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CELP Module
Analog Levels
TABLE 2-9. OPTION SELECTION, INPUT/OUTPUT LEVELS
Feature
Nominal Input Level
Nominal Output Level
The nominal VF input and output analog levels are selected by DIP
switches S1-1 and S1-8. Table 2-9 describes the setting of these switches.
These switches are programmed for peak levels with a safety margin of
approximately 3 dB allowed.
Switch(S), Jumper(X)
Selection
Desig.
0 dBm
S1-1
– 16 dBm
S1-1
+7 dBm
S1-8
0 dBm
S1-8
Position
The nominal input level selection is deter-
OFF
mined by the nominal output level of the
telephone equipment connected
channel. Most systems specify either 0 dBm
ON
or –16 dBm as their nominal output. If actual
output levels of connected equipment vary
from the nominal levels of 0 dBm or –16 dBm,
switches S1-2, S1-3, S1-4 and S1-5 may be
set to achieve some level of compensation in
the range of –6 dB to +1.5 dB.
The nominal output level for the Voice Chan-
ON
nel is either 0 dBm or +7 dBm. This selection
depends on the nominal input expected into
the telephone equipment connected to the
OFF
channel. Adjustments to the actual measured
output level of the voice channel may be
made through the CRT interface, by setting a
degree of attenuation or amplification in the
range of – 6 dB to + 1.5 dB.
0 dBm input and output levels are pre-
ferred, where possible.
The transmit nominal input level of
–16dBm actually amplifies the input by
16 dBm. A setting of 0 dBm performs
no amplification.
INSTALLATION
Application
to
NOTES
2-9
the
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