"Doc" wrote in message

In a simplistic way, Intermod (intermodulation distortion) is the result
of
two or more separate signals being combined. The intermixing of these
signals creates distortion of the signal you are receiving.
In a round about way, multi-path is similar because the combined multiple
images are out of phase and they will mix in the same way as do two
unrelated signals, and create distortion.


THANKS,

H.J.

Honest John wrote regarding multipath:
Is that the same thing as what ham radio operators of 2 meter repeaters call
"intermod" ?

No. Multipath is from the same signal arriving via two different paths
(typically resulting from a reflection), one of which is delayed enough
to cause phase cancellation.

Intermod is from separete signals of different frequencies mixing in
some nonlinear componenent either in or near the receiving apparatus,
producing signals that are the sum and difference of the two frequencies.

--
John Miller

I think I did say "in a simplistic way". Yes I do understand what intermod
is, however, I thought a discussion of 3rd order intercept series was not in
order to answer his question. I was using the KISS approach.

"John Miller" wrote in message
...
Honest John wrote regarding multipath:
Is that the same thing as what ham radio operators of 2 meter repeaters
call
"intermod" ?

No. Multipath is from the same signal arriving via two different paths
(typically resulting from a reflection), one of which is delayed enough
to cause phase cancellation.

Intermod is from separete signals of different frequencies mixing in
some nonlinear componenent either in or near the receiving apparatus,
producing signals that are the sum and difference of the two frequencies.

--
John Miller

Doc wrote:
I think I did say "in a simplistic way". Yes I do understand what intermod
is, however, I thought a discussion of 3rd order intercept series was not in
order to answer his question. I was using the KISS approach.

Check your threading, Doc, and you'll see that it was not your post I
was responding to -- in fact I don't think it had even hit my server
yet. So you weren't being contradicted.

--
John Miller
insert pithy quote here

Sorry for jumping to conclusions...
My thread shows your post as a reply to mine. That's probably because I had
just purged old posts.


"John Miller" wrote in message
...
Doc wrote:
I think I did say "in a simplistic way". Yes I do understand what
intermod
is, however, I thought a discussion of 3rd order intercept series was not
in
order to answer his question. I was using the KISS approach.

Check your threading, Doc, and you'll see that it was not your post I
was responding to -- in fact I don't think it had even hit my server
yet. So you weren't being contradicted.

--
John Miller
insert pithy quote here

On Thu, 12 Jan 2006 17:50:02 GMT, John Miller wrote:

Intermod is from separete signals of different frequencies mixing in
some nonlinear componenent either in or near the receiving apparatus

Or the transmitter apparatus. (We have a great one here, resulting
from a hospital paging transmitter intermodding with just about
everything on a hill that has enough RF floating around to run a few
homes. The paging transmitter - that's supposed to cover only the
interior of the building - is dirty enough and strong enough to cause
intermod in tower joints, fences, who knows what, 5 miles away.)