Grass Valley NV8500 Series v.3.5 - Manual (Page 69)

53
NV8500 Series
User’s Guide
Output of Disembedder/Embedder Cards
The disembedder/embedder card receives 16 video signals (SD, HD or 3Gig) from the crosspoint
cards (via the motherboard). It accepts audio signals from the TDM matrix. The card has 16
embedders. Each embedder embeds 16 audio (AES or Dolby E) channels from multiple sources
into a video stream. The embedder then forwards the output to a reclocker. The card’s reclockers
sends one copy of each signal to the monitor selector and another copy to the cable drivers, ulti-
mately to the output connectors. Except in the NV8140, the monitor selector is 16×1 MUX that
sends its output to a monitor card. The NV8140 does support monitoring. (See
Monitoring on
page 89.)
The following diagram shows the flow of a signal through hybrid disembedder and embedder
cards. Video signals are routed through the crosspoint matrix. Audio signals are routed through
the TDM matrix.
Fig. 2-19: Block Diagram of Hybrid 3Gig Signal F low
The disembedder/embedder output card has — for each embedder — a disembedder and 16
audio multiplexers. Router logic selects for each audio channel of each output one of the
following sources: (1) the equivalent audio channel from the video at the output, (2) generated
silence, or (3) audio from other sources, via the TDM audio matrix.
Each multiplexer is controlled by its audio channel’s ‘null’ flag and ‘pass-through’ flag. If the ‘null’
flag is set, the channel is null. The channel carries silence unless all 4 channels in a group are null,
in which case, the entire group is omitted from the output.
If the channel is not null, it receives audio either from the same channel of the video at that
output if its pass-through flag is set. Otherwise, it receives audio from another source through
the TDM matrix.
 Note: Hybrid disembedder/embedder cards mute during a control card fail-over.
Hybrid (3Gig/TDM)
For routers other than the NV8140, hybrid 3Gig/TDM input cards receive 8 video stream plus 1
MADI stream. For the NV8140, hybrid 3Gig/TDM input cards receive 16 video stream plus 2 MADI
streams. The input cards accept MADI streams of up to 64 channels. Audio embedded in the
video streams is not disembedded and passes through the router unchanged. The audio chan-
nels carried in the MADI stream are routed through the TDM matrix. MADI signals are locked to
48
kHz. (See Audio and Video References on page 60.)
Hybrid 3Gig/TDM output cards (1) receive 24-bit PCM audio with AES channel status (C), user (U)
and validity (V) bits preserved, (2) insert 24-bit silence with valid C, U, V bits on inactive chan-
nels, and (3) perform phase alignment of all channels.
16 video
Disembedder/Embedder Cards
Monitor
Selector
Embedder
Cable
Driver
(with 256 audio
embedded)
to Monitor
Card
TDM
Matrix
(Audio)
Crosspoint
Matrix
(Video)
Reclocker
16 video
video
audio
(There are no monitor
Disembedder
Silence
MUX