CHAPTER 16 |
105
SYSTEM MENU
♦
The
Phase
Rotator
button enables or disables the phase rotator. Phase rotation is recommended primarily
for stations airing talk programming who are also trying to achieve high levels of loudness as it can
adversely affect transient “punch” desirable on music formats.
♦
The
TX Out
menu contains controls used for feeding analog AM transmitters and includes adjustments
for output level, tilt, and equalization.
♦
The
TX Output Level
control is the analog equivalent to the 100% Mod control in the Main AM Options
menu and sets final output modulation level for the analog outputs. However, no warning messages are
provided to indicate overdriving the analog outputs.
♦
The
Tilt Compensation
control adjusts the amount of outward tilt when viewing a 60Hz square wave
from the built-in tone generator on an external oscilloscope fed from the transmitter’s RF sample output.
This control is set to “Off” by default. Typically, more positive (outward) tilt will be required which can
be achieved by sliding the control to the right, though it is possible to achieve more negative (inward) tilt
by moving the control to the left if needed.
♦
The
Tilt Coefficient
control sets the frequency at which the tilt compensation is applied. The lower the
coefficient setting, the lower the frequency. The 60Hz square wave can also be used here while the Tilt
Coefficient slider is adjusted to yield the flattest response.
♦
The three-band
Parametric Equalizer
is provided to offset any characteristics or irregularities of the
analog transmitter or any transformers in line after the Omnia.9.
¸
The
Frequency
slider is used to set the center frequency for each band. The range of this control is 20
to 22,050Hz.
¸
The
Width
slider determines how much audio above and below the center frequency will also be
affected by any boosts or cuts in gain. The range of this control is 0.0 to 10.0 octaves in one-tenth
octave increments. Lower values provide a narrower (sharper) boost or cut, while higher values
provide a wider (gentler) boost or cut.
¸
The
Gain
slider determines how much the audio selected with a combination of the Frequency and
Width sliders is boosted or cut. Each band can be boosted or cut by 12dB in one-quarter dB incre-
ments for a total range of 24db per band.
¸
The
Phase
characteristics of each equalizer is selectable from the associated dropdown menu. The
Phase Forward setting matches the behavior of an analog filter and is most applicable when pre-com-
pensating for anything downstream caused by a transformer or the transmitter itself, though both
Phase Reverse and Phase Linear options are also provided.