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Glossary
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■ Audio information
Dolby Digital
Dolby Digital is a digital surround sound system that gives
you completely independent multi-channel audio. With 3
front channels (front L/R and center), and 2 surround
stereo channels, Dolby Digital provides 5 full-range audio
channels. With an additional channel especially for bass
effects, called LFE (Low Frequency Effect), the system
has a total of 5.1-channels (LFE is counted as 0.1
channel). By using 2-channel stereo for the surround
speakers, more accurate moving sound effects and
surround sound environment are possible than with Dolby
Surround. The wide dynamic range from maximum to
minimum volume reproduced by the 5 full-range channels
and the precise sound orientation generated using digital
sound processing provide listeners with unprecedented
excitement and realism. With this unit, any sound
environment from monaural up to a 5.1-channel
configuration can be freely selected for your enjoyment.
Dolby Pro Logic II
Dolby Pro Logic II is an improved technique used to
decode vast numbers of existing Dolby Surround sources.
This new technology enables a discrete 5-channel
playback with 2 front left and right channels, 1 center
channel, and 2 surround left and right channels instead of
only 1 surround channel for conventional Pro Logic
technology. There are three modes available: “Music
mode” for music sources, “Movie mode” for movie
sources and “Game mode” for game sources.
Dolby Surround
Dolby Surround uses a 4-channel analog recording system
to reproduce realistic and dynamic sound effects: 2 front
left and right channels (stereo), a center channel for dialog
(monaural), and a surround channel for special sound
effects (monaural). The surround channel reproduces
sound within a narrow frequency range. Dolby Surround is
widely used with nearly all video tapes and laser discs,
and in many TV and cable broadcasts as well. The Dolby
Pro Logic decoder built into this unit employs a digital
signal processing system that automatically stabilizes the
volume on each channel to enhance moving sound effects
and directionality.
DTS Digital Surround
DTS digital surround was developed to replace the analog
soundtracks of movies with a 5.1-channel digital sound
track, and is now rapidly gaining popularity in movie
theaters around the world. DTS, Inc. has developed a
home theater system so that you can enjoy the depth of
sound and natural spatial representation of DTS digital
surround in your home. This system produces practically
distortion-free 5.1-channel sound (technically, left, right
and center channels, 2 surround channels, plus an LFE 0.1
channel as a subwoofer, for a total of 5.1-channels).
LFE 0.1 channel
This channel reproduces low-frequency bass signals. The
frequency range of this channel is from 20 Hz to 120 Hz.
This channel is counted as 0.1 because it only enforces a
low-frequency range compared to the full-range
reproduced by the other 5 channels in Dolby Digital or
DTS 5.1-channel systems.
PCM (Linear PCM)
Linear PCM is a signal format under which an analog
audio signal is digitized, recorded and transmitted without
using any compression. This is used as a method of
recording CDs and DVD audio. The PCM system uses a
technique for sampling the size of the analog signal per
very small unit of time. Standing for “Pulse Code
Modulation”, the analog signal is encoded as pulses and
then modulated for recording.
Sampling frequency and number of quantized
bits
When digitizing an analog audio signal, the number of
times the signal is sampled per second is called the
sampling frequency, while the degree of fineness when
converting the sound level into a numeric value is called
the number of quantized bits. The range of rates that can
be played back is determined based on the sampling rate,
while the dynamic range representing the sound level
difference is determined by the number of quantized bits.
In principle, the higher the sampling frequency, the wider
the range of frequencies that can be played back, and the
higher the number of quantized bits, the more finely the
sound level can be reproduced.
Glossary
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