HP 1660CS-Series User Manual page 205

The Scope Trigger Menu
When field
specification of HX, a duration specification of >100 ns, and a count of 3, a
pulse string with pulse widths 80 ns, 150 ns, 50 ns, 75 ns, 20 ns, 200 ns would
trigger on the trailing edge of the 75 ns pulse. In this example, the 150 ns
pulse meets the duration specification and is count 1, the 50 ns pulse is count
2, and the 75 ns pulse is count 3.
Present < When this field is active, the scope triggers on the first
transition that causes the pattern specification to be false for any input
used in the pattern trigger specification if the specified pattern has been
true for less than the time duration specified. If the pattern specification
remains true after the specified duration time has elapsed, the search for
a trigger condition starts again the next time the pattern specification
becomes true. If the pattern specification becomes false before the
specified duration time, the trigger point will be the point at which the
pattern specification becomes false.
The pattern duration time can be any value between 20 ns and 160 ms in 10
ns steps.
If the count set in the Count field is one, the trigger event will be the first
pattern event that meets both the pattern specification and the duration
specification. If the count is greater than one, only the first pattern event
must meet the duration specification. Once the pattern duration
specification has been met, subsequent pattern events that meet the pattern
specification can be of any duration and each such pattern event will
contribute to meeting the count specification. For instance, with a pattern
specification of HX, a duration specification of <100 ns, and a count of 3, a
pulse string with pulse widths 200 ns, 80 ns, 150 ns, 50 ns, 75 ns, 20 ns would
trigger on the trailing edge of the 50 ns pulse. In this example, the 80 ns
pulse meets the duration specification and is count 1, the 150 ns pulse is
count 2, and the 50 ns pulse is count 3.
Range When this field is active, the scope triggers on the first transition
that causes the pattern specification to be false for any input used in the
pattern trigger specification if the specified pattern has been true for
greater than the first time value and less than the second time value that
make up the pattern duration range.
If the pattern specification remains true for longer than the maximum
duration range limit or becomes false before the minimum duration range
limit, the search for a trigger condition starts again the next time the pattern
specification becomes true. If the pattern specification becomes false within
the specified duration time range, the trigger point will be the point at which
the pattern specification becomes false.
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