User Manual

Appendix - "Bus analysis" mode
129
12.8.3. Measure (Ethernet 100Basse-T)
Diagnosis
Use this table to troubleshoot problems on a measurement :
Measurement
Description
Diagnosis
Vout
Positive pulse amplitude measurement

Termination problem

Junction connection (oxidation, bad contact, etc.)

Cable length not compliant with standard

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
Time Rise
Rise time between 10% and 90% of a positive
signal amplitude

Unsuitable or damaged cable (the rise and fall
times increase with the cable impedance)

…
Time Fall
Fall time between 90% and 10% of a
negative signal amplitude
DCD
Measurement of the duty cycle between
positive and negative pulses
Measurements taken using a total of the
positive and negative pulses

Unsuitable or damaged cable

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

Cable length not compliant with standard

…
JitterPtoP
Measurement made using the positive and
negative pulses
•
Significant noise (check the cable route, ground braid not
connected, faulty chassis-ground, etc.)
…
Over+
Overshoot measurement on positive pulses.
The max. pulse overshoot is compared to its
amplitude

Unsuitable cable impedance

Termination problem (if there is no termination,
major overshoot and the opposite if the bus
impedance is too high)

Significant noise (check the cable route, ground
braid not connected, faulty chassis-ground, etc.)

…
Over-
Overshoot measurement on negative pulses.
The max. pulse overshoot is compared to its
amplitude.