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DIGITAL PA SYSTEM
dditional Descriptions
dditional Descriptions
• MP3 (MPEG udio Layer-3)
MP3 is one of music file formats that can contain music with stereo sound quality as good as audio CD,
which is a type of MPEG as audio, video compression standards. Compression rate is 1Mb by 1 minute
and thus about 3~ 5 minutes are sufficient if recording songs of 3~ 5 min or so. Differently from audio CD,
a music file made of MP3 can contain over 130 songs for popular songs or folk songs and playing time is
also about 10 hours. MP3 clears frequency range for a human being not to discernable and so has
advantage to compact it to 1/12 or so while maintaining music as sound quality equivalent to CD level. For
example, deriving a song in a music CD while maintaining music as sound quality equivalent to CD level
becomes capacity of 50MB or so but if compressing and converting it to a MP3, size of the MP3 largely
reduces to 4~5MB.
• WM (Windows Media udio)
WMA is a multimedia compression method developed by Microsoft Corporation and is technology to
compress only music from 'Window Media Technologies', and provides same sound quality as format of
MP3 up to 128Kbps, which has lower 64Kbps format than MP3.
In other words, it has a file size of the half of the MP3 and provides same sound quality as MP3.
• Digital I/O and standards
Replaces electrical digital signal with optical signal by coaxial cables, semi-conductor laser or light emitting
diode (LED), and connect to other devices with optical fiber cables. The unit that receives optical signal
changes optical signal to electrical signal for various processing. If transmitting digital data as they are,
data errors are little since it is not less affected by electrical noise than electrical signal.
Digital interface used in this product is a form of S/PDIF(Sony/Philips Digital Interface), complying with
standards called as IEC958.
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PSI-5120A/5240A
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