GRASS VALLEY APEX -, Installation And Service Manual

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APEX — Installation and Service Manual 85
Reference Connections
Reference Connections
Each Apex chassis must have a video reference or an AES reference in order
for switches to occur on the proper audio frame boundary.
If a video reference is being used in the facility to synchronize AES audio,
then this reference can be employed. (Dolby E operation requires use of a
video reference.) The video reference can be NTSC or PAL video, or black
burst. The video reference input uses looping 75 Ohm BNC connectors; if
the signal does not continue to another device a 75 Ohm terminator must
be installed. Factory default settings on the CX-34000 Control Crosspoint
board assume that a video reference signal will be connected to the VID
REF A connector.
Alternatively, an AES reference (AES3-1992
1
bit stream or SPDIF
1
bit
stream) that is used to synchronize AES audio in the facility can be con-
nected to the Apex. Two connectors are provided for this reference: a BNC
type for 75 Ohm cabling and a 9-pin D female type for 110 Ohm cabling.
Pinouts for the D connector are shown in
Figure 33 . Note that some pins on
this connector are used for 110 Ohm Output Monitor cabling.
Figure 33. Output Monitor / AES Reference Connector (110 Ohm)
The A references are brought to Matrix Board A and the B references are
brought to Matrix Board B. If redundant Matrix boards are installed, the
same reference must be presented to both REF A and REF B connectors, the
system will automatically operate the Matrix boards as a redundant pair.
For example, a video reference could be connected to Video Reference A
and looped to Video Reference B. If Matrix board A failed, Matrix board B
would become active. This same single video reference should be selected
for use on all input and output boards.
If necessary, each chassis can use separate, independent references.
Please refer to the following system examples, which are presented in order
of increasing complexity.
1.
See Glossary.
7 Plus
2 Minus
110 W Reference
5 6 3 9 1
Plus
Minus 4 8
Output Monitor