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?
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.
(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)
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.
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)
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 ?
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.
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
> > >
> > >
>