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USRP Rx PLL Not Locked

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I'm working with USRP 2900 to monitoring 2.4GHz Bandwidth. I did VI to scan every BLE frequency. Program is working in loop and measured values are logged in databases. My program base on templete Ex Spectral Monitoring (History). Unfortunatly I have a problem, because in random time stamp(from 1 to 3 hours) occuring error Rx PLL NOT LOCKED. Where is the problem?

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Message 1 of 4
Accepted by topic author RPOD

Dear RPOD,


what drivers (version) are you using? In which LV version are you programming? In some older versions of NI-USRP there was a bug that caused Reference Clock PLL in the FPGA to fail to lock to the internal source. Please try to use the 16.1 version of the drivers, and we will see if this helps. If no, please let us know the SW versions you are using, and add some print screen of the error, or if possible attach your code. You can also use some debugging techniques to locate the source of the error, if not possible to get this info from the error message. So we know from where is the error coming. Also: do you have your USRP directly connected to the PC, or via some sort of USB HUB?



Jozef Lipták
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Message 2 of 4

Hi Josef,

Thank you for the answer.

I had old relese (16.0) and the new relese resolved all my problems. At this time when I was testing the USRP for 5 hour the error did not occur. I hope it will work 24h per day without any errors. We will see. 

Anyway, thank you for your help.




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Message 3 of 4

Welcome! Hopefully you will be able to continue with your project, if not, please do not hesitate to contact us again. Also you can mark my previous post as a solution.


Have a nice day!

Jozef Lipták
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Message 4 of 4