Oscilloscope Trigger Menu Fields - HP 8921A User Manual

Chapter 14, Oscilloscope Screen
Field Descriptions

Oscilloscope Trigger Menu Fields

Figure 85 Oscilloscope Triggering
Internal
Auto/Norm
396
This field selects the trigger source.
• Internal uses the signal being displayed for triggering.
• External uses the rear-panel EXT SCOPE TRIGGER INPUT for triggering. This is
a TTL level trigger (approximately 2.5 V).
1
uses the signaling encoder for triggering. The encoder must be sending its
• ENCODER
signal to trigger the oscilloscope.
This field specifies how the trigger level is set.
• Auto automatically triggers if a triggering signal is not detected within approximately
50 ms of the last trigger.
• Norm requires a specific triggering signal before triggering.
Operating Considerations
Automatic triggering should be used for signals >20 Hz. Normal triggering should
be used for signals 20 Hz.
Also, when measuring 1 Hz signals, you should set the
ANALYZER screen to
1. Optional on some Test Set models
to provide dc coupling to the oscilloscope's input.
Input
oscscrn4.wmf
field in the AF
Scope To