Sony RDR-GX7 - Manual (Page 32)

■ Functions integrated on two newly developed ICs
In the design of the RDR-GX7, two new ICs were specifically
created. The CXD9711R contains the RF amp which is used to
read and write signals, while the larger S4 is mainly used for
encoding and decoding circuitry. The S4 also contains the servo
DSP and ATAPI control circuitry. In addition, the S4 also
includes the circuitry for various signal processing functions for
DVD recording which are explained in the following sections.
■ Precise signal control for DVD recording
In order to perform highly precise DVD recording in an optimal
manner on each form of DVD media, both the write strategy
control (that includes DVD laser power control) and address data
extraction are important factors. The Dual RW Drive employs a
digital PLL to create write strategy, while LPP extraction is
performed by digital processing for DVD-R/-RW media and
ADIP extraction for DVD+RW media. In particular, for LPP
signal processing, an automatic following function is employed
to vary the slice level depending upon the hardware. For ADIP
signal processing, original detection methods are utilized after
A/D conversion. In these ways, various types of media are easily
handled, enabling a high level of Dual RW recording capability.
Solidly designed mechanism
for top performance in all areas
Behind the stylishly flat design, serious considerations were
made to the fundamental construction of this DVD recorder. One
essential requirement is the need for virtually silent operation in
order to minimize any intrusive noise during use. Also, to ensure
stable DVD recording, heat generation must also be thoroughly
studied. In the planning of the RDR-GX7, these points were
carefully considered during the design and construction of the
mechanism.
■ Highly rigid chassis and
newly developed insulator feet
Resonance from external sources is an extremely important
factor in playback quality. In order to ensure the highest possible
sound quality from recorded video content and DVD software,
newly developed asymmetrical insulator feet are employed.
These have been specifically developed for use with the RDR-
GX7 and effectively minimize external resonance effects,
enabling maximum performance from the Dual Drive. In
addition, L-shaped beams are employed in the chassis interior to
maintain high rigidity, further limiting the effects of external
resonance.
■ Comprehensive measures
for heat dissipation and silent operation
Since the pickup section in the drive has a high output, a great
deal of heat is generated. In addition, when a large amount of
processing is performed by the ICs, high heat generation cannot
be avoided. Since this is a recorder which operates at sub-micron
precision levels, it is important to find ways of holding down
temperature increases in the drive section in order to achieve
highly stable DVD recording. When recording in the DVD-R
format, it's essential to avoid the effect where high surrounding
temperatures cause the laser wavelength to increase. Due to these
factors, detailed heat dissipation analysis of the RDR-GX7 was
undertaken. Appropriate placement of the parts and the careful
placement of heat dissipation hardware has resulted in a design
that features highly efficient countermeasures.
Also, quiet operation of the unit is very important for the
thorough enjoyment of recorded content and DVD and CD
software. For this reason, the back panel of the RDR-GX7 is
equipped with a cooling fan with extremely quiet operation. Plus,
the fan has a control system to change between two speeds
depending upon the internal temperature in order to assure quiet
operation.
Chapter 4-6
Drive and
Deck mechanism
RDR-GX7 Technical Notes
32
The CXD9711R and the S4 are used in the Dual Drive circuitry