antilog

[René Schmitz]

Hi Colin and List!

At 14:25 10.08.00 +0100, Fraser, Colin J wrote:
>The LM13600 temperature compensation scheme looks really smart and might be
>the answer.

Right if thermal coupling is good enough. (Although I suspect it won't beat
a tempco resistor.) 

>How come nobody noticed it hidden away at the end of the data sheet all
>these years ?

I think thats because designers are often "conservative", why should one
spend time to evaluate a new (or unknown) circuit, when one has a proven
one at hand. 
The cut-and-paste approach. IMHO theres nothing wrong with that. Therefore
the "Ohhs" and "Ahhs" when such an "unusual" circuit shows up. Surprising,
since I suspect that many of us have thumbed thru the datasheet and seen it
many times. 

To me it makes little sense to build solid state compensations anymore,
platinum temperature sensors are available, and one can use NTCs or
Si-Sensors to get close to their performance, if cost is an issue. 

>And why on earth does the data sheet suggest using a fully temperature
>compensated expo convertor to control the stereo volume control, rather than
>the tri-square oscillator also shown on the data sheet ?

I think they had merely Audio/"Hi-Fi" applications in mind, and knew little
about synths. 

Bye,
 René
-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159