Tektronix CSA7404B, Руководство пользователя

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Triggering
CSA7000B Series & TDS7000B Series Instruments User Manual
3- 65
The instrument provides the following categories of trigger types:
H
Edge is the simplest and most commonly used trigger type. You can use it
with analog or digital signals. An edge trigger event occurs when the trigger
source (the signal the trigger circuit is monitoring) passes through a specified
voltage level in the specified direction (the trigger slope).
H
Advanced triggers are a collection of trigger types that are primarily used
with digital signals to detect specific conditions. The glitch, runt, width,
transition, and timeout types trigger on unique properties of pulses that you
can specify. The pattern and state types trigger on logic combinations of
several signals. The setup/hold type triggers on the relative timing between
two signals.
H
Comm (optional on TDS7000B Series) is a special trigger used on commu-
nication signals. You can use Comm triggers to test communications signals,
and Mask testing automatically uses Comm triggers to set up signals for
mask testing. You can trigger on the clock recovered from optical
(CSA7000B Series only) or electrical communication signals.
H
Serial (optional on TDS7000B Series) is a special trigger used on signals
with serial data patterns. You can trigger on the clock recovered from optical
(CSA7000B Series only) or electrical communication signals.
The trigger mode determines how the instrument behaves in the absence of a
trigger event:
H
Normal trigger mode enables the instrument to acquire a waveform only
when it is triggered. If no trigger occurs, the instrument will not acquire a
waveform, rather the last waveform record acquired remains “frozen” on the
display. If no last waveform exists, none is displayed. See the
Normal
trigger mode
part of Figure 3--22. (You can push FORCE TRIGGER, in the
Trigger control window, to force the instrument to make a single acquisi-
tion.)
H
Auto trigger mode (automatic mode) enables the instrument to acquire a
waveform even if a trigger does not occur. Auto mode uses a timer that starts
after a trigger event occurs. If another trigger event is not detected before the
timer times out, the instrument forces a trigger. The length of time it waits
for a trigger event depends on the time base setting.
Trigger Types
Trigger Modes