Grass Valley NV5128 v.2.5 - Manual (Page 40)

30 Rev 2.5 • 24 Sep 09
2. Introduction
Active Cards
Input Card
The analog video input card ( EM0375 ) receives up to 16 analog video signals through backplane
I/O connectors. Incoming signals are directly coupled to a differential Op-amp, which act as input
buffers. The buffered outputs are applied to balanced bus drivers that forward the signal to the
motherboard.
Output Card
The analog video output card (EM0376) receives up to 16 signals from the motherboard. Incoming
analog video signals are buffered and converted to unbalanced video signals. The signals are then
forwarded to four crosspoint arrays (32 inputs x 16 outputs) for switching creating a 128 inputs x
16 outputs switching matrix. From the crosspoints, the signals are sent to a 4 x 1 Mux, which for-
wards the signals to a buffer before sending the signals to backplane I/O connectors for distribution.
Figure 2-24 shows the signal path for analog video signals:
Figure 2-24. Analog Video Signal Flow
Analog Video Converter
The Analog Video Converter (AVC) input card and output card add versatility to the NV5128
Multi-Format Router by converting signals, as follows:
• The AVC input card converts incoming composite analog video signals (NTSC or PAL) to SD,
serially-interfaced signals.
• The AVC output card accepts SD inputs from the motherboard and outputs them as analog com-
posite signals in NTSC or PAL format.
An AVC input card can be paired with an AVC output card, SD output card or SWB output card.
An AVC output card can be paired with an AVC input card, SD input card or SWB input card. Any
video I/O card paired with an AVC input card or AVC output card must be able to manage a signal
rate of 270
Mb/s.
Converting a signal from analog to SD delays the signal by approximately 1-1/4 lines; frame syn-
chronization and sub-carrier phase alignment are not maintained with respect to reference. AVC
input cards and output cards provide an economical way to convert NTSC/PAL inputs where signal
I/O
Connectors (up to 16) Motherboard
Input Card Output Card
XPT
32x16 I/O
Connectors (up to 16)
MUX
4x1
XPT
32x16
XPT
32x16
XPT
32x16