input output impedance formula?

[jaya000]

input impedance formula

Last time i asked about input/output impedance formula with reference to one circuit from a boook. I got good info at my post "&highlight=" .

But now i found another wideband circuit of similar type from
hxxp://antrak.org.tr/gazete/082003/yilmaz_dosyalar/WB_amp.pdf
I am herewith posting pages from it. But i got confused how they hv calculated input/output impedance? It is not matching to the info i got previously.
waiting for guidance from experts.

 

[toonafishy]

impedance formula

His measured input return loss is around 10dB so the imput impedance is either 25 or 100 ohms. You can't tell which since the graph is a scalar measurement and you would need to see a vector measurement.

reflection coefficient = +0.32 or -0.32
refrection coefficient (in power) = 0.10
VSWR = 1.92 (5.69 dB)
reflection loss = 0.46 (dB)
return loss = 10.00 (dB)
normalized impedance = 1.92 or 0.52
1.92 * 50 = ~200 ohms or 0.52 *50 = ~ 25 ohms.

Likewise, for the output return loss of 7 dB

reflection coefficient = +0.45 or -0.45
refrection coefficient (in power) = 0.20
VSWR = 2.61 (8.35 dB)
reflection loss = 0.97 (dB)
return loss = 7.00 (dB)
normalized impedance = 2.61 or 0.38

 

[biff44]

output impedance formula

Tuna, ever think of a complex impedance?

 

[jaya000]

impedance formula ratio

Is this patent document about impedance has anything to do with above mentioned wideband amp?

 

[palesha]

input con una formula

This is latest document from Intersil about broadband matching. Principle is almost same as document loaded by jaya000.
Anybody hv used this method & made any design?

 

[jaya000]

impedance input output

According to formula mentioned in the paper
Ire = 25/Ie i.e. Ie 10ma here means Ire=2.5
Formula is Zin = suare root of ( feedback resistor x Ire )
so 330 x 2.5 = 825
so the square root of 825 is almost 28.73
So it is input/output impedeance.
The input impedance calculation is very much near to calculation done by toonafishy
i.e. 25 ohms.
Looking forward to more comments about this method