MR8740、MR8741_user_manual_eng_20191016H.pdf - 第216页

8.9 Pre-Trigger Settings 204 [ This applies to the Memory function, and FFT function only. By setting a portion (number of divi sions or percentage) of the recording length to o ccur before trig- gering, the waveform is …

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8.7 Applying an External Trigger (MR8741 Only)
203
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Chapter 8 Trigger Settings
8
An external signal applied to the External Control terminal can serve as a trigger source (External
Trigger). It can also be used to synchronously drive parallel triggering of multiple MR8741s.
8.7 Applying an External Trigger (MR8741 Only)
Procedure
To open the screen: Right-click and select [DISP] Waveform screen Right-click and select [TRIG.SET] Trig-
ger settings window
1
Enable external triggering.
Move the flashing cursor to the [Ext Trig] item.
Select
2
Apply the input signal to the external trigger (EXT.TRIG)
terminal.
See: "16.2.5 External Trigger terminal (EXT.TRIG)" (p.342)
Off Disables external triggering.(default setting)
On
Enables external triggering.
8.8 Triggering Manually (Manual Trigger)
Triggers can be applied manually by clicking [MANUAL TRIG] in the right-click
menu. Manual triggering takes priority over all other trigger sources, regardless
of settings.
To stop recording:
Click [STOP] in the right-click menu.
Click once Recording is carried out for one recording length and then
stops.
Click twice
Recording stops when [STOP] is clicked.
As for other trigger types, triggering does not occur during pre-trigger standby.
Set the trigger priority function to
[On].
See: "8.9.2 Setting Trigger Acceptance (Trigger Priority)" (p.206)
8.9 Pre-Trigger Settings
204
[
This applies to the Memory function, and FFT function only.
By setting a portion (number of divisions or percentage) of the recording length to occur before trig-
gering, the waveform is recorded before as well as after the trigger point.
You can also set the duration of a waveform to be recorded after a trigger point.
Set the position of the trigger point relative to the specified recording length.
There are two setting methods. (Setting by percent and setting by div)
8.9 Pre-Trigger Settings
T
Pre-Trigger Setting
Amount
Recording
Length
T
Pre-Trigger Setting
Amount
Recording Length
Recording Before Triggering
Recording for a Specified Duration
After Triggering
• When all trigger sources (analog, timer trigger, etc.) are disabled (Off), pre-trig-
ger settings are ignored.
• Pre-triggers cannot be set by div with the FFT function.
8.9.1 Setting the Trigger Start Point (Pre-Trigger)
Procedure
To open the screen: Right-click and select [DISP] Waveform screen
1
Select the unit to set the pre-trigger.
Move the flashing cursor to the Pre-trigger.
Select
2
Enter the numerical value.
(When [%] is selected)
With the recording start point as 0% and the recording end point as
100%, set the % for the trigger point.
Select
(When [div] is selected)
With the recording start point as 0div and the recording end point as
the set recording length, set the number of div for the trigger point.
Select
% Settings are by percent. (default setting)
div
Settings are by number of div. For external sampling, set by
number of samples.
-95%, 100%, 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, 5%,
2%, 0%
-Recording length (div) to +Recording length (div)
8.9 Pre-Trigger Settings
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Chapter 8 Trigger Settings
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Description About pre-triggering and the recording period (recording length)
Difference between [Pre-Trigger wait] and [Trigger wait]
When measurement is started, the specified pre-trigger length is recorded. This
period is indicated as the [Pre-Trigger wait].
After the specified pre-trigger length has been recorded, the period indicated as
[Trigger wait] continues until a trigger occurs.
See: "Measurement and Internal Operations" (p.82)
Trigger Point
95% 95% of the recording length is
recorded before the trigger
point
50% 50% of the recording length is
recorded before and 50% after
the trigger point
-95% 95% of the recording length is
recorded after the trigger point
T
Pre-Trigger setting examples
• Trigger events during the specified pre-trigger recording period are ignored. To
enable recognition of such triggers, set Trigger Priority to [On].
See: "8.9.2 Setting Trigger Acceptance (Trigger Priority)" ( p.206)