Miranda NV8256-Plus, Руководство пользователя

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NV8256-Plus Digital Video Router • User’s Guide 17
2. Introduction
Active Cards
ies of the signal. One copy is sent to a 2×1 MUX and then a buffer. The buffer forwards the signal
to the motherboard, which sends the signal to the crosspoint card in the
middle slot (redundant cros-
spoint). The other copy is sent to a buffer and then the motherboard, which forwards the signal to
the crosspoint card in the
right slot (inputs 257–512).
Figure 2-13 shows the signal flow for a standard input card.
Figure 2-13. Standard Input Card Block Diagram
Standard output cards on the local router and standard output cards on a second connected router
“mirror” each other, performing identical tasks.
Filler Input Cards
A filler input card manages SWB (
EM0437-50) or 3Gig (EM0619-50)
incoming signals from expan-
sion connectors when two routers are connected together. Filler input cards receive signals only
through the expansion connections and not through the coaxial connections.
The filler input card receives 16 inputs from the expansion connectors. Each input is forwarded to
one of 16 cable receivers, which creates two copies of the signal. Both copies are sent to a buffer
and then the motherboard. The motherboard forwards one copy to the crosspoint card in the
middle
slot (redundant crosspoint) and one copy to the crosspoint card in the right slot (inputs 257–512).
Figure 2-14 shows the signal flow for a filler input card.
Figure 2-14. Filler Input Card Block Diagram
Analog-to-SD Input Cards
An analog-to-SD input card (EM0451) converts incoming analog PAL or NTSC composite video
signals to SMPTE 259M-C digital component signals (4:2:2, 270 Mb/s).
Inputs
from
coaxial
connectors
(16)
Motherboard
Buffer
Cable
Equalizer
Cable
Driver
Crosspoint
LEFT
2x1
Mux
Expansion
Connectors
Motherboard
Connector
Buffer
Crosspoint
MIDDLE
Inputs
from
Expansion
Connectors
(16)
Cable
Receiver
Buffer Crosspoint
RIGHT
Motherboard
Motherboard
Motherboard
Connector
Crosspoint
MIDDLE
Cable
Receiver
Buffer
Crosspoint
RIGHT
Inputs
from
Expansion
Connectors
(16)