Error in ADS - RF Cafe Forums
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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
Joined: Tue May 02, 2006 4:59 am
I use the Budget tool and got that error message :
[b]Error detected by HPEESOFSIM during Budget Analysis `Budget'.
Term3: ERROR: During Budget cascaded noise analysis; possible element with
unrealistic S-parameters; look for |S11| > .8; |S22| > .8; |S12| near, equal
or greater than |S21|. [/b]
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 pm
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.