Re: AW: [802.3ae_Serial] Issue with 1500 Power
I am in full agreement with Piersexcept that I believe the minus sign in
the document is correct. The OMA minus TDP should be equal to -1.39.
If
the TDP is large the OMA has to increase.
"DAWE,PIERS (A-England,ex1)" wrote:
> Juergen,
>
> You are less confused than you say! I have compared my understanding with
> yours: see below. There are some editorial/clarity issues and one
> outstanding point which is: is the 802.3ae D3.1 ER/EW receive sensitivity
> very demanding or expensive?
>
> Piers
>
> > -----Original Message-----
> > From: Rahn, Juergen (Juergen) [mailto:krahn@xxxxxxxxxx]
> > Sent: 03 July 2001 09:01
> > To: 'Mike Dudek'
> > Cc: stds-802-3-hssg-serialpmd@xxxxxxxx; 'Ron Miller'
> > Subject: AW: AW: [802.3ae_Serial] Issue with 1500 Power
> >
> >
> > Sorry,
> > I am still confused.
> > You talk about ISI penalty now but this is stated at transmitter power
> > anyway and not quantified.
> > In the table it reads:
> > Launch power (min) in OMA minus TDP * -1.39 dBm
> > with a note:
> > * TDP is transmitter and dispersion penalty
> > up to now I interpreted that we have to consider the
> > penalties and than
> > compensate the penalties by increasing the power (Whatever
> > the penalties
> > are) First question is this a correct understanding?
>
> Yes
>
> > If yes you will not have any advantage at the receiver when
> > increasing the
> > power by the amount of penalty as a penalty represents the decrease in
> > sensitivity, so this should add up to zero.
>
> Yes
>
> > (It comes to my mind that the - in this parameter suggests
> > that the power
> > may be decreased by the penalties which would give trouble
> > but this may be a
> > short editorial discussion)
>
> Juergen please make a comment. Editor please note!
>
> > If this understanding is correct let me make the calculation:
> > Simple case ideal transmitter no penalties :
> > Launch power (min) in OMA minus TDP * -1.39 dBm
> >
> > Stressed receive sensitivity (max) in OMA ?, ? , §
> > (-11.40)
> > (dBm)
> >
> > I calculate an attenuation budget of about 10 dB out of this not 13db.
>
> No, you have it right below.
>
> > However there is a term in the receiver table .
> > ( I interpret max sensitivity here also as a minimum
> > requirement, I don not
> > hope that this means the sensitivity should not be better
> > than this value,
> > but this may be an editorial problem)
>
> Maximum is more dBm, representing worst case for a receiver sensitivity, so
> I think this one is the right way round. Please make a comment if any doubt
> remains.
>
> > Vertical eye closure penalty ** (max) 3.0 dB
> > with a note
> > **Vertical eye closure penalty is a test condition for
> > measuring stressed
> > receive sensitivity. It is not a required charac-teristic
> > of the receiver.
> > This note is a bit misleading for me, however I interpret
> > this note in the
> > way that when measuring stressed sensitivity there has to be
> > used a signal
> > that has 3 dB penalty, what means that for a signal that does
> > not show this
> > penalty ( as assumed at the transmitter in this
> > consideration) we can add
> > this to the sensitivity. Is this the ISI penalty you mention?
> > In this case
> > we really at the end coming out with 13 dB budget.
> > Calculation would look like:
> > _________________________________________________________
> > transmitter OMA min -1.39 dBm
> > _________________________________________________________
> > receiver sensitivity (OMA) -11.40 dBm
> > + receiver test signal penalty 3.0 dB
> > _____________________________________________
> > Total )penalty free signal) sensitivity in OMA
> > -14.4 dBm
> > __________________________________________________________
> > attenuation budget
> > 13.01 dB
> >
> > So can you confirm this understanding ?
>
> Yes.
>
> > If not would it be possible to set up a similar calculation
> > like this and
> > clarify.
> >
> > If this understanding is correct than we have 14.4 dBm sensitivity
> > requirement in OMA and this for instance get it comparable to
> > transponders
> > you can by translates (being optimistic into average power
> > sensitivity of :
> > - 14.4 dBm OMA will give -17.4 dBm ideal ER sensitivity or
> > -16 dBm (average
> > power sensitivity) at ER of 8.2 dB as used in ITU. This is 2
> > dB harder as
> > ITU and represents the BOL typical value that you get for
> > such components.
> > For an interface spec we however require EOL worst case!
> > For my understanding this is not realistic today and if done will be
> > expensive.
>
> Is it relevant to point out that SONET receiver sensitivities are
> standardised for a "worst" Tx eye which has the same 3 dB penalty? Not sure
> if you have already taken that into account.
>
> > Regards Juergen Rahn
> >
> >
> > > ----------
> > > Von: Mike Dudek[SMTP:mdudek@xxxxxxxxxxxx]
> > > Gesendet: Dienstag, 3. Juli 2001 03:02
> > > An: Rahn, Juergen (Juergen)
> > > Cc: stds-802-3-hssg-serialpmd@xxxxxxxx; 'Ron Miller'
> > > Betreff: Re: AW: [802.3ae_Serial] Issue with 1500 Power
> > >
> > >
> > > A further attempt to clarify this.
> > > The 3dB difference is the ISI penalty that is imposed when
> > performing the
> > > stressed receiver sensitivity test which corresponds to the
> > maximum value
> > > of the
> > > Transmitter and Dispersion Penalty of the Transmitter. If one has a
> > > transmitter
> > > that produces this amount of penalty then one has to
> > increase the output
> > > power
> > > by 3dB. Hence the 13dB is attained.
> > > Regards Mike
> > >
> > > "Rahn, Juergen (Juergen)" wrote:
> > >
> > > > Hi
> > > > The difference between current defined sensitivity and
> > what would be
> > > > required (straightforward without any additional margin
> > penalty....) is
> > > 3
> > > > dB, what means the attenuation budget would be 10 dB.
> > > > Does this clarify?
> > > > Regards Juergen
> > > >
> > > > > ----------
> > > > > Von: Ron Miller[SMTP:rmiller@xxxxxxxxxxx]
> > > > > Gesendet: Mittwoch, 27. Juni 2001 18:10
> > > > > An: Rahn, Juergen (Juergen);
> > stds-802-3-hssg-serialpmd@xxxxxxxx
> > > > > Betreff: RE: [802.3ae_Serial] Issue with 1500 Power
> > > > >
> > > > >
> > > > > juergen
> > > > >
> > > > > Please check your numbers below. Thanks
> > > > >
> > > > > Ron Miller
> > > > >
> > > > > -----Original Message-----
> > > > > From: Rahn, Juergen (Juergen) [mailto:krahn@xxxxxxxxxx]
> > > > > Sent: Wednesday, June 27, 2001 3:30 AM
> > > > > 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.
> > > > >
> > > > > LOOKS MORE LIKE ABUT 3 DB TO ME.
> > > > >
> > > > > 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
> > > > >
> > > > >
> > >
> >