On Wed, Mar 22, 2006 at 04:14:36PM -0500, Charles Swiger wrote: > On Thu, 2006-03-16 at 14:39 -0800, Eric Blossom wrote: > > On Thu, Mar 16, 2006 at 05:24:26PM -0500, Charles Swiger wrote: > > > On Thu, 2006-03-16 at 12:35 -0800, Eric Blossom wrote: > > > > > > > > > Here's the only place they're used: > > > > > > d_freq = d_freq + d_beta * error; > > > d_phase = mod_2pi(d_phase + d_freq + d_alpha * error); > > > > > > It's way over my head but is d_freq supposed to be in the d_phase > > > calculation, 2nd line? phase is mod_2pi but freq can be a very big > > > number, like mod_2pi(100000 + 1.572849). That is I'm USING very big > > > numbers for max_freq and min_freq - don't suppose they're normalized > > > somehow. > > > > OK. I can see why that would be a problem. mod_2pi is optimized for > > the expected "close in case" (symmetric around zero), thus the phase > > isn't *really* getting folded down to [-pi,pi]. > > > > Try changing mod_2pi to make the bounds check and then compute the > > modulus if it needs to using division, floor, multiplication and > > subtraction. It's not cheap, but it'll probably compute the right > > answer. > > Does anybody know how to fix this in c++ ?
Chuck, It's not broken. I was wrong. The "problem" is the lack of documentation on what *any* of the arguments mean. In fact, the freq args are in radians/sample. Thus it will always fall in +/- pi and the existing code will keep it in range. freq_in_hz * 2 * pi / sample_rate_in_hz --> radians/sample Matt, will you *please* add doxygen comments to gr_pll_*.h? Thanks, Eric _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
