Flexible Configuration - Orban OPTIMOD 6300 Operating Manual

OPTIMOD 6300 DIGITAL

Starting with V2.2 software, the 6300 implements "true peak" control by
oversampling the peak limiter's sidechain at 192 kHz. This allows the 6300 to
prevent clipping in a playback device's analog signal path by predicting
and controlling the analog peak level following the playback device's recon-
struction filter to an accuracy of better than 0.5 dB. For typical program mate-
rial, accuracy is 0.2 dB
Without true peak control, analog clipping can occur even if all peak values of
the digital samples are below 0 dBFS. This phenomenon has also been termed
"0 dBFS+."
Thanks to true peak control, sample rate conversion, unless it removes high
frequency program energy or introduces group delay distortion, cannot cause
sample peaks to increase more than 0.5 dB. For example, sample rate con-
version from 48 kHz to 44.1 kHz is highly unlikely to cause sample peak clipping
in the 44.1 kHz audio data.

While primarily oriented toward "flat" media, the 6300 can also provide
preemphasis limiting for the two standard preemphasis curves of 50s and
75s. This allows it to protect pre-emphasized microwave links, satellite uplinks
and similar channels where protection limiting or light processing is required. It
can also be used to process analog television FM aural carriers in television ap-
plications because these are usually processed lightly compared to FM radio.
Because its processing is configured to be most effective with "flat me-
dia," the 6300 cannot provide extreme loudness for pre-emphasized ra-
dio channels. Use one of Orban's Optimod-FM processors for this applica-
tion.

Flexible Configuration


The 6300 includes analog and dual AES3 digital inputs and outputs. The digi-
tal input and digital outputs have sample-rate converters and can operate 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 outputs.
Note that the 6300 cannot provide simultaneous, independent audio
processing for flat and preemphasized channels. Even though one output
may be pre-emphasized while other is flat, the only difference between
the outputs is that the "flat" output has de-emphasis applied to it after
the processing while the preemphasized output does not.

OPTIMOD 6300's outputs can be independently configured to emit the output of
the AGC or the output of the multiband compressor/limiter, all configurable
to use or bypass look-ahead limiting. So a 6300 can be configured to drive an
STL with a peak-limited output from the AGC while also providing a fully
processed digital radio/netcast feed and a low delay, multiband com-
pressed talent headphone feed.
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INTRODUCTION