[sdiy] Interesting VCA circuit on MAT04 schematic

[Yves Usson]

Well it somehow looks like a gilbert cell. I think you'd be interested  
by the
following link :

http://members.tripod.com/michaelgellis/gilbert.html

It gives a nice overview of the theory behind the circuit.

Cheers

Yves

Le 25 avr. 06, à 11:33, jhaible at debitel.net a écrit :

> No Blackmer derivate here.
>
> It's close to the MC1496 4-quadrant multiplier.
>
> The 1496 and similar structures have a linear input
> (the current sources ...), and a tanh input
> (the differential pairs). The MC1494 (and AFAIK,
> modern chips like the AD633, too), add linearising
> diodes to the nonlinear input. I think the wole thing
> is called Gilbert multiplier then.
>
>
> JH.
>
>>
>> http://users.ece.gatech.edu/~lanterma/sdiy/datasheets/transistors/ 
>> mat04.pdf
>>
>>
>> Is this some kind of souped up Blackmer cell? The datasheet says it's
>> "widely used in professional audio circles."
>>
>> - Aaron
>>
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Yves Usson
email :       yves.usson at yusynth.net
web site :    http://yusynth.net