Apparatus for generating tracking error signal in optical disc drive

• US 7,633,842 B2
• Filed: 09/23/2005
• Issued: 12/15/2009
• Est. Priority Date: 07/08/2004
• Status: Active Grant

• Current Assignee: Realtek Semiconductor Corp.
• Original Assignee: Realtek Semiconductor Corp.
• Inventors: Yen, Kuang-Yu, He, Wei-Hung
• Primary Examiner(s): Young; Wayne R
• Assistant Examiner(s): GIESY, ADAM
• Application Number:
  US11/162,794
• Publication Number:
  US 20060007808A1
• Time in Patent Office: 1,544 Days
• Field of Search: 369/44.34, 369/44.28, 369/44.41, 369/44.11, 369/53.35, 369/44.32, 369/53.28, 369/44.29
• US Class Current: 369/44.35
• CPC Class Codes: G11B 7/0906 Differential phase difference systems

Abstract

The present invention discloses an apparatus for generating a TE signal in an optical disc drive. The disclosed apparatus includes a signal generation module, a quality detection module coupled to the signal generation module, and a signal-synthesizing module coupled to the signal generation module and the quality detection module. The signal generation module generates a first and a second candidate TE signal according to a light beam reflected off an optical disc. The quality detection module estimates the signal quality of the first and/or the second candidate TE signal and controls the signal-synthesizing module accordingly. The signal-synthesizing module generates the TE signal according to the first and/or the second candidate TE signal.

Claims

1. An apparatus for generating a tracking error signal comprising:

a signal generation module for generating a first and a second candidate tracking error signal according to a light beam reflected off an optical disc;

a quality detection module coupled to the signal generation module for detecting quality of the first and/or the second candidate tracking error signal; and

a signal-synthesizing module coupled to the signal generation module and the quality detection module, wherein the signal-synthesizing module is controlled by the quality detection module for selectively generating a tracking error signal according to the first and/or the second candidate tracking error signal;

wherein if the quality detection module determines that quality of the first candidate tracking error signal is better than quality of the second candidate tracking error signal, the quality detection module controls the signal-synthesizing module to generate the tracking error signal exclusively according to the first candidate tracking error signal;

if the quality detection module determines that quality of the second candidate tracking error signal is better than quality of the first candidate tracking error signal, the quality detection module controls the signal-synthesizing module to generate the tracking error signal exclusively according to the second candidate tracking error signal.

2. An apparatus for generating a tracking error signal comprising:

a signal generation module for generating a first and a second candidate tracking error signal according to a light beam reflected off an optical disc;

a quality detection module coupled to the signal generation module for detecting quality of the first and/or the second candidate tracking error signal; and

a signal-synthesizing module coupled to the signal generation module and the quality detection module, wherein the signal-synthesizing module is controlled by the quality detection module for selectively generating a tracking error signal according to the first and/or the second candidate tracking error signal;

wherein if the quality detection module determines that qualities of the first and second candidate tracking error signals are neither superior nor inferior from each other, the quality detection module controls the signal-synthesizing module to generate the tracking error signal according to both the first and second candidate tracking error signal.

3. An apparatus for generating a tracking error signal comprising:

a signal generation module for generating a first and a second candidate tracking error signal according to a light beam reflected off an optical disc;

a quality detection module coupled to the signal generation module for detecting quality of the first and/or the second candidate tracking error signal; and

a signal-synthesizing module coupled to the signal generation module and the quality detection module, wherein the signal-synthesizing module is controlled by the quality detection module for selectively generating a tracking error signal according to the first and/or the second candidate tracking error signal;

wherein the quality detection module triggers a first indication signal if the quality detection module detects inferior quality in the first candidate tracking error signal, or the quality detection module triggers a second indication signal if the quality detection module detects inferior quality in the second candidate tracking error signal; and

the signal-synthesizing module comprises;

a first multiplexer coupled to the signal generation module and the quality detection module for outputting the second candidate tracking error signal when the quality detection module triggers the first indication signal, and outputting the first candidate tracking error signal when the quality detection module does not trigger the first indication signal;

a second multiplexer coupled to the signal generation module and the quality detection module for outputting the first candidate tracking error signal when the quality detection module triggers the second indication signal, and outputting the second candidate tracking error signal when the quality detection module does not trigger the second indication signal; and

an adder coupled to the first and second multiplexers for synthesizing signals outputted from the first and second multiplexers to generate the tracking error signal.

4. An apparatus for generating a tracking error signal comprising:

a signal generation module for generating a first and a second candidate tracking error signal according to a light beam reflected off an optical disc;

a quality detection module coupled to the signal generation module for detecting quality of the first and/or the second candidate tracking error signal; and

a signal-synthesizing module coupled to the signal generation module and the quality detection module, wherein the signal-synthesizing module is controlled by the quality detection module for selectively generating a tracking error signal according to the first and/or the second candidate tracking error signal;

wherein the quality detection module triggers a first indication signal if the quality detection module detects inferior quality in the first candidate tracking error signal, or the quality detection module triggers a second indication signal if the quality detection module detects inferior quality in the second candidate tracking error signal; and

the signal generation module comprises;

an optical sensing module for generating a first, a second, a third, and a fourth analog signal according to the light beam reflected off an optical disc; and

a first phase detection module coupled to the optical sensing module for generating a first and a second control signal according to the first and second analog signal respectively;

a first charge pump coupled to the first phase detection module for generating the first candidate tracking error signal according to the first and second control signal;

a second phase detection module coupled to the optical sensing module for generating a third and a fourth control signal according to the third and fourth analog signal respectively; and

a second charge pump coupled to the second phase detection module for generating the second candidate tracking error signal according to the third and fourth control signal;

wherein the quality detection module comprises a first quality detector coupled to the first phase detection module for calculating triggered sample numbers of the first and second control signal within a predetermined time to respectively generate a first and a second statistical value, and triggering the first indication signal when both the first and second statistical value are larger than a predetermined threshold value.

5. The apparatus of claim 4, wherein the first phase detection module comprises:

a first ADC unit coupled to the optical sensing module for converting the first and second analog signals into a first and a second digital signal respectively;

a first delay unit coupled to the first ADC unit for delaying the first and second digital signals to generate a first and a second delay signal respectively; and

a first digital logic module coupled to the first ADC unit and the first delay unit for generating the first and second control signals according to the first and second digital signals and the first and second delay signals respectively.

6. The apparatus of claim 5, wherein the first and second digital signals, and the first and second delay signals are all 1-bit digital signals, wherein the first digital logic module triggers the first or second control signal when one out of the first and second digital signals, and the first and second delay signals differs from the other signals.

7. The apparatus of claim 6, wherein the first digital logic module triggers the first control signal when a value of the first digital signal differs from values of the first and second delay signals and a value of the second digital signal, or when a value of the second delay signal differs from the first and second digital signals and a value of the first delay signal.

8. The apparatus of claim 6, wherein the first digital logic module triggers the second control signal when a value of the second digital signal differs from values of the first and second delay signals and a value of the first digital signal, or when a value of the first delay signal differs from the first and second digital signals and a value of the second delay signal.

9. The apparatus of claim 6, wherein the first charge pump increases a level of the first candidate tracking error signal when the first digital logic module triggers the first control signal, or the first charge pump decreases the level of the first candidate tracking error signal when the first digital logic module triggers the second control signal.