Characteristics

Professional Quality

The NEXUS is made for professional use. Apart from exceptional audio quality, the developers were committed to outstanding reliability. This is especially true for external events such as power failure or physically broken fibre-optic cables.

Audio Quality

First-class analogue components ensure the highest sonic fidelity in recording, mix-down, and sound-reinforcement applications. The A/D and D/A converters feature a dynamic range of 133 dB(A), and the microphone A/D converter exceeds 150 dB.

The NEXUS meets all standards imposed by functional specifications 3/2 and 3/5 (as defined by the German Institute for Radio Broadcasting Technology, IRT). Digital and analogue components have successfully been tested by the Institute for Radio Broadcasting Service Technology (RBT) in Nuremberg/Germany, the Italian Radio Broadcasting Service, and the Swiss Radio Broadcasting Service.

Fibre-optic Networking

The wiring requirements of a NEXUS system are reduced to a minimum. NEXUS Base Devices are interconnected solely via duplex fibre-optic cables for audio-signal, word-clock and control-data distribution. This simplifies the installation of widely distributed sys-tems and avoids problems in mobile use.

Distributed Control

Thanks to its dedicated controller board, the basic functions of a Base Device are provided independently of control computers and fibre-optic connections. Thus, the failure of one or more control computers does not affect audio transfers on the routing system.
The NEXUS message system uses all connections available on the Base Device network. Therefore, it remains in operation even if some fibre-optic lines or Base Devices break down; thus, the audio network and any emerging partial networks remain largely operable.

Data Integrity

The working memory of an XCPU controller board is battery-buffered. In case of power failure, the Base Device status is memorized. When power is up again, it will take only seconds to restore all settings — the Base Device will be operable in no time.
System settings and signal routing in the Base Device also maintain data integrity: When the overall NEXUS system is powered up, it resumes its most recent status within a few moments. All this is achieved automatically within the NEXUS system, independently of any control computers.

Self-monitoring Functionality

The Base Devices continuously monitor their own functionality and the network status. Problems detected by the system include:

• Failed or wrongly installed module boards
• Breakdown of fibre-optic lines
• Power-supply failure
• Sync-source failure
• Base Device failure on the network
• Exhausted routing capacity of Base Devices or connections

Failed or wrongly installed module boards will normally not affect other functions or module boards. The boards can even be replaced during operation.

Failure Indicators

Error messages are distributed system-wide and are displayed on all active control computers. Further, the graphical control software logs error messages to simplify subsequent analysis.
In the system view, the graphical control software indicates failed boards, power supplies, and Base Devices by red-coloured icons, thus providing a quick overview of the system status. In addition, the dedicated Power Check window provides detailed information about the supply voltages of the Base Devices.

Redundancy

Additional security thanks to redundancy: The NEXUS supports the use of parallel units in manifold ways.

›  Fibre-optic lines Redundant fibre-optic lines are employed for Base Device interconnection. When a line fails, the backup line will be enabled within one sample.

›  Sync sources The Auto Sync Search function launched at sync-source failure is an integral part of the NEXUS system. If no external source is available, the system will synchronise to a Base Device internal clock generator.

›  Power-supply units Base Devices can be equipped with redundant power supplies, for example, for operation on separate mains circuits. At power-supply failure or power outage, the backup power supply will resume operation without interruption.

Maintenance and Service

Servicing is mostly a non-issue in the NEXUS context — there is not even a necessity for calibrating the »analogue« boards as there are no adjustment controls. Maintenance is limited to the replacement of the XCPU‘s buffer battery. This must be performed when the system reports that the battery is exhausted (once every five years or so).
When service is required, the system provides numerous support options:

• A control computer such as a notebook PC can be connected to any Base Device at any time for failure analysis.
• The graphical system view of the control software shows the physical location of failed boards.
• All module boards and their ports are accessible from the front, so they can easily be checked.
• All boards can be installed and/or removed during operation without affecting any signal (hot-swap capability).
• Newly installed module boards are detected and updated within seconds.
• The firmware of all Base Devices on the network can be updated from a single control computer.
• A remote-maintenance system is available on request. This system provides for quick and low-cost support by the manufacturer over ISDN, phone lines, or the Internet.