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1.2.4 Focus Jump
The function of Focus Jump is for single-sided or double-sided dual layers. The nearer layer from the Objective
Lens is called Layer 0 (L0) and the farther layer called Layer 1 (L1).
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Here are the waveforms of Focus Jump.
Waveforms of Focus Jump
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FE
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FD
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Focus Jump is conducted as follows:
1. Open the tracking in the layer currently played.
2. Issue a command to execute jump to the target layer.
3. Close the tracking in the layer after the jump and restart the play.
When a jump command is issued, the processing will be:
1. Accelerate the lens toward a target layer until an FE signal detects the Focus Jump Acceleration End Level.
If the acceleration time-out time is reached before detecting the Acceleration End Level, however, it will forcibly
end the acceleration.
2. Move the lens through inertia until an FE signal detects the Deceleration Start Level without outputting drive voltage.
3. Decelerate the lens once the Deceleration Start Level is detected until it detects the Deceleration End Level.
D
If the deceleration time-out time is reached before detecting the Deceleration End Level, however, it will forcibly end
the deceleration.
1.3 AUTOMATIC ADJUSTMENT FUNCTION
The system automates all kinds of circuit adjustment.
The section describes how each automatic adjustment works.
1.3.1 Offset Cancel of VIN7, VIN8, VIN9, and VIN10
Each signal of VIN7 - 9, and 10 from PU will be converted to a digital signal by the AD converter in the servo block.
The Offset Cancel function cancels the input offset of the AD converter when turning the power on.
E
1.3.2 VCO Gain Adjustment (VARI Adjustment)
The system has the function to automatically adjust VCO gain so that it will be constant by absorbing the variations
from part to part through learning.
To do that, VCO is locked against the reference frequency for learning.
Then, it reads a Frequency Control Value (FCNT) and adjusts the VARI register so that the value will be equal to the
target FCNT value.
1.3.3 FE Normalization Adjustment
The function is to adjust the FE signal level so that the level measured during Focus Close will be 190LSB at the digital
equalizer input stage.
F
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Objective Lens
B
CX-3283
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C
D
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