Quote Originally Posted by lerameur View Post
but still a lot of noise after the filter, and only dials 50% of the times
k
Well, the PBP manual does say that any 'sound' output from the PIC, being 1-bit analog, is going to be 'noisy', a lot of harmonic content. And I would think that even if it's filtered well, it would still have a load of 'noise' in it. A low-pass 'brick wall' filter, with a steep 'slope/cutoff', with the -3db point set just above your highest frequency might handle that.
I guess I'm not really sure. I haven't relied on the PIC to do much sound (other than moving MP3 data back and forth for a player).