Hello Ismael, No, the AD9361 transceiver chip which the B200 uses does not support that.
Regards, Derek On Tue, May 22, 2018 at 12:00 PM, Ismael Peruga <gtfism...@gmail.com> wrote: > Hello Derek, > > Thank you for your answer. Is it possible to use the same LO for transmit > and receive? That would fix the problem... > > Best regards, > Ismael. > > On Tue, May 22, 2018 at 12:35 PM, Derek Kozel <derek.ko...@ettus.com> > wrote: > >> Hello Ismael, >> >> With the B200 it is not possible to get the same phase offset at all >> frequencies, in fact that is not possible to obtain with any USRP. Some, >> such as the UBX and TwinRX, provide the ability to have the same phase >> offset every time you tune to a specific frequency. That allows the USRP to >> be calibrated once so you can remove the phase offset. With the B200 it is >> necessary to do a calibration every time it is tuned as there is no >> synchronization of the LO output phase with regards to the reference >> frequency. The B200 does not support the use of an external local >> oscillator for driving the mixers. You may be able to do the calibration >> without additional hardware by using the TX to RX leakage and timed >> commands to receive a test tone, but it will require appreciable work to >> calibrate out the various sources of time offsets and phase shifts. >> >> This application note discusses the different USRPs and different levels >> of synchronization. >> https://kb.ettus.com/Synchronization_and_MIMO_Capability_ >> with_USRP_Devices >> >> Regards, >> Derek >> >> On Tue, May 22, 2018 at 9:58 AM, Ismael Peruga via USRP-users < >> usrp-users@lists.ettus.com> wrote: >> >>> Hello everyone, >>> >>> I am developing a radar application with the USRP B200. For that >>> purpose, it is necessary that the phase difference between the TX and the >>> RX local oscillator remains constant in different frequencies (that is, I >>> send a pulse in a frequency, and after that, I change the frequency and >>> send another pulse, and so on...). The problem is that this phase >>> difference is not constant (even if I send the same frequency after I >>> launch the program two times). >>> >>> I've tried to find information, and it seems that it is a hardware >>> limitation. However I still think that this should be possible (maybe is it >>> possible to use an external oscillator for both TX and RX?) >>> >>> Thanks in advance, >>> >>> Best regards, >>> >>> Ismael. >>> >>> _______________________________________________ >>> USRP-users mailing list >>> USRP-users@lists.ettus.com >>> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >>> >>> >> >
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