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RE: [802.3ae_Serial] Issue with 1500 Power




Hi again,

You are correct about the -11.4 dBm. I used the old value. To me it
looks like we get the same numbers now (the average power sensitivity of
"-18 dBm + ER penalty" in the end). However, I do not agree that the 13
dB attenuation is optional. A transmitter with e.g. 2 dB TDP would
require a OMA output of +0.6 dBm, giving a received OMA of -12.4 dBm.
The sensitivity (in OMA) of a compliant receiver would be around -15
dBm, and around -13 dBm using a signal with 2 dB TDP.

/Peter

> -----Original Message-----
> From: Rahn, Juergen (Juergen) [mailto:krahn@lucent.com]
> Sent: den 28 juni 2001 10:54
> To: _Serial PMD Ad Hoc Reflector (E-mail); Peter Öhlén
> Cc: 'tsg15q16@itu.int'
> Subject: AW: [802.3ae_Serial] Issue with 1500 Power
> 
> 
> Hi, 
> 
> My  question is now about the additional 3 dB you mention. Are the
> additional 3 dB you are talking off  the :
> Vertical eye closure penalty ** (max) 3.0 dB  
> as stated in the receiver table? If this is true then maybe 
> some text would
> be helpful because this means the worst case sensitivity you 
> require for
> interworking is 3dB higher ( Which are the missing 3 dB). 
> You state a stressed sensitivity (in OMA) of -11.8 in the 
> table I find -11.4
> dBm.
> However also in this case I have problems to see how an eye 
> penalty can be
> used for attenuation budget. For my interpretation this does 
> mean that in
> case of a signal with 3 dB eye penalty the full attenuation cannot be
> bridged. This means that either it has to be made sure that 
> this penalty is
> not there (but why specifying it ) and should be removed  or 
> it has to be
> made clear under which  conditions the 13 dB attenuation can 
> be reached as
> this makes this optional. This is at least not really easy to 
> understand.
> So if I now follow this and add this penalty to the 
> sensitivity we would
> require a receiver that supports a OMA sensitivity of -14.4 
> (or following
> your figures -14.8 dBmOMA) This translates into average power 
> sensitivity
> (for infinite ER) of about - 18 dBm + ER penalty. Is this 
> consideration
> correct in your eyes now? 
> 
> Regards Juergen
> 
> 
> > ----------
> > Von: 	Peter Öhlén[SMTP:Peter.Ohlen@optillion.com]
> > Gesendet: 	Mittwoch, 27. Juni 2001 13:27
> > An: 	Rahn, Juergen (Juergen); _Serial PMD Ad Hoc 
> Reflector (E-mail)
> > Betreff: 	RE: [802.3ae_Serial] Issue with 1500 Power
> > 
> > Here is a short power budget the way I see it. For 
> simplicity, let the
> > ISI & dispersion penalty be 0. All powers in OMA [dB].
> > 
> > The transmitter output power is -1.39 dBm. At the receiver you have
> > -14.39 dBm. I think the confusing part is the stressed sensitivity.
> > 
> > The stressed sensitivity is measured with an eye having 3 dB eye
> > closure. In addition to that, there will be a small 
> additional vertical
> > eye closure due to sinusoidal jitter, which I don't account 
> for here.
> > With the stressed eye the sensitivity in OMA (measured between the
> > nominal 1 and 0 levels) is -11.8. If we instead of the 
> stressed eye have
> > an eye without the 3 dB eye closure, the sensitivity would be
> > -11.8-3=-14.8 dBm. This would give you roughly 0.4 dB margin.
> > 
> > To make this more accurate, you would have to take the 
> sinusoidal jitter
> > in the stressed eye into account (--> more margin), as well as some
> > penalties that could occur in the real link (e.g. 
> interferometric noise
> > and other known and unknown penalties --> less margin).
> > 
> > Hope this helps,
> > 
> > 	/Peter
> > 
> > 
> > > -----Original Message-----
> > > From: Rahn, Juergen (Juergen) [mailto:krahn@lucent.com]
> > > Sent: den 27 juni 2001 12:30
> > > To: stds-802-3-hssg-serialpmd@ieee.org
> > > Subject: AW: [802.3ae_Serial] Issue with 1500 Power
> > > 
> > > 
> > > 
> > > Hi,
> > > as discussed in the PMD call I understand there is a mismatch 
> > > in the values
> > > defined for the 1550 case. The minimum transmitter OMA is 
>  -1.39dBm +
> > > penalties. Link attenuation is set to 13 dB , so this would give a
> > > sensitivity requirement of -14,39 dBm OMA ,. however the stressed
> > > sensitivity (In OMA) is defined to be -11.4 dBm. so there 
> are 10 dB
> > > difference between those two values. The trade off that has 
> > > been introduced
> > > (that I do not like, but this is a different discussion) will 
> > > shift this
> > > complete link power level. When comparing this with powers 
> > > and sensitivities
> > > as defined in ITU the following appears: ITU defines 2 dB 
> > > path penalty with
> > > this OMA we would end at a minimum transmitter power average 
> > > of   about - 1
> > > dBm which is in line to ITU. with 109 dB attenuation there is 
> > > margin in the
> > > ITU numbers, with 11 dB and ITU sensitivity (Which has been 
> > > confirmed by
> > > measurements) we add up to 0. ( -14 dBm average power 
> > > sensitivity and 2 dB
> > > penalty gives us the G.691 application). When simply taking 
> > > this transmitter
> > > power and 13 dB attenuation we end up with 2 dB better sensitivity
> > > requirement as currently experienced by measurements 
> (worst case EOL).
> > > This may start this conversation.
> > > Regards Juergen
> > > 
> > > 
> > > 
> > 
>