ATI DDA212-BNC User Manual

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© Copyright 2011, ATI Audio Inc.

DDA-212 SERIES 2

Models DDA-212BNC and DDA-212XLR

192kHz AES/EBU DIGITAL AUDIO

DISTRIBUTION AMPLIFIERS

OPERATING AND MAINTENANCE MANUAL

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DESCRIPTION
DDA-212 Series 2 Digital Audio Distribution Amplifiers are 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 or AES3.

DDA-212 Series 2 units have two inputs and 12 outputs, with the assignment of
inputs and outputs configurable from a front panel switch. The unit may be
operated as a Dual 1X6 or as a 2-Input 1X12, depending on the Input Select
switch setting. The selected input feeds AES audio to either six or all 12 separate
outputs.

A front panel switch selects either re-clocking or non-reclocking of the input
signal. In most cases, re-clocking is preferred, as this feature improves the
integrity of weak or distorted input signals. Re-clocking may be switched off to
allow distribution of AES sync signals, Dolby E encoded AES signals, or other
signals that should not be re-clocked.

DDA-212 Series 2 units work with AES signals that contain sample rates from 27
through 192kHz and 16-bit through 24-bit density, thus permitting very high
resolution signals to be distributed.

The front panel displays full status of the input signal, including Sample rate,
Word Length, Digital Errors and Pro or Consumer Mode.

DDA-212 Series 2 units contain a unique automatic equalization function that can
adjust for extremely long input lines. Equalization works independently for each
input. A Front Panel Lock feature protects all your settings.

The Model DDA-212XLR uses XLR connectors and operates from and drives a
110-ohm balanced shielded twisted pair distribution system per AES3-1992.

The Model DDA-212BNC uses BNC connectors and operates from and drives
single-ended 75-ohm coaxial cable per AES-3id-1995 and is designed to
integrate easily into video facilities.

S/PDIF (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 DDA-212BNC with use of an RCA-to-BNC input cable.

Input Loop-through connections for each of the two inputs are provided to permit
multiple units to be stacked, or to insert the DDA-212 into your digital workflow.
Switchable line termination is provided. Standard practice dictates that the last
AES input be terminated; therefore, if you are not using the loop-through feature,
Input Termination should be switched ON.

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FEATURES

• Configurable for Dual 1X6 or 2-Input 1X12 operation

• Accepts sample rates from 27 to 192kHz

• Displays standard sample rates of 32, 44.1, 48, 88.2, 96, 176.4 and 192 kHz

• Displays Word Length of 16, 18, 20 and 24 bit

• Status and error LEDs show clock lock and data validity

• Automatic input equalizers compensate for very long cable runs

• Switchable re-clocking regenerates stable data before distribution

• Loop thru transformer balanced and isolated inputs

• Switchable input termination

• Individual, transformer balanced and isolated 110-ohm XLR outputs (XLR only)

• Individual isolated 75-ohm BNC outputs (BNC only)

• Two front-panel-selectable inputs

• 12 outputs

• Front panel control locking system

• Quiet, internal linear power supply

• Attractive and rugged 1RU package

DESCRIPTION
INPUTS

Incoming AES/EBU formatted digital audio data from Inputs 1 and 2 is applied to
individual input transformers. Input termination resistors at 75 ohms for BNC
inputs or 110 ohms for XLR inputs can be switched in or out of the circuit with the
front panel Input Term switch. Inputs should always be terminated unless they
are looped thru to another device or DDA input. The last device or input should
always terminate the line.

INPUT EQUALIZERS

The input signals feed automatic cable equalizer circuits. Input equalization
should only be necessary for extremely long input cable lengths and should only
be used if proven to be necessary. Automatic equalization is enabled by pressing
the front panel button labeled Input EQ. The automatic equalizer provides only
the minimum amount of boost required to compensate for excess cable roll-off to
avoid over-equalization, which can degrade noise margins. Input equalizers work
independently for Input 1 and Input 2.

RECEIVERS
When input re-clocking is enabled, the equalized AES/EBU data stream is

applied to the receiver circuit which 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 192 kHz.