To set the Pre-Emphasis, rotate the jog-wheel to cycle through the three choices:
None
,
50 µs
or
75 µs.
Click
the jog-wheel to set the pre-emphasis selection.
Note:
Normally, the
None
selection 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 pre-processing prior to a
satellite uplink in distributed radio networks.
De-Emphasis
The Left/Right outputs are pre-emphasized under normal circumstances, such as when feeding an outboard
stereo generator or discrete microwave studio-transmitter link. The same applies when feeding a digital exciter
from the AES/EBU output. These outputs can also be de-emphasized for installations that require a flat
response, as is the case when feeding land lines. The factory default de-emphasis setting is
75 µs
.
To change the
Deemphasis
setting, rotate the jog-wheel to cycle through the three choices:
None
,
50 µs
or
75
µs
. Click the jog-wheel to set the de-emphasis selection. If choosing a de-emphasis time constant, be sure it
matches the pre-emphasis time constant. Bear in mind that selecting
None
means that the outputs have pre-
emphasis, assuming that one of the time constants was selected in
Pre-Emphasis
.
Note:
The
Deemphasis
setting does not affect the composite MPX outputs, which always follow the
Preemphasis
setting.
ITU BS-412 Power Limiter (fm Turbo style only)
In certain parts of the world, the average multiplex signal power must be controlled to reduce adjacent channel
interference. The currently enforced standard falls under the ITU BS-412 regulations. The Omnia-3fm Turbo
has a very effective Multiplex Power Limiter that may be enabled to comply with these regulations.
The Power Limiter control sets the average multiplex power from 0.0dB up to 9.0dB (in 0.25dB steps) above
the original 0.0dB ITU BS-412 standard. The default setting is
Off
.
Effectiveness of the Omnia’s ITU BS-412 Power Limiter
36
