[sdiy] CEM3340 question -- interpolating scanners (again)

Mike Beauchamp list at mikebeauchamp.com
Fri Dec 4 05:45:08 CET 2020

On 12/3/20 10:28 PM, Bernard Arthur Hutchins, Jr wrote:
> David –
> In your video of your scanner you seem to be scanning at a sub-audio 
> rate exclusively (?).  Thus your output is a sequence of notes (short 
> tunes) with each pitched note having several-to-many cycles.
> Have you tried scanning at an audio rate?  Specifically, what if each 
> channel was a different waveform from the same VCO and   the scan rate 
> were at an audio rate (perhaps 8 times higher than the VCO PLUS, say, 1 
> Hz)?  Each VCO waveform would be visited slightly faster than once per 
> cycle in an evolving manner.  Wouldn’t this produce an “animated” output 
> perhaps similar to my “Tone Wheel Animator”?
> http://electronotes.netfirms.com/AES4.PDF

That sounds interesting for sure Bernie,

Yeah a multiplier of the core VCO frequency modulating the interpolating 
scanner would make for some new and static waveforms... a different one 
for each multiplier and phase difference.

Being off by a Hz or two would make them slowly evolve by that 
difference and could be pretty interesting. (At least on the scope - I'm 
usually pretty amazed that very complicated stuff on the scope actually 
all ends up "sounding kinda like pwm").


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