[sdiy] Passive Ring Modulator

[Magnus Danielson]

From: Tim Ressel <madhun2001 at yahoo.com>
Subject: Re: [sdiy] Passive Ring Modulator
Date: Thu, 18 Jul 2002 13:48:43 -0700 (PDT)

Well, just to make things worse...

I've seen this thread cook over here and I have honestly not really followed
it particularly well. However, this diode discussion thing is something I just
have a little comment on...

I am a man in habit of reading up on subjects here and there. I have yeat to
seriously dig into radio and particularly mixer issues (I am considering to
do such a dig-in in a not so distant future). However, in one of the text I
was reading (relating to precission frequency and phase noise measurements)
particularly the arrival of Schottky diodes in mixers where praised as a good
advancement of the field, and this for the good suppression of carrier and
local oscillator signals. I think this is what you are discussing, which diodes
gives the best suppression and keeps the sideband alone.

So, I'm not an expert on mixers, and this is just what popped in when I read
this thread. It might need some investigation.

Also, forget about the "offset" values. They are constructs out of a rather
high current through a dioded. Recall that the diode really has a
current/voltage relation that is exponential/logarithmic (depending on what
you want) and this is what is important here.

If we are going to discuss "offset voltages", Schottky diodes have lower values
than Germanium diodes as I recall it.

Original diode rings used Copper-oxide diodeds. Those where the glorious days
of heros and wizards. Electronics where a craft mastered by few. Soon that
order is restored... OUPS!

Cheers,
Magnus