Audio Processing And The Multiplex Power Threshold Control; Test Modes - Orban Optimod-FM 8300 Operating Manual

OPTIMOD-FM DIGITAL
lation) by 3 dB, set the MULTIPLEX POWER THRESHOLD to "+3."

Audio Processing and the Multiplex Power Threshold Control

The multiplex power controller reduces multiplex power by applying gain reduction
before the Optimod's FM peak limiting, thereby reducing the drive into the clippers.
With no power control, some of the louder 8300 presets can exceed the ITU stan-
dard by as much as 9 dB. This means that the clipper drive must be reduced by as
much as 9 dB, and this will vary according to the dynamics and spectral content of
the input program material. To prevent unnatural loudness variations, your Optimod
applies a static loss (set by the M
power controller is activated. This complements the dynamic gain reduction pro-
duced by the multiplex power controller. See the notes on the M
control on page 3-35.
The multiplex power controller is operational with all of the Two-Band and Five-
Band processing structures. It is not operational in Test mode and will not prevent
the 8300's test oscillator from producing illegal modulation. It is the responsibility of
the operator to make sure that the test oscillator does not violate the ITU require-
ments. (To ensure this, never modulate the carrier with a single L+R tone that pro-
duces total carrier modulation, including pilot tone, of more than 24%.)
Setup: Test
Parameter
Labels
MODE
BYPASS GAIN
TONE FREQ
TONE LVL
TONE CHAN
PILOT

Test Modes

The Test Modes screen allows you to switch between O
When you switch to B
restored when you switch back to O
Table 3-11: Test Modes on page 3-59 shows the facilities available, which should be
self-explanatory.
P
PX OWER
Units Default
--- Operate
dB 0.0
Hz 400
% 91
--- L+R
--- ON
Table 3-11: Test Modes
or T , the preset you have on air is saved and will be
YPASS ONE
.
PERATE
control) when the multiplex
O
FFSET
Range (CCW to CW)
Operate, Bypass, Tone
18 ... +25
16, 20, 25, 31.5, 40, 50,
63, 80, 100, 125,
200, 250, 315, 400, 500,
630, 800, 1000, 1250, 1600,
2000, 2500, 3150, 4000, 5000,
6300, 8000, 9500, 10000,
12500, 13586.76, 15000
0 ... 121
L+R, LR, LEFT; RIGHT
ON, OFF
, B
PERATE
OPERATION
P O
PX OWER FFSET
Step
---
1
LOG
160,
1
---
---
, and T
.
YPASS ONE
3-59