User manual

27
Trigger System
❙ ti > t: The pulse width ti, which will generate the trigger is
greater than the adjustable reference time t.
❙ ti < t: The pulse width ti, which will generate the trigger is
less than the adjustable reference time t.
❙ ti = t: The pulse width ti, which will generate the trigger
equals the adjustable reference time t. The reference time
is a combination of time t plus the adjustable deviation.
❙ ti ≠ t: The pulse width t
i
, which will generate the trigger
is unequal to the adjustable reference time t. The
reference time is a combination of time t plus the
adjustable deviation.
❙ t
1
<t
i
<t
2
: The pulse width ti which will generate the trigger
is less than the adjustable reference time t
2
and greater
than the adjustable reference time t
1
.
❙ not(t
1
<t
i
<t
2
): The pulse width which will generate the
trigger is greater than the adjustable reference time t
2
and
less than the adjustable reference time t
1
.
The comparison time can be set between 8 ns to
134.217 ms. For any value up to 1 ms the resolution is
8 ns and for any value greater than 1 ms the resolution is
1 µs. The deviation can be set anywhere between 4ns to
262.144 µs with a resolution of 4 ns. The time resp. the va-
riation (tolerance zone) can be selected via universal knob
or KEYPAD key in the CURSOR/MENU section. Selecting
the corresponding soft menu item allows you to set any of
these settings for positively (POS.) or negatively polarized
pulses(NEG.).Fortheassociatedpositivepulse,youdene
the width from rising to falling slopes, and accordingly for
the associated negative pulse from falling to rising slopes.
As is consistent with the principle, triggering always oc-
curs on the second slope of the pulse.
6.3.3 Logic Trigger
Selecting the LOGIC trigger in the soft menu after pressing
the TYPE key
31
will switch the trigger source to the digital
inputs. Pressing the SOURCE key
32
after selecting this
trigger type displays a soft menu for additional settings
and a window to list these settings. The soft menu key
You may test all settings in the logic trigger without any active
logic probes R&S®HO3508 connected.
LOGIC CHANNEL enables you to select a logic channel for
which you wish to determine the trigger condition. Use
the universal knob in the CURSOR/MENU section for this
purpose. In the general menu, the selected digital input
ismarkedwithabluebackground.Intheeld,thetrigger
level is marked as High (H), Low (L) or (X). Use the corres-
ponding soft menu key to select the trigger level. The soft
menu item COMBINATION allows the logic combination of
the digital channels. They can be combined by logic AND
or OR. If AND is selected, the set conditions of all channels
must be met simultaneously for the input signal so that the
combination produces a logic High (H) as a result. If OR is
selected,atleastoneofthedenedlevelconditionsmust
be met. The last item in this menu is the option TRIGGER
ON. Use the soft menu key to select TRUE or FALSE. This
allows you to preselect whether the trigger will be genera-
ted at the beginning (TRUE) or the end of the logic condi-
tion (FALSE). After selecting the desired set of conditions,
you can use the FILTER key
36
for additional settings. A
soft menu will open allowing you to add a time limit to
the TRIGGER ON option (this menu shows the condition
selected in the SOURCE menu). Press the top soft menu
key DURATION to add a time limit. This option compares
the duration of the output signal for the combination of
the logic conditions to the set duration ti. If the duration is
identicalornotidentical,youcansetthedeviation∆t.Ift
is within these parameters, the trigger condition has been
met.Themenueldbelowallowstheselectionofthe
comparison criteria. The following criteria are available:
❙ t
i
≠ t: The duration of the applied bit pattern which will
generate the trigger is unequal to the adjustable reference
time.
❙ t
i
= t: The duration of the applied bit pattern which will
generate the trigger is equal to the adjustable reference
time.
❙ t
i
< t: The duration of the applied bit pattern which will
generate the trigger is less than the adjustable reference
time
❙ t
i
> t: The duration of the applied bit pattern which will
generate the trigger is greater than the adjustable
reference time.
Fig. 6.3: Menu for pulse trigger settings
Fig. 6.4: Menu for logic trigger settings