Orban OPTIMOD-FM 8600Si, Руководство по эксплуатации

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OPERATION ORBAN MODEL 8600Si
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Two-Band Gated AGC, with target-zone window gating and silence gating
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Equalization, including high-frequency enhancement
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Multiband Compression with embedded HF clipping and additional HF limiter
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“Intelligent” Clipping with distortion control, distortion cancellation, and anti-
aliasing
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Overshoot Compensation
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DSP-derived Stereo Encoder (generator)
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Composite Level Control Processor
Input Conditioning: The 8600Si operates at a 64 kHz sample rate and power-of-
two multiples thereof (up to 512 kHz in the stereo encoder). This allows user-
selectable bandwidths from 15 to 20 kHz at the HD output.
The 15 kHz lowpass filtering in the analog processing’s peak limiting section has a
stopband that begins at 17 kHz. This provides the necessary
±
2 kHz protection for
RDS/RBDS subcarriers as well generous protection of the 19 kHz pilot tone.
The 8600Si’s output spectral control is immaculate, ensuring maximum stereo and
RDS coverage. Because there is very little energy above 16 kHz, the 8600Si’s digital
output will pass through any uncompressed digital STL without adding noticeable
overshoot and without the need for distortion-producing overshoot compensation
schemes.
A defeatable 30 Hz 18 dB/octave highpass filter and a defeatable phase rotator com-
plete the input-conditioning block. These have both been features in Orban FM pro-
cessors for many years. Most users will defeat the 30 Hz filter and leave the phase
rotator in-circuit, although the choice is always yours.
Stereo Enhancement: The 8600Si provides two different stereo enhancement al-
gorithms. The first is based on Orban’s patented analog 222 Stereo Enhancer, which
increases the energy in the stereo difference signal (L–R) whenever a transient is de-
tected in the stereo sum signal (L+R). By operating only on transients, the 222 in-
creases width, brightness, and punch without unnaturally increasing reverb (which is
usually predominantly in the L–R channel).
Gating circuitry detects “mono” material with slight channel or phase imbalances
and suppresses enhancement so this built-in imbalance is not exaggerated. It also
allows you to set a “width limit” to prevent over-enhancement of material with sig-
nificant stereo content, and will always limit the ratio of L–R / L+R to unity or less.
The second stereo enhancement algorithm is based on the well-known “Max” tech-
nique. This passes the L–R signal through a delay line and adds this decorrelated sig-
nal to the unenhanced L–R signal. Gating circuitry similar to that used in the “222-
style” algorithm prevents over-enhancement and undesired enhancement on slight-
ly unbalanced mono material.