AW: [802.3ae_Serial] Issue with 1500 Power
Thanks for this clarification,
but if this is the case readers of this who was not present when generating
those figures should be informed that this "Eye closure penalty" needs to be
added to sensitivity. As written in the current version I must tell you that
nobody will understand this.
So now after getting the numbers right I have to ask where one can get such
receiver under reasonable conditions. From what our experience is, we are at
the upper limit of sensitivity distribution of receivers that you can get
today (As PIN implementation), the rest of the spec however makes (much more
expensive) APD very difficult to be used also. This means there will be an
extremely low yield of compliant receivers today and we have to wait for new
technology (will this be cheaper), or need to do something else on the power
budget e.g. using the underlying values as defined in the telecom's world in
G.691. This should a viable option as the infrastructure (40 km interoffice
single mode fibre cable) will be the same as the traditional telecom's
infrastructure. In this case we have 11 dB, which should be feasible with
the stated transmitter values and available receivers.
Regards Juergen
> ----------
> Von: Peter Öhlén[SMTP:Peter.Ohlen@xxxxxxxxxxxxx]
> Gesendet: Donnerstag, 28. Juni 2001 13:13
> An: Rahn, Juergen (Juergen); _Serial PMD Ad Hoc Reflector (E-mail)
> Betreff: 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@xxxxxxxxxx]
> > Sent: den 28 juni 2001 10:54
> > To: _Serial PMD Ad Hoc Reflector (E-mail); Peter Öhlén
> > Cc: 'tsg15q16@xxxxxxx'
> > 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@xxxxxxxxxxxxx]
> > > 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@xxxxxxxxxx]
> > > > Sent: den 27 juni 2001 12:30
> > > > To: stds-802-3-hssg-serialpmd@xxxxxxxx
> > > > 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
> > > >
> > > >
> > > >
> > >
> >
>