User manual

7 Appendix
MIDI MIDI stands for ’Musical instrument digital Interface’ and is a standard of transmitting
control signals for sound expanders. It transmits e.g. note information, which request a sound
expander to play certain notes.
MME Is an abbreviation for ’Microsoft Multimedia Extension’. It is a driver interface for the
audio transport on Windows Systems.
Pitch In the field of audio techniques, this means the difference of a samplerate from a pre-
defined one. If several digital audio devices are present, this fluctuation of samplerate has to be
supported by all devices.
Routing This word describes which paths on switches audio signals and clock signals take
within a system.
Sample rate In order to convert analog audio signals into digital audio data, they are chopped
into a time grid. In this rate, the volume of the audio signal is measure, e.g. 44100 times a
second. The smaller the grid, the better is the resulting audio quality.
S/PDIF S/PDIF stands for ’Sony Philips Digital Interface’ and was developed by the
companies Sony and Philips. With it a digital audio signal is transported either with a light
conductor cable (TOSLINK) or a RCA coaxial cable.
WDM WDM stands for ’Windows
TM
Driver Model’ and is an extensive driver model developed
by the company Microsoft. Other drivers can build upon this. A derivation of it is used, to
handle digital audio data within the computer – see Direct X.
WordClock Is the name for a synchronization signal for digital audio systems. It ensures, for
all devices connected, to work with the identical samplerate (e.g. 44.1 kHz). Most digital audio
formats transmit a clock besides the audio information. E.g. S/PDIF, AES/EBU or ADAT. If
no synchronization is possible via the audio connection (e.g. TDIF), digital audio devices have
to be supplied with the WordClock signal. Please don’t confuse this with MIDI clock or time
code synchronization (e.g. SMTPE).
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