Grass Valley NV5128 v.2.5 - Manual (Page 41)

NV5128 Multi-Format Router • User’s Guide 31
2. Introduction
Active Cards
timing is not critical; there is a processing delay of approximately 4 pixels when using an AVC out-
put card. With AVC output cards, frame synchronization and sub-carrier phase alignment are not
maintained with respect to reference. This timing is not adjustable.
Incoming and outgoing analog video signals are received or distributed through 16 BNC connec-
tors housed on a backplane. (See
Backplanes on page 13.)
AVC Input Card
The AVC input card ( EM0432 ) receives up to 16 composite analog video signals through backplane
I/O connectors. Each incoming signal is received by a differential input amplifier. The amplifiers
create single-ended outputs. The outputs are forwarded to anti-aliasing filters and then onward for
processing by an NTSC decoder (AVC) synchronized to 27
.
MHz. The converter feeds the signal to
a SMPTE 259M formatter and bus driver. A 27 MHz phase-locked loop (PLL), locked to the video
converter, reduces jitter during the data formatting process. The SD output is line-locked to the
incoming composite signal.The signals is then forwarded to the motherboard for distribution to a
SD output card (EM0384) or to an AVC output card (EM0433).
AVC Output Card
The AVC output card (EM0433) receives up to 16 SD signals from the motherboard. Differential
inputs from the motherboard are buffered by receivers on the output card. The signals are fed to a
128 inputs x 16 outputs crosspoint array for switching. Each of the 16 outputs is re-clocked and
deserialized. The signals are then encoded as baseband video signals, buffered by an output line
driver and sent to the backplane as composite analog.
Figure 2-25 shows the signal path through the two AVC I/O cards:
Figure 2-25. Analog Video Conversion Signal Flow
Machine Control Signals
The NV5128 supports machine control signals, either EIA-232 or EIA-422. Machine control sig-
nals are used to communicate between two machines, such as editing equipment and a tape
machines. This enables control of two machines through a single interface.
The Machine Control card set (EM0482) is composed of two cards and occupies two slots in the
router. The Machine Control card set receives 32 signals through two passive backplanes, each con-
taining 16 RJ-45 connectors. (See
Backplanes on page 13.)
I/O
Connectors (up to 16)
Input Card
I/O
Connectors (up to 16)
Anti-
aliasing
filter
A/D
Converter
(27 Mhz)
Motherboard
I/O
Connectors (up to 16) SD or
AVC
Output Card
XPT
128x16
Re-clocker
Deserialized
D/A
Converter
Motherboard (x16)