8 Trigger
8.1 Trigger
shown. The instrument trigger occurs at a time delayed by the accumulated offset
from the period trigger event. The periodic timer continues to run, and triggers
continue to occur, with a periodicity determined by the instrument time base. The
timer output (labeled "late event") will drift away from its ideal time due to imperfect
matching between the time base of the signal being measured and the time base of
the instrument, and also because of imperfect setting of the period parameter. But
the synchronization is restored on the next even-second clock event. ("Accumulated
offset" is described in the in the Offset function section.)
8.1.1.11 TV
When TV Trigger is selected, a new sweep/measurement starts synchronized with
the next occurrence of the synchronizing pulse of the selected TV line number.
TV Trigger is used when triggering on analog TV signals. It is only available in the
Swept SA measurement.
The Trigger tab contains the following Trigger Source dependent controls when TV
Trigger is selected:
–
"TV Line" on page 2674
–
"Field" on page 2675
–
"Standard" on page 2675
Additional controls are also present that are not dependent on the selected Trigger
Source.
See "More Information" on page 2654
Example
:TRIG:SOUR TV
Annunciation TV (in the Meas Bar)
More Information
Pressing this key, when it is not selected, selects the TV input signal as the trigger.
Pressing this key, when it is already selected, opens a menu of TV Trigger setup
functions. The default active function in this menu is the TV line number on which
you want to trigger.
The Frame and Field options enable you to determine how the fields of the TV
picture signal will be affected by the trigger system. One complete TV image
consists of one frame of 525 or 625 horizontal lines depending on the TV standard
being used. Each frame is composed of two fields of interlacing lines, each
consisting of 262 1/2 lines (or 312 1/2 lines). The fields are called Field One and
Spectrum Analyzer Mode User's &Programmer's Reference 2654
To Next Page
Loading...
Need help?
General
