1000BASE-T/100BASE-TX/10BASE-T Physical Layer Compliance Tests Manual
Intel Confidential
51
100Base-TX Duty Cycle Distortion (DCD)
13 100Base-TX Duty Cycle Distortion
(DCD)
ANSI Section 9.1.8
13.1
Test Purpose
To measure the duty cycle at the four MLT-3 transitions using a pattern in non-scrambled mode.
13.2
Specification
“Duty cycle distortion shall be measured at the 50% voltage points on rise and fall transitions of the
differential output waveform. The 50% times at the four successive MLT-3 transitions generated by
a 01010101 NRZ [non-return to zero] bit sequence shall be used. The deviations of the 50%
crossing times from a best fit to a time grid of 16 ns spacing shall not exceed ±0.25 ns as shown in
[
].”
1
Figure 13-1. Active Output Interface Duty Cycle Distortion
2
13.3
Test Equipment
•
Oscilloscope with at least 1 GHz bandwidth
•
Differential probe with at least 1 GHz bandwidth and capacitance less than or equal to 1 pF
•
Host computer running gigconf.exe
1.
ANSI X3.263-1995, p 28.
< 0.5ns
0.5ns >
< 0.5ns
0.5ns >
16 ns
2.
Based on ANSI X3.263-1995, p 30, figure 9-3.