EXFO PSO-100 Series Optical Sampling Oscilloscopes - Manual (Page 52)

Setting up and Using the Optical Sampling Oscilloscope
44 PSO-100
Using the Clock Input
Using the Clock Input
In some situations, you cannot fully rely on the software synchronization of
the input signal alone, for example when sampling very noisy or distorted
signals, or when using unconventional data formats or setting up OTDM
data. In such situations, the external clock option is very useful.
You can work using different types of clocks for your testing.
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Internal clock (default): the signal is software synchronized without an
external clock.
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External clock (optional): the clock signal determines the time scale,
which should be synchronous with the signal.
The external clock is useful in a number of measurement situations
where the internal synchronization may fail, for example with very
noisy or distorted signals, unconventional modulation formats, and
sub-optimally multiplexed signals. In the external clock selection you
can select either an absolute or adaptive time scale, where the
absolute time scale is the standard selection and the adaptive is
recommended for an external clock with large timing jitter.
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Gated clock (optional): for burst measurements, for example in
circulating loop- or packet- switching experiments, you can use the
gated clock mode. A window then opens where you can customize
parameters such as the burst period and duty cycle.
Note: The external clock option must be installed for the gated clock to be
available.
To activate the internal clock:
1. From the main window, select the Clock menu.
2. Select Internal.