[sdiy] harmonic generator

[Arun Bohm]

>From: Scott Bernardi <sbernardi at attbi.com>
>CC: synth-diy at dropmix.xs4all.nl
>Subject: Re: [sdiy] harmonic generator
>Date: Thu, 21 Feb 2002 05:42:07 -0800
>
>That's a tall order.  You can do frequency division fairly easily with
>square waves, in which case you would actually start with a high
>frequency and derive the subharmonics; the divide-by-10 subharmonic
>would become your "derived fundamental". The problem with this method is
>that you get a bunch of extra harmonics from the square waves.
>Using a fundamental and deriving the upper harmonics is a lot trickier,
>because then you need to do frequency multiplication.  Frequency
>doubling is pretty easy - you take a symmetrical triangle wave and run
>it through an absolute value circuit, which gives you a triangle wave of
>double the frequency. There you can get your 2nd, 4th, and 8th (even)
>harmonics.  You can run the triangles into tri-to-sine converters to
>warp them into sine waves.
>To get the other harmonics, you would need to generate the 3rd, 5th, and
>7th.  You could get the 6th by doubling the 3rd, and the 10th by
>doubling the fifth.
>I suppose you could use phase locked loops to do frequency
>multiplication, but the problem is getting a PLL to track over a wide
>frequency range (they typically only have about a 10:1 frequency range).
>
>I've thought about doing a circuit like this to make a Hammond
>organ-like module (you know, the drawbars). Didn't know how to get past
>the hurdles, however.
>
>
>Rob Hukin wrote:
>
> > Can anyone recommend a harmonic generator circuit - I need about the
> > first 10 harmonics of a given fundamental.
> >
> > thanks,
> > rob.
>
>--
>Scott Bernardi
>sbernardi at attbi.com
>
>


Hi, Can you do frequency division with the square waves and then wave 
shape(using some diode network) and sum in as the fundamental? I was going 
to use this method for a version of the Trautonium i had in mind. I just 
need to figure out a way to shift phase and amplitude. Oh yeah, what 
material should i use to make the voltage control plate from. I mean, what 
has 10k resistance per foot of material. I think the original trauts had 
resistance wire across conducting plates. However, I don't have the tools 
for winding such wire. Any ideas guys?

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