EMRFD Message Archive 10388
Message Date From Subject 10388 2014-10-26 12:18:15 Weddig, Henning-C... AW: [emrfd] Testing Xtal Ladder Filter Impedance may be the reaso is that the filter is not unilateral, i.e. S12 is similar to S21.
Von: 'Steve VK2SJA' firstname.lastname@example.org [emrfd] [mailto:email@example.com]
Gesendet: So 26.10.2014 08:33
Betreff: Re: [emrfd] Testing Xtal Ladder Filter Impedance
Rod, I finally got around to watching that video while playing with the
software. Very useful/powerful stuff. Thanks.
I was able to import my vna/J .s2p file without any difficulty and was
looking at my filter sweep in no time. All to easy in fact.
But when I went I told RFSim99 to generate a "Auto Match" -> "Simultaneous
conjugate", I got the following error message:-
"Simultaneous conjugate match not possible at that frequency because
S-Parameters produce a negative square root in the solution."
I found that if I told it to match Port 1 only it gave me values (only for
port 1 of course) that were *very* close the the values it had arrived at
by a much longer and arduous route.
Anyway just wondering if there is something that I could have done to work
around the error? And if you may happen to know why my filter caused a
negative square root?
> Hi Steve,
> Good, it looks like you have it under control. 0.2dB is better than 2dB
> Roderick Wall, vk3yc.
10389 2014-10-26 14:16:36 radioaustralia123 Re: AW: [emrfd] Testing Xtal Ladder Filter Impedance Hi Steve,I think Henning is correct. In that your Touchstone.s2p file is faulty. I don’t know anything about the MiniVNA as to how to generate two port s2p files. I guess it would be somewhere in the manual.You look as if you almost have it correct when you are able to do a match for one port. It looks as if the s-parameters for the other port are not correct?Roderick.