Tektronix TDS 644A Sprinkler User Manual


 
Triggering
Reference
3Ć134
H When READY is lighted, it means the digitizing oscilloscope can accept
a valid trigger event, and the digitizing oscilloscope is waiting for that
event to occur.
H When ARM is lighted, it means the trigger circuitry is filling the pretrigger
portion of the waveform record.
H When both TRIG'D and READY are lighted, it means the digitizing
oscilloscope has recognized a valid main trigger and is waiting for a
delayed trigger. When the digitizing oscilloscope recognizes a delayed
trigger, it will fill in the posttrigger portion of the delayed waveform.
H When ARM, TRIG'D, and READY are all off, the digitizer is stopped.
Trigger Display Readout
At the bottom of the display, the Trigger readout shows some of the key
trigger parameters (Figure 3Ć72). The readouts are different for edge, logic
and pulse triggers.
Main Trigger Slope =
Rising Edge
Main Time Base
Main Time Base Time/Div
Main Trigger
Source = Ch 1
Main Trigger
Level
Figure 3Ć72:ăExample Trigger Readouts
The record view at the top of the display shows the location of the trigger
signal in the waveform record and with respect to the display (see FigĆ
ure 3Ć73).
Trigger Position and Level Indicators
In addition to the numerical readouts of trigger level, there are also graphic
indicators of trigger position and level which you can optionally display.
These indicators are the trigger point indicator, the long trigger level bar, and
the short trigger level bar. Figure 3Ć73 shows the trigger point indicator and
shortĆstyle trigger level bar.
The trigger point indicator shows position. It can be positioned horizontally
off screen, especially with long record length settings. The trigger level bar
shows only the trigger level. It remains on screen, regardless of the horizonĆ
tal position, as long as the channel providing the trigger source is displayed.