1000BASE-T/100BASE-TX/10BASE-T Physical Layer Compliance Tests Manual
Intel Confidential
79
10Base-T TD Circuit Common-Mode Output Voltage
4. Adjust trigger level until just triggering on signal. Place cursor on maximum or peak voltage.
(The figure below provides a reference for the positive peak.)
Figure 20-2. Positive Peak Voltage Scope Reference
5. Record max peak positive amplitude value.
6. Set scope settings for negative common-mode measurement as shown in table below.
Table 20-2. Scope Configuration for TD Circuit
Negative Common-Mode Output Voltage
Scope Parameter
Setting
Horizontal Scale
10 ns/division
Vertical Scale
-80 mV to +80 mV (at 8 divisions, this equals 20 mV/
division)
Trigger Type
Negative edge
Trigger Level
Typically 0 V to -50 mV
Display Persistence
Infinite persistence