GPS signal acquisition with USRP 2974

[Nydearon]

Good morning, everyone.

Before we start I would like to say that I am a perfect beginner on USRPs and LabVIEW.

I would also like to inform you that my USRP 2974 does not have an Internet connection (by choice).

I want to try to make the example work” norUSRP Ex TX with GPS” on a USRP 2974.
I have already read the next two articles however this does not help :

https://forums.ni.com/t5/USRP-Software-Radio/GPS-signal-acquisition-with-USRP-2953R/td-p/3241070

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z000000g0BwSAI&l=fr-FR

Here are my problems and questions:

- I have no idea what to put in “Device Name. ” I thought it would first be the Trimble antenna that I have at my disposal, plugged into the ANT GPS port.Or an SMA cable connected to RF0 of TX/Rx in front panel. Which is itself connected to an Anritsu MS2721A spectrum analyzer. But I don’t have any suggestions to put in Device Name, except “Browse” and “Refresh. ” And I can't described anything in MAX.

- When you connect your antenna on the GPS ANT port, do the PPS and REF LEDs need to be turned on? Or is it related to the reference signal (not the GPS antenna)?

Another question but for a NI PXIe-5673 :

- Does anyone know the AWG generation capacity (the accurancy of AWG) ? Because when I try to enter the following number XXXXXX,XXXXXX in S/s, it will remain only the first six XXX,XXX (KS/S). But does he remember the other numbers and it depends on the display? Or does it round off the result?

Thanks in advance.

[Nydearon]

I managed to find the solution for the first part. In “Device Name” it is enough to enter the name of the USRP registered under Ni-Max.

However, I still don’t have a solution for the rounding of the IQ Rate on the RFSG SFP of the PXIe-5673 chassis.
According to the documentation, the accepted sample rate is 150/n MS/s.
My values mean that I have a n equal to 402, which is not a multiple of 4 as RFSG wants. What can I do to solve this problem?

[ahovhann]

Hi,

Did you find solution regarding to the second part?

[Nydearon]

Hi,

If you talk about the problem of coerced value with RFSG, I choosed to use FGEN librairy to generate. The sample rate allowed is 400MS/S with the NI-5451 module. So with a decimator factor equals to 1072, I can have the sample rate I want.