GS1560A/GS1561 Data Sheet
3.4.2 Reclocker Bypass Control
The serial digital loop-through output may be either a buffered version of the serial
digital input signal, or a reclocked version of that signal.
When operating in slave mode, the application layer may choose the reclocked
output by setting RC_BYP to logic HIGH. If RC_BYP is set LOW, the data stream
will bypass the internal reclocker and the serial digital output will be a buffered
version of the input.
When operating in master mode, the device will assert the RC_BYP pin HIGH only
when it has successfully locked to a SMPTE or DVB-ASI input data stream, (see
Lock Detect on page 35). In this case, the serial digital loop-through output will be
a reclocked version of the input.
3.4.3 Serial Digital Output Mute
The GS1560A will automatically mute the serial digital loop-through output in both
master and slave modes when the internal carrier_detect signal indicates an
invalid serial input.
The loop-through output will also be muted in slave mode when SDO/SDO is
selected as reclocked, (RC_BYP = HIGH), but the lock detect block has failed to
lock to the data stream, (LOCKED = LOW).
Table 3-1 summarizes the possible states of the serial digital loop-through output
data stream.
Table 3-1: Serial Digital Loop-Through Output Status
SLAVE MODE
RC_BYP
SDO
CD
LOCKED
(INPUT)
RECLOCKED
BUFFERED
MUTED
LOW
LOW
LOW
HIGH
HIGH
X
HIGH
LOW
HIGH
X
LOW
LOW*
MUTED
MASTER MODE
RC_BYP
(OUTPUT)
CD
SDO
LOCKED
RECLOCKED
BUFFERED
MUTED
LOW
LOW
HIGH
HIGH
LOW
HIGH
LOW
LOW
LOW*
*NOTE: LOCKED = HIGH if and only if CD = LOW
27360 - 8 September 2005
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