Cobalt Digital COMPASS 9414 4 In _ 4 Out Fiber-to-BNC Receiver _ Crosspoint Card - Manual (Page 10)

1
9400-series Functional Description
1-6 9400-SERIES PRODUCT MANUAL 9400S-OM (V1.1)
9400-series Functional Description
Figure 1-1 shows a functional block diagram of the 9400-series transmit cards
9401 thru 9404 which are 4x1 thru 4x4 75
Ω BNC-to-fiber transports with I/O
crosspoints. Figure 1-2 shows a functional block diagram of the 9400-series
transmit cards 9411 thru 9414 which are 1x4 thru 4x4 fiber-to-75
Ω BNC
transports with I/O crosspoints.
Transmitter (Tx) and receiver (Rx) card groups are individually described
below. Except for channel capacity, all respective Tx cards and Rx cards
function identically.
Non-SMPTE Signal Handling
All 9400 cards (whether Tx or Rx) are equipped with EQ/reclocking and
automute tailored for SMPTE signals. Typically, automute is invoked for
signals outside of a range from 19 Mbps to 3 Gbps. These functions help
reject noise in the transport and help recover received signals that may be
degraded due to long cable runs. EQ/reclocking is applied before the
automute function, allowing the automute to blank signal transfer when a
signal is not reliably locked by reclocking. When handling non-SMPTE
signals (specifically signals slower than 19 Mbps), the card’s reclocking and
automute functions can be set to bypass so that non-SMPTE signals are not
rejected by these functions.
Tx Card Description
Four 75
Ω BNC ports are routed to individual EQ/reclocking which provide
on-off selectable EQ/reclock/automute. Via card hardware switches or remote
control, EQ/reclocking and automute can be disabled (on an individual
channel-by-channel basis) to allow signals lower than 19 Mbps from being
rejected as noise. The reclocker and automute can manually be set to bypass
operation to reliably pass non-SMPTE signals (see Non-SMPTE Signal
Handling above).
The crosspoint allows the four BNC inputs to be routed to up to four fiber
outputs (via individual fiber optic modules) per card as specified in Overview
(p. 1-1). The crosspoint can also allow multiple outputs to serve as a DA with
the same input BNC source being applied to multiple fiber outputs.
Electrical-to-fiber conversion is via discrete Tx fiber optic modules which can
be fitted with various connector types as ordered.