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Jumper
Placement for
Sidechain
Connection
Configured for sidechain operation, the rear-panel
PILOT OR
MPX INPUT
connector simply bridges the output of the stereo
generator and monitors the composite/MPX signal to derive
timing information from the 19kHz stereo pilot. Alternatively,
a TTL-level 19kHz sync squarewave may be applied to this in-
put. We do not recommend this, however, because of possible
phase ambiguities between the synchronizing squarewave and
the 19kHz pilot component in the composite, multiplex output
of the stereo generator.
In sidechain operation the encoder’s
RDS OR MPX OUTPUT
will
contain
only
the RDS subcarrier. With a sidechain connection
the composite/MPX signal is
not
routed through the 730. Side-
chain connection insures multiplex signal integrity and uninter-
rupted program transmission in the highly unlikely event of an
internal encoder failure.
NOTE:
As delivered, the 730 is configured for sidechain opera-
tion.
Referring to Figure 2, locate the 3-terminal jumper strip, si-
tuated behind the rear-panel
RDS OR MPX OUTPUT
connector
on the circuit board. The shorting shunt is positioned to the
right
for sidechain operation.
Jumper
Placement for
Loop-Through
Operation
With the 730 Encoder jumpered for loop-through operation
(shorting shunt to the
left
), the RDS subcarrier is internally
combined with the composite/MPX signal and the
RDS OR MPX
OUTPUT
will include
the composite/MPX program signal at uni-
ty gain. The 730 provides a relay bypass of the composite/MPX
signal in the event of power loss.
Figure 2 –
Encoder Mode Jumpering
Sidechain
Mode
(RDS ONLY)
Loop-Through
Mode
(MPX ON)
K1
JP1
R11
LOOP/SIDE
MPX/RDS
OUTPUT
R12
IC6
