have linear relation with real-world > powers. > > > Best regards, > > Marcus > > On 01/13/2017 11:40 AM, Soumaya el barrak wrote: > > Dear all, > > I am working with USRP B200 for spectrum sensing, I want to scan the band > from 2.4 to 2.5 Ghz, I use fft size 256, and sample_rate 4M, and tune > _delay 0,001s. I am not sure if the parameters are correctely chosen > because when I try to scan another band without wireless activities, I > still receive hight power levels. Can anyone has any idea about where I am > mistaken ? > > Also, in the formula used to calculate the PSD : > > Power_dB = 10*math.log10(m.data[i_bin]/tb.usrp_rate); > > Normally it is the magnitude squared averaged , I want to know why it is > averaged by the usrp_rate ? > > > Thank you in advance ! > > Soumaya > > -- > > *EL BARRAK Soumaya* > > *Telecommunication & Networking Engineer / Phd Student* > > *Innovative Technologies Laboratory* > > *National School of Applied Sciences of Tangier - (ENSA Tanger)* > > *Abdelmalek Essaâdi University - Morocco* > > *Tel : (+212) 6 65 9 625 40/ (+ 39) 327 198 5064 <+39%20327%20198%205064>* > > > _______________________________________________ > Discuss-gnuradio mailing > listDiscuss-gnuradio@gnu.orghttps://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- *EL BARRAK Soumaya* *Telecommunication & Networking Engineer / Phd Student* *Innovative Technologies Laboratory* *National School of Applied Sciences of Tangier - (ENSA Tanger)* *Abdelmalek Essaâdi University - Morocco* *Tel : (+212) 6 65 9 625 40/ (+ 39) 327 198 5064 <+39%20327%20198%205064>* -- *EL BARRAK Soumaya* *Telecommunication & Networking Engineer / Phd Student* *Innovative Technologies Laboratory* *National School of Applied Sciences of Tangier - (ENSA Tanger)* *Abdelmalek Essaâdi University - Morocco* *Tel : (+212) 6 65 9 625 40/ (+ 39) 327 198 5064*
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