Thanks a lot Nick! So I guess I need something like tune_delay in usrp_spectrum_sense.py? At least I finally got data that looks much more like the expected spectrum when I used the latter behaving like uhd_rx_cfile.py. -Sebastian On Wed, 14 Mar 2012 10:15:14 -0700 Nick Foster <nick@ettus.com> wrote: > Sebastian, > > You are seeing the effect of finite tuning time. The >N210 will start > returning samples immediately after the tune command, >and so you will be > able to observe the SBX/WBX PLL locking on and settling >at its final > frequency. You need to discard the first few hundred >microseconds of data > after a tune command before you will see reliable data. > > --n > > On Wed, Mar 14, 2012 at 6:05 AM, Sebastian Döring > <sdoering@rhrk.uni-kl.de>wrote: > >> >> >> On Wed, 14 Mar 2012 11:21:29 +0100 >> Andre Puschmann <andre.puschmann@tu-ilmenau.de**> >>wrote: >> >>> On 03/14/2012 10:03 AM, Sebastian Döring wrote: >>> >>>> @ steam: UHD version is "UHD_003.004.000-b8e41cb" and >>>>FPGA image is the >>>> corresponding one for revision number R2. >>>> @ Nick: I attached 2 figures. The supposed-to-look-like >>>>case I get with >>>> XCVR and independent spectrum analyzer and the one I get >>>>using the SBX. >>>> >>>> Both data sets have been recorded using "uhd_rx_cfile.py >>>>-f 2.4G -N >>>> 1024". >>>> I processed the samples with octave performing fft, >>>>square magnitude and >>>> translated them to dB level scaled with 20*log10(x). >>>> >>> >>> What rx rate are you using? Have you tried modifying it? >>>I've seen >>> similar things happening at certain rx rates. >>> >>> -Andre >>> >> >> Yes, tried it and always had the same effect. >> Also tried it with the WBX by now --> same distortion. >> >> -Sebastian >> >> >>> >>> >>>> -Sebastian >>>> >>>> >>>> On Tue, 13 Mar 2012 18:25:34 +0100 >>>> "steam2009@t-online.de" <steam2009@t-online.de> wrote: >>>> >>>>> Out of curiousity what FPGA / UHD version are you using. >>>>> >>>>> >>>>> Von: "Sebastian Döring" <sdoering@rhrk.uni-kl.de> >>>>> Datum: Tue, 13 Mar 2012 10:11:22 +0100 >>>>> >>>>> The output of uhd_usrp_probe is the following: >>>>>> >>>>> >>>>> ______________________________**_______________________ >>>>> / >>>>> | Device: USRP2 / N-Series Device >>>>> | >>>>> ______________________________**_______________________ >>>>> | / >>>>> | | Mboard: USRP-N210 >>>>> | | hardware: 2561 >>>>> | | mac-addr: a0:36:fa:25:32:f2 >>>>> | | ip-addr: 192.168.10.2 >>>>> | | gpsdo: none >>>>> | | serial: EFR12W2UP >>>>> | | >>>>> | | Time sources: none, external, _external_, mimo >>>>> | | Clock sources: internal, external, mimo >>>>> | | Sensors: mimo_locked, ref_locked >>>>> | | >>>>> ______________________________**_______________________ >>>>> | | / >>>>> | | | RX DSP: 0 >>>>> | | | Freq range: -50.000 to 50.000 Mhz >>>>> | | >>>>> ______________________________**_______________________ >>>>> | | / >>>>> | | | RX DSP: 1 >>>>> | | | Freq range: -50.000 to 50.000 Mhz >>>>> | | >>>>> ______________________________**_______________________ >>>>> | | / >>>>> | | | RX Dboard: A >>>>> | | | ID: SBX (0x0054) >>>>> | | | Serial: E8R12X9XS >>>>> | | | >>>>> ______________________________**_______________________ >>>>> | | | / >>>>> | | | | RX Subdev: 0 >>>>> | | | | Name: SBX RX >>>>> | | | | Antennas: TX/RX, RX2, CAL >>>>> | | | | Sensors: lo_locked >>>>> | | | | Freq range: 400.000 to 4400.000 Mhz >>>>> | | | | Gain range PGA0: 0.0 to 31.5 step 0.5 dB >>>>> | | | | Connection Type: IQ >>>>> | | | | Uses LO offset: No >>>>> | | | >>>>> ______________________________**_______________________ >>>>> | | | / >>>>> | | | | RX Codec: A >>>>> | | | | Name: ads62p44 >>>>> | | | | Gain range digital: 0.0 to 6.0 step 0.5 >>>>>dB >>>>> | | | | Gain range fine: 0.0 to 0.5 step 0.1 dB >>>>> | | >>>>> ______________________________**_______________________ >>>>> | | / >>>>> | | | TX DSP: 0 >>>>> | | | Freq range: -250.000 to 250.000 Mhz >>>>> | | >>>>> ______________________________**_______________________ >>>>> | | / >>>>> | | | TX Dboard: A >>>>> | | | ID: SBX (0x0055) >>>>> | | | Serial: E8R12X9XS >>>>> | | | >>>>> ______________________________**_______________________ >>>>> | | | / >>>>> | | | | TX Subdev: 0 >>>>> | | | | Name: SBX TX >>>>> | | | | Antennas: TX/RX, CAL >>>>> | | | | Sensors: lo_locked >>>>> | | | | Freq range: 400.000 to 4400.000 Mhz >>>>> | | | | Gain range PGA0: 0.0 to 31.5 step 0.5 dB >>>>> | | | | Connection Type: QI >>>>> | | | | Uses LO offset: No >>>>> | | | >>>>> ______________________________**_______________________ >>>>> | | | / >>>>> | | | | TX Codec: A >>>>> | | | | Name: ad9777 >>>>> | | | | Gain Elements: None >>>>> >>>>> >>>>> >>>>> I really appreciate any further information. >>>>> >>>>> Regards >>>>> Sebastian >>>>> >>>>> >>>>> On Mon, 12 Mar 2012 11:07:39 -0700 >>>>> Jason Abele <jason@ettus.com> wrote: >>>>> >>>>>> Sebastian, >>>>>> >>>>>> The units displayed in uhd_fft.py are not absolute and >>>>>>the XCVR and SBX >>>>>> have vastly different absolute gain at a setting of >>>>>>"0dB". Thus, they >>>>>> are not really comparable at the same gain setting. >>>>>> >>>>>> If you want to compare them, apply a sine wave of known >>>>>>power (say >>>>>> -50dBm) and use it to "calibrate" the units in >>>>>>uhd_fft.py into dBm. >>>>>> >>>>>> Then you can compare SBX to XCVR. >>>>>> >>>>>> Also note that the implicit scale factor in the >>>>>>"calibration" performed >>>>>> above will vary with gain setting. >>>>>> >>>>>> If you send your uhd_ffy.py command, it will be easier >>>>>>to comment on >>>>>> the >>>>>> expected SBX behavior. >>>>>> >>>>>> It is also helpful to provide the output of >>>>>>uhd_usrp_probe such that we >>>>>> can see the UHD and hardware versions you are using. >>>>>> >>>>>> Thanks >>>>>> Jason >>>>>> >>>>>> On Mon, Mar 12, 2012 at 01:51:51PM +0100, Sebastian >>>>>>Döring wrote: >>>>>> >>>>>>> Hello, >>>>>>> >>>>>>> I have been doing some spectrum sensing with the USRP >>>>>>>N210 and the >>>>>>> XCVR2450. >>>>>>> Today I tried the same stuff with the SBX daughterboard >>>>>>>and suddenly >>>>>>> the signal level at the output seems to have an offset >>>>>>>of around >>>>>>> +20dB. >>>>>>> With the XCVR I usually measure a noise level around >>>>>>>-100dB and with >>>>>>> the SBX I get something around -80dB (both with gain >>>>>>>tuned to "0"). >>>>>>> >>>>>>> My question is, if there's some other gain parameter in >>>>>>>the SBX that >>>>>>> I can´t control? >>>>>>> I used the same antenna and the same USRP. >>>>>>> >>>>>>> Any hints highly appreciated! >>>>>>> >>>>>>> Regards >>>>>>> Sebastian >>>>>>> >>>>>>> ______________________________**_________________ >>>>>>> USRP-users mailing list >>>>>>> USRP-users@lists.ettus.com >>>>>>> http://lists.ettus.com/**mailman/listinfo/usrp-users_** >>>>>>> lists.ettus.com<http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com> >>>>>>> >>>>>> >>>>> >>>>> ______________________________**_________________ >>>>> USRP-users mailing list >>>>> USRP-users@lists.ettus.com >>>>> http://lists.ettus.com/**mailman/listinfo/usrp-users_**lists.ettus.com<http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com> >>>>> >>>>> >>>>> >>>>> >>>>> ______________________________**_________________ >>>>> USRP-users mailing list >>>>> USRP-users@lists.ettus.com >>>>> http://lists.ettus.com/**mailman/listinfo/usrp-users_**lists.ettus.com<http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com> >>>>> >>>> >>>> >>>> ______________________________**_________________ >>>> USRP-users mailing list >>>> USRP-users@lists.ettus.com >>>> http://lists.ettus.com/**mailman/listinfo/usrp-users_**lists.ettus.com<http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com> >>>> >>> >>> >>> -- >>> Andre Puschmann >>> Ilmenau University of Technology, Integrated >>>Communication Systems Group >>> Phone: +49 3677 69-4132, Fax: +49 3677 69-1614 >>> Email: andre.puschmann@tu-ilmenau.de, Web: >>>http://www.tu-ilmenau.de/ics >>> Office: Zuse Building, room 1071 >>> >> >> >> ______________________________**_________________ >> USRP-users mailing list >> USRP-users@lists.ettus.com >> http://lists.ettus.com/**mailman/listinfo/usrp-users_**lists.ettus.com<http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com> >>