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[802.3ae_Serial] Stressed eye resolution submitted for D4.2, #2

This one does NOT have the eye pattern attached.

All - here is the final comment resolution given to Dave at the end of last week. This should help in advance of getting D4.2. It has lost most of its format in the email system, and so may be a little tough to interpret.

Tom.

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Dave - reminders to include change about how stressed eye specs are defined with an ideal filter, that ER is referenced from other tables, that sine jitter is stepped, etc.

Modify the end of the 1st sentence in 52.9.5, page 469, line 40: "...in Figure 52-7, using waveform averaging or histogram means." (Dave, this section may have changed due to another comment, so details must be checked).

Below vertical eye closure, add a row each to Tables 52-9, 52-14, and 52-18 as follows:

  Stressed eye jitter                 0.3                   UI peak-peak

The new row needs a new footnote: "Stressed eye jitter is a test condition for measuring stressed receiver sensitivity. It is not a required characteristic of the receiver."

52.9.11.1

  1. Add a new paragraph, page 478, line 26. "The clock output from the Clock source in Figure 52-11 will be modulated with the sinusoidal jitter. In order to calibrate final stressed eye jitter that includes the sinusoidal jitter component using an oscilloscope, a separate clock source is required that is synchronized to the source clock but not modulated with the jitter source."
  2. Page 476, line 24. Add to the end of the 2nd paragraph "nor used during testing.
  3. Page 478, line 14. Rewrite to "...filter should have the appropriate frequency response to result in the appropriate level...".
  4. Page 478, insert a new paragraph ahead of line 14.

A small amount of residual noise and jitter from all sources is normal, but should not exceed 0.25 UI peak-peak (approximately 0.02 UI rms) of jitter.

  1. Page 478, line 15. Delete the sentence about filter tolerance.
  2. Page 478, line 17. Modify to "Electrical summing requires high linearity of all elements including the E/O modulator. Summing with an optical coupler after the modulator is an option that eases linearity requirements, but requires a 2nd source for the interfering signal, will complicate settings of extinction ratio, and add more RIN.
  3. In Figure 52-11, re-label the Sinusoidal generator block to "Sinusoidal AM interference". Also, search and change all text instances of "AM" to "AM interference".
  4. In Figure 52-11, add a label to the signal coming from Clock source to "Sinusoidally jittered signal".
  5. In Figure 52-11, remove the CRU from the characterization block. Show an input arrow into the outer block coming from the outside, in parallel with the present signal input arrow.

52.9.11.2

  1. Page 478, line 33. Reword paragraph to "Signal characteristics are described below along with a suggested approach for calibration."
  2. Insert a new paragraph ahead of line 36, page 478.

The test signal includes vertical eye closure and high probability jitter components. For this test, these two components are defined by peak values that include all but 1% of their histograms. Histograms should include at least 1000 hits, and shall be ~1%-width in the direction not being measured. Per above, residual low probability noise and jitter should be minimized - that is, the outer slopes of their final histograms should be very steep.

  1. Then, modify the steps as follows (Dave - I've tried to use and be consistent with step #s):

 1.      No change for step 1.

Swap steps 2 & 3 from D4.1. In the new step 2, add "A pattern shorter than PRBS10 is not recommended." to the end of the step.

 3.      Set the optical extinction ratio (ER) per the method in 52.9.4. ER should be... (Dave - see other comment referring to values from specific tables). Sinusoidal interference and jitter signals should be turned off at this point. If optical summing is used, ER may need to be adjusted after the sinusoidal interference signal is added below.

 Dave - at this point, the balance of 52.9.11.2 should be completely replaced by the following except for the VECP equation.

 4.      Measure the OMA of the test signal (without attenuation). OMA is measured per the method in 52.9.5 using the square wave pattern.

 5.      The requirements for vertical eye closure and jitter of the stressed eye test signal are given by the Vertical eye closure penalty (VECP) and Stressed eye jitter (J) values given in Table 52-9 for 10GBASE-S, Table 52-14 for 10GBASE-L, Table 52-18 for 10GBASE-E. Vertical closure is measured at the time center of the eye (halfway between 0 and 1 on the unit interval scale as define in 52.9.7) and is the vertical eye closure penalty is calculated relative to the measured OMA value. J is measured at the average optical power, which can be accomplished with AC coupling. The peak values of these components are defined as above by their histogram results.

Dave - insert the VECP equation and supporting text in here, per line 17 etc., page 479 of D4.1. Change all instances of AN to OMA.

There are three components involved in calibration for vertical closure and J. These are a linear phase filter, sinusoidal interference, and sinusoidal jitter.

 Without sinusoidal jitter or sinusoidal interference, greater than one-half of the vertical eye closure penalty value should be created by use of a linear phase, low jitter filter (such as Bessel Thomson). The filter should be tested with the prescribed test patterns to verify that residual jitter and baseline wander are small, not to exceed 0.25 UI peak-peak (approximately 0.02 UI rms). If not, the stress may be more than desired, leading to conservative results. However, compensation is not allowed. Once done, revert to the calibration pattern.

Any remaining vertical eye closure required must be created with sinusoidal interference or sinusoidal jitter.

The frequency of the sinusoidal interference may be set at any frequency between 100 MHz and 2 GHz, although be careful to avoid a synchronous or harmonic relationship between the sinusoidal interference and the data rate and the pattern repetition rate.

Sinusoidal jitter (phase modulation) must be added per the template of Table 52-20. For calibration purposes, sinusoidal jitter frequencies must be above the flat portion of the template greater than 4 MHz.

Iterate the settings for sinusoidal interference and/or jitter until all constraints are met, including jitter (J), vertical closure (VECP), and that sinusoidal jitter is between 0.05-0.15 peak-peak above 4 MHz.

Verify that the optical power penalty for the stressed eye (relative to the reference transmitter per 52.9.12) is greater than or equal to VECP.

If high linearity exists, then the sinusoidal interference should not change the OMA value. OMA can be approximated with histograms as suggested in Figure 52-12. However, the normative definition for OMA is as given in 52.9.5.

To emulate the effects of DCD or data-dependent jitter, at least 5 psec peak-peak of pulse shrinkage jitter should have been achieved.

Dave - Insert the eye pattern example here, submitted in a separate file.

 6.      Decrease the amplitude with the optical attenuator until the OMA complies with the OMA values given in Table 52-9 for 10GBASE-S, Table 52-14 for 10GBASE-L, Table 52-18 for 10GBASE-E.

 7.      For testing, turn on the actual required test pattern(s) per Table 52-21.

Dave - done with the signal calibration section.

Page 480, line 6. Change to "...filters, oscilloscope and BERT, and/or...".

Page 480, line 9. Change to "the specified requirements."

Page 466, line 21. Truncate the present sentence after "...tolerance", then fix the grammar. Then add: "Sinusoidal jitter may vary over a magnitude range as required to accurately calibrate a stressed eye per 52.9.11. The range is limited by the constraints of Table 52-20."

Page 466, Table 52-20. Change only right column. Change final row to S = 0.05-0.15. Add a footnote "S is the magnitude of sine jitter actually used in the calibration of the stressed eye per the methods of 52.9.11.2.

Page 466, Table 52-20. Change middle row to Sx4x106/f. Refer to the same footnote just created. Then, swap the middle and last rows.

Page 467, Figure 52-5. Show a range for high frequency flat portion from 0.05 to 0.15. Show that the entire curve can vary vertically by this 3:1 variation (recall this is a log scale). 4 MHz corner does not change.

Page 480, line 17. Add a new paragraph: "The implementer must ensure that the proper amount of sinusoidal jitter is met at all test frequencies."