USRP: Time and phase synchronization for source localization ??

[cochenob]

DUT = Device under test.  Or if you prefer..."thing you want to measure the phase of".  In your case...it would be the atmospheric channel or whatever.

There is an RF switch in the WBX boards (or the NI 2920's) that allows you to switch either antenna port into the Rx chain.  However, the isolation of the switch is not perfect.  If you have a signal present on the "off" port, some of it will still leak through the switch.  The above example (and the MUSIC code) takes advantage of this to measure both the desired signal and the calibration signals at the same time.

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Brandon

[ErikL]

USRP 1 is not supported in LabVIEW.

USRP 2, N210, and NI USRP 292x, or NI USRP 294x can all be used for this example.

The TX signals are coherent, but not phased aligned.  This means they do not change once the program is run, but the phases of each channel are different.  A common RF signal is sent to each unit for calibration of phase.  Once you have aligned phases in software you can determine direction.

[baharehbb]

Thank you so much Brandon for your help.

So I guess we will go ahead and buy the devices. Do you think we need anything more than the following items :

2 NI USRPs 2920

2 Antennas

10 MHZ reference clock with PPS output

Giga bit ethernet switch

A signal generator

anything else? 

Thanks alot

Bahareh

[baharehbb]

Thank you so much for the video and tutorial. 

But I don't understand what is the use of USRP TX1 in the tutorial. should we use it? So should we buy 3 USRPs ? 

[cochenob]

If you're only doing two receiver radios....don't bother with an exteran Ref and PPS....it's much easier to just use a MIMO cable, which shares an internal Ref and PPS from one device to another.

[Esmou]

thanks for your VI 

but it doesn't work there is a shared variable missing 

please post it so that your VI will be useful 

[hadeelobaid]

I would like to do (two phase-locked receiving channels). I have two USRP RIO 2054... and connected to the CDA 2990.

I will use one USRP for receiving and the other one is for transmitting.

what hardware do I need else? and what is the hardware setup will be?

how can I make the two receiving channels be synchronized and phase-locked?

Sorry for asking many questions but I haven't used USRP before nor LabView.

Hadeel