Panasonic RXDT630 - New Digital Servo Circuit

| RX-DT630
Mi NEW DIGITAL SERVO CIRCUIT
This model employs a new digital servo circuit. Compared to the old digital servo circuit, the
following points have been improved.
1. Reduced operated noise 3. Improved vibration resistance
Loading mechanism 2-level speed reducer
2. Reduced access time
[(old) 2.9 seconds =}{new) 1.9 seconds]
Change of traverse gear
Rubber and spring 2-level floating mechanism
[fo=50 Hz (old) = 20 Hz (new)}
4. Reduced number of parts
Use of a single super IC chip
3 chips (MN6626, MN6650, MN6475) are reduced to a single chip(MN66271RA)
5. The servo processor IC (MN66271RA) of the newly-developed digital servo circuit automatically performs the following adjustments which
were previosly manually adjusted in the analog servo circuit:(1) Focus offset, (2) Tracking offset, (3) Focus gain, (4) Tracking gain
and (5) Tracking balance. Therefore, the above mentioned 6 electrical adjustments are discarded in the new digital servo circuit. The unit
optimizes the servo for each loaded disc. (The Best eye (PD balance) adjustment is to be performed manually.)
DIGITAL SERVO SYSTEM (OLD)
S)
Only 1 VR requires adjustment (best eye adjustment) MN6626 MN6475
To EMF demodulation |_JDigital
circuit Filter
MN6650 (Digital servo processor)
Digital audio
playback
Focus coil
Focus error
output signal
Soft
microprogram
processing
Microcomputer
MN66271 RA
(Digital servo processor)
Tracking error Traverse coil
output signal
DIGITAL SERVO SYSTEM (NEW)
§
Only 71 VR requires adjustment (best eye adjustment)
RF signal ==> | EMF
demodulation
Digital Filter
A/D conversion
Digital audio
——SSnee
playback
AN8802
Focus coil
Focus error
output signal
Soft
microprogram
processing
Microcomputer
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1
I
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Tracking error Traverse coil
output signal