[sdiy] accu phase tuning knob?

[Paul Maddox]

Christian,

> If i want to implement a tuning "knob" in a digital phase accu oszilator
design
> - how could that be done?
> the accu value has a linear Hz response so a simple "offset" will not do
the
> trick.. the offset has to double each octave.
> a lookup table ? higher math in avr assembler ?
> (i already implemented a lookup table that holds values for each midi
note...)

:-)
The Monowave uses two PAOs and yes, they are linear...
And the monowave tune knob is also linear :-)

as most people simply hold down a note on two synths and turn the tuning
until sounds right, it doesn't matter that its not log..

You could also do a kind of peicewise log thing..
And for example say if the value from the ADC is greater than 12 then take
the ADC value and add an extra 12, then if the value is greater than say 24
add an extra 24 to the ADC value..

Its quicker than math, slower than a LUT though...

paul