USRP B210 overflow and underflow

[Karen young]

Hi,

I am using a USRP B210 to transmit and receive pulse signals using attached antennas, and try to measure the phase delay between the transmitted and received signals. I do not understand why the following problems are happening. What can I do to fix them? Attached is the model.

1. The usrp_source overflow and usrp_sink underflow errors occur frequently, the received signal (in Red) is jumping accordingly as shown in Fig 1. 

2. Since the transmitted signal is positive pulse, I am expecting the received signal is also positive. While the received signals are: sometimes positive peak, sometimes negative peaks as shown in Fig 2.

Thanks

Karen

USRP B210 phase measurement.JPG
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USRP B210 phase measurement 1229a.grc
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fig2.png
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fig1.png
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