INSTALLATION AND C ONFIGURATION MANUAL
HXT150
52
Appendix 2 Quad speed ADD-ON bus
Scope
The internal audio ADD-ON bus needs an upgrade. We want more channels
(32 per video stream seems possible in the near future). And we want the bus
to be bidirectional, so 32 channels in and 32 channels out at the same time.
The new interface needs to be compatible with all existing hardware (frames)
and in the implementation of the master card it needs to be backward
compatible with the original ADD-ON bus.
The master card will have two modes:
Normal ADD-ON mode
or
Quad Speed audio ADD-ON mode
These modes are selectable on the Master Card. If a mode is selected all
ADD-ON cards to that Master need to be in the same mode.
You can mix Master-Cards in one frame using the two different modes, but
all cards to the right of the master must be in the same mode as the master.
A new Master breaks the chain and the Master Card ADD-ON mode can be
selected again.
Features
The following features and rules will apply:
Up to 32 channels output from the master card with looping to up to 3
ADD-ON cards
The ADD-ON card just picks the channels it wants to process
Up to 32 channels input on the master card
If the master card can handle less then 32 channels, the lowest channel numbers will
be used, as the ADD-ON card will always generate 32 channels (where some can be
zero)
Channel shuffling is done in the ADD-ON card
The Master Card has only one setting to enable the quad speed audio bus
Every Quad-Speed ADD-ON card takes 32 channels from the ‘right hand
ADD-ON card’ and adds (or overwrites) the local processed channels.
This can be done for any of the channels that are processed in the ADD-ON card
Master Cards are switchable between normal and quad-speed bus
Channel designations on the block schematics:
Channel 1-32 (or less) are injected into the dark green large arrow from Master Card
to ADD-ON card and looped on to the next ADD-ON card via the dark green arrow
The ADD-ON card injects up to 32 channels into the brown large arrow
An ADD-ON card will also actively loop extra processed channels into the next
ADD-ON card, and finaly into the Master Card
The cross looping of the original design is now a straight loop
The quad speed bus can also work in one direction
You can use a Quad Speed audio bus to de-embed audio from the master and present
on the ADD-ON card as AES/EBU, Bitstream (like Dolby) or analog audio
If applicable the ADD-ON card can also be used as in injection point of physical
