SynthModules

I am missing something here, a keyboard is already quantized, 
why would you want to quantize it again?

A quantizer expects an unquantized input to work properly, if you 
feed it an already quantized voltage, strange things will happen.

Think of it as a classifier. The software "classifies" the input into 
one discrete output step. The classifier rules are adjustable. 
That is you can program the 0 to 10 volt input to generate as 
many or few outputs steps as you want, by changing the 
classifier rules.

So it is not going to match the output steps of a keyboard, unless 
precisely calibrated to do so and with specific software. Also the 
absolute input precision on the PSIM is about 5%. (because the 
ADC reference is the untrimmed 5 volt supply) 

Quite good for most things, but to track another quantized source 
(like the Roland OP-8m tries to do) trim pots would be need on 
the inputs for both scale and offset for each input channel. And 
the 5 volt supply will need to be precisely trimmed.

--- In SynthModules@yahoogroups.com, "djbrow54" 
<davebr@e...> wrote:
> As I use my PSIM for CV functions, the output never seems to 
be 'in
> tune' with what I expect.  If I use the basicqu2.bas program as 
an
> example to sample and quantize my keyboard CV, there is a
> significant difference between the output and the keyboard CV.
> 
> I thought I would try and do the calculations in semitones.  The
> input is 1023 steps over 10 volts.  Every 8.5 steps is a 
semitone (83
> mV).  If I could divide the input by 8.5 then I would have the
> semitone value. Since I can't divide by 8.5, I can multiply by 2 
and
> divide by 17.
> 
> Since the output is 4095 steps over 10.666 volts, every 32 
steps is a
> semitone. To convert the input from a semitone to the correct 
output
> voltage, I would multiply by 32.  Thus if I take the input, multiply
> by 64 and divide by 17 I convert it to the correct output and
> quantize to the semitone.
> 
> In basicqu2, replacing the RAWDAC1=((ADC1V/16)*32)+49152 
calculation
> with RAWDAC1=((ADC1V*64)/17)+49152 yields an output that 
tracks the
> keyboard CV quite well.
> 
> Does this math make sense?  I haven't seen any code use 
anything
> similar to this.  I've been having issues with a program I'm 
writing
> that samples and delays my keyboard output and this seems 
to correct
> the issue.
> 
> Dave