Triggering on Waveforms
TDS 684A, TDS 744A, & TDS 784A User Manual 3–85
menu. You will still need to display the Horizontal menu if you wish to leave
Delayed Triggerable.
The Source menu lets you select which input will be the delayed trigger
source.
8. Press Source (main) Ch1, Ch2, Ch3, Ch4, or DC Aux (side).
NOTE. Selecting DC Aux as source in BOTH the main and delayed triggering
menus forces main and delayed trigger levels to adjust in tandem. As long as
their source remain DC Aux, adjusting the trigger level for either system adjusts
it for both systems.
9. Press Coupling (main) Main Trigger, DC, or Noise Rej (side) to define
how the input signal will be coupled to the delayed trigger.
Main Trigger sets delayed trigger coupling to match the main trigger
coupling setting. For descriptions of the DC and Noise Rej coupling types,
see To Specify Coupling on page 3–58.
10. Press Slope (main) to select the slope that the delayed trigger will occur on.
Choose between the rising edge and falling edge slopes.
When using Delayed Triggerable mode to acquire waveforms, two trigger
bars are displayed. One trigger bar indicates the level set by the main trigger
system; the other indicates the level set by the delayed trigger system.
11. Press Level (main) Level, Set to TTL, Set to ECL, or Set to 50% (side).
Level lets you enter the delayed trigger level using the general purpose knob
or the keypad.
Set to TTL fixes the trigger level at +1.4 V.
Set to ECL fixes the trigger level at –1.3 V.
Set to 50% fixes the delayed trigger level to 50% of the peak-to-peak value
of the delayed trigger source signal.
NOTE. When you set the Vertical SCALE smaller than 200mV, the oscilloscope
reduces the Set to TTL or Set to ECL trigger levels below standard TTL and
ECL levels. That happens because the trigger level range is fixed at ±12
divisions from the center. At 100mV (the next smaller setting after 200 mV) the
trigger range is ±1.2 V which is smaller than the typical TTL (+1.4 V) or ECL
(–1.3 V) level.