CHAPTER 16
| 118
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
increments.
♦ The Pre-emphasis setting controls the de-emphasis circuit used when the MPX Input patch point needs to be de-
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
Omnia.9.
♦ Since the outputs of most modulation monitors and tuners have some tilt present, controls to adjust compensate for
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
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
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.
To Next Page
Loading...
Need help?
General
