The DAC-3440, together with the DAC 3450, forms a
transmitter/receiver system, which is designed to
allow an AES/EBU digital audio signal to be
distributed via the phone network.
The DAC-3440 converts an AES/EBU digital audio
signal into a non-framed G.703 compatible signal.
The DAC-3440 combines the 20 bit audio data with
either C data or U data into an output stream at 2.048
Mb/s. This stream is then output as a standard G.703
HDB3 encoded 75Ω unframed signal.
The DAC-3450 converts a G.703 signal, whose
content is formatted as per the output of the DAC-
3440, to an AES/EBU data stream. The receiver
obtains synchronism with the incoming stream and
then separates the audio data from the combined C
(or U) data.
The DAC-3450 allows a local reference AES/EBU
signal to be input for rate synchronization of the
output. With no reference signal present, output rate
is automatically set to 48 kHz. |
The system can handle mono or stereo 20 bit
AES/EBU audio at any rate from 25 KHz to 55 kHz,
although it is designed for a nominal 48 kHz.
The system also allows either the Channel (C) or User
(U) data to be conveyed.
Front panel LEDs indicate when an AES/EBU signal
is present and when the input AES/EBU signal
sample rate is 48 kHz on the DAC-3440, and when a
valid 2.048 Mb/s G.703 input signal is present and
when a valid AES/EBU reference signal is applied to
the DAC-3450.
A relay output is provided on each of the rear
assemblies for remote status indication for when a
valid AES/EBU signal is present or invalid.
The DAC-3440 is fabricated in IRT's standard
Eurocard format and may be housed in a variety of
IRT Eurocard frames alongside other standard
modules. |
