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1.
Navigate to the Omnia ONE's Output Menu, and reduce the output levels to 0dBU on both Left and Right
channels.
2.
Connect a sine wave Audio Oscillator to the Omnia ONE AM audio inputs. Set the oscillator to provide a
50 Hz, 0dBu output.
3.
Adjust the Omnia's input level controls so that at least 10 dB of gain reduction is seen on the Wideband
AGC bargraph meter.
In the Mixer menu, increase the output of the LF Limiter to its +3.0dB maximum value.
4.
In the Clipper Menu, increase the Clipper Drive to the +4.0 dB setting. This will produce sufficient clipping
5.
on the 50 Hz tone to allow the following adjustments to be performed.
In the Output Menu, increase the Omnia's output level to produce no more than 50% to 75% modulation as
6.
shown on the station's modulation monitor.
Connect a RF sample to the oscilloscope input and observe the signal envelope. The modulated carrier
7.
should appear similar to Figure 1. The clipped 50 Hz waveform should have a flat-top if there is no low
frequency tilt in the transmitter. If Tilt is visible, as in Figure 2, then adjustment of the Tilt Equalization
control is required.
Use a mixture of the Tilt EQ and Tilt Freq parameters to change the appearance of the tilt in the waveform
8.
so that the top becomes as flat as possible. A properly compensated transmitter's modulation envelope
should appear similar to Figure 1. If too much Tilt Correction is applied, the modulated envelope will
appear similar to Figure 3.
9.
After optimizing the Tilt controls for your particular transmitter, the Tilt adjustment is complete. Normal
programming may be applied and the Omnia ONE's output levels adjusted for the desired negative and
positive modulation. Please see the following oscilloscope photographs of three examples of tilt
equalization.
Low Frequency Tilt Equalization Adjustment Examples
Insufficient Tilt Equalization
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