Nautel NV7.5, Operation And Maintenance Manual

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NV10/NV7.5 Operations and Maintenance Manual Operating the transmitter
Issue 3.4 2016-08-03 Page 2-59
Figure 2.37: Presets - SCA
SCA - (see Figure 2.37 )
:
•
MPX SCA
Connector
(J7:A for SCA1, J7:B for SCA2)
for use with an externally
generated SCA; select
Enabled
or
Disabled.
When enabled, all the
selections listed below are active.
– Input Level:
signal level that represents 10% modulation. Enter a
value between 1 and 5 V p-p (typically 2.83 Vpp).
•
SCA Reduction
Attenuation applied to the SCA input; set between 0 and 20% (used
to reduce the modulation level of the main audio when SCAs are
enabled; typically, for every 2% of SCA modulation, the main audio
modulation must be reduced by 1%).
•
Internal SCA1/2
Enable or disable the appropriate internal SCA (
SCA1
or
SCA2
).
When enabled, the settings listed below are active for the associated
SCA signal (1 or 2).
– SCA1 or SCA2 Injection Level:
enter value between 0 and 20%
(typically 10%); this level is added to the composite baseband signal.
– SCA1 or SCA2 Frequency:
enter value between 20 and 100 kHz
(typically set to 67 kHz or 92 kHz).
– SCA1 or SCA 2 Input Level:
enter value between -12 and +12 dBu,
which represents the input voltage level that yields 10% modulation
(typically 4.7 dBu).