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RE: [EFM] RE: Link Model and Return Loss


I did not try to follow the formula.  Does the formula represent the noise
increase in the transmitter due to the presence of an external cavity or
does it represent the effective noise increase at the receiver due to the
presence of interfering out of phase signals?


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-----Original Message-----
From: piers_dawe@xxxxxxxxxxx [mailto:piers_dawe@xxxxxxxxxxx]
Sent: Thursday, December 13, 2001 7:23 AM
To: Thomas.Murphy@xxxxxxxxxxxx
Subject: [EFM] RE: Link Model and Return Loss


T4, receiver reflection, and G12, transmitter reflection (if you shine light
into a switched-off transmitter, how much comes back?) are used with channel
insertion loss, ISI, extinction ratio and the magic "Reflection Noise
factor" L10 to calculate column N, reflection penalty due to partly coherent
beating of a signal with its own echo.  If wish, you can follow the trail of
references to find more about the formula used.


> -----Original Message-----
> From: Thomas.Murphy@xxxxxxxxxxxx [mailto:Thomas.Murphy@xxxxxxxxxxxx]
> Sent: 13 December 2001 12:14
> To: piers_dawe@xxxxxxxxxxx
> Cc:
> Subject: Link Model and Return Loss
> Hello All,
> A question regarding the link model.  Is it possible to estimate the
> penalty of a receiver in the presence of reflected signal.  In the
> spreadsheet I see a parameter Refl Rx (T5) with a value of -26dB.
> However, I am unsure if this is the parameter I am after?
> Thanks
> Tom Murphy