Orban OPTIMOD-FM 5518, Руководство по эксплуатации

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5518-FM DIGITAL INTRODUCTION
1-3

A dual-mode composite limiter is available. The composite limiter uses a
unique, “you can only do this in DSP” process that beats composite clippers by
preserving stereo imaging while fully protecting the stereo pilot tone,
RDS/RBDS, and subcarriers . It can operate in either “Half-Cosine Interpola-
tion” mode or conventional hard clipper mode. The “Half-Cosine” mode pro-
vides better separation and preservation of stereo imaging, while the “Hard”
mode provides brighter sound because it creates waveforms that are closer to
square waves. Both modes provide excellent spectral protection of the pilot tone
and subcarrier regions. To ensure accurate peak control, the limiter operates at
512 kHz sample rate.

Using its built-in left/right domain and composite peak limiters, the 5518
achieves extremely tight
peak control .

A high-accuracy ITU412 multiplex power controller is available, with user
control over the multiplex power threshold. This allows you to compensate for
overshoots in the signal path upstream from the 5518, preventing excessive re-
duction of the multiplex power.

The input signal can be flat or pre-emphasized to 50 µs or 75 µs.

The 5518 can apply J.17 deemphasis to the input signal.

The 5518 can delay its output by as much as 16 seconds. This delay can be used
as the diversity delay in HD Radio™ installations, which allows the 5518’s ste-
reo encoder (including composite limiter) to be used in an HD Radio installation.

The stereo encoder’s stereo subchannel modulator can operate in normal double
sideband mode and in an experimental
compatible single sideband mode
that is offered to enable users to compare and assess the two modes. See SSB
Stereo Encoder Operation on page 3-6.
Controllable

An LCD and full-time LED meters make setup, adjustment and programming
of the 5518 easy — you can always see the metering while you are adjusting the
processor. Navigation is by dedicated buttons, soft buttons (whose functions are
context-sensitive), and a large rotary knob.

The 5518 can be remote-controlled by 5-12V pulses applied to eight pro-
grammable, optically-isolated “general-purpose interface” (GPI) ports available
at the REMOTE INTERFACE connector on the rear panel.

PC Remote software is a graphical application that runs under Windows
2000/XP/Vista/7. It communicates with a given 5518 via TCP/IP over modem, di-
rect serial, and Ethernet connections. You can configure PC Remote to switch
between many 5518s via a convenient organizer that supports giving any 5518