Synchronization without GPSDO

GNU Radio
1

Hello everyone,

I’m trying send Gaussian distributed data form one node to another by
just RRC pulse shaping. I don’t want to use any modulation scheme.
on the receiver side, i’m doing matched filtering, clock recovery and
costas loop(with order = 2).

When i decrease my gain phase shifts are very frequent (0 degrees, 180
degrees). I cannot able to decide what is the correct value.

Is it really possible synchronization without GPSDO ??
And in the www.ettus.com, it is mentioned that GPSDO cannot be used for
USRP1. I’m using USRP1 and RFX2400.

If GPSDO cannot support USRP1 , is there any other way ??

Thanks & Regards

2

Hey,
There is a “quick and dirt” solution provided by the GNU radio for this.
Well to fix this :
cd into /usr/local/bin and run uhd_siggen at one USRP. At the second
USRP, cd into /usr/local/bin and run uhd_fft. Find the frequency offset
on the fft plot at the receiving end. Fix the offset and enjoy your
work.

Regards,
Ravi Sharan B A G.,
A GNU Radio Enthusiast.