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Logic Triggering
Reference
Logic Function (AND) Becomes TRUE
Logic Function Becomes FALSE and
Triggers Acquisition
Time Logic Function is TRUE
Time Logic Function Must be TRUE
Figure 3-44: Logic Trigger Menu — Time Qualified TRUE
When you select State logic triggering, the oscilloscope uses channel 4
(Aux 2 on the TDS 620A & TDS 524A) as a clock for a logic circuit made from
the rest of the channels. See page 3-80 for details on operations common to
both pattern and state triggers.
The state trigger logic works as follows: the oscilloscope waits until the fourth
channel meets the selected slope and voltage threshold. It then checks the
logic function applied to the first three channels, and if the function condition
is as specified in the the Trigger When menu (Goes TRUE or Goes FALSE)
a trigger occurs.
Define Inputs
To set the logic state for each of the input channels (Ch1, Ch2, ...):
1. Press TRIGGER MENU ➞ Type (main) ➞ Logic (pop-up) ➞
Class (main) ➞ State (pop-up) ➞ Define Inputs (main).
2. Choose either High (
H
), Low (
L
), or Don’t Care (
X
) (side) for the first
three channels. The choices for Ch4 (Aux 2 on the TDS 620A &
TDS 524A) are rising edge and falling edge.
State Operations