ATI DXA112-BNC User Manual
ATI Audio Inc.
Tel: 856-719-9900
sales@atiaudio.com
www.
audio.com
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DXA
SERIES
AES/EBU DIGITAL AUDIO
DISTRIBUTION AMPLIFIERS
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OPERATING AND MAINTENANCE MANUAL
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© Copyright 2011, ATI Audio Inc.
ATI Audio Inc.
Tel: 856-719-9900
sales@atiaudio.com
www.
audio.com
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PURPOSE
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The DXA Series of Digital Audio Distribution Amplifiers is designed to regenerate,
isolate and distribute digital audio data formatted in accordance with
specifications AES3-1992 and IEC 958. This is commonly called AES/EBU
formatting.
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DXAxxx-XLR models use XLR connectors and operate from and drive a 110-ohm
balanced shielded twisted pair distribution system per AES3-1992.
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DXAxxx-BNC models use BNC connectors and operate from and drive singleended 75-ohm coaxial cable per AES-3id-1995 and are designed to integrate
easily into video facilities.
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SP/DIF (consumer) formatted digital audio data differs primarily in the use of
consumer type "RCA" audio connectors in an unbalanced 75 ohm system and
can be handled by a DXAxxx-BNC with use of an RCA to BNC input cable.
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FEATURES
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• Accepts sample rates from 27 to 96kHz
• Loop-thru transformer balanced and isolated inputs
• Switchable input termination resistors
• Individual, transformer balanced and isolated 110 ohm XLR outputs
• Individual isolated 75-ohm BNC outputs
• Single or dual inputs
• Up to 12 XLR or 24 BNC outputs
• Quiet, internal linear power supplies
• Attractive, one rack unit package
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DESCRIPTION
INPUTS
Incoming AES/EBU formatted digital audio data is applied to input transformer T8
(and T9 for second input channel of dual unit). Both XLR and BNC inputs are
balanced and DC isolated from ground. Input blocking capacitors C22 (C24)
prevent accidental DC inputs from saturating (and perhaps damaging) the input
transformers. Input termination resistors R25 (R26) at 75 ohms for BNC (and
SP/DIF) inputs or 110 ohms for XLR inputs can be switched in or out of the circuit
with rear panel DIP switches S1a (S1b). Inputs should always be terminated
unless they are looped-thru to another device or DXA input. The last device or
input should always terminate the line.
ATI Audio Inc.
Tel: 856-719-9900
sales@atiaudio.com
www.
audio.com
!
RECEIVERS
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The equalized AES/EBU data stream is applied to the receiver circuit U8 (U17), a
Crystal Semiconductor CS8414 96kHz Digital Audio Receiver IC. The CS8414
receives the data, recovers the clock and synchronization signals and separates
the audio and digital data. The audio data may be 16 to 24 bits at sample rates
from 27 to 96 kHz.
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OUTPUT DRIVERS
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DXAxxx-XLR use balanced, 110-ohm, transformer-coupled outputs and XLR type
connectors. DXAxxx-BNC units use the alternative 75-ohm unbalanced outputs
to BNC coax connectors. The XLR outputs are in full compliance with
specification AES3-1992 and the BNC outputs are in accordance with the
recommendations of AES-3id-1995. RS-422 differential line drivers U1 and U2
(U5 and U6) provide a balanced drive for XLR outputs of 8Vp-p, open circuit
through 110-ohm source resistance to yield 4Vp-p when loaded by a 110-ohm
load. XLR outputs are transformer-coupled for ground isolation. Each side of the
differential line driver output is used to separately drive a 75-ohm capacitorcoupled BNC output. Each BNC output provides 4Vp-p open circuit thru 75 ohms
for a loaded output of 2Vp-p. Although the two sides of a differential line driver
are out of phase with each other there is no phase difference in the recovered
audio since the AES/EBU digital data is defined only by the presence or absence
of transitions. It makes no difference whether those transitions are hi-to-low or
low-to-hi.
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REFERENCE OSCILLATORS AND POWER SUPPLIES
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U7 and U13 provide regulated and quiet +/-5VDC for all circuits. Power
transformer primary windings are paralleled for 115VAC or wired in series for
230VAC. Jumper group E1 allows field modification if necessary.
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