7700 MultiFrame Manual
7707VAT Digital Video and AES Audio Fiber Transmitter
7707VAT-16
Revision
2.3
5.3.1. Configuring Audio Presence Detection
The ADET sub menu contains 3 menu items (for each audio channel) relating to the Audio detection. The
menu items for each channel are identical so for the sake of simplicity, only the menu items for
A1
channel
are shown.
DET1
OFF
ON
The
DET
controls enable audio presence detection on each of the
channels.
The
LVL
and
DUR
controls are used to detect when the audio is considered to be missing. The
LVL
control sets the audio level under which the audio is considered to be missing. The audio must be under
the
LVL
level
for the duration set by the
DUR
control before the audio is considered missing. When audio
is missing, the audio must be over the
LVL
level for 1 sec. before the audio will be considered present.
LVL1
–67 to 0
-40
The
LVL
control sets the audio level under which audio is considered to
be missing. This value is expressed in dBu.
DUR1
1 to 20
10
The
DUR
control sets the amount of time (in seconds) the audio is below
the level set by the
LVL
control before the audio is considered missing.
5.3.1.1. Procedure to Calibrate Audio Presence Detection
1. Supply the 7707VAT-A4 module that is being calibrated with your plant's noisiest audio feed without
any audio program material present. This will be a baseline noise level to calibrate the audio-missing
detector.
2. Set
the
DUR
control to 1 sec so that you can see the results of adjusting the
LVL
parameter without
getting confused with the detection time.
3. Adjust the audio
LVL
control upward from its minimum value until the corresponding
AUDIO PRESENT
LED on the card edge goes Off. This will be the noise floor level. Raise the
LVL
a few dB to make the
detector insensitive to this noise level.
4. Set
the
DUR
control to a time appropriate to your application. This should be set to a value longer than
your worst case acceptable quiet period.
5.4.
CHANGING THE ORIENTATION OF THE TEXT ON THE DISPLAY
DISP
VERT
HOR
The
DISP
control allows the user to select a horizontal or vertical
orientation for the displays to accommodate mounting the module in the
3RU or 1RU frames.
5.5. CONFIGURING
EDH ERROR DETECTION
EDH
OFF
ON
The
EDH
control enables the EDH (error detection and handling) error
display on the Dot matrix display.
