Grass Valley Profile Family Audio Signal Processing Board - Manual (Page 58)

ASPB Installation
58 ASPB Installation
A single ASPB supports 16 audio channels. These 16 channels are divided into
four audio groups with four audio channels in each group. Group 1 consists of
channels 1 to 4. Group 2 consists of channels 5 to 8, and so on up to Group 4.
There is a phase lock loop and audio sample clock for each audio group 1 through
4 as seen in Figure 19. You can also see in Figure 19 how the Reference Select
Crosspoint allows selection of the reference to the Audio Sample Phase Lock
Loops. Profile software allows the user to select the appropriate reference for the
Audio Sample Phase Lock Loops, either “system clock” derived from house
reference or one of the four audio clocks derived from video inputs.
When the potential for recording non-synchronous video feeds exists, it becomes
important to select the correct video reference and to have the coaxial audio clock
cables connected properly. Here are the audio clock cabling guidelines.
• Profile software recognizes and numbers video inputs beginning with
Channel A of the board in the lowest numbered motherboard slot.
• When two ASPBs are installed, ASPB1 is the ASPB in the lower number
board slot and ASPB2 is in the higher numbered slot.
• Profile software refers to the four ASPB audio clock references as
“Video Input 1” through “Video Input 4”.
• ASPB1 audio clocks 1 through 4 should be connected to video inputs 1
through 4.
• ASPB2 audio clocks 1 through 4 should be connected to video inputs 4
through 8, if installed.
• Audio clock references connected to ASPB1 cannot be used by ASPB2. The
opposite is also true, references attached to ASPB2 cannot be used by
ASPB1.
NOTE: Do not connect any audio clock cables to the connectors on the four
channel Composite Analog Video Output board. These are system clock
connectors and are not used because the ASPB receives system clock through
its motherboard connector.
If your Profile unit has one ASPB, you can connect only four audio clock
references to it. If your Profile unit has two ASPBs installed, a total of eight audio
clocks can be connected. In practice, if your Profile unit has more video inputs
than the number of ASPB clock inputs, you should connect audio clocks from