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 > >
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