DAC-4440:   AES/EBU to G.703 (2 Mb/s) Network Interface Adapter.

FEATURES:

      Conversion of AES/EBU audio to 2Mb/s G.703 for transport via telecom circuits.
      Bi-direction operation possible with independent transmit and receive functions on the
         one card.
      Choice of 75Ω unbalanced or 110Ω balanced AES/EBU line connections.
      48 kHz 20 bit default sample rate, 25 - 55 kHz rates supported.
      Optional external AES/EBU reference input for rates other than 48 kHz.
      Allows Channel (C), User (U) or RS232 data to be conveyed.

Brochure  

User Manual  

GENERAL:

The DAC-4440 forms a transmitter/receiver system, which is designed to allow an AES/EBU digital audio signal to be distributed via a 2Mb G.703 (E1) network.

The DAC-4440 converts an AES/EBU digital audio signal into a non-framed 2 Mb G.703 (E1) compatible signal.

The DAC-4440 combines the 20 bit audio data with either C data, U data or RS232 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-4440 also converts a G.703 signal, whose content is formatted as per the output of another DAC-4440, to an AES/EBU data stream. The receiver obtains synchronism with the incoming stream and then separates the audio data from the combined C, U or RS232 data.

The DAC-4440 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), User (U) or RS232 data to be conveyed.

Front panel LEDs indicate when an AES/EBU signal and RS232 data is present on the transmit side of the DAC-4440, and when a valid 2.048 Mb/s G.703 input signal, and RS232 data, is present and when a valid AES/EBU reference signal is applied to the receive side of the DAC 4440.

Relay outputs are provided on the rear assembly for remote status indication for when a valid AES/EBU or E1 signal is present or invalid.

SNMP (Simple Network Management Protocol) remote monitoring is possible when used in conjunction with an IRT frame fitted with SNMP capability.


TECHNICAL SPECIFICATIONS:

AES Input:
AES/EBU (75Ω unbalanced or 110Ω balanced).
Input Level
200 mVp-p minimum.
Format
AES3-1992 standard.
Sample Rate
25kHz to 55kHz.
Input Cable Length
 > 500 m   75Ω (Belden 8281).
> 200 m   110 Ω (AES digital high quality shielded pair).

Data Input:
Type
RS-232.
Rate
9600 baud.

G.703 Output:
2.048 Mb/s G.703
Impedance
75Ω unbalanced terminating.
Format
CCITT G.703 compliant.

G.703 Input:
2.048 Mb/s G.703
Impedance
75Ω unbalanced terminating.
Format
CCITT G.703 compliant.

AES Reference Input:
AES/EBU (75Ω unbalanced or 110Ω balanced)
Input Level
200 mVp-p minimum.
Format
AES3-1992 standard.
Sample Rate
25 kHz to 55 kHz.
Input Cable Length
 > 500 m   75Ω (Belden 8281).
> 200 m   110 Ω (AES digital high quality shielded pair).

AES Output:
AES/EBU (75Ω unbalanced or 110Ω balanced).
Format
AES3-1992 standard.

Alarms:
MAJOR
Settable for either loss of AES or E1. Open circuit on alarm.
MINOR
Settable for either loss of AES or E1. Open circuit on alarm.

System Performance (End to End):
Dynamic Range
120 dB
(20 Hz to 20 kHz, -60dB input).
THD+N
< -88 dB
(20 Hz to 20 kHz, full scale input).
(Fin1 & Fout2 between 25 and 55 kHz).
< -100 dB
(1kHz, full scale input).
(Fin1 & Fout2 between 34 and 55 kHz).
< -94 dB
(10kHz, full scale input).
(Fin1 & Fout2 between 34 and 55 kHz).
Output signal rise and fall times
< 20 ns.
Frequency Response
±0.05 dB 20 Hz to 20 kHz.

Power Requirements:
Voltage
28 Vac CT (14-0-14) or ±16 Vdc.
Power Consumption
< 2 VA.

Connectors:
Balanced
Phoenix 3 terminal plug-in blocks.
Unbalanced
BNC.

Other:
Temperature range
0 - 50°C ambient.
Connectors:    Unbalanced
BNC.
                       Balanced
Removable screw terminal blocks.
Mechanical
Suitable for mounting in IRT 19" rack chassis with input output and power connections on the rear panel.
Finish:             Front panel
Grey background, black lettering & red IRT logo.
                       Rear Panel
Detachable silk-screened PCB with direct mount connectors to Eurocard and external signals.
Dimensions
6 HP x 3 U x 220 mm IRT Eurocard.

                       NOTES:   1
Fin = sample rate of AES/EBU input to DAC-4440;
                                      2
Fout = sample rate of AES/EBU output from DAC-4440.



           
Due to our policy of continuing development, these specifications are subject to change without notice.