On Mon, 12 Jun 2006 18:34:51 GMT, Jan Panteltje
wrote:

+++On a sunny day (12 Jun 2006 11:20:24 -0700) it happened "Telstar Electronics"
wrote in
oups.com:
+++
+++Hmmm... that's what I thought originally. Now I'm getting confused. I'm
+++real interested how this discussion shakes out...
+++
+++Do not listen to him, it is 100% nonsense.
+++
+++Very simply:
+++An AM detector is an 'enveloppe' detector,
+++a DSB and SSB detector is a 'product detector'.
*****

A product Detector is prefered due to its mixer characteristics. Being
balanced, the two inputs are supressed sufficiently to make filtering
their components in the output much easier. Product detectors and
Envelope dection is not the only means of detecting DSB-SC and DSB-LC
signals. They are the most simplest and easiest to implement.

+++
+++You have seen that waveform I pointed out in fig 4 for a sine wave single
+++tone modulation, the amplitude of the RF signal dos not really look like a
+++sinewave does it?
+++
+++So you hear sever distortion, in fact you cannot make out what it is.
+++
*****

Distortion of the RF waveform may not nescessarily indicate that the
detected audio is unintelligable. As long as the recovered audio is
reproduced accuarately during demodulation then there is no
distortion. Spectral content of the demodualted signal can be set by
post detection filtering. This can reduce to some extent the harmonics
of the modulating signal.

By the way the lab you point to is more about the generation of a DSB
signal. From figure 4 you are making statements about demodulation.

+++In a product detector the BFO is the 'substitute' carrier, and multiplication
+++of one (SSB) or both (DSB) sideband[s] gives the original modulation.
+++
+++There is in fact no need for the 'other' sideband in DSB-SC, no problem if
+++the receiver filters it out, that is why you can receive DSB-SC both with
+++USB and LSB!
+++
***********

Since the information in both sidebands are indentical the only need
for the second sideband is to increase demodulated audio.

+++But for the non-believers, try it out, all you need is an audio amp,
+++oscillator, 4 diodes, and of course a 27 HHz xtal oscillator.
+++http://www.nzart.org.nz/nzart/examin...les/Mixers.htm
+++
+++There is a description and diagram a bit down on the page.
+++
+++Listen to it on an AM receiver, and you will KNOW.
+++


james