i used USRP2921 and LabVIEW NXG 2.1 and I setting the RF Communications that
<Tx setting>
IQ rate = 8M
Tx Gain = 8
Tx Carrier Frequency = 2.5G
<Rx setting>
Rx IQ rate = 10M
Rx Gain = 10
Rx Carrier Frequency = 2.5G
Tone amplitude = 0.707
Tone Frequency = 5k
size of waveform = 15k
number of samples =10k.
//
If set and executed as above, an error occurs at Tx, Rx and the program does not work.
Tx error = niUSRP write Tx data (CDB cluster).gvi [ERR] underflow: Empty the Tx buffer before new data is available. Consider reducing the I/Q ratio, speeding up writing, or increasing the number of samples per write. The recommended number of samples per write is multiplied by 363.
Rx Error = niUSRP Import Rx data (CDB WDT)Gvi [ERR]Packet timed out before receiving or sending. Not all samples may have been received or shipped. Consider increasing the timeout.
I don't know where the Tx, Rx errors occurred.