APEX
™
Exciter Incorporating FLO
™
Technology
Details of the System Setup Screens
Navigating the LCD Display Screens
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03/08/07
888-2604-001
Page: 3-37
WARNING: Disconnect primary power prior to servicing.
If set too high, it could allow nuisance overdrive trips in some transmitter models,
where the high amplitude peaks could overdrive the PA modules.
This correction takes place before the RTAC circuits.
Note
Nuisance overdrive trips can also be caused by peak stretch, see
Main Menu \ Setup \ RTAC Setup \ Max Peak Stretch on
page 3-38.
Max. Mod. Crest Factor Setup
1.
Set Lin HPF and Non-Lin RTAC functions to bypass.
2.
In the Setup > Exciter screen, start with the Max. Mod. Crest Factor at 13 dB.
3.
Monitor the output of the exciter with a spectrum analyzer and note the shoulder-
level.
4.
lower the Max. Mod. Crest Factor by 0.5 dB intervals and stop when the shoulder
level rises.
5.
Raise the Max. Mod. Crest Factor 0.5 dB above this point. This is the correct set-
ting.
Mute (soft key on right side of screen)
• Mute: When Enabled, the exciter RF output is switched to an internal load. When
Disabled, RF is present at the exciter RF output connector.
In either mode the exciter is capable of performing self tests which involve the RF
output of the exciter. This provides a test of the up converter, down converter, and
output amplifier. This loopback can be viewed by selecting Exciter from the Chart
Source selections of the Setup > Display > Display Setup screen.
The RF Mute status of the exciter is displayed on the at the bottom of all screens. It
will indicate On-Air, Off-Air, or Mute.
If the exciter stays muted when attempting to unmute from the exciter setup screen,
check the mute status on the System Control Status 2/4, External I/O Board. If it indi-
cates On, a mute command is being sent to the external I/O board via connector J1
