Triggering on Waveforms
3–94 TDS 500C, TDS 600B, & TDS 700C User Manual
Select the Source. To specify which channel becomes the pulse trigger source:
Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞
Source (main) ➞ Ch1, Ch2, Ch3, or Ch4 (side). The source selected becomes
the trigger source for all four trigger classes.
Select the Polarity. To specify the direction of the runt pulse:
Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞ Class (main) ➞
Runt (pop-up) ➞ Polarity (main) ➞ Positive, Negative, or Either (side).
Positive looks for positive-going runt pulses.
Negative looks for negative-going runt pulses.
Either looks for both positive and negative runt pulses.
Set to Trig When. To determine how wide a runt pulse the oscilloscope will
trigger on:
1. Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞
Class (main) ➞ Runt (pop-up) ➞ Trig When (main).
2. Press Occurs to trigger on all runt pulses regardless of width.
3. Press Runt is Wider Than (side) to trigger only on runt pulses that exceed
the width you set. Enter the width using the general purpose knob or keypad.
Set the Thresholds. To set the two threshold levels used in detecting a runt pulse:
1. Press TRIGGER MENU ➞ Type (main) ➞ Pulse (pop-up) ➞
Class (main) ➞ Runt (pop-up) ➞ Thresholds (main).
2. Use the general purpose knob or keypad to set the values for the high and
low thresholds.
Hint: To use the Trigger Bar feature to set the threshold levels on the pulse
train, press DISPLAY ➞ Readout Options (main) ➞ Trigger Bar Style
(side) until Long appears in that menu item.