Keysight N778xC Series Polarization Instruments User’s Guide 57
User Interface Reference 4
The Oscilloscope Mode
The default operation mode is Oscilloscope. In this mode, data is sampled
at a constant sampling rate. You can choose the desired number of
samples.
The sampling rate together with the number of samples determines the
observed time scale. The number of samples is defined by setting the
Post-Trigger Samples value, even when no external trigger is used.
There are two options in this mode: Continuous and Oneshot. In the
continuous mode, the measurement is restarted after receiving a trace. In
oneshot mode the acquisition has to be (re)started manually by pressing
the Trigger button.
Triggering
You can synchronize the start of a measurement cycle to certain events
such as an external trigger signal.
When using an N778xC instrument, trigger settings are configured using
the Trigger option.
Select TTL High or TTL Low to choose the desired trigger edge of an
externally applied digital signal. The signal has to be applied to the BNC
input named Trig. In. The actual measurement is performed continuously,
so the trigger event defines the portion of the measured data stream to be
shown. You can set the number of samples to be stored from right before
the trigger event (Pre-Trig. Samples) and right after the trigger event
(Post-Trig. Samples).