Mpx Input 1 And Mpx Input 2 Menus - Omnia .9 Installation & User Manual

FM MENU MPX INPUTS

MPX Input 1 and MPX Input 2 Menus

The MPX Input 1 and MPX Input 2 menus contain the controls to set the input gain, choose a pre-emphasis level, add delay,
compensate for tilt, and add equalization.
The Input Gain slider sets the input level of each of the two MPX Inputs in a range from -12dB to +18dB in one-tenth dB
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increments.
The Pre-emphasis setting controls the de-emphasis circuit used when the MPX Input patch point needs to be de-
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emphasized, such as would be the case when it is selected as the source in a monitor input or if Left De-mod is selected
when viewing the patch point in an oscilloscope display window. Typically, this should be set to match the pre-emphasis
of the input signal, either 50 or 75us.
The Add Delay control allows you to delay the audio coming in from the external MPX Input to match that of the
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Omnia.9.
Since the outputs of most modulation monitors and tuners have some tilt present, controls to adjust compensate for
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Tilt Amount and Tilt Coefficient are provided. To get a good square wave reference, tune in a station with bass-heavy
programming and heavy processing for visual flatness on the oscilloscope. You can also tune in your own station to verify
STL and exciter performance.
The PEQ button enables the 2-band parametric equalizer. When the PEQ is enabled, the sliders to adjust center
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frequency, width, and gain are available to make any necessary adjustments.
The PEQ can be set to be phase linear, phase forward, or phase reverse via the Phase drop-down menu below the gain
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slider. The most likely mode will be phase forward to match an analog filter inaccuracy, but phase linear may be the
preferred choice to counter a digital filter. If you have an exciter that you know to be perfectly accurate (such as a direct-
digital-synthesis exciter) but a receiver that is not, you can use Omnia.9's MPX test tone generator in conjunction with
the MPX Input PEQ to equalize the high frequency response of your receiver to achieve a more accurate result.
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