Musical Instrument User Manual

FUNCTION REFERENCE 5 - 73
Key sequence:
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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