Re: [USRP-users] interpretation of received signal
Also note that at 0 dBm, you're at the maximum safe input power, so your received signal might be saturated. --Neel Pandeya On Oct 17, 2017 22:30, "Marcus D. Leech via USRP-users" < usrp-users@lists.ettus.com> wrote: On 10/18/2017 12:08 AM, Nirmala Soundararajan via USRP-users wrote: > Hi all, > > I am trying to transmit and receive a simple 10 kHz tone using a single > USRP B205mini-i. The input power is 0 dbm ( The amplitude of 10kHz tone > being 45mV). The transmitting and receiver antenna are same omnidirectional > type each having 3 dbi gain. I set the transmitter gain as 8 and receiver > gain as 70. The carrier frequency is around 800 MHz. The path loss comes to > around 20 db considering the fact that transmitting and receiving antenna > are just a foot apart. ( I took far field and did not consider near field) > > The received spectrum shows -26 dbm. How should I interpret these results? > > regards > > Nirmala > > How did you get -26dBm? Unless you have painstakingly *calibrated* your USRP B205mini, and wrote code that converts the received data into dBm, given your carefully-derived calibration tables, an FFT will simply show received power relative to the mathematical maximum in the system. Further, given that modulating signals in the SDR world are purely digital number, how did you derive a figure of 45mV of modulation? ___ 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
[USRP-users] USRP Sequence error
Hi, I am using USRP X310, I want to transmit data from file in repeat mode. The command that I type in linux terminal is: ./tx_samples_from_file --file tx_0.25_2_rep3_v2.bin --args="addr=192.468.10.2" --ant TX/RX --delay 0.1 --rate 20e6 --freq 5.75e9 --gain 25 --repeat But as result, i receive at the end : UUSS Error: Environmenterror: I0error:[0/DmaFIFO_0] sr_write() failed... Does anybody have any experience with this error. I would appreciate so much if you help me. Thank you in advance. Regards, Meysam ___ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
Re: [USRP-users] interpretation of received signal
Hi Marcus, I made a simple model using Matlab Simulink and used spectrum analyser block to observe the transmitted and received waveform. Since 0 dbm was the maximum input power, I just calculated (input volatge)^2 / 2. It comes to 0.045V. I specified block parameters and gave different values. Actually with 0 gain of transmitter and receiver I was getting -97 to -105 dbm for the same input voltage 45mV. regards Nirmala On Wed, Oct 18, 2017 at 3:03 AM, Neel Pandeya via USRP-users < usrp-users@lists.ettus.com> wrote: > Also note that at 0 dBm, you're at the maximum safe input power, so your > received signal might be saturated. > > --Neel Pandeya > > > On Oct 17, 2017 22:30, "Marcus D. Leech via USRP-users" < > usrp-users@lists.ettus.com> wrote: > > On 10/18/2017 12:08 AM, Nirmala Soundararajan via USRP-users wrote: > >> Hi all, >> >> I am trying to transmit and receive a simple 10 kHz tone using a single >> USRP B205mini-i. The input power is 0 dbm ( The amplitude of 10kHz tone >> being 45mV). The transmitting and receiver antenna are same omnidirectional >> type each having 3 dbi gain. I set the transmitter gain as 8 and receiver >> gain as 70. The carrier frequency is around 800 MHz. The path loss comes to >> around 20 db considering the fact that transmitting and receiving antenna >> are just a foot apart. ( I took far field and did not consider near field) >> >> The received spectrum shows -26 dbm. How should I interpret these results? >> >> regards >> >> Nirmala >> >> How did you get -26dBm? > > Unless you have painstakingly *calibrated* your USRP B205mini, and wrote > code that converts the received data into dBm, given your carefully-derived > calibration tables, an FFT will simply show received power relative to > the mathematical maximum in the system. > > Further, given that modulating signals in the SDR world are purely digital > number, how did you derive a figure of 45mV of modulation? > > > > ___ > 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 > > ___ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
Re: [USRP-users] interpretation of received signal
