Omnia 6 Use and Installation Guide – Version 1.00a
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Pre-Emphasis
For the transmission side of FM broadcasting, some form of high-frequency boost, or pre-emphasis is used.
The most commonly used values of pre-emphasis are 50 and 75 µs (microseconds). For North and South
America, 75 µs is used. In Europe, Australia and New Zealand, 50 µs is employed. The factory default pre-
emphasis setting is 75 µs. The pre-emphasis selection affects the operation of the audio processing and is
applied to the composite, discrete, and digital outputs. The pre-emphasized signal at the Left/Right and
digital outputs can be restored to flat, if needed, by the De-Emphasis parameter selection.
To set the Pre-Emphasis, rotate the jog-wheel to highlight one of the three choices: Off, 50 µs or 75 µs.
Click the jog-wheel to set the pre-emphasis selection.
Note: Normally, the Off selection under the Pre-emphasis options would not be used in FM transmission
applications, but is provided in instances where processing of a flat signal is desired. One example would
be when preprocessing prior to a satellite uplink in distributed radio networks.
Output
There are four settings under this menu
item:
• Peak Output Level
• De-Emphasis
• Output Sample Rate
• ITU BS-412 Multiplex Power
Limiter
Output Submenu
Peak Output Level
The left/right peak output level adjustment is done in a similar manner as the setting of the input levels.
These level settings take place in the digital domain and before any D/A converters. Therefore, the output
level settings affect the digital (AES/EBU) output, and the analog outputs including the headphones. The
control range is from 0 dBu (-22 dBFS) to +22 dBu (0dBFS) peak output level. This level is normally set
to the maximum input level, or just below it, of the device that the Omnia-6 is driving (STL, transmitter,
etc.).
