GUIDE TO INSTALLATION AND OPERATION
14
| HCO-1822
Video – Freeze Detect
This error detects the presence of a signal freeze (i.e. no change in
content) for a period of time; the error is flagged only when the time
duration criterion has been satisfied.
This error can be Enabled using the checkbox, and the level set to 1,
2 or OFF.
The user sets the detection parameters for this error using two sliders:
•
Threshold – sets a sensitivity level for detection that will allow
minor level changes due to noise, but will detect a lack of
change in the picture content. The value (in the range 0 to 15)
is arbitrary, and may need to be set by trial and error depending
on the signal characteristics.
A smaller threshold value will be less tolerant to video noise
than a higher value and the card may not be able to detect the
freeze in presence of changing pixels. If you want to detect a
pure digital video freeze, you can use the value zero.
Otherwise, the threshold should be increased until a consistent
freeze is detected.
•
Set Duration (sec) – sets the time interval over which a freeze
must be continuously detected before the error is flagged. The
nominal range of durations is 0.5 to 90 seconds. When
durations
≥
1 sec are selected, there is an additional 0.5 seconds intrinsic to the error detection algorithm that
will prevent switching when there are nearly-coincident errors at the two inputs.
•
Clear Duration (sec) – sets the time interval during which an active signal must be continuously detected before
a previously-flagged Freeze error will be cleared.
Use the
LED Color
pulldown to choose the color that will be displayed
by the status LED on the card edge when a Freeze Detect error is
detected. Choices are:
•
Green, Yellow, Red, Flashing Red
Audio – Audio Grp 1 (same for Grp.2, 3, 4)
This error detects the absence of audio in the named group.
This error can be Enabled using the checkbox, and the level set to 1,
2 or OFF.
The user sets the detection parameter for this error using the slider:
•
Duration (sec) – sets the time interval over which loss of audio
must be continuously detected before the error is flagged
Use the
LED Color
pulldown to choose the color that will be displayed
by the status LED on the card edge when an Audio Grp error is
detected. Choices are:
•
Green, Yellow, Red, Flashing Red
Figure 3.15 Audio Grp alarm config.
Figure 3.14 Freeze Detect alarm Config.
