CHAPTER 16 |
104
SYSTEM MENU
♦
There is a
Test Generator
that provides various tones that are useful for system analysis and setup.
Turning on any of the tones in the
Test Generator
dropdown menu will interrupt normal program audio.
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Square:
A square wave with mild low-pass filtering which can be used to adjust and pre-compensate
for transmitter tilt by connecting an external oscilloscope to the RF sample output of the transmitter.
¸
Sweep:
A linear sweep that includes frequencies in the range determined by the settings of the High
Pass and Low Pass filters, and useful for adjusting transmitter EQ.
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400Hz:
The standard 400Hz reference tone.
¸
60Hz Sawtooth:
Useful for testing system linearity when connecting the output of the processor to the
X input of an “X/Y” ‘scope and connecting the RF sample output of the transmitter to the Y input.
¸
6Hz Sa Detent:
The same signal as the standard 60Hz Sawtooth but with a handy detent to
make finding 50% easier on the ‘scope. (Aren’t we thoughtful?)
♦
The
Test Level
slider adjusts the output of the test generator.
♦
Omnia.7 can accept the output of another processor, allowing it to be used as a delay-compensated,
level-matched switcher between the two devices. The setting of the
Air:
control determines whether the
output of the processor or the test generator is fed to the transmitter. When the
Air
dropdown control
is set to “AM Processor Out”, Omnia.7 is on the air. Setting it to “Test Input” places the other processor
on the air. Information about the processor feeding the test input can be viewed on Omnia.7’s built-in
oscilloscope and other analysis tools.
♦
The
100% Modulation
slider sets final output modulation reference level for the digital outputs. If the
digital outputs are in danger of being overdriven, a red warning message will appear at the top of the front
panel or NfRemote screen indicating this control (or the Positive Peak control) should be turned down.
♦
The
Night
menu allows unique and independent settings for positive peaks as well as high pass and low
pass frequencies when running your transmitter in night mode. Night mode can be turned on manually
with the
Night Mode
control, by setting a time-based event in the
System > Scheduling
menu, or by
setting a GPI function in the
System > GPI > GPI
menu.
♦
The
Phase Menu
contains the controls for the phase scrambler and phase rotator. The
Phase Scrambler
button enables or disables the phase scrambler. Certain sharp sounds with high harmonic content (such
as trumpets or some synthesized sounds) are low in energy but contain high peaks. Since peaks must be
limited to prevent over-deviation of the AM carrier, and the majority of those peaks will be removed by
clipping, the sound may become dull and distorted.
♦
The Phase Scrambler, without employing limiting or clipping of its own, slightly offsets the various
harmonics present in the audio to drastically lower the peak level, thereby allowing much more of the
audio to pass through the final clipper. The result is a dramatically improved high end and less distortion.