Orban OPTIMOD-FM 5518, Руководство по эксплуатации

Страница: 45 / 217

5518-FM DIGITAL INSTALLATION
2-7

Use two-conductor foil-shielded cable (Belden 8451, or equivalent).

At the 5518’s output (and at the output of other equipment in the system), do
not connect the cable’s shield to the CHASSIS GROUND terminal (pin 1) on the
XLR-type connector. Instead, connect the shield to the input destination. Con-
nect the red (or white) wire to the pin on the XLR-type connector (#2 or #3) that
is considered
H
IGH by the standards of your organization. Connect the black wire
to the pin on the XLR-type connector (#3 or #2) that is considered
L
OW by the
standards of your organization.
AES3 Digital Input and Output
There is one AES3 input and one AES3 output. The program input and output are
both equipped with sample rate converters and can operate at 32, 44.1, 48, 88.2,
and 96 kHz.
Per the AES3 standard, each digital input or output line carries both the
left and right stereo channels. The connection is 110

balanced. The
AES3 standard specifies a maximum cable length of 100 meters. While
almost any balanced, shielded cable will work for relatively short runs (5
meters or less), longer runs require used of 110

balanced cable like
Belden 1800B, 1801B (plenum rated), multi-pair 180xF, 185xF, or 78xxA.
Single-pair category 5, 5e, and 6 Ethernet cable will also work well if you
do not require shielding. (In most cases, the tight balance of Category
5/5e/6 cable makes shielding unnecessary.)
The AES3id standard is best for very long cable runs (up to 1000 meters).
This specifies 75

unbalanced coaxial cable, terminated in BNC connec-
tors. A 110

/75

balun transformer is required to interface an AES3id
connection to your 5518’s digital input or output.
The digital input clip level is fixed at 0 dB relative to the maximum digital
word. The maximum digital input will make the 5518 input meters dis-
play 0 dB. The reference level is adjustable using the
DI R
EF
control.
Composite Output and Subcarrier Input
There are two composite outputs . They carry the encoded stereo signal, the stereo
pilot tone, and any subcarriers that may have been applied to the 5518’s subcarrier
inputs .
These are unbalanced, with the shell connected directly to chassis/circuit ground.
Each output’s level is independently adjustable from –12 dBu to +16.0 dBu.
The output impedance of composite 1 output and composite 2 output can be set to
0

or 75

via jumpers J7 and J8 respectively (located on the Composite/SCA daugh-
terboard). As shipped, the link is on pins 3 and 4, yielding 0

impedance. To reset a
given output to 75

, place the link on pins 1 and 2 of its associated jumper. (See the
schematic on page 6-38 and the parts locator diagram on page 6-34.)