1. Home
  2. Electronics Design
  3. Drawing Mathematical Blank This A.M.
  4. Page 2

Drawing Mathematical Blank This A.M.

Looks like the ATAN in function FRACT makes it blow up inside the feedback loop :-(

...Jim Thompson

--
|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
|  Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
|  Phoenix, Arizona            Voice:(480)460-2350  |             |
|  E-mail Address at Website     Fax:(480)460-2142  |  Brass Rat  |
|       http://www.analog-innovations.com           |    1962     |
             
I love to cook with wine.      Sometimes I even put it in the food.
Reply to
Jim Thompson
Loading thread data ...

Ah. Well then I think this might do what you are looking for

-TANH(K*(FRACT(X)-1/2))/2+FRACT(X)-1/2

Happy to help with math puzzles

Reply to
Don Taylor

I was thinking of 2 things:

(1) The TAN fuction in not defined at PI/2. Unless the evaluator is one of those trick ones with rules for passing +INF, -INF, and NAN along to see if further operations fix the problem, the convergence doesn't get a chance to continue if you happen onto that point. Even with the trick evaluator, there could be a problem with the curve near the point where the value overflows.

(2) Linear's spice contains "hacks". I assumed that using the FLOOR fuction would be more likely to engage the right hack than a method that goes through a few steps to the result.

--
--
kensmith@rahul.net   forging knowledge
Reply to
Ken Smith

"Jim Thompson" schrieb im Newsbeitrag news: snipped-for-privacy@4ax.com...

Hello Jim, just pass the sawtooth thtough a TABLE function. You have then the choice where SPICE interpolates betwenn 0 and 0.5-eps, e.g. 0.49, 0.499 or however close you want go towars 0.5/-0.5.

sawtooth table-out

0.5 0 0.499 0.499

-0.499 -0.499

-0.5 0

Best Regards, Helmut

Reply to
Helmut Sennewald

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.