[sdiy] Filter Structure Question

[René Schmitz]

Hi all,

harrybissell wrote:
> The technique of using a spare inverter to estimate the bias point
> is an old (and useful one).  If I followed correctly, you want to tie the
> output of that inverter to "real" ground ?  (to the center of a pair
> of resistors connected to the positive and negative rails).  I don't
> know about that part. The output of the inverter would have only a
> very limited ability to move that point to the correct one.

Besides that, the supply to the 4069 wouldn't be very stiff, and this 
could lead to "interesting" if not disturbing side effects, since the 
current consumption of the gates varies with the signal. It would lead 
to severe crosscoupling between the gates, something which is already 
present to some extent, since the internal traces and bonding wires were 
never designed for the amount of current present in a linear application 
of these chips.

Cheers,
  René

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