Noisy noise generator

[WeAreAs1 at aol.com]

In a message dated 10/18/00 8:58:21 AM, buchi at takeonetech.de writes:

<< OK, but my very first idea was to have the noise very close to GND,
with no DC offset. Also, i wanted to get a mixed signal from 2 noise
sources. >>

Why not just simply AC-couple the noise generator output through a fairly 
large cap?  That will eliminate any DC offset.  If the cap is large enough, 
you should be able to pass noise components all the way down to near zero 
Hertz (if you need low frequency noise).  You could still filter it after the 
cap to constrain the noise to whatever frequency range(s) you might need.

This, however, won't help you get rid of that 50Hz hum component.  Martin, 
Harry, and Scott have already given good advice in that regard.

BTW, if you can find a noise device that can self-generate a higher amplitude 
noise in the first place, you will have less problem with DC offsets, since 
you wouldn't need to amplify the noise so much (the more you amplify the 
noise, the more you also amplify any offset that is present).  Maybe you need 
to try something other than those Zener diodes?

Michael Bacich