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Thorough Vibration-resistant Design
Since the high-density data recorded on DVD must be read with absolute
accuracy, vibrations from outside or from internal sources, such as the
power supply, will adversely affect sound and picture quality. A variety of
designs have been incorporated in the DVD-A1 to suppress these unwanted
vibrations. The bottom plate forming the foundation of the chassis is a 6-mm
thick, 4-layer hybrid construction made up of a 1.2-mm thick copper-plated
metal sheet and three layers of 1.6-mm metal sheets. Large insulators of
sintered alloy (the same type used in Denon's high-end S1 series) have
been used for the DVD-A1's feet to absorb external vibrations. Reinforcing
plates for the base, front, and rear are composed of four 1.2-mm thick copper-
plated sheets, that have been utilized in a 3-box construction design to
strengthen the chassis. The chassis also uses copper plating to bring the
ground electric potential of the overall chassis close to equipotential in order
to suppress electrical noise. The top cover uses three types of 1.2-mm thick
metal sheets in different shapes, while 2.5-mm thick aluminum panels have
been used for the sides, giving rigidity to the entire chassis. The DVD
mechanism is mounted on a cast-aluminum base between the mechanism
and the chassis. Parts made of different materials effectively absorb vibra-
tions caused by the unit itself as well as from outside to ensure stable opera-
tion.
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THX Ultra Certified
The THX Ultra certification standards are comprised of tests in three cat-
egories; Audio Quality, Video Quality and User Interface. These tests
ensure that a certified DVD player is fully capable of bringing out the best
visual and sonic quality of all your DVD discs.
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Newly-Developed Loading Mechanism
for Suppression of Vibrations
The newly-developed loading mechanism uses a guide and tray
painted with protein material that is highly resistant to vibrations in
order to prevent unwanted vibrations to the tray.
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New PureProgressive
TM
Circuit
(NTSC Conversion Output Only)
The DVD-A1's interlace to progressive converter is the new SiI504
Converter with PureProgressive
TM
circuitry from Silicon Image. The SiI504
features faster moving picture detection and improved film/video mode
recognition capability.
High-speed processing: This Sil504 Progressive Converter is capable of
processing 6 billion operations per second, providing the finest in motion-
adaptive de-interlacing.
Moving picture detection: PureProgressive
TM
features 2:3 pulldown
detection, which converts 24-fps Film based material to 60-fps TV/Video
playback, while also detecting Video based material, animation and
graphics. PureProgressive
TM
is capable of reproducing DVD-Video discs
containing both Film and Video material, as well as high picture quality
progressive video sources, while avoiding the flickering caused by
detection delays of these different formats. In processing moving video
signals, a conventional progressive converter performs detection on a full
frame-by-frame basis, while PureProgressive
TM
stores 4 fields of video
signals in a 64-Mbit SDRAM buffer, enabling the detection and processing
on a pixel-by-pixel basis to achieve greater precision in discriminating
between moving and still pictures.
Improved 2:3 pulldown detection: There are cases in which 2:3 pulldown
data signals on DVD-Video discs are not in sync. The PureProgressive
TM
converter will quickly detect the non-sequential points and perform
appropriate corrective measures at high speed to minimize picture flickering.
It is now also possible to select Level Detection or Flag Detection as the
detection method used for Film and Video material. If an incorrect flag was
recorded or the difference between the video level and noise level is very
small and distinctions on the disc are difficult to detect, this selection ensures
optimum detection capability and minimizes picture quality degradation.
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14-bit, 108-MHz Video D/A Converter
The DVD-A1 uses a total of six 14-bit, 108-MHz video D/A converters to
tap the maximum potential of the new PureProgressiveTM circuit's
performance. The DVD-A1 uses independent D/A converters for
Progressive and Interlaced picture reproduction.
These converters provide a very high sampling frequency of 108-MHz,
with 4x oversampling used for Progressive and 8x oversampling for
Interlaced operation, resulting in the highest detailed D/A conversion.
Since a filter with ample cutoff characteristics can also be used for the
analog low-pass filter, the DVD-A1 reproduces the delicate nuances of
video signals, allowing viewers to enjoy the original picture at the highest
level of realism.
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Noise Shaped Video (NSV)
The NSV feature works in the digital domain to reduce noise in the video
signal frequency band in order to enhance video signal linearity.
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Super Sub Alias Filter
The S/N ratio can be improved when unwanted signals of higher than
6.75 MHz following D/A conversion are cut. The DVD-A1 thus uses a
Super Sub Alias Filter that produces flat characteristics, ensuring that
adverse influences do not affect video signals inside the essential fre-
quency band, and folding noise is eliminated. In the DVD-A1, the
Super Sub Alias Filter is applied to the chroma signal as well as the
luminance signal, improving color reproduction.
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A Wealth of Picture Quality
Adjustment Functions
Contrast, Brightness, Hue, Sharpness, and Gamma can be adjusted
as desired by the user.
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AL24 Processing Plus
Denon has further developed its proprietary AL24 Processing, an analog
waveform reproduction technology, to support the 192-kHz sampling frequen-
cy of DVD-Audio. This new technology, AL24 Processing Plus, thoroughly
suppresses quantization noise associated with D/A conversion of LPCM sig-
nals to reproduce the low-level signals with optimum clarity that will bring out
all the delicate nuances of the music.
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24-bit, 192-kHz Audio D/A Converters
The DVD-A1 uses 8 Burr-Brown PCM-1704, high-performance 24-bit,
192-kHz D/A converters to faithfully and accurately enable high-quality
performance required for any multi-channel playback. Each main chan-
nel(FL/FR) have 2 DACs per channel in a differential configuration,
while the Center/Surround Left/Surround Right/Subwoofer channels
receive one per channel.
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Pure Direct Mode
The DVD-A1 includes two Pure Direct modes that further improve sound
quality. For example, during analog audio output, Pure Direct can turn off
digital signal outputs, video signal outputs, and the front panel display
which can easily influence the sound quality of the analog audio signals.
The user can define which operations are to be turned off and store those
preferences in memory.
Noise level without NSV
N
oise
le
ve
l w
ith
N
S
V
Analog filter characteristics
Noise level with NSV + analog filter
Fig 1. Noise Shaped Video (NSV) Characteristics
Level
13.5 27 54 108 MHz
Video signal
Video noise Video noise Video noise Video noise
13.5 27 54 108 MHz
13.5 27 54 108 MHz
Video signal
Video signal
27 MHz Sampling
54 MHz Sampling
108 MHz Sampling and Super Sub Alias Filter
Signal loss and phase characteristics degradation occur here
Signal loss and phase characteristics degradation occur here
Noise mixes in
Analog filter
Analog filter
Analog filter
Sufficiently flat characteristics
in the required frequency range
Ample cutoff characteristics
Video noise Video noise
Video noise
Fig 2. Super Sub Alias Filter Characteristics