On Mon, Apr 29, 2013 at 4:10 AM, Sam mite <mite.eng...@gmail.com> wrote: >> Sam, >> >> No, I don't think that you are doing something wrong here. But those >> figures you've posted look like the circuit is under-damped. It should >> be critically damped, > > > Why the circuit should be critically damped? In my first mail, I said that I > am using damp_factor= 0.707. It should be under-damped. No? The problem, i > think, is that its taking too long 9000/4 symbols to get lock. No ?
Hm, it appears you're right that it's under damped. I thought I had translated it so that 0.707 was crtically damped, but apparently I didn't. I was looking at the Costas loop implementation to make sure. But they converges at the same time. However, in the case of the timing loop, we're not talking about a slight under damping. With .707, I would expect it to dip slightly before converging. But the way this looks, it is significantly under damped with the number of cycles of oscillation. So I still think something isn't quite right. Not sure if it will necessarily converge any faster, but it should behave more like expected. >> so it'd be interesting to see what's going wrong >> inside of the algorithm. I've looked at it with this in mind, but I >> can't see that anything is being done differently than the normal >> control loops that we use, and the parameters should be set to be >> critically damped. >> This sounds like something we can develop and discuss on the signal >> processing wiki page. Would you be able to start something here? >> There's already a section for Synchronization. Maybe just create a new >> page off that for discussing this particular algorithm/block. > > > I'll be glad to :) Thanks! Tom >> >> (for signing up to post on the wiki: >> >> http://gnuradio.org/redmine/projects/gnuradio/wiki/FAQ#How-can-I-post-on-this-wiki-use-the-bug-tracker) >> >> Thanks! >> Tom > > > > -- > > Best Regards, > > Sam _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
