FUNCTION REFERENCE

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Key sequence:

TEXT OFF

Toggle key to cycle through three states of information given in CRT viewing area.

TIMEBASE MODES

Description:

The Main Timebase (MAIN TB) can function in three different modes : AUTO, TRIG, or SINGLE. The choice is mainly determined by the frequency of the trigger signal. The modes are explained below.

AUTO

In ‘auto’ mode, the MAIN TB always gives a display, even when

 

no signal is present. It checks for the occurrence of the trigger

 

signal for some 100 ms, but if none is found, it automatically

 

starts a new sweep or acquisition. On repetitive signals this mode

 

is most common except for signal frequencies lower than 10 Hz

 

where unstable displays will occur.

TRIG

In the triggered (trig) mode, traces are displayed only when the

 

MAIN TB is actually triggered by a signal. This mode is

 

recommended for frequencies lower than 10 Hz because it

 

assures a stable display. The ARM’D indicator indicates if no

 

trigger occurs.

SINGLE

In single shot mode, the MAIN TB runs only once after a trigger.

 

Pressing the SINGLE key resets the scope for single shot

 

operation; the trigger level is automatically set to 0.5 division

 

above ground (indicated by T-). The ARM’D indicator lights when

 

the MAIN TB is waiting for a trigger (MAIN TB armed). The single

 

mode is used to capture and observe (photograph) events that

 

happen only once.

In the digital mode the single mode can be used in combination with pre-triggering to observe and store single events, along with signal information occurring before the trigger point.

Auto, trig, and single can be chosen in the menu under the TB MODE menu key.

In the digital mode the TB MODE menu is expanded to include MULTI (only with the optional MATH+ functions installed), ROLL and REAL TIME ONLY mode.

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Image 193
Fluke PM3370B user manual Timebase Modes, Text OFF