[sdiy] lookup table as expo converter

[mark verbos]

I hadn't even thought about the oscillator core being digital, but I 
guess that's cool too. I mean since you are there and everything...

but in that case, why not make it a wavetable oscillator and forget 
about the saw wave? Whatever, it's also cool to go analog after that I 
guess. To keep it real. ;) Is the upcoming MOTM thing something like this?

Mark

Tim Ressel wrote:

>Mark,
>
>I've been giving this some thought. I think one could
>get away with having one entry per note (about 120)
>and interpolating between the values for microtonal
>and modulation. 
>
>My first cut would probably use an ATMEL, and use the
>internal ADC for sampling CV and mod inputs. A 120
>note table of values would feed into a
>Numeric-Controlled Oscillator. Another lookup table
>would convert the inherently sawtooth output of the
>NCO into other waveforms. Then an audio DAC provides
>the noise.
>
>I think the use of an oversampling DAC on the output
>would take care of the sharp edges you get with was
>and square waves. Since the DACs are almost all stereo
>these days, you could have two simultaneous outputs.
>
>--tr
>
>--- mark verbos <mverbos at earthlink.net> wrote:
>  
>
>>I know it has been suggested before, but has anyone
>>on here actually 
>>ever used a digital look up table as an exponential
>>converter? I'm just 
>>curious. This would eliminate the temperature drift,
>>but would be a bit 
>>more complicated. It could have relatively high
>>resolution if you used a 
>>big EPROM and a high bit rate.
>>
>>Mark
>>
>>
>>
>>    
>>
>
>
>
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