Orban OPTIMOD-FM 8600Si, Operating Manual

Page: 36 / 356

1-10
INTRODUCTION ORBAN MODEL 8600Si
Analog Left/Right Input/Output
The left and right analog inputs are on XLR-type female connectors on the rear pan-
el. Input impedance is greater than 10k
Ω
; balanced and floating. Inputs can accom-
modate up to +27 dBu (0 dBu = 0.775Vrms).
The left and right analog outputs are on XLR-type male connectors on the rear pan-
el. Output impedance is 50
Ω
; balanced and floating. The outputs can drive 600
Ω
or
higher impedances, balanced or unbalanced. The peak output level is adjustable
from –6 dBu to +24 dBu.
Level control of the analog inputs and outputs is accomplished via software control
through System Setup (see step 3 on page 2-27 and step 10 on page 2-31) or
through PC Remote.
Stereo Analog Baseband Composite Output
The stereo encoder has two unbalanced analog baseband outputs on two BNC con-
nectors on the rear panel. Each output can be strapped for
0
or 7
5Ω
source imped-
ance and can drive up to 16dBu (
±
13.82V peak) into 7
5Ω
in parallel with up to
0.047
μ
F (100ft/30m of RG-59/U cable) before any significant audible performance
degradation occurs.
See the footnote on page 1-15 and refer to Figure 2-3 on page 2-9.
Independent level control of each output is available via software (see step 6 on
page 2-29.
Subcarriers
The stereo encoder has two unbalanced 60
0Ω
subcarrier (SCA) inputs with rear-
panel BNC connectors to accept any subcarrier at or above 23 kHz. The subcarriers
are mixed into each composite output and their level is not affected by the compos-
ite level control for that output. The 8600Si does not digitize subcarriers; the mixing
occurs after D/A conversion and is analog.
Subcarrier inputs sum into the composite baseband outputs. Rear-panel accessible
PC-board-mounted trim pots allow the user to adjust the sensitivities of the two SCA
inputs from <100 mV p-p to >10 V p-p to produce 10% injection with respect to
100% modulation = 4 V p-p at the 8600Si’s composite outputs (the factory setting is
4 V p-p to produce 10% injection). Thus both inputs accommodate subcarrier gen-
erators with output levels as low as 100 mV p-p.
The correct peak level of the stereo program applied to the stereo encoder some-
times depends on the number of subcarriers in use. Some regulatory authorities re-
quire that total baseband peak modulation be maintained within specified limits.
The 8600Si’s remote control feature allows you to reduce the stereo main level by
connecting an on/off signal from your subcarrier generator (See page 2-8). You de-