On Sep 10, 2010, at 1:19 AM, vincent habchi <vi...@macports.org> wrote:
> Le 9 sept. 2010 à 21:58, Remco Poelstra a écrit : > >> I'm looking for some way to generate a tone that resembles the sound of an >> instrument. I need precise control of the base frequency (pitch). I'm >> wondering what would be the best way to generate it on an iPhone. >> Store a file with a know frequency and resample it to the desired frequency? >> Synthesize a tone by calculating a bunch of sines? Doing some FFT trick on a >> file? >> If someone can give some insight into what would best fit the H/W available >> it would be grateful. > > Basically, that's not really a Cocoa related question. If you want to > generate a sine wave with a very precise frequency, try to dig into the > fairly simple DDS theory. That's the way HF generators achieve sub-hertz step > precision at 100 MHz or above. Very easy to replicate on an iPhone. Also read through the archives of the coreaudio-api list. Lots of information about your specific case there. --Kyle Sluder_______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
