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</o:shapelayout></xml><![endif]--></head><body lang=NL link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546A'>Hi Stefan<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546A'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546A'>Thanks for explaining. I think I understand now. The higher octave channel must be changed before a full period has passed. A full period @ 61Hz(8MHz / 2^17 ) is ~16.4 ms.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546A'>doing a delay of 192 scanlines is ~12.31ms which is good enough. This delay method was probably chosen as it is a convenient way to generate the required delay.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546A'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546A'>></span> I do not think that I'm hearing a ticking distortion in SimCoupe (I'm using v1.2.3 dated 2021-08-15<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Ah! that explains it. I was using the 1-1-alpha release from Simcoupe website. I should have know to grab the latest version from GitHub:)<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks for the help Stefan.<o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546A'><o:p> </o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>Van:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Stefan Drissen [mailto:stefan.drissen@gmail.com] <br><b>Verzonden:</b> donderdag 2 september 2021 19:06<br><b>Aan:</b> Edwin blink; sam-users@nvg.ntnu.no<br><b>Onderwerp:</b> Re: [Sam-users] So what's up in SAM Wolrd?<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Hi Edwin (moving back on list) :-)<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Regarding Anton's 4 bit SAA1099 sample player:<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>You stated: "<span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#44546A'>Snap niet helemaal waarom 192 scanlines gewacht wordt want dit is ongeveer 12,3 ms (192/312*20ms/frame) (een halve periode @ 61Hz is ongeveer 8,2 ms. Maar er zal vast een reden voor zijn en de sample in Rick Dangerous klinkt geweldig!</span>" (you all know how google translate works)<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Just jotting some numbers down to see if I can reason why this works:<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Tone 0, octave 0 is 31 Hz.<o:p></o:p></p></div><div><p class=MsoNormal>To counter phase this, you need to jump in at 62 Hz.<o:p></o:p></p></div><div><p class=MsoNormal>Frame is 50 Hz<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>All channels are triggered on line 0 (detected by lightpen port)<o:p></o:p></p></div><div><p class=MsoNormal>Counter phase channels are triggered on line 192 (detected by lightpen port).<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Total screen lines (1 frame) = 312.<o:p></o:p></p></div><div><p class=MsoNormal>192 / 312 = 61% <o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>So I must be missing something - since you are also suggesting something else, <o:p></o:p></p></div><div><p class=MsoNormal>Unless the lightpen port would return 0 on the first border line, which it does not.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Anton did open an issue on SimCoupe about some very minute differences, see <a href="https://github.com/simonowen/simcoupe/issues/36">https://github.com/simonowen/simcoupe/issues/36</a> - but that was about gradual phase shift that became increasingly noticeable.<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>I do not think that I'm hearing a ticking distortion in SimCoupe (I'm using v1.2.3 dated 2021-08-15) - but well, a SAM playing samples and no distortion? ;-)<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Cheers!<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal>Stefan<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div></div></div></div></body></html>