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Re: I: Input impedance of DEMI2400-144RX?



Hi Domenico,
Where can you download PUFF? I would love to have a copy.
Thanks,
Tony AA2TX
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At 09:57 PM 7/28/01 +0200, i8cvs wrote:

>  Hi  Scott,
>
>  If the input device of DEMI2400-144RX is a GaAsFET and if the input network
>  has been adjusted for the lowest Noise Figure to 50 ohm input,than the
>  reflection coefficient S11 allow you to get at best a return loss of
>  3 to 4 dB or an input VSWR very high around 5 or 6.
>
>  Such high input VSWR is normal in a devices such a GaAsFET adjusted for the
>  lowest Noise Figure.
>
>  If you look at the scattering parameters of a GaAsFET for minimum noise ad
>  make an exercise using PUFF,Computer Aided Design for Microwave Integrated
>  Circuits Version 2.0 you will get the answere to your question.
>
>  PUFF is widely used in Europe and originated as a teaching tool for
>  Caltech's microwave circuits course by professors:
>
>  Scott W. Wedge
>  Richard Compton
>  David Rutledge
>
>  PUFF Distribution
>  Electrical Engineering M/S 116-81
>  California Institute of  Technology
>  Pasadena, CA 91125
>
>  FAX to (818) 356-2137
>  73 de i8CVS Domenico
>
>
>  ----- Original Message -----
>  From: Scott Townley <nx7u@arrl.net>
>  To: <amsat-bb@AMSAT.Org>
>  Sent: Monday, July 23, 2001 1:37 AM
> > Subject: [amsat-bb] Input impedance of DEMI2400-144RX?
> >
> >
> > Has anyone measured the input impedance/VSWR of the DEMI 2400-144RX
> > downconverter?
> > Trying to assess whether mine is nominal or not.
> > So far have measured 20dB conversion gain but input VSWR is very high,
> > which may mean nothing depending on the design philosophy.
> > TIA,
> > Scott Townley
> > nx7u@arrl.net
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>
>
>
>
>
>
>
>
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----
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