Orban OPTIMOD-FM 8600Si, Руководство по эксплуатации

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OPTIMOD-FM DIGITAL MAINTENANCE
4-13
You will have to press the N
EXT
button to access all of these parameters.
E) Navigate to
Setup
> S
TEREO
E
NCODER
.
F) Set the
C
OMP
1 L
VL
control to make the stereo monitor read
100%
total modu-
lation.
G) Navigate to
Setup
> T
EST
to access the 8600Si’s tone oscillator parameters
.
H) Measure the L–R level on the stereo monitor at several frequencies, in units of
dB below 100% modulation. This is the main channel to subchannel crosstalk.
It should not exceed –70 dB, 50-15,000 Hz.
I) Set the
T
ONE
C
HAN
to
L–R
. (You will have to press the
Next
button to access
this setting and then the Prev button to return to the
T
ONE
F
REQ control.)
Measure the L+R level on the stereo monitor at several frequencies, in units of
dB below 100% modulation. This is the subchannel to main channel crosstalk.
It should not exceed –70 dB, 50-15,000 Hz.
J) Set the
T
ONE
C
HAN to
L
EFT . Measure the Right level on the stereo monitor at
several frequencies, in units of dB below 100% modulation. This is left-into-
right stereo separation. It should not exceed –55 dB, 50-15,000 Hz.
K) Set the
T
ONE
C
HAN
to
R
IGHT
. Measure the Left level on the stereo monitor at
several frequencies, in units of dB below 100% modulation. This is right-into-
left stereo separation. It should not exceed –55 dB, 50-15,000 Hz.
L) Set the
T
ONE
C
HAN
to
L–R
and the
T
ONE
F
REQ
to
5000.0 H
Z
. Measure the 38
kHz subcarrier suppression on the stereo monitor. It should not exceed –60
dB.
M) Measure the Pilot Modulation on the stereo monitor. It should read 0%.
N) Set
Setup
> S
TEREO
E
NCODER
> C
OMP
1 L
VL
to 0.0%. Measure the de-
emphasized noise at the left and right outputs of the stereo monitor. It
should not exceed –80 dB below 100% modulation.
O) Repeat steps (D) through (N) for the 8600Si’s
C
OMPOSITE
O
UTPUT
2.
(Use the
C
OMP
2 L
VL control instead of the
C
OMP
1 L
VL control.)
P) Using the stereo monitor, verify that pilot tone injection is between 8% and
10% modulation. If it is outside these parameters, adjust it to 9% via
Setup
>
S
TEREO
E
NCODER
>
Next
> P
ILOT
L
VL
.
If the measured pilot level varies by more than a few tenths of percent
from the pilot level indicated, this indicates there may be a problem
elsewhere — either in your measuring setup, or with the 8600Si.
Q) With the
C
OMP
2 L
VL still set to 0.0%, connect a frequency counter to either of
the 8600Si’s composite outputs. Verify that the pilot tone frequency is 19,000
Hz
±
1 Hz.
10. Optional tests.
A) You can test each GPI (Remote Interface) input for functionality in the obvi-
ous way, by programming a function for it and then verifying that the func-