Orban OPTIMOD-FM 8600, Руководство по эксплуатации

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OPTIMOD-FM DIGITAL INTRODUCTION
1-5
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The 8600 has two independent composite baseband outputs with digitally
programmable output levels. Robust line drivers enable them to drive 100 feet
of RG-59 coaxial cable without audible performance degradation.
•
The 8600’s two
subcarrier inputs
are mixed with the output of the 8600’s ste-
reo encoder before application to the composite output connectors. One input
can be re-jumpered to provide a 19 kHz pilot reference output. Both inputs have
internal level trims to accommodate subcarrier generators with output levels as
low as 220 mV.
•
The 8600 precisely controls the audio bandwidth of its analog FM pro-
cessing
to 16.5 kHz. This prevents significant overshoots in uncompressed digi-
tal links operating at a 44.1 kHz-sample rate or higher and prevents interference
to the pilot tone and RDS (or RBDS) subcarrier. The bandwidth of the 8600’s
dig-
ital radio output is adjustable in 1 kHz increments between 15 kHz and 20 kHz.
•
The 8600 has a defeatable
multiplex power limiter
that controls the multiplex
power to ITU-R BS412 standards. An adjustable threshold allows a station to
achieve maximum legal multiplex power even if the downstream transmission
system introduces peak overshoots into the 8600-processed signal. Because this
limiter closes a feedback loop around the audio processing, it allows the user to
adjust the processor’s subjective setup controls freely without violating
BS412 limits, regardless of program material. The multiplex power limiter acts on
all outputs (not just the composite output). In its most common configuration, it
reduces clipper drive when it reduces power, simultaneously
reducing clipping
distortion . However, to accommodate customers who wish to use heavier
clipping to achieve a certain sound
, the MPX power controller can be con-
figured to reduce gain after the clippers.
•
All input, output, and power connections are rigorously RFI-suppressed to
Orban’s traditional exacting standards, ensuring trouble-free installation.
•
The 8600 is designed and certified to
meet all applicable international safe-
ty and emissions standards .
Adaptability through Multiple Audio Processing Struc-
tures
•
A processing structure is a program that operates as a complete audio pro-
cessing system. Only one processing structure can be on-air at a time, although
all are active simultaneously to permit mute-free switching between them. The
8600 realizes its processing structures as a series of high-speed mathematical
computations made by Digital Signal Processing (DSP) chips.
•
The 8600 features six processing structures. Four of these are the same as Opti-
mod-FM 8500:
Five-Band (or “Multiband”) for a consistent, “processed” sound
with 17 ms delay (typical), free from undesirable side effects,
Low-Latency