Re: Changing USRP subdevice on the fly

[Marcus D. Leech]

On 22/11/2022 16:24, Moses Browne Mwakyanjala wrote:

Hi everyone,

I wrote a simple program for a usrp b210. I would like to change the RX antenna on the fly. That is, antenna 0 should be RX2 on Subdevice A:A and antenna 1 RX2 on Subdevice A:B as shown in the piece of code below. The problem I face is that I can't change the subdevice on the fly. The usrp->set_rx_subdev_spec(sRxSubDev) call doesn't seem to have any effect if it is called more than once. How should I proceed?

        std::string sRxSubDev;
        switch(m_Settings.m_nTMAntenna)
        {
        case 0:// Using antenna 1
            sRxSubDev = std::string("A:A");
            break;
        case 1:// Using antenna 2
            sRxSubDev = std::string("A:B");
            break;
        }
        usrp->set_rx_subdev_spec(sRxSubDev);
        usrp->set_rx_antenna("RX2");

Thanks in advance,

Moses. 

    You would likely have to tear down the streamer and start a new one.
    
    Alternately, you could just stream both channels at the same time,
    and simply drop the samples from the part of the stream
      you don't care about.