Synchronize tx and rx

[sight-on]

Hi everyone.

I started to study how to use USRP-N2920 and Lab VIEW recently.

There is a question that I can’t know how to do even though use Web search.

I want to run TX and RX in same time with same VI and same device (use TX1 and RX2).

This system sent TX signal to a plant and receive RX signal form the plant.

My purpose is measurement the phase difference between TX and RX, but the result change each time when I run my VI such like the attached program.

I think this problem is caused by that my VI doesn't synchronize between TX and RX, so that I can't measure accurately the time different the TX sample and the RX sample.

I want to start TX block and RX block same time.

Please teach how to synchronize TX and RX with same VI and same device.

Best Regard.

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McGuinness

[suncraft]

hi, I'm not expert on USRP nor do I have one,

but in general I think you need to synchronize the two channels with some kind of start trigger.

I found triggered aquisition example on "niUSRP EX Rx Continuous Sync.vi", and edited your vi based on that.

Can you try to see if it works?

[sight-on]

suncraft

Thank you for your reply and your vi!

I tried to work your vi, but it display an  error such bellow.

"niUSRP Write Tx Data (CDB).vi<ERR>Underflow: the Tx buffer was emptied before new data was provided. "

I changed some parameters such as IQ rate, waveform size, start trigger time.., but It didn't work well.

I appreciate your suggesution.

[fspadafora]

me too I have the same problem