Try disabling automatic DC offset removal, or performing an offset tuning operation.
Brian On Wed, May 23, 2018 at 3:50 PM Martin K via USRP-users < usrp-users@lists.ettus.com> wrote: > BPSK modulated RF at 2.2 GHz, -15dBm, feeding a power splitter >> | >> (A) --> -9dB pad --> B210 >> (B) --> Agilent VSA. >> >> >> TX Symbol rate is 1389 Hz and RX symbol rate was set to 5556 Hz to give >> the illusion of 4 symbols high and 4 symbols low. (11110000) which is what >> you see illustrated in each of the two images (if they displayed correctly >> in the email) >> >> I am capturing the signal by using a simple GNURadio block --> file sink >> Sample rate is 222kHz. Fctr is 2.2 GHz. >> >> (message from GNURadio console) >> Win32; Microsoft Visual C++ version 14.0; Boost_106000; >> UHD_003.010.001.001-0-unknown >> >> >> UHD Error: >> Device discovery error: input stream error >> -- Detected Device: B210 >> -- Operating over USB 3. >> -- Initialize CODEC control... >> -- Initialize Radio control... >> -- Performing register loopback test... pass >> -- Performing register loopback test... pass >> -- Performing CODEC loopback test... pass >> -- Performing CODEC loopback test... pass >> -- Setting master clock rate selection to 'automatic'. >> -- Asking for clock rate 16.000000 MHz... >> -- Actually got clock rate 16.000000 MHz. >> -- Performing timer loopback test... pass >> -- Performing timer loopback test... pass >> -- Asking for clock rate 56.832000 MHz... >> -- Actually got clock rate 56.832000 MHz. >> -- Performing timer loopback test... pass >> -- Performing timer loopback test... pass >> gr::pagesize: no info; setting pagesize = 4096 >> -- Asking for clock rate 56.832000 MHz... OK >> -- Asking for clock rate 56.832000 MHz... OK >> >> >>> Done >> >> (GNURadio block diagram) >> (run_gr console) >> >uhd_usrp_probe >> Win32; Microsoft Visual C++ version 14.0; Boost_106000; >> UHD_003.010.001.001-0-unknown >> >> >> UHD Error: >> Device discovery error: input stream error >> -- Detected Device: B210 >> -- Operating over USB 3. >> -- Initialize CODEC control... >> -- Initialize Radio control... >> -- Performing register loopback test... pass >> -- Performing register loopback test... pass >> -- Performing CODEC loopback test... pass >> -- Performing CODEC loopback test... pass >> -- Setting master clock rate selection to 'automatic'. >> -- Asking for clock rate 16.000000 MHz... >> -- Actually got clock rate 16.000000 MHz. >> -- Performing timer loopback test... pass >> -- Performing timer loopback test... pass >> _____________________________________________________ >> / >> | Device: B-Series Device >> | _____________________________________________________ >> | / >> | | Mboard: B210 >> | | revision: 4 >> | | product: 2 >> | | serial: 312B45E >> | | name: MyB210 >> | | FW Version: 8.0 >> | | FPGA Version: 14.0 >> | | >> | | Time sources: none, internal, external, gpsdo >> | | Clock sources: internal, external, gpsdo >> | | Sensors: ref_locked >> | | _____________________________________________________ >> | | / >> | | | RX DSP: 0 >> | | | >> | | | Freq range: -8.000 to 8.000 MHz >> | | _____________________________________________________ >> | | / >> | | | RX DSP: 1 >> | | | >> | | | Freq range: -8.000 to 8.000 MHz >> | | _____________________________________________________ >> | | / >> | | | RX Dboard: A >> | | | _____________________________________________________ >> | | | / >> | | | | RX Frontend: A >> | | | | Name: FE-RX2 >> | | | | Antennas: TX/RX, RX2 >> | | | | Sensors: temp, rssi, lo_locked >> | | | | Freq range: 50.000 to 6000.000 