Fluke PM6690 - Time Interval; Time Interval a to B; Time Interval B to a; Time Interval a to A, B to B

tion that virtually moves the trigger points by
half the hysteresis band.
Time Interval
All time interval functions can be found under
the function menu Time.
The toggling SLOPE keys (marked with a
positive or negative edge symbol) un
-
der the menus INPUT A/B decide which edge
of the signal will start resp. stop the measure
-
ment.
Time Interval A to B
The counter measures the time between a start
condition on input A and a stop condition on
input B.
Time Interval B to A
The counter measures the time between a start
condition on input B and a stop condition on
input A.
Time Interval A to A, B to B
When the same (common) signal source sup
-
plies both start and stop trigger events, con
-
nect the signal to either input A or input B.
These functions can be used for measuring
rise and fall times between arbitrary trigger
levels.
Rise/Fall Time A/B
These functions can be found under the func
-
tion menu Time.
Rise and fall time can be measured on both in
-
put A and input B.
By convention, rise/fall time measurements
are made with the trigger levels set to 10 %
(start) and 90 % (stop) of the maximum pulse
amplitude, see Figure 4-15.
The counter measures the time from when the
signal passes 10 % of its amplitude to when it
passes 90 % of its amplitude. The trigger lev
-
els are calculated and set automatically.
Auxiliary parameters shown simultaneously
are Slew Rate (V/s), V
max
and V
min
For ECL circuits, the reference levels are
20 % (start) and 80 % (stop). In this case you
can use either of two methods:
1. Select the general Time Interval function de
-
scribed above and set the trigger levels man
-
ually after calculating them from the abso
-
lute peak values. Then you can benefit from
the auxiliary parameters V
max
and V
min
.For
measurements made on input A, use the fol
-
lowing settings:
Rise T ime:
Trig Level A = V
min
+0.2(V
max
-V
min
)
Trig Level B = V
min
+0.8(V
max
-V
min
)
Fall T ime:
Trig Level A = V
min
+0.8(V
max
-V
min
)
Trig Level B = V
min
+0.2(V
max
-V
min
)
2. Select one of the dedicated Rise/Fall Time
functions, and exploit the possibility to man
-
Measuring Functions
4-14 Time Interval
T r i g g e r L e v e l B
T r i g g e r L e v e l A
1 0 0 %
9 0 %
1 0 %
0 %
I n p u t A / C o m m o n B
Fig. 4-15 Trigger levels for rise/fall mea-
surements.