Tektronix TDS 420A User Manual

Pulse Triggering
3–96
TDS 420A, TDS 430A, TDS 460A & TDS 510A User Manual
 When Either is set in the Polarity side menu, one threshold must be first
crossed going in either direction, then recrossed going in the opposite
direction without crossing the other threshold at all.
 Regardless of the polarity setting, triggering occurs at the point the runt
pulse recrosses its first threshold.
Width Operation
When you select the pulse class Width, the oscilloscope will trigger on a pulse
narrower (or wider) than some specified range of time (defined by the upper
limit and lower limit).
To define whether the pulses are positive or negative:
Press TRIGGER MENU
➞ Type (main) ➞ Pulse (pop-up) ➞ Class (main) ➞
Width
(pop-up) ➞ Polarity (main) ➞ Positive or Negative (side).
To establish the range of widths (in units of time) the trigger source will search
for and whether to trigger on pulses that are outside this range or ones that fall
within the range:
1. Press TRIGGER MENU
➞ Type (main) ➞ Pulse (pop-up) ➞
Class
(main) ➞ Width (pop-up) ➞ Trig When (main).
2. Press Within Limits
(side) to trigger on pulses that fall within the specified
range. To trigger on pulses that are outside the range, press Out of Limits
(side).
3. To set the range of pulse widths in units of time, press Upper Limit
(side)
and Lower Limit
(side). Enter the values with the general purpose knob or
keypad. The Upper Limit is the maximum valid pulse width the trigger
source will look for. The Lower Limit is the minimum valid pulse width.
To set the trigger level with the Level main menu:
Press TRIGGER MENU
➞ Type (main) ➞ Pulse (pop-up) ➞ Class (main) ➞
Width
(pop-up) ➞ Level (main) ➞ Level, Set to TTL, Set to ECL, or Set to
50%
(side).
Polarity
Trig When
Level

Tektronix TDS 420A Specifications

General

Brand	Tektronix
Model	TDS 420A
Category	Test Equipment
Language	English