Specifications

VTM Series Installation and Operation Handbook
5-1
Section 5 ♦ Alarm Descriptions
Setting Alarms
Most alarms monitor all lines of the video signal. The VITS alarm is an exception.
The VITS alarm is used to monitor activity or the lack of activity on a particular line.
The GAMUT alarm is more typical. The GAMUT alarm will monitor the entire active
picture for errors over the selected limits chosen on the menu.
Limits are selected in the SETUP Menu by choosing a value using the UP/DOWN or
CURVED ARROW knobs, or the UP or DOWN Navigation buttons while additionally
causing a limit cursor line to appear in the waveform or vector display. Do not confuse
these limit cursor lines with the cursor lines selected in the Cursor group on the front
panel. The limit cursor lines disappear when exiting the alarm menu.
Sensitivity and Duration are two general terms used in the alarm menus:
• Sensitivity
Sensitivity is set by Consecutive Errored Samples (CES). When setting amplitude
limits, a noise spike can exceed the limit while the video amplitude can be within
the limit. With the CES set to a low number, a spike is detected and an alarm is
displayed. Set the CES to a higher number to ignore the fast spike. Each CES
occurs at 37ns intervals for SD and 13.5ns for HD. Use this as a guideline to select
the appropriate CES value.
Not all alarms have CES associated with them; in such cases, use the duration to
increase or decrease the general sensitivity.
• Duration
This value is used to determine how long an error must persist before it is reported.
Set the duration to 0 to cause an error to be displayed as soon as the CES value is
met.