MHz >> | | | | Gain range PGA: 0.0 to 76.0 step 1.0 dB >> | | | | Bandwidth range: 200000.0 to 56000000.0 step 0.0 Hz >> | | | | Connection Type: IQ >> | | | | Uses LO offset: No >> | | | _____________________________________________________ >> | | | / >> | | | | RX Frontend: B >> | | | | Name: FE-RX1 >> | | | | Antennas: TX/RX, RX2 >> | | | | Sensors: temp, rssi, lo_locked >> | | | | Freq range: 50.000 to 6000.000 MHz >> | | | | Gain range PGA: 0.0 to 76.0 step 1.0 dB >> | | | | Bandwidth range: 200000.0 to 56000000.0 step 0.0 Hz >> | | | | Connection Type: IQ >> | | | | Uses LO offset: No >> | | | _____________________________________________________ >> | | | / >> | | | | RX Codec: A >> | | | | Name: B210 RX dual ADC >> | | | | Gain Elements: None >> | | _____________________________________________________ >> | | / >> | | | TX DSP: 0 >> | | | >> | | | Freq range: -8.000 to 8.000 MHz >> | | _____________________________________________________ >> | | / >> | | | TX DSP: 1 >> | | | >> | | | Freq range: -8.000 to 8.000 MHz >> | | _____________________________________________________ >> | | / >> | | | TX Dboard: A >> | | | _____________________________________________________ >> | | | / >> | | | | TX Frontend: A >> | | | | Name: FE-TX2 >> | | | | Antennas: TX/RX >> | | | | Sensors: temp, lo_locked >> | | | | Freq range: 50.000 to 6000.000 MHz >> | | | | Gain range PGA: 0.0 to 89.8 step 0.3 dB >> | | | | Bandwidth range: 200000.0 to 56000000.0 step 0.0 Hz >> | | | | Connection Type: IQ >> | | | | Uses LO offset: No >> | | | _____________________________________________________ >> | | | / >> | | | | TX Frontend: B >> | | | | Name: FE-TX1 >> | | | | Antennas: TX/RX >> | | | | Sensors: temp, lo_locked >> | | | | Freq range: 50.000 to 6000.000 MHz >> | | | | Gain range PGA: 0.0 to 89.8 step 0.3 dB >> | | | | Bandwidth range: 200000.0 to 56000000.0 step 0.0 Hz >> | | | | Connection Type: IQ >> | | | | Uses LO offset: No >> | | | _____________________________________________________ >> | | | / >> | | | | TX Codec: A >> | | | | Name: B210 TX dual DAC >> | | | | Gain Elements: None >> >> >> >> >> >> On Wed, May 23, 2018 at 3:31 PM, Marcus D. Leech via USRP-users < >> usrp-users@lists.ettus.com> wrote: >> >>> On 05/23/2018 03:13 PM, Martin K via USRP-users wrote: >>> >>> Hello, >>> I have B210 hooked up to a signal generator putting out BPSK. >>> When I look at the signal on a signal analyzer I see what I expect: the >>> baseband, synchronized 'I' signal looks like a square wave. (Fig.1) >>> >>> When I capture the signal with the B210 and view it in GNU Radio or >>> MATLAB, the square wave is not square, it turns into a decaying square (a >>> sawtooth you could say) (Fig 2) >>> >>> It looks as if the baseband is being highpass filtered. I don't >>> understand where this response could be coming from. I hope there is a >>> simple explanation. >>> >>> I considered that the signal may be too powerful, however it is around >>> -25dBm and I notice that the effect does not change over different signal >>> power levels. >>> >>> I appreciate any help - thank you. >>> >>> >>> >>> >>> >>> -- >>> Martin K. >>> >>> YOu're going to have to tell us a bit more about your setup. >>> >>> You're generating BPSK *baseband* and sending it to the USRP? Or you're >>> generating a BPSK signal at some RF frequency? >>> >>> When you say you "capture" the signal, exactly how to you capture the >>> signal? >>> >>> >>> >>> > > -- > Martin K. > _______________________________________________ > USRP-users mailing list > 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
