I was gonna say, there's actually three of them ;) On Thu, Feb 1, 2018, 9:06 PM Robin Coxe via USRP-users < usrp-users@lists.ettus.com> wrote:
> On p.8 of B200 schematic: > T801 is Macom ETC1-1-13TR (RF2) > T800 is Minicircuits TC1-1-43A+ (RF3) > U802 is Anaren BD3150L50100AHF (RF1) > > On Thu, Feb 1, 2018 at 5:45 PM, Ron Economos via USRP-users < > usrp-users@lists.ettus.com> wrote: > >> There's also a balun on the AD9361 input. Unfortunately, the balun part >> number for the low frequency path is not on the schematic. >> >> Ron >> On 02/01/2018 05:39 PM, Dan CaJacob via USRP-users wrote: >> >> That's an interesting thought. The 9361 does have a pretty bad match. >> I'll try adding a 50 Ohm attenuator and see if that helps. >> >> On Thu, Feb 1, 2018 at 5:14 PM Robin Coxe <robin.c...@ettus.com> wrote: >> >>> Hi Dan. Both the B200 and the E312 use the Analog Devices AD9361 RF >>> integrated transceiver. This chip does have an integrated LNA. Perhaps >>> there's some sort of mismatch between your DUTs and this integrated LNA at >>> <1 GHz? >>> >>> ADI publishes the RX S-parameters: >>> https://ez.analog.com/thread/41208#137929 >>> >>> -Robin >>> >>> On Thu, Feb 1, 2018 at 7:46 AM, Dan CaJacob via USRP-users < >>> usrp-users@lists.ettus.com> wrote: >>> >>>> Hey guys, >>>> >>>> I have put together a noise figure meter application that uses a USRP >>>> as the sensing device. It started off as a way to measure the NF of the >>>> USRP itself. I have a calibrated noise source from an HP 8970B Noise Figure >>>> Meter. To test the NF of the USRP, I connect the head to the USRP input. My >>>> GNURadio flowgraph maximizes the USRP gain and measures a moving average of >>>> the received power while I switch the noise source on and off. The >>>> difference in the received power level, in addition to the ENR table from >>>> the noise source, can then be used to calculate the NF of the USRP itself >>>> using the y-factor method. >>>> >>>> Once you have the NF for the USRP at many frequencies (I test every 50 >>>> MHz from 50 MHz - 6000 MHz), you can modify the same procedure to test the >>>> NF of a Device Under Test (DUT) which is connected between the noise source >>>> and the (now calibrated) USRP. You can use the USRP cal table we generated >>>> in the previous step to derive the NF of the DUT corrected for the NF of >>>> the USRP. >>>> >>>> In short, this all works incredibly well and garners very repeatable >>>> results. One complication is that you will see wild NF at certain >>>> frequencies due to local interference like LTE and WIFI. I've also compared >>>> the results to that which the HP device measures and they're very >>>> comparable. ... Except below ~ 1GHz. >>>> >>>> And here's the issue - I am seeing higher NF for DUTs below about 1GHz >>>> and particularly worse below 500 MHz. I was hoping someone at Ettus might >>>> be able to shed some light on why this might be. Curiously, the USRPs NF >>>> doesn't seem to be too bad, just the DUT. >>>> >>>> I'll note that I am nominally using a B200 for these tests, but I also >>>> tried an E312 just in case the filter banks might help out somehow. I >>>> didn't see a difference - they both had the same problem. >>>> >>>> I have used several DUTs for this test, including LNA boards we have >>>> designed ourselves and a Mini-Circuits ZX60-P103LN+ ( >>>> https://www.minicircuits.com/pdfs/ZX60-P103LN+.pdf). Both seem to >>>> exhibit higher NF when measured with a USRP below 1 GHz. When testing them >>>> on the HP NF meter, the NF is as expected all the way down to 50 MHz. >>>> >>>> I have attached the B200 cal data for your enjoyment as well as the >>>> B200-measured ZX60 NF and the HP-measured ZX60. The HP NF meter only goes >>>> up to 1600 MHz, which is why that data file stops there. I was surprised to >>>> see the B200 seemed to have a better NF than the E312, which averaged 8 dB >>>> NF, by the way. >>>> -- >>>> Very Respectfully, >>>> >>>> Dan CaJacob >>>> >>>> _______________________________________________ >>>> USRP-users mailing list >>>> USRP-users@lists.ettus.com >>>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>>> >>>> >>> -- >> Very Respectfully, >> >> Dan CaJacob >> >> >> _______________________________________________ >> USRP-users mailing >> listUSRP-users@lists.ettus.comhttp://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 > -- Very Respectfully, Dan CaJacob
_______________________________________________ USRP-users mailing list USRP-users@lists.ettus.com http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
