Heikki,
I'm not sure exactly what this particular circuit looks like, but I strongly
suspect it's just a balanced mixer made from 4066 analog switches. I have
used this technique and it is quite good at low IF frequencies (a few MHz or
less). Are you sure you have the switches biased properly? The thru-path
should be biased at about 1/2 of the 4066 DC supply voltage in order to
avoid severe signal clipping. Can you point to a link where the circuit is
shown??
Joe
W3JDR
"Heikki Ahola" wrote in message
...
Dr. Ulrich Rohde described in one of his articles (QST ?) a novel
product
detector based on CD4066 MOS-switch, which is supposed to have a
superior
performance compared to other types. I have tried the schematic and
found the distortion quite unacceptable.
I have not found any other reference to this type of product detector
and may have misunderstood the cocept somehow. Therefore I would like to
know if this idea is still alive and/or if somebody has any experience
of it. Otherwise I will rely on either DMB or MOSFET in my homebrew
receiver which is intended to be an advanced .
project.
I have already successfully constucted the front end with Fairchild
FST3125
switching mixer followed by a strong postmix amp, 12-pole xtal filter
and the following if-stages. It would a shame to destroy the whole thing
with an inferior detector/af-portion when I am trying accomplish
something better than my previous
design which is heavily based on the W7ZOI Progressive receiver.
73 de Heikki
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