2-10
INSTALLATION
ORBAN MODEL 8300
locator drawing. To find the I/O board, see the circuit board locator
drawing on page 6-29. The schematic showing J400 is on page 6-49.
Connect your subcarrier generator(s) to the 8300’s subcarrier input(s) with coaxial
cable terminated with BNC connectors.
The subcarrier inputs have greater than 600
load impedance and are
unbalanced. The two SCA inputs have different behaviors. SCA1’s sensi-
tivity is variable from 220 mV p-p to >10 V p-p to produce 10% injection,
while SCA2’s sensitivity is fixed at 772 mV p-p to produce 10% injection.
VR400 on the I/O board sets SCA1’s sensitivity. To access VR400, remove
the top cover according to the instructions in step 1 on page 4-2. To find
VR400, see page 6-46 for the I/O board parts locator drawing.
A special variant of the I/O board is available having an added trimmer
(VR401) to set the gain of SCA2. This variant should be specified at time
of order. Please contact Orban customer service (see page 5-13) for more
information.
You can use the
19K
R
EF
control in
S
ETUP
to determine whether the 19 kHz pilot
reference output will be in-phase (
0
DEG
) with the pilot tone present in the compos-
ite output or will lead it by 90 degrees (
90
DEG
).
0
DEG
is correct for most installa-
tions. Use
90
DEG
only if your RDS/RBDS generator’s 19 kHz reference input specifi-
cally requires this phase relationship.
Grounding
Very often, grounding is approached in a “hit or miss” manner. However, with care
it is possible to wire an audio studio so that it provides maximum protection from
power faults and is free from ground loops (which induce hum and can cause oscilla-
tion).
In an ideal system:
All units in the system should have balanced inputs. In a modern system with
low output impedances and high input impedances, a balanced input will pro-
vide common-mode rejection and prevent ground loops — regardless of
whether it is driven from a balanced or unbalanced source.
The 8300 has balanced inputs. Its subcarrier inputs are unbalanced, but fre-
quency response is rolled off at low frequencies to reject hum.
All equipment circuit grounds must be connected to each other; all equipment
chassis grounds must be connected together.
In a low RF field, cable shields should be connected at one end only — prefera-
bly the source (output) end.
In a high RF field, audio cable shields should be connected to a solid earth
ground at both ends to achieve best shielding against RFI.
Summary of Contents for 8300J
Page 1: ...Operating Manual OPTIMOD FM 8300 Digital Audio Processor Version 2 1 Software...
Page 7: ...Operating Manual OPTIMOD FM 8300 Digital Audio Processor Version 2 1 Software...
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Page 247: ...OPTIMOD FM DIGITAL TECHNICAL DATA 6 29...
Page 254: ...6 36 TECHNICAL DATA ORBAN MODEL 8300 CPU Module...
Page 260: ...6 42 TECHNICAL DATA ORBAN MODEL 8300 8300 RS232 BOARD PARTS LOCATOR...
Page 262: ...6 44 TECHNICAL DATA ORBAN MODEL 8300 8300 POWER SUPPLY PARTS LOCATOR...
Page 264: ...6 46 TECHNICAL DATA ORBAN MODEL 8300 8300 I O BOARD PARTS LOCATOR...
Page 270: ...6 52 TECHNICAL DATA ORBAN MODEL 8300 DSP BOARD PARTS LOCATOR DRAWING 32170 000 14...
Page 278: ...6 60 TECHNICAL DATA ORBAN MODEL 8300 8300 DISPLAY BOARD PARTS LOCATOR...
Page 279: ...OPTIMOD FM DIGITAL TECHNICAL DATA 6 61 DISPLAY BOARD...