UHF Analog Driver/Transmitter/
Chapter 5, Detailed Alignment Procedures
Translator
LX Series, Rev. 3
5-3
VISUAL UNLOCK (DS6)
– Red
Indicates that the Nominal 45.75 MHz
visual IF is unlocked from the 10 MHz
reference.
AUDIO OVER DEVIATION (DS4)
–
Red Indicates that the input Audio level is
too high. (±75 kHz max)
VIDEO LOSS (DS1)
– Red Indicates
that the input Video level is too low.
OVER MODULATION (DS3)
– Red
Indicates that the input Video level is too
high.
ALTERNATE IF (DS7)
– Red Indicates
that an external Nominal 45.75 MHz IF is
not present to the modulator.
10 MHz PRESENT (DS2)
– Red
Indicates that an external 10 MHz
reference is not present to the
modulator.
Look at the front panel LCD meter on the
Control/Power Supply Module Assembly.
Set the LCD screen to the Modulator
Details video output level screen, the
screen indicates active video from 0 to 1
Vpk-pk. The normal video input level is 1
Vpk-pk on the front panel screen. If this
reading is not at the proper level, the
overall video level can be changed by
adjusting the VIDEO LEVEL control R42
on the front panel of the Modulator to the
1 Vpk-pk level on the front panel screen.
NOTE:
An NTSC or FCC composite signal
should be used for video metering
calibration.
Switch the LCD display to the Modulator
Details screen that indicates the AUDIO
DEVIATION (modulation level) of the
signal up to ±75 kHz.
MONO SET UP:
The modulator was
factory set for a ±25 kHz deviation with a
mono, balanced, audio input of
+10 dBm. If the reading is not at the
correct level, adjust the MONO Audio
Gain pot R110, located on the front panel
of the modulator, as necessary, to attain
the ±25 kHz deviation on the front panel
screen.
STEREO SET UP:
The modulator was
factory set for a ±75 kHz deviation with a
stereo, composite, audio input of
1 Vpk-pk. If this reading is not correct,
adjust the STEREO Audio Gain pot R132,
located on the front panel of the
modulator, as necessary, for the ±75 kHz
deviation.
SECONDARY AUDIO SET UP:
NOTE:
Remove any stereo or mono audio
modulation input to the transmitter
during the set up of the secondary audio.
The modulator was factory set for a
±15 kHz deviation with a secondary
audio input of 1 Vpk-pk. If this reading
is not correct, adjust the SAP/PRO Audio
Gain pot R150, located on the front panel
of the modulator, as necessary, for the
±15 kHz deviation.
5.2.3 IF Processor Module Assembly
Verify that all red LEDs located on the IF
Processor front panel are extinguished.
The following details the meaning of each
LED when illuminated:
•
Input Fault (DS1)
– Indicates that
either abnormally low or no IF is
present at the input of the IF
Processor module.
•
ALC Fault (DS2)
– Indicates that the
ALC circuit is unable to maintain the
signal level requested by the ALC
reference. This is normally due to
excessive attenuation in the linearity
signal path or the IF phase corrector
signal path, or that switch SW1 is in
the Manual ALC Gain position.
•
Mute (DS4)
– Indicates that a Mute
command is present to the system.
Switch the transmitter to Standby. The
ALC is muted when the transmitter is in
Standby.
