Nautel VX150, Operation & Maintenance Manual

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VX150 TO VX2 OPERATIONS & MAINTENANCE MANUAL OPERATING THE TRANSMITTER
PAGE 2.2.34 VERSION 1.0 2022-12-08
• SCA MPX1/2 Input: Connectors for use with an externally generated SCA; when MPX 1 or
MPX 2 is selected (i.e., enabled), all the selections listed below are active for the selected SCA
MPX input.
– SCA MPX 1/2 Analog Level: signal level that represents 10% modulation. Enter a value
between 1 and 5 V p-p (typically 3.5 Vpp).
– SCA MPX 1/2 Main Carrier 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%)
– SCA MPX 1/2 Low Alarm: When enabled, you can select the SCA MPX 1/2 Low Alarm
Threshold and the SCA MPX 1/2 Low Alarm Timeout. The Low Alarm only applies to the
main audio source’s level and no further action is taken on them after their respective
alarms are triggered.
• SCA1/2 Input: Enable or disable the appropriate internal SCA (SCA1 or SCA2). When set to an
audio input, internal SCA generators can use AES or Analog, 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 Analog Level (when SCA 1/2 Input is Analog Left or Right): enter value
between -12 and +12 dBu, which represents the input voltage level that yields 10%
modulation (typically 0.0 dBu).
– SCA1 or SCA 2 Digital Level (when SCA 1/2 Input is AES 1 or 2): enter value between -25
and 0 dBFS, which represents the input voltage level that yields 10% modulation (typically
-4.0 dBFS).
– SCA1 or SCA2 Lowpass: select Enabled (applies 7.5 kHz low-pass filter to audio input) or
Disabled.
– SCA1 or SCA2 Pre-emphasis: select 0 us, 50 us or 75 us.
– SCA1 or SCA2 Mode: select FM (frequency modulated sub-carrier, typical).