Orban OPTIMOD-FM 8600Si, Руководство по эксплуатации

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OPTIMOD-FM DIGITAL OPERATION
3-103
quiet piano background. There is little program energy in the upper midrange, so
any clipper-induced distortion tends to stand out.
The twelfth-octave ratio shows as much as 4 dB suppression of narrowband differ-
ence-frequency IM distortion in the midrange. To cause the 8500 to produce notice-
able distortion, we used the IMPACT preset, which is a louder preset than GREGG or
GREGG MX. To keep the comparison “apples and apples,” we used the IMPACT MX
preset in the 8600. Even with these presets, the distortion in either Orban processor
was negligible compared to the effect of even modest multipath and considerably
less than certain other non-Orban processors produce with this material. (Note that
the increase in the output starting slightly above 6 kHz does not represent distortion
but is instead another manifestation of the 8600’s better HF power handling capa-
bility, which we first presented in Figure 3-5.)
Figure 3-8 on page 3-102 shows an example of program material with much more
energy above 6 kHz than in the midrange, making difference-frequency intermodu-
lation in the midrange easily audible. Although other, non-distorted material in the
midrange makes the measurement less dramatic compared to the previous pictures,
Figure 3-9
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