0dBm is the maximum power that is recommended to prevent damage to the hardware. But the actual response of the entire signal processing chain, including variable-gain elements, the ADCs, and such, cannot simply be "modeled" in such a simple manner. In order to map the digital-domain results back through the chain into "what is the antenna port actually seeing", you MUST do a calibration exercise, using signal sources of known power. You have to do this exercise over your frequency/gain/sample-rate settings of interest. Real-world RF hardware does not have a perfectly-uniform response over its operating range, neither is it always perfectly-linear. On 2017-10-18 12:29, Nirmala Soundararajan via USRP-users wrote: > Hi Marcus, > > I made a simple model using Matlab Simulink and used spectrum analyser block > to observe the transmitted and received waveform. Since 0 dbm was the > maximum input power, I just calculated (input volatge)^2 / 2. It comes to > 0.045V. I specified block parameters and gave different values. Actually > with 0 gain of transmitter and receiver I was getting -97 to -105 dbm for > the same input voltage 45mV. > > regards > > Nirmala > > On Wed, Oct 18, 2017 at 3:03 AM, Neel Pandeya via USRP-users > wrote: > > Also note that at 0 dBm, you're at the maximum safe input power, so your > received signal might be saturated. > > --Neel Pandeya > > On Oct 17, 2017 22:30, "Marcus D. Leech via USRP-users" > wrote: > > On 10/18/2017 12:08 AM, Nirmala Soundararajan via USRP-users wrote: > Hi all, > > I am trying to transmit and receive a simple 10 kHz tone using a single USRP > B205mini-i. The input power is 0 dbm ( The amplitude of 10kHz tone being > 45mV). The transmitting and receiver antenna are same omnidirectional type > each having 3 dbi gain. I set the transmitter gain as 8 and receiver gain as > 70. The carrier frequency is around 800 MHz. The path loss comes to around 20 > db considering the fact that transmitting and receiving antenna are just a > foot apart. ( I took far field and did not consider near field) > > The received spectrum shows -26 dbm. How should I interpret these results? > > regards > > Nirmala > > How did you get -26dBm? > > Unless you have painstakingly *calibrated* your USRP B205mini, and wrote code > that converts the received data into dBm, given your carefully-derived > calibration tables, an FFT will simply show received power relative to the > mathematical maximum in the system. > > Further, given that modulating signals in the SDR world are purely digital > number, how did you derive a figure of 45mV of modulation? > > ___ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com [1] ___ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com [1] ___ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com Links: -- [1] 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
Re: [USRP-users] interpretation of received signal
Yeah got it! But don't you think the tool has those capabilities to consider the entire chain and then display the output? Since I don't have actual spectrum analyzer in the lab I am forced to use the software spectrum analyzer. The initial phase is to first confirm that the transmit and receive are proper enough to comprehend the results. I can send a table of input voltages and gains that I set and the results that I observed. I would atleast expect that given the same numbers as input , the results do not vary beyond a certain margin. That way I can declare / set that my channel of interest has passed the loop back test of transmission and reception! I am only confused that the results do not match the expected values as per path loss, power transmitted and gain equation or it could be that I am not looking the right way! regards Nirmala > > > > > On 2017-10-18 12:29, Nirmala Soundararajan via USRP-users wrote: > > Hi Marcus, > > I made a simple model using Matlab Simulink and used spectrum analyser > block to observe the transmitted and received waveform. Since 0 dbm was > the maximum input power, I just calculated (input volatge)^2 / 2. It comes > to 0.045V. I specified block parameters and gave different values. > Actually with 0 gain of transmitter and receiver I was getting -97 to > -105 dbm for the same input voltage 45mV. > > regards > > Nirmala > > On Wed, Oct 18, 2017 at 3:03 AM, Neel Pandeya via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> Also note that at 0 dBm, you're at the maximum safe input power, so your >> received signal might be saturated. >> >> --Neel Pandeya >> >> >> On Oct 17, 2017 22:30, "Marcus D. Leech via USRP-users" < >> usrp-users@lists.ettus.com> wrote: >> >> On 10/18/2017 12:08 AM, Nirmala Soundararajan via USRP-users wrote: >> >>> Hi all, >>> >>> I am trying to transmit and receive a simple 10 kHz tone using a single >>> USRP B205mini-i. The input power is 0 dbm ( The amplitude of 10kHz tone >>> being 45mV). The transmitting and receiver antenna are same omnidirectional >>> type each having 3 dbi gain. I set the transmitter gain as 8 and receiver >>> gain as 70. The carrier frequency is around 800 MHz. The path loss comes to >>> around 20 db considering the fact that transmitting and receiving antenna >>> are just a foot apart. ( I took far field and did not consider near field) >>> >>> The received spectrum shows -26 dbm. How should I interpret these >>> results? >>> >>> regards >>> >>> Nirmala >>> >>> How did you get -26dBm? >> >> Unless you have painstakingly *calibrated* your USRP B205mini, and wrote >> code that converts the received data into dBm, given your carefully-derived >> calibration tables, an FFT will simply show received power relative to >> the mathematical maximum in the system. >> >> Further, given that modulating signals in the SDR world are purely >> digital number, how did you derive a figure of 45mV of modulation? >> >> >> >> ___ >> 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 >> >> > ___ > 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
Re: [USRP-users] UBX-160 with X310 communication issue
Nate, I upgraded to UHD 003.009.007, and it worked in CentOS7.2. I can now probe the daughtercard and get a return. Thank you so much! Mark From: Nate Temple Date: Tuesday, October 17, 2017 at 5:19 PM To: Mark Koenig Cc: "usrp-users@lists.ettus.com" Subject: Re: [USRP-users] UBX-160 with X310 communication issue Hi Mark, The UBX v2 is not supported using UHD 3.9.3. Support for the UBX v2 was added with UHD 3.9.5 and UHD 3.10.2.0. Can you please try updating to the newest UHD, such as 3.9.7 or 3.10.2.0 and try probing USRP/DBs again? Regards, Nate Temple On Tue, Oct 17, 2017 at 1:01 PM, Mark Koenig via USRP-users mailto:usrp-users@lists.ettus.com>> wrote: Hello, I am looking for some help with respect to the UBX-160. I have two version 2 daughtercards which were purchased a couple of months ago. I am running on CentOS 7.2 and CentOS 6.5 with GNU radio version 3.7.4 and UHD version 003.009.003. I can ping the USRP and also return information on the uhd_find_devices command, however, when I run the uhd_usrp_probe command I do not get a return for the daughtercards. The example output is below. Any help would be EXTREMELY appreciated. Thank you Mark linux; GNU C++ version 4.4.7 20120313 (Red Hat 4.4.7-16); Boost_105300; UHD_003.009.004-0-g2b5a88bb -- X300 initialization sequence... -- Determining maximum frame size... 1472 bytes. -- Setup basic communication... -- Loading values from EEPROM... -- Setup RF frontend clocking... -- Radio 1x clock:200 -- Detecting internal GPSDO Found an internal GPSDO -- Initialize Radio0 control... -- Performing register loopback test... pass -- Initialize Radio1 control... -- Performing register loopback test... pass _ / | Device: X-Series Device | _ |/ | | Mboard: X310 | | revision: 11 | | revision_compat: 7 | | product: 30818 | | mac-addr0: 00:80:2f:17:43:3f | | mac-addr1: 00:80:2f:17:43:40 | | gateway: 192.168.10.1 | | ip-addr0: 192.168.10.2 | | subnet0: 255.255.255.0 | | ip-addr1: 192.168.20.2 | | subnet1: 255.255.255.0 | | ip-addr2: 192.168.30.2 | | subnet2: 255.255.255.0 | | ip-addr3: 192.168.40.2 | | subnet3: 255.255.255.0 | | serial: 311FF4E | | FW Version: 4.0 | | FPGA Version: 19.0 | | | | Time sources: internal, external, gpsdo | | Clock sources: internal, external, gpsdo | | Sensors: gps_gpgga, gps_gprmc, gps_time, gps_locked, gps_servo, ref_locked | | _ | |/ | | | RX DSP: 0 | | | Freq range: -100.000 to 100.000 MHz | | _ | |/ | | | RX DSP: 1 | | | Freq range: -100.000 to 100.000 MHz | | _ | |/ | | | RX Dboard: A | | | ID: Unknown (0x007e) | | | Serial: 3120D56 | | | _ | | |/ | | | | RX Frontend: 0 | | | | Name: Unknown (0x007e) - 0 | | | | Antennas: | | | | Sensors: | | | | Freq range: 0.000 to 0.000 MHz | | | | Gain Elements: None | | | | Bandwidth range: 0.0 to 0.0 step 0.0 Hz | | | | Connection Type: IQ | | | | Uses LO offset: No | | | _ | | |/ | | | | RX Codec: A | | | | Name: ads62p48 | | | | Gain range digital: 0.0 to 6.0 step 0.5 dB | | _ | |/ | | | RX Dboard: B | | | ID: Unknown (0x007e) | | | Serial: 3120D4A | | | _ | | |/ | | | | RX Frontend: 0 | | | | Name: Unknown (0x007e) - 0 | | | | Antennas: | | | | Sensors: | | | | Freq range: 0.000 to 0.000 MHz | | | | Gain Elements: None | | | | Bandwidth range: 0.0 to 0.0 step 0.0 Hz | | | | Connection Type: IQ | | | | Uses LO offset: No | | | _ | | |/ | | | | RX Codec: B | | | | Name: ads62p48 | | | | Gain range digital: 0.0 to 6.0 step 0.5 dB | | _ | |/ | | | TX DSP: 0 | | | Freq range: -100.000 to 100.000 MHz | | _ | |/ | | | TX DSP: 1 | | | Freq range: -100.000 to 100.000 MHz | | _ | |/ | | | TX Dboard: A | | | ID: Unknown (0x007d) | | | Serial: 3120D56 | | | _ | | |
