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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I would choose a cheap $1 ARM M0+ processor with a fast clock – STM32G03 or RP2040 for example. You can then run a tight loop which samples the input and modifies
the increment on a software accumulator, outputting the top bit of the accumulator as the new timer. Jitter will be clockfreq divided by looplength which should give better than 100nS with careful coding.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span lang="EN-US" style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> Synth-diy [mailto:synth-diy-bounces@synth-diy.org]
<b>On Behalf Of </b>Spiros Makris via Synth-diy<br>
<b>Sent:</b> 17 December 2021 07:03<br>
<b>To:</b> synth-diy mailing list<br>
<b>Subject:</b> [sdiy] Techniques for Multiplying MIDI Clock frequency?<o:p></o:p></span></p>
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<p class="MsoNormal">Hello List,<o:p></o:p></p>
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<p class="MsoNormal">I want to experiment with polymetric structures and create "non standard" subdivisions within the standard ones supported by MIDI. I have only worked with the 24ppq, using the timing messages to directly drive the sequencers. I would like
a way to multiply the clock frequency in order to increase resolution, let's say by 10 or maybe 100 times, if that's feasible (I think it is?).<o:p></o:p></p>
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<p class="MsoNormal">I think this is achieved by a PLL. I understand the basic concepts of it and have used in the analog domain, but never did it in a digital only format. Furthermore, I suppose having an array of hardware peripherals, such as timers and interrupts,
and a fairly fast processor (teensy 3.2) could open up other approaches that don't follow the standard PLL configuration.<o:p></o:p></p>
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<p class="MsoNormal">This has been on my mind for some time, but I don't really know where to start. Any advice, or resources are greatly appreciated<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Regards,<o:p></o:p></p>
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<p class="MsoNormal">Spiros<o:p></o:p></p>
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