Orban OPTIMOD-FM 8600, Руководство по эксплуатации

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INSTALLATION ORBAN MODEL 8600
P
RE
-
E
+J17
applies both FM preemphasis and J.17 preemphasis (in cas-
cade) to the signal and is only used with STLs using J.17 preemphasis
when their own J.17 preemphasis filters are bypassed. These are rare.
D) Set the
D
IGITAL
O
UTPUT
#1 S
AMPLE
R
ATE
to 32, 44.1, 48, 88.2, or 96 kHz.
[Skip this step if you will not be using the “AES1” digital output.]
The 8600’s fundamental sample rate is always 64 kHz, but the internal
sample rate converter sets the rate at the 8600’s digital output. This ad-
justment sets the output sample rate to ensure compatibility with equip-
ment requiring a fixed sample rate.
8. Set output levels.
A) Locate to the Set Output Levels screen (
S
YSTEM
S
ETUP
> Q
UICK
S
ETUP
7
).
B) You can use either program material or tone to set the output level (and thus,
the on-air modulation). If you want to use tone, set the
400H
Z CALIBRATION
TONE
to
O
N
.
C) Using a modulation monitor or modulation analyzer, adjust the outputs you
are using (analog, digital, composite 1 and composite 2) to make the modula-
tion monitor read 100% modulation (usually
±
75 kHz deviation).
D) If you are using program material, make sure that the program material is
loud enough to produce peaks of frequent recurrence that hit the 8600’s peak
limiting system, thereby defining the maximum peak level that the 8600 will
produce. In the U.S., we recommend using 900
µ
s peak weighting on the peak
modulation indicator, as permitted by F.C.C. rules. This will cause the monitor
to ignore very low energy overshoots and will produce the highest peak mod-
ulation permitted by law.
In other countries, use a peak-indicating instrument as specified by the
regulatory authority in your country.
If you are required to implement the multiplex power limits specified by
ITU-R 412, you may seldom see peaks hitting
±
75 kHz deviation. In this
case, we advise you to set the output level using the 8600’s reference
400Hz tone.
In the United States, F.C.C. Rules permit you to add 0.5% modulation for
every 1% increase in subcarrier injection. For example,
if your subcarrier
injection totals 20%, you can set the total modulation to 110% (
±
82.5
kHz deviation).
The 8600 can reduce audio modulation to compensate for subcarriers.
Once you are finished with Quick Setup, navigate to
SYSTEM SETUP >
NETWORK REMOTE 1
and program the Remote Interface Terminal for
M
OD
. R
EDUCTION
1
or
M
OD
. R
EDUCTION
2
. Set the amount of modulation re-
duction by navigating to
I
NPUT
/
OUTPUT
> C
OMPOSITE
and adjusting the
M
OD
. R
ED
. 1
and
M
OD
. R
ED
. 2
parameters. When both are active, the mod-
ulation reduction is the sum of their settings. In general, set the modula-
tion reduction to one-half the injection of the associated subcarrier.
For example, if your subcarrier injection totals 20% from two 10% sub-
carriers, set
M
OD
. R
ED
. 1
to “5%” and
M
OD
. R
ED
. 2
to 5%. This will reduce
your audio modulation to 90% (100% – 5% – 5%). When you add back