EXFO PSO-100 Series Optical Sampling Oscilloscopes - Manual (Page 101)

Troubleshooting
Optical Sampling Oscilloscope 93
Solving Common Problems
My short RZ pulses look like an
eye diagram.
It is difficult to
correctly synchronize
very low duty cycle
pulses <1 %.
Start and stop the
sampling to
resynchronize the
pulses, until it looks
like short pulses. If it
does not work, use
the external clock.
The eye diagram looks jittery
even if you use an external
clock
The clock signal may
suffer from large
phase noise.
Change the phase
tracking algorithm
(Utilities >
Advanced menu), or
use the adaptive
clock mode.
The DC level is not zero even if
the input signal is off.
The DC level drifts
slightly with
temperature.
Adjust the zero level
from the Utilities
menu.
The samples are unevenly
distributed or appear at discrete
points in the signal. When you
start and stop the sampling the
data may be incorrectly
synchronized.
Frequency holes. Wait and see if it
disappears. Increase
the number of layers
and/or the number of
samples/layer.
Tune the signal
frequency a few
100 Hz if possible.
The application crashes. Error
messages appear in the DOS
window.
Software bug. Click Start again. If
that does not help,
restart the
application. Contact
EXFO.
Problem Cause Possible Solution