Orban OPTIMOD-FM 8700, Operating Manual

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INTRODUCTION ORBAN MODEL 8700i
can exaggerate flaws in the source material, it is very important that the source au-
dio be as clean as possible.
For best results, feed OPTIMOD-FM unprocessed audio . No other audio processing is
necessary or desirable.
If you wish to place level protection prior to your studio / transmitter link (STL), use
the Orban Optimod 6300 or Optimod-PC 1101 or 1101e. These processors can be ad-
justed so that they substitute for the AGC circuitry in OPTIMOD-FM, which is then
defeated.
The 8700i simultaneously processes for analog FM and digital channels like the iBiq-
uity™ HD Radio™ system, DAB, DRM, or netcasts. The 8700i’s HD output provides
look-ahead peak limiting that is optimized to make the most of limited bit-rate co-
decs used in many digital radio systems. By eschewing any clipping, the HD output
prevents the codec from wasting precious bits encoding clipping distortion products,
allowing the codec to use its entire bit budget to encode the desired program mate-
rial.
Thanks to a base sample rate of 64 kHz throughout the 8700i’s processing, the HD
output can be set for audio bandwidths between 15 and 20 kHz. Many codecs oper-
ate better when fed 15 kHz audio because this enables them to use their available
bit bandwidth most efficiently by concentrating on the part of the audio spectrum
that is critical to perceived audio quality. This is particularly true for low rates, like
32 kbps. However, at higher sample rates, full 20 kHz bandwidth provides the same
bandwidth as typical source material, so you may prefer to use it for rates of 96 kbps
and above.
User-Friendly Interface

A large 5.7” (quarter-VGA) color liquid crystal display (LCD) makes setup, adjust-
ment and programming of the 8700i easy. Navigation is by a miniature joystick,
two dedicated buttons, and a large rotary knob. The LCD shows all metering
functions of the processing structure in use.

Use the Locate joystick to navigate through a menu that lets you recall a preset,
modify processing (at three levels of expertise), or to access the system’s setup
controls.
Absolute Control of Peak Modulation

The 8700i provides universal transmitter protection and audio processing for FM
broadcast. It can be configured to interface ideally with any commonly found
transmission system in the world, analog or digital.

The 8700i provides preemphasis limiting for the internationally used preemphasis
curves of 50

s and 75

s. Compared to its predecessor, its new clip-
ping/preemphasis-control technology preserves 2.5 to 3 dB more frequency en-
ergy while significantly reducing audible clipping distortion at all frequencies.