What Is An Smx System; Complete Audio And I/O System Solution; Smx Terminology; System Architecture - Simphonics SMx User Manual

SMx Audio System User's Manual, V1.41

2.1 What is an SMx System?

The SMx Audio System is a visually programmable, multi-channel audio system primarily
used in real-time simulation and training equipment. The needs of such systems are
somewhat unique. Many features of the SMx system are designed specifically to suite the
needs of flight simulation, such as low latency mixing of all channels, and special add-on
interfaces that can connect to various types of computer systems and support hardware.

2.2 Complete Audio and I/O System Solution

SMx is more than an audio system. In fact, SMx has been used as a complete I/O system.
Thanks to the various I/O devices such as our National Instruments I/O device, V+ can take
advantage of existing PC I/O hardware on the market. Also, since SMx uses existing
software standards, any network interface card with a Windows driver can be used directly.
Want to use Gigabit Ethernet? Fiber? FDDI? No problem. The Host and the DIS/HLA network
can be connected via any of these. Other custom devices are available such as VMIC's
Reflective Memory, SCRAMNet, Camber/Bit-3 VME-to-PC, and PROFIBUS just to name a few.

2.3 SMx Terminology

Before we get started, lets agree on some terminology. Commercial audio systems generally
use audiophile terminology. However, the SMx system sticks to the engineering definitions.
Analog Input (AI or AIn) – An AI signal is an actual physical audio input connection. These
are present on breakout boxes as inputs and are labeled channel 1 through 64.
Analog Output (AO or AOut) – An AO signal is an actual physical audio output connection.
These are present on breakout boxes as outputs and are labeled channel 1 through 64.
Breakout Box – A Breakout Box provides the external interface for Analog Inputs and
Outputs. Each Breakout Box contains 8 AIs and 8 AOs which are physically situated on the
back panel using industry standard ¼" phone jacks.
Wave Output (WO or WOut) – A WO is a digital stream of output audio samples flowing from
the PC system. The term WAVE OUT is taken from the Windows file extension for sound files
(.WAV). Windows XP ships with a number of wave files in the c:\WINDOWS\MEADIA
directory, and can be played directly by the system. When Windows plays a sound, it is
usually a wave file. The WO channels in the SMx are often referred to as "virtual channels"
since these are not actually connected directly to physical outputs.
Wave Input (WI or WIn) – A WI is a digital stream of input audio samples flowing into the
PC system from a physical input. This is usually considered recording audio. The SMx uses
WI to send digital audio to the PC system. SMx WI streams can be recorded in the same way
any other sound can be recorded using windows. However, the SMx system can also send
these streams to the voice network, or a number of other destinations. The WI channels in
the SMx are often referred to as "virtual channels" since these are not actually connected
directly to physical inputs.

3 System Architecture

Figure 1 shows a simplified overall view of the system. A CPU powers the system and runs
the visual programming software, V+, which controls all aspects of the system. Audio
signals are connected to the system via ¼" phone plugs on the breakout boxes. Each
breakout box features eight inputs and eight outputs, and one (1) system chassis can
support up to eight breakout boxes for a total of 64 inputs and 64 outputs. The flexibility of
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