Dear Richard:

Last week's lab job in both Electronics I and II (at different levels)
explored just this issue.
How great it is to have really good scopes and a spectrum analyzer in a
student tab.

73 Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Richard Clark" wrote in message
...
On Tue, 23 May 2006 19:11:00 -0400, "J. Mc Laughlin"
wrote:

Dear Richard:

I have had occasion to note to students that some of what they call music
would not be noticeably modified by being amplified by a amplifier having
a
great deal of distortion.

Your point is right on target.

Hi Mac,

My point may have been on target, but the specifics left an escape for
those quick enough to pick up on it. In fact, I would speculate that
most audio (as do RF) amplifiers exhibit the gain characteristic of
f(x) = y = mx + b
and this is called class AB. When you build an amp employing two of
them in a push-pull configuration the constants b negate each other
and the 2mx remains.

Of course, the push-pull configuration is built to nullify the
distortion of this "linear" curve.

The single power supply Op Amp also suffers from
f(x) = y = mx + b
with the output floating at half the supply voltage - this has got to
be an application killer if it goes straight to the speakers without
removing the b with a capacitor.

73's
Richard Clark, KB7QHC