[sdiy] Analog Computational Unit

[James Patchell]

A,B, and C are pots, and you are right, you only need two mulitpliers, the 
linear term can be done with nothing more complex that a pot.

At 03:42 PM 2/1/2004 +0100, Ingo Debus wrote:

>Am Sonntag, 01.02.04 um 04:32 Uhr schrieb James Patchell:
>
>>I was also thinking of doing a module that would produce:
>>
>>Y = +/-Ax^3 +/-Bx^2 +/- Cx
>>
>>It can be easily done using three AD633, a summer and three opamps set up 
>>as an adjustable attenuator with both positive and negative gain (I use a 
>>similar circuit in my diode shaper)....
>
>Why three? If you want x^3 and x^2, can't you just use two, one to get x^2 
>from x, and another one to get x^3 from x^2 (i.e. output of the first 
>AD633) and x?
>
>Or are A, B and C control voltages? In this case I don't see why you need 
>*only* three.
>
>Ingo

         -Jim
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