Vorsis AirAura, Руководство пользователя

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AirAura Installation Tips:
•
Grounding: Establish a low impedance common ground in your facility and try
to route all grounds to that point. AirAura’s ground reference (its chassis) should
be connected to the station ground. This is especially important in a high RF
environment.
•
Surge protection: Place surge protection circuits as close as possible to the
AirAura being protected. Surge currents should be steered to power ground
instead of station ground if possible.
•
UPS/Power Conditioning: Choose the best power conditioning/UPS units that
you can afford, focusing on the most important features and options that you
need. The better UPS products can prevent equipment damage and some even
come with an external equipment damage warranty.
•
Analog Audio Connections: Balanced audio sources should be connected to
AirAura using shielded audio cable. Unbalanced audio connections, if they are
necessary, should be made with shielded two conductor cable such as Belden
8451 or 9451 as if connecting a balanced source. At the unbalanced source’s
output connect its “+ Output” to AirAura’s “Hi” (XLR pin2) input and connect the
unbalanced source’s shield wire to AirAura’s “Lo” (XLR pin-3) input wire. If the
cable shield is used (recommended) connect it to the AirAura end only (XLR pin
1) to prevent ground loops.
•
Digital Audio Connections: For digital audio connections always use a good
quality digital audio cable with a characteristic impedance of 110 ohms. The
AES/EBU specification with its broad impedance tolerance allows for cables with
impedances from 88 ohms to 132 ohms - 110 ohms is ideal. Twisted pair cable
should be shielded, and in the case of multi-pair cable, each pair should be
individually shielded. Foil shielding is recommended for permanent installations.
Cable with a foil shield plus an overall braid should be used in applications where
frequent flexing of the cables may occur. Each cable pair is capable of carrying
two channels of AES3 digital audio.
Generic “audio” cable such as Belden 8451 and 9451
can be used for
interconnecting AES3 digital audio devices, but the wire length should be
minimized. The actual cable length that will work is primarily determined by the
error correction and jitter tolerance of the AES3 receiver device and the specific
cable used and its length.
The impedance of most ‘analog’ audio cables ranges from 40 ohms to 70 ohms
and represents a fairly large impedance mismatch from the nominal 110 ohms
required by the AES3 standard. Such impedance mismatch will result in signal
reflections which can cause bit errors and audio dropouts at the AES3 receiver.
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