[sdiy] Gilbert Cells and VCAs with Predistortion

[Ryan Williams]

hi,

Don Tillman wrote:
> This is actually an old technique; check out the data sheet for the
> Motorola MC1494 Four Quadrant Multiplier.  
> 
> Motorola implemented it with far fewer parts by using a diff amp with
> an emitter resistor for the balanced current sources.

neat, I've just glanced at the data sheet so far. It looks a little 
different than others I've seen. it will take me some time to figure out 
how this one works.

> This is very different from the CA3280 approach, which uses the input
> diodes as a dynamic resistor.
> 
>    > So my questions. Have I made a mistake, is this not as good as I
>    > thing it is?
> 
> I think it will be roughly the performance of the CA3280 linearizer.

If that is the case then I'll be pretty happy.

-ryan