Orban OPTIMOD-FM 8600, Operating Manual

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INTRODUCTION ORBAN MODEL 8600
In facilities that use PPMs that indicate level directly in dBu, maximum program and
line-up level is often +6dBu. Instantaneous peaks will reach +11dBu or more.
Transmission Levels
The transmission engineer is primarily concerned with the peak level of a program
to prevent overloading or over-modulation of the transmission system. This peak
overload level is defined differently, system to system.
Figure 1-1: Common Audio Meter Scales, Aligned to the Same Reference Level
Figure 1-2: Absolute Peak Level, VU and PPM Indications
-20 -10 -7 -5 -3 -2 -1 0 +1 +2 +3
-60 -50 -45 -40 -35 -30 -25 -20 -6 -2 0 -4 -8 -10 -15
-12 -10 -8 -6 -4 -2 0 +8 +12 14 +10 +6 +4 +2
1 2 3 4 6 7 5
-50 -30 -5 +5 -40 0 -10 -20
-36 -24 -18 -12 -6 +6 +12 TEST -42
0 dBFS
Reference
-20 dBFS
HEADROOM