voltage controllable harmonic generator idea ( Was Re: clock multiplier )

[Scott Gravenhorst]

On Thu, 16 Apr 1998 09:28:44 +1000 (EST), Paul Perry
<pfperry at melbpc.org.au> wrote:

>At 03:56 PM 15/04/98 +0200, you wrote:
>
>>At 12:57 PM 15/04/98 +0200, Martin Czech  wrote:
>>>Another idea for multiplying frequency:
>>>
>>>A sawtooth input wave is converted with a thermometer code ADC
>>>in order to get equidistant time markers. 
>>>
>>>This sounds horribly complicated and expensive, but it is not.  It
>>>takes just a handfull of LF311 comparators
>>
>>....this is good.... but I think possibly what people were wanting is
>>to multiply the clock rate, which will be changing with tempo.. so you
>>will have to derive a triangle (or more likely sawtooth) with fixed 
>>height from the input clock, which is not easy!
>>which is why I suggest a variable comparator comparison level which 
>>tracks the triangle peak..

Hmmm.  Use min. 4? comparators, sum the outputs and differentiate the
sum.  Amplify to clip and full wave rectify, then level convert for
CMOS, into a JK flop setup for toggle.  Each time a comparator changes
state, a pulse appears at the sum output.  Put a pot or a CV one leg
of each comparator.  Has limitations, but might sound interesting


-- Scott Gravenhorst