Ericsson MX8400, Справочное руководство

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Installing and Powering Up
2.15 HSYNC Clock Reference
2.15.1 Overview
2.15.1.1 HSYNC IN (2 off)
The HSYNC IN analogue input enables external video clock
reference support.
An internal 27 MHz clock, when configured by nCompass Control, is
frequency-locked to the studio clock using one or other of the HSYNC
IN inputs. If the external studio reference fails, the MX8400 continues
to operate holding a close frequency approximation to the lost
external reference.
The two HSYNC signal inputs are used to support redundancy. If configured, the
MX8400 switches to the secondary HSYNC input when the primary HSYNC input is
missing or off frequency. The action of switching to the secondary input does not
impact on the output services. The MX8400 switches back to the primary input when
reconfigured by the user or if the secondary input fails.
Table 2.24 HSYNC IN
Item Specification
Connector type
BNC 75
Ω
Connector designation HSYNC IN 1
HSYNC IN 2
Pin Centre:
Shield: Signal
Ground/Chassis
Each connector has an associated indicator which displays the status of
the connector.
Table 2.25 describes the meaning of the indication states.
Table 2.25 HSYNC IN Interface Indicators
State Indication Comment
Off Not configured
Green Receiving
Red Fail
2.15.1.2 HSYNC OUT (2 off)
Support is provided for the distribution of a reference clock output in
the form of a pulse with its negative-going edge at HSYNC
frequency. This is frequency-locked to either the internal 27 MHz
clock or the active HSYNC IN reference. Clock selection is via
nCompass Control.
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