Orban OPTIMOD-FM 5518, Operating Manual

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INTRODUCTION ORBAN MODEL 5518

The 5518 includes analog and AES3 digital inputs and outputs. Both digital in-
put and digital output are equipped with sample-rate converters and can oper-
ate at 32 kHz, 44.1 kHz, 48, 88.2, and 96 kHz sample rates. The preemphasis
status and output levels are separately adjustable for the analog and digital out-
puts.

The analog inputs are transformerless, balanced 10k

instrumentation-
amplifier circuits , and the analog outputs are transformerless balanced, and
floating (with 50

impedance) to ensure highest transparency and accurate
pulse response.

The 5518 has two subcarrier inputs that are mixed with the output of the
5518’s stereo encoder before application to the composite output connectors.
One input can be re-jumpered to provide a 19 kHz pilot reference output. Rear-
panel accessible PC-board-mounted trim pots allow the user to adjust the sensi-
tivities of the two SCA inputs, allowing both inputs to accommodate subcarrier
generators with output levels as low as 100 mV p-p.

The 5518 has a Wordclock/10 MHz Sync Reference Input , which can be used
to lock the stereo pilot tone to a high precision external reference like a GPS-
based frequency standard. This facilitates using the 5518 in single-frequency
network applications.

Silence alarm and digital audio fault tally outputs are available.

All input, output, and power connections are rigorously RFI-suppressed to
Orban’s traditional exacting standards, ensuring trouble-free installation.

The 5518 is designed and certified to meet all applicable international
safety and emissions standards .
Signal Processing Features

The sample rate is 64 kHz and multiples thereof , up to 512 kHz. The inter-
nal audio bandwidth is high enough to prevent overshoot caused by spectral
truncation of the left/right input signals that are band-limited to 18 kHz or
lower. This makes the 5518 compatible with all Orban OPTIMOD-FM audio proc-
essors.

15, 16, or 17 kHz linear-phase lowpass filtering can be applied to the input
signal. To minimize input/output delay, this filter can be bypassed, which is ap-
propriate if the input signal is correctly band-limited by the audio processor driv-
ing the 5518.

A left/right domain overshoot limiter is available. This combines look-ahead
and band-limited clipping techniques to control STL-induced overshoots while
minimizing artifacts.