I find the sampling rate of USRP is surprisingly accurate.
Now I set the sampling rate as 4 MHz, and there are always exactly 4M
between two pps signals.
Even if I take off the GPS antenna, the sampling rate is still very
This means I only need the GPS antenna at the beginning to get an
Later I can take off the antenna and still can get accurate time from
My colleagues and I do not understand how does USRP make the sampling
We had used other types of A/D converters before.
They usually do not have such accurate sampling rate.
Sometimes they have around 4M plus and minus 100 points in one second
4M sampling rate.
Thanks for your attention.