Omnia 6 Use and Installation Guide – Version 1.00a
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from affecting the stereo pilot and SCA regions.
Adjusting and Using the BS-412 Multiplex Power Limiter
The Output Menu contains controls for the Omnia 6's proprietary ITU BS-412 Multiplex Power Limiter
algorithm. This algorithm is an enhancement of a DSP based design first pioneered by Frank Foti as an
enhancement for the original Omnia FM product.
ITU BS-412 Multiplex Power Limiter Controls
The concept behind the Multiplex Power Limiter is deceptively simple. It watches the average power of the
processed, pre-emphasized audio in the left and right channels, and adjusts the audio density so that the
peak to average ratio is controlled to the desired degree. By turning on the multiplex power limiter and
setting the control to 0.0dB, compliance with the original standard is assured. Raising the control to values
above 0.0dB will increase the multiplex power as allowed in certain, less-restrictive countries. The graph
on the next page demonstrates the effectiveness of the power limiter algorithm.
