[sdiy] Sine shaper from AD633

[Ben Stuyts]

Hi,

On 18 aug 2010, at 05:06, Paul Perry wrote:

> Curiously enough - though it has nothing whatever to do with
> Juergen's device - there is a way of approximating a sine
> converter using an analog multiplier such as an AD633.
> Unfortunately my electronics books are in storage at the
> moment - but maybe someone can remember back from the
> late 60s.
> Like many things back then, it was based on some trigonomical
> approximation, generating the sine as a function of X, Xsquared,
> Xcubed but with an ingenious arrangement of feedback to
> minimise the number of expensive multipliers required.
> Personally, whenever I want a triangle to sine converter I overdrive an OTA,
> this seems cheapest to me, and also close enough for rock and roll.
> 
> paul perry Melbourne Australia
> 
> ----- Original Message ----- From: "Gergo Palatinszky" Subject: [sdiy] Sine shaper from AD633
>> Hi,
>> Anybody did a sine wave shaper out from AD633?
>> I'm thinking about it for Jurgen's living VCO sine output...
>> Pros/cons?

I remember something like that too, but I only found this patent involving two (or more) multipliers:
http://www.freepatentsonline.com/5132636.pdf

Also found an interesting app note with a few other sine shaping techniques at the National Semi site:
http://www.national.com/an/AN/AN-263.pdf

Kind regards,
Ben