Hi,
I am using USRP 2944 (X310). The host is running Ubuntu 18.04.
Recently, I upgraded the UHD version in host from 3.10.0 to 4.1.0, and correspondingly FPGA in USRP was also refreshed. I use USRP to capture NR5G UL signal and analyze it with a software.
After UHD change, I find problem in Rx signal: the quality of the last part of the capture seems to be degraded, for example, if I capture 10ms of signal, the last ms will have higher interference. Below is one example. The values are EVM. In my test, 44.35% EVM is too much. Our criteria is 3%. Each value represents a subframe. There are 9 subframes in this case.
pucchEvm = [0.834, 0.757, 0.82, 0.773, 0.926, 0.715, 0.778, 0.677, 44.35]
When using UHD 3.10.0, I didn't have this problem.
If I deliberately capture longer time and then ignore the extra capture when analyzing the signal, then I won't avoid the high EVM in the desired time duration. For example, in the case above, if I capture 10 subframe and only analyse the first 9 subframes, then EVM in 9th subframe will be good.
Anyone has encountered similar issue? Thanks for any comment.
