Tektronix CSA7154, Руководство пользователя, Страница: 181 / 480

Triggering
CSA7000 Series, TDS7000 Series, & TDS6000 Series Instruments User Manual
3- 103
Overview Control elements and resources To trigger based on transition time (Cont.)
Set to trigger
when
The instrument compares the pulse edge of the trigger
source against the transition time (slew rate) set by the upper
and lower threshold settings and the delta time set in the
window. To select whether to trigger on edges with transitions
times (slew rates) faster than or slower than that set by these
controls, do the following step:
7. Touch Trigger When Transition Time < or Trigger When
Transition Time >:
H
< triggers when the transition time is greater than
the time you set.
H
> triggers when the transition time is less than the
time you set
If you select Trigger When Transition Time > (greater than)
and the instrument does not trigger, it may be because the
pulse edge is too fast rather than too slow. To check the edge
speed, switch to edge triggering. Then trigger on the pulse
edge and determine the time the edge takes to travel
between the levels set in the slew rate Thresholds menu. The
instrument cannot transition trigger on pulse edges that
traverse between threshold levels in 600 ps or less.
Also, to reliably transition trigger, a pulse must have a width
of 8.5 ns or more. A pulse of less width may trigger on the
wrong slope or not trigger at all. Switch to edge triggering
and check the pulse width if you can’t transition trigger as
expected.
To set mode
and holdoff
8. Mode and holdoff can be set for all standard trigger
types.
See To set holdoff on page 3--84 and To select
trigger mode on page 3--81 for mode and holdoff
setup. To learn more about trigger mode and
holdoff, see Trigger Modes on page 3--74 and
Trigger Holdoff on page 3--75.