Honored Contributor
Honored ContributorIf tx pattern is same as rx pattern (after slicing) and for every sample then it means the chain is working in principle.
If you plot constellations before slicing it will show how much scatter you have (due to filters) which could degrade the loop. Next activate the loop and do some prayer. Remember this simple principle: nco step at start is correct for frequency as frequency is locked. With phase loop active the nco step must become same as its initial value otherwise you lose frequency lock as well. All the phase lock should do is in effect give it a push (a nodge if my spelling is right) to create offset towards correct phase and revert back to initial increment value. So the error adding to nco word must be really scaled gently. I know some people increment the nco word at slow rate and revert back to initial step after cange of phase accumulator value (offset).
