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[802.3ae_Serial] Serial PMD call Tuesday - Jitter testing




Hi,
In fact my assumption is correct at least with the transponder modules we
have in hand you cannot simply add the 15ps pp to the jitter. The 15 ps I
mentioned in my last mail, was the extreme, however the behaviour against
sinusoidal jitter added we found not to be different between transponders
with higher or lower of such DCD. From this it seems that this effect in
this dimension seems really to be separate to other jitter.
Regards Juergen

	----------
	Von:  Rahn, Juergen (Juergen)
	Gesendet:  Dienstag, 22. Januar 2002 16:46
	An:  stds-802-3-hssg-serialpmd@xxxxxxxx; 'piers_dawe@xxxxxxxxxxx'
	Betreff:  AW: [802.3ae_Serial] Serial PMD call Tuesday - new test
methods


	Hi,
	In preparation some more info on the measurement that have been base
for my
	presentation at the last meeting. 
	As I stated during the presentation, the jitter generated between
50KHz and
	80MHz was about 0.05 UI PP (exact value up  to 0.062 max according
to the
	jitter analyzer) and 0.004 UI RMS.
	However not visible in here is that the crosspoint of the eye was
shifted.
	If this shift is added  (it can be interpreted as duty cycle
distortion) it
	would give us 15ps PP extra (for those transponders). However while
this is
	visible in the eye I do not think that this will generate a penalty
like
	something that closes the eye really as this is a crossing shift
only and
	may even not be visible at the decision point in relation to the CDR
	implementation. 
	Such effect is also visible in the 1550 feasibility  presentation
eye  masks
	and the effect is stronger at high extinction ratios while we see
BER
	penalties at low rates. (Here the eyes really close).
	Regards Juergen Rahn


		----------
		Von:  piers_dawe@xxxxxxxxxxx [SMTP:piers_dawe@xxxxxxxxxxx]
		Gesendet:  Montag, 21. Januar 2002 17:48
		An:  stds-802-3-hssg-serialpmd@xxxxxxxx
		Betreff:  [802.3ae_Serial] Serial PMD call Tuesday - new
test
	methods


		There will be a PMD teleconference tomorrow at the usual
time where
	we will
		continue work on the alternative optical test methods
discussed at
	last
		week's face to face meeting.

		Briefly, these are:

		Replace jitter bathtub with:
			Longer lower eye mask to screen for high probability
events,
	and
			Transmitter and dispersion penalty measurement using
	bit-error ratio
		tester to screen for low probability events.

		Simplify stressed receiver generation: simulate high
probability
	vertical
		and horizontal eye closure, and sinusoidal jitter, only.
Suggested
	method
		of adding a PRBS and an interfering sine wave.

		I will try to get some notes to the reflector from last
week's
	meeting
		before tomorrow's, which will be at:

		Usual coordinates:
			4:15 pm GMT = 17:15 CET = 11:15 am EST = 8:15 am
PST,
	Tuesday
			+1(816)650-0631  Access code 39209

		Piers