Orban OPTIMOD-FM 8700, Operating Manual

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OPTIMOD-FM DIGITAL TECHNICAL DATA
6-1
Section 6
Technical Data
Specifications
It is impossible to characterize the listening quality of even the simplest limiter or
compressor based on specifications, because such specifications cannot adequately
describe the crucial dynamic processes that occur under program conditions. There-
fore, the only way to evaluate the sound of an audio processor meaningfully is by
subjective listening tests.
Certain specifications are presented here to assure the engineer that they are rea-
sonable, to help plan the installation, and make certain comparisons with other pro-
cessing equipment.
Performance
Except as noted in the text, specifications apply for measurements from analog left/right in-
put to stereo composite output and to FM analog left/right output.
Frequency Response (Bypass Mode; Analog Processing Chain): Follows standard
50 µ s or 75 µ s preemphasis curve ± 0.10 dB, 2.0 Hz - 15 kHz. Analog left/right output and
Digital output can be user configured for flat or pre-emphasized output.
Sample Rate: 64 kHz to 512 kHz, depending on processing being performed.
Noise: Output noise floor will depend upon how much gain the processor is set for (Limit
Drive, AGC Drive, Two-Band Drive, and/or Multi-Band Drive), gating level, equalization,
noise reduction, etc. It is primarily governed by the dynamic range of the A/D converter,
which has a specified overload-to
–noise ratio of 110 dB. The dynamic range of the digi-
tal signal processing is 144 dB.
Total System Distortion (de-emphasized, 100% modulation): <0.01% THD, 20 Hz - 1 kHz,
rising to <0.05% at 15 kHz. <0.02% SMPTE IM Distortion.
Total System Separation: > 55 dB, 20 Hz - 15 kHz; 60 dB typical.
Polarity (Two-Band and Bypass Modes): Absolute polarity maintained. Positive-going signal
on input will result in positive-going signal on output when HD Polarity and FM polarity
controls are set to
P
OSITIVE
.
Peak Control at HD Output: The peak limiter is oversampled at 256 kHz, yielding a worst-
case overshoot of 0.5 dB at the analog output and for all output sample rates. (To
achieve this performance at 32 kHz output sample rate, it is necessary to set the 8700i
’s
HD lowpass filter cutoff frequency to 15 kHz.)