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3-8
OPERATION
Studio AGC
About OPTIMOD-PC's Signal Processing Features
Dual-Mono Architecture
You can use OPTIMOD-PC as a studio AGC and STL protection peak limiter. In a typi-
cal application, OPTIMOD-PC substitutes for the AGC in an Optimod at the transmit-
ter and provides protection limiting for the STL, which can be flat or preemphasized
at 50 or 75 µs. The AGC is turned off in the transmitter-side Optimod.
If the STL has at least 16 bits of dynamic range, it is often practical to
drive it with the AGC alone, allowing additional headroom for the over-
shoots that OPTIMOD-PC's peak limiter would have otherwise removed.
Defeating the peak limiter will remove about 16 milliseconds of delay
from the signal path.
OPTIMOD-PC's AGC uses the same dual-band, window-gated, matrix technology as
the AGCs in Orban's 2300, 5300, 8300, 8382, 8400, 8500, 9300, and 9400 Optimods.
Therefore, it can accurately substitute for the AGCs in these devices and can help
maintain an all-digital signal path throughout the facility. Because OPTIMOD-PC's
AGC is more advanced than the AGCs in Orban's 2200, 8200, and 9200 Optimods,
OPTIMOD-PC can upgrade the performance of these older products when substi-
tuted their AGCs.
Moreover, because OPTIMOD-PC supports presets that be recalled by remote con-
trol, it can be automatically synchronized to the presets on-air at a transmitter-side
Optimod when presets are dayparted.
To achieve this match:
A) Recall one of the STUDIO AGC presets. There are three such presets, for flat,
50 µs, and 75 µs preemphasized STLs. See AGC+[FLAT, 50
on page 3-18.
You must also configure the peak limiter to match the preemphasis that
your STL uses. See step 5 on page 2-23.
B) Edit AGC parameters of the OPTIMOD-PC preset so they are the same as the
AGC parameters on-air at the transmitter-side Optimod. Then save your work
as an OPTIMOD-PC User Preset.
If you use more than one preset in the transmitter-side Optimod, make
one OPTIMOD-PC User preset for each transmitter-side Optimod preset.
C) Adjust the transmitter-side Optimod's input reference level so that the Opti-
mod performs the correct amount of multiband gain reduction (i.e., the same
amount of GR that it would have performed if its internal AGC were active).
OPTIMOD-PC implements full dual-mono architecture in both the AGC and the five-
band compressor sections. You can couple each band in both the AGC and five-band
compressors to a variable extent—anywhere from perfect stereo coupling to com-
pletely uncoupled operation. The coupling control determines the maximum
ORBAN MODEL 1101
µ
µ
, 75
] LIMITER
S
S
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