[ibis-macro] Re: E-element in analog model BIRD
- From: Bob Ross <bob@xxxxxxxxxxxxx>
- To: fangyi_rao@xxxxxxxxxxx
- Date: Thu, 27 Jan 2011 00:48:24 -0800
Hi Fangyi:
(Credit to Vladimir Dmitriev-Zdorov for approaching the ideal
E-element using 2-ports.)
Yes, R1=infinity, and R2=0
------
You can model this ideal E-element in terms of G-parameters
[I1] = [G11 G12][V1] , [Ge] = [0 0]
[V2] [G21 G22][I2] [1 0]
Using standard 2-port transformation formulas (I do not have a good
link with all the formulas) to find the transmission parameters [T]:
[Ge] --> [Se] = [1 0] --> [Te] = 0.5*[1 1]
[2 -1] [1 1]
If the TX, RX models are defined as in BIRD122:
[Stx] = [0 0] --> [Ttx] = (1/S21)*[0 0]
[S21 S22] [-S22 1]
[Srx] = [S11 0] --> [Trx] = (1/S21)*[0 S11]
[S21 0] [0 1]
Pre/Post Cascading the E-element yields T-parameter
products for TX/RX and their corresponding S-parameters:
[T-etx] = [-0.5*S22/S21 0.5/S21] --> [S-etx] = [1 0]
[-0.5*S22/S21 0.5/S21] [2*S21 S22]
[T-rxe] = [0.5*S11/S21 0.5*S11/S21] --> [S-rxe] = [S11 0]
[0.5/S21 0.5/S21] [2*S21 -1]
The cascaded unity E-element creates the infinite input
impedance for the TX model and zero output impedance for the RX
model and causes the resuling S21 value to double for each case.
The formulation you presented several weeks ago illustrated
that S21 needed to be double its value if S11=1 to produce
the same output voltage from a zero impedance voltage
source at the TX model input.
Bob
fangyi_rao@xxxxxxxxxxx wrote:
Hi, Arpad;
Can you please clarify that the ideal E-element (VCVS) in the analog
model you showed at last ATM has R2=0 for Tx and R1=infinity and R2=0
for Rx (R1 & R2 are defined in the figure below)?
Thanks,
Fangyi
--
Bob Ross
Teraspeed Consulting Group LLC Teraspeed Labs
121 North River Drive 13610 SW Harness Lane
Narragansett, RI 02882 Beaverton, OR 97008
401-284-1827 503-430-1065
http://www.teraspeed.com 503-246-8048 Direct
bob@xxxxxxxxxxxxx
Teraspeed is a registered service mark of Teraspeed Consulting Group LLC
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