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: Error in ADS Posted: Tue May 02, 2006 5:05 am
May 02, 2006 4:59 am
I use the Budget tool and got that error message :
by HPEESOFSIM during Budget Analysis `Budget'.
Term3: ERROR: During Budget cascaded noise analysis; possible
unrealistic S-parameters; look for |S11| > .8; |S22| > .8; |S12| near, equal
or greater than
Maybe anyone understand it ?
I know its depend on the attenuators location but im not
understand why .
Post subject: ADS error messagePosted: Tue May 02, 2006 6:32 pm
Joined: Wed Feb 22, 2006 3:51 pm
That's actually a
more-helpful error message than many, because it tells you what to look for in your design. Unfortunately it's not
very specific - it doesn't tell you where to look, and it gives 3 alternatives.
The S11 and S22 checks say
that maybe there's a severe impedance mismatch between two stages, the S12/S21 message says that maybe there's a
large amount of (unexpected/undesired) feedback around an active stage.
Post subject: Posted: Tue May 02, 2006 10:03 pm
Joined: Mon Jun 27, 2005 2:02
I took the initiative and replied to this post directly by
email as we had already a brief correspondence in the past. I mentioned that the main cause of such a problem is
instability (As fred47 mentioned), this is also noticed by the values of S11, S22 which are greater than 1. This
is likely to be caused by poor matching. I also suggest you to do the budget analysis simulation step by step from
the start: Block after block. And to see in which step the error message displays. By doing that you can find out
the problemtaic element and check it separately.