AW: Tri 2 Sin

[Haible Juergen]

	>....well I am pretty happy with the CA3080 ckt from electronotes
via 
	>Barry Klein. And I suspect that if you look inside the CA3080 you 
	>find (suprise) the ckt typology you mention.. 

No. You only have one differential pair, with emitters directly connected,
in the 3080. The rest is just current mirrors.

	>BTW what I particularly like is that as you drive the ckt harder
you
	>get a 'rounded square' which is perfect for modulating by, 

As far as I see the method Martin mentioned, the first stage does a similar
thing as the 3080 would do, and the 2nd stage, with resistor between the
emitters, flattens the corner that's left from the first stage. 

In general, the ranking of diff amp based sine shapers would be

1. dual stage method (as Martin described)
2. single stage with resistor between emitters (1496 etc.)
3. simple diff amp (3080 etc.)

The calculation and trimming efforts are more difficult for 2. and 1. than
for 3.

Anybody knows how the FET method, the two diodes method, and a 6 diodes
method (VCS3) fit in this ranking ?

JH.