On 09 Sep 2014, at 15:42, Tom Rondeau <t...@trondeau.com> wrote: > On Mon, Sep 8, 2014 at 5:49 PM, Bastian Bloessl <bloe...@ccs-labs.org> wrote: > Hi all, > > looking at the clock recovery MM code, I wonder if d_omega_relative_limit is > a relative or absolute deviation from d_omega. > > Here it looks like absolute > https://github.com/gnuradio/gnuradio/blob/next/gr-digital/lib/clock_recovery_mm_ff_impl.cc#L107 > > Here it is relative > https://github.com/gnuradio/gnuradio/blob/next/gr-digital/lib/clock_recovery_mm_ff_impl.h#L57 > > (even though this code has no impact since d_{min,max}_omega is not used.) > > > I don’t have access to the book linked in the docs atm. > > Best, > Bastian > > > It is supposed to be relative. I'd have to verify the math on that line 107 > in the .cc file, but it's supposed to adjust the center position of the > current omega estimate and then apply the clipping. Then it adds the mid > point back to get it back to where it's centered. Try walking through that > line one more time to verify that it's doing that properly. But yes, it's > supposed to be relative to the original setting of omega. >
So this line asserts that the current (absolute) deviation (d_mega - d_omega_mid) is smaller than the maximum allowed absolute deviation (d_omega_mid * d_omega_relative_limit). AFAIS, the second argument is missing “* d_omega_mid”. I will create a patch, then you can check if I got you right. Bastian _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
