Subcarrier Phase - DEVA Broadcast SmartGen Micro Maintenance And Operation Instruction Manual

SUBCARRIER PHASE

In the interest of maintaining optimum carrier modulation by the program signal, the 57kHz
RDS subcarrier should be in quadrature with the 19kHz stereo pilot. Both in-phase and quadrature
relationships are shown here in figures below, respectively. Note that a quadrature relationship
yields a slightly lower peak level, which allows the greatest carrier modulation by the program
audio signal.
Subcarrier in-Phase
The SmartGen Micro is skillfully and carefully aligned at the factory to ensure that the
subcarrier is in quadrature with the stereo pilot, whether the encoder is used in the sidechain or in
the loop-through operating mode. Although some stereo generators supply a pilot-sync reference
for RDS (usually a TTL-level squarewave), this reference may or may not be in exact phase with
the actual stereo pilot component of the composite/MPX signal. For this reason we recommend
using the composite/MPX signal for synchronization. In the sidechain mode, the SmartGen Micro
simply bridges the output of the stereo generator and does not load or otherwise compromise the
composite/MPX signal.
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E-mail: office@devabroadcast.com ,Web: www.devabroadcast.com
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Subcarrier in Quadrature