1000BASE-T/100BASE-TX/10BASE-T Physical Layer Compliance Tests Manual
Intel Confidential
151
100Base-TX Test Procedure for the 82544 Chip
Figure I-16. MLT-3 mid-level width at 50% levels.
Figure I-17. Negative pulse width at 50% amplitude level
I.5.8
Duty Cycle Distortion Data
For
through
When measured between 50% voltage points on +Vout and –Vout, positive pulse widths, negative
pulse widths, and mid-level time periods must be between 15.50 nsec and 16.50 nsec.
Interpretation the ANSI TP-PMD version of this spec is somewhat confusing. The text suggests the
acceptable range for each pulse is 15.75 nsec to 16.25 nseconds, but the 9.3 illustration in the
specification clearly shows a range from 15.50 to 16.50 nsec. We believe the illustration is correct,
and it helps to explain the text within the spec, regarding a fit to a time grid with 16 nsec spacing –
That is, each edge of each pulse is a/- 25 nsec deviation, so the net result is a range from
15.50 nsec to 16.50 nsec.