Components

The MADI-format board provides a economical solution for connecting external audio devices with a large number of channels – up to 64 I/O channels on a single board.

64-channel I/O

The XMF board not only supports all operating modes specified in the MADI standard but extends the number of transmitted channels to 64 for both the input and the output sides.
Of course, the input signal can serve as a sync source on the NEXUS audio network.
The board complies with the AES 10-1991 (ANSI S4.43-1991) and AES 10id-1995 standards. In addition, the 96-kHz mode is supported in compliance with the AES 10-1991 draft revision 2000 (legacy-frame format 3.1.3 and 3.1.2).

Input and Output

The duplex board features one input and one output. Ports are available in BNC (75 ohm, coaxial) or optical formats (SC, 1310 nm, 62.5/ 125 µm).
Exceeding the MADI standard, the BNC ports are differential and galvanically isolated for reliable transmission. Thanks to the galvanic isolation, the ports can safely be connected to unbalanced terminals. A version featuring an unbalanced input can also be supplied on request.

Input Data

The XMF board receives audio on all 64 channels. The channel count is reduced to 32 in 96-kHz mode. The board automatically detects the number of input channels in use. User information received is transparently forwarded on the NEXUS system, for example, to AES/EBU boards or other MADI boards.
The system also evaluates the following ancillary information in the data stream:

• Input-channel count
• Channel-status bytes 0 to 3 of each channel (format, emphasis, lock, sampling frequency, channel mode, aux use, audio-sample word length, and multi-channel descriptor)
• Channel parameters (on/off, A/B, validity)

Output Data

The XMF board sends all audio channels in MADI standard. The number of channels can be set to either 56 or 64 (28 or 32 channels in 96-kHz mode). In addition, the on/off and A/B settings can be set individually for each channel.
In transparent mode, all ancillary information is taken from the source signal (MADI, AES/EBU). In addition, the board includes a hardware facility for setting the user and validity information to a static level. This also regenerates the parity information.

Indicators

The XMF board features front-panel LEDs separately indicating the send and receive statuses (for example, missing or asynchronous input signal).

Error Detection

The input sample rates are automatically detected to ensure safe operation. Also, the parity information is checked
for legitimacy, and the validity information is also evaluated. When errors are found or connections are unstable (for example, when the signal is missing or asynchronous, or when jitter, format errors, or parity errors occur), the board automatically stops forwarding the input signal to the NEXUS network.