Rybags Posted April 18, 2006 Share Posted April 18, 2006 PWM sound uses a duty cycle which averages out over the sample period to generate the same result as modulating a wave to a certain position. Has anyone tried, or got any software which does it? There is an article here http://www.ffd2.com/fridge/chacking/c=hacking20.txt and here http://www.ffd2.com/fridge/chacking/c=hacking21.txt about digitized sound on the C-64. I've been playing about with it on the 130XE, using various techniques like POKEY timers, and have tried playing direct POKEY sound and forced volume (alternating 0 and 15). So far, my results aren't so great. I'm using voice 1/2 combined on a 1.79 base, which allows Timer resolutions to a single machine cycle. Quote Link to comment Share on other sites More sharing options...
DamageX Posted April 19, 2006 Share Posted April 19, 2006 you may be interested in this http://members.aol.com/MJMahon/ Mr. Mahon created a program to play 5-bit samples on an Apple IIe using PWM. Quote Link to comment Share on other sites More sharing options...
UNIXcoffee928 Posted April 30, 2006 Share Posted April 30, 2006 How are these experiments working out? Signal Modultion can be quite useful in feedback-oriented control systems... (if you redirect that output for non-audio control...). L8R, UNIXcoffee928 Quote Link to comment Share on other sites More sharing options...
Rybags Posted May 1, 2006 Author Share Posted May 1, 2006 I got it to the point where it played recognisable samples, using 2 methods. 1st method was the classic "Volume only" output. 2nd method was using a voice pair at 1.78 MHz -plus using Pokey timer (which forces modulation cycle to restart). Both results poor so far, plus you get the carrier frequency which can't easily be filtered. I haven't touched it for some time - devoting programming time to Impossible Mission project. Quote Link to comment Share on other sites More sharing options...
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