SR2 Technical Manual EN
Indice : C 25/03/2019
Firmware v2.9
10 / 31
ERECA SAS - 75 rue d'Orgemont, 95210 St Gratien France T : +33 1 39 89 76 23 W : www.ereca.fr
2.3.4 AES / MADI
Digital audio is available on true 75 Ohms BNC sockets.
The total capacity of the Stage Racer 2 is 4 simultaneous bidirectional AES signals. Thru the web server,
the AES 3 and 4 can be disabled to allow for MADI.
Caution: Avoid connecting 50 ohms plugs it will damage the socket central pin causing costly repair
especially if this one is on the lower part of the connector side.
2.3.4.1 Bidirectional AES
Each AES port is internally equipped with a 2-4 wire converter connected to transmit a fully bidirectional
path to any distant AES port of the Stage Racer 2 network. It appear in the AES audio grid of the network.
This allow to interconnect talkback panels working in a bidirectional manner on one 75 Ohms coax. The
ports still can be used without configuration to transport unidirectional signal, no setup needed for channel
direction.
Note1: For the internal 2-4 wire converter correct behaviour the source/terminal impedance of the machine
connected to the AES ports must be 75 Ohms.
Note2: The bidirectional function of the device constraint the design especially to provide an accurate AES
activity led display and avoid signal loop if port impedance is not 75 ohms. The internal FPGA seeks for
AES3 audio XYZ preamble at 48 KHz to light the corresponding AES Led and enable transmission in this
direction.
2.3.4.2 MADI
When selected through the web server, madi can be transmitted and port 3 become MADI input and port 4
become MADI output.
Stage racer 2 offers 2 principles for MADI transmission described below.
•
MADI RAW transport and routing:
MADI is transmitted with the packet engine and the stage racer does not takes care of the MADI content.
A MADI signals can be distributed to multiple MADI outputs thanks to the routing grid.
For transmission, the MADI clock information is transmitted along the MADI signal. At the receiving side the
original clock is precisely regenerated and the MADI data is delivered accordingly to this clock.
The MADI output VCXO capture range is +/- 100 ppm.
•
MADI signal pick-up and insertion:
In parallel to the raw transport, the MADI input signal can be internally decoded and its channels affected to
other internal audio resources (Analog/Dante/Madi/SDI Embedded) of the stage racer 2 network. All
decoded MADI audio transits thru SRC on order to be at Stage racer internal audio frequency.
Similarly a Madi output can be created by picking signals of various sources (Analog/Dante/Madi/SDI De-
Embedded) present in the stage racer 2 network. In this case MADI is synchronous of the internal audio
clock.
Madi formats supported are 56/64 channels at 48 Khz.
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