Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
It seems that the more formal social media like Facebook pretty much dominate this kind of venue anymore anyway, so if
you would like to post something on RF Cafe's
page, please do.
Below are all of the forum threads, including all
the responses to the original posts.
Post subject: IP3 out of band
Unread postPosted: Mon May
30, 2005 5:56 am
What is the method to mesure and calculate
Input IP3 Out of band,
meaning 2 signal out of the IF filter caused
postPosted: Mon May 30, 2005 5:34 pm
You know, I think you need
to create your own method but what about this:
tones trough a broadband directionnal coupler,
IMDs at the output,
Divide by the gain the IMD products as measured
at the output
The ratio of what measured at the input and the
products is some sort of IMD measure.
Post subject: IP3 "out of band"
Unread postPosted: Tue May 31,
2005 11:26 am
Umm - It appears the question is poorly put.
IP3 is the (hypothetical) point where the power in the 3rd order
IM distortion products is equal to the power in the desired output.
If there is zero desired output (as there will be if your filters are
adequate), then there cannot be an IP3 as usually defined.
previous respondent hinted at this when he said that you'd get "some
sort of IMD measure" with the process he outlined.
If this measurement
is for meeting a requirement, then you need to get the specifier to
clarify the intent and execution of tests for this spec.
Thu Jun 09, 2005 9:57 pm
Jun 09, 2005 9:50 pm
I may be failing to understand
Are you talking about two out of band signals
mixing and causing an unwanted inband signal? If so, can't you inject
two tones into the part of the circuit you are concerned about?