METHOD AND SYSTEM FOR DETERMINING THE QUALITY OF A STORAGE SYSTEM

• US 20130155827A1
• Filed: 09/06/2011
• Published: 06/20/2013
• Est. Priority Date: 09/08/2010
• Status: Active Grant

• Current Assignee: Thomson Licensing (Vantiva SA)
• Original Assignee: Thomson Licensing (Vantiva SA)
• Inventors: Hepper, Dietmar, Theis, Oliver, Chen, Xiaoming, Hoelzemann, Herbert, Pilard, Gael
• Granted Patent: US 8,958,274 B2
• Time in Patent Office: Days
• US Class Current: 369/47.5
• CPC Class Codes: G11B 20/10481 optimisation methods
• CPC Class Codes: G11B 20/1816 Testing
• CPC Class Codes: G11B 20/182 using test patterns
• CPC Class Codes: G11B 20/20 for correction of skew for multitrack recording
• CPC Class Codes: G11B 2220/2537 Optical discs
• CPC Class Codes: G11B 7/1267 Power calibration
• CPC Class Codes: G11B 7/24 Record carriers characterised by shape, structure or physical properties, or by the selection of the material characterised by the arrangement of information on the carrier G11B7/007

Abstract

In accordance with an exemplary embodiment of the present invention, a method for measuring a quality parameter of an optical storage system comprising a non-diffraction-limited optical storage medium and a readout device, the method comprising the process of deriving an impulse response of the optical storage system, and the process of analyzing the impulse response to determine at least one of a width of the impulse response and a skewness of the impulse response as the quality parameter.

Claims

1. A method for measuring a quality parameter of an optical storage system, the storage system comprising a readout device and a non-diffraction-limited optical storage medium carrying predefined data, the method comprising:

deriving, based on a readout of the predefined data, an impulse response of the optical storage system, as a sequence of impulse response samples; and

analyzing the impulse response to determine as the quality parameter at least one of a width of the impulse response and a skewness of the impulse response.

2. A method according to claim 1, wherein the optical storage medium contains one of predefined sync data, predefined test data, and predefined user data, and the impulse response is derived at least in part by evaluating a readout signal of the predefined data from the storage medium.

3. A method according to claim 1, wherein the width of the impulse response is determined by evaluating one of

the spatial distance of those locations where the impulse response has decreased to a predefined fraction of its maximum value, and

a second-order central moment of squares of the impulse response samples.

4. A method according to claim 1, wherein the skewness of the impulse response is determined by evaluating a third-order central moment of squares of the impulse response samples.

5. A system for measuring a quality parameter of an optical storage channel, comprising means configured to carry out a method according to claim 1.

6. A method for determining an optimum readout laser power for a non-diffraction-limited optical storage medium, the method comprising:

setting the laser power to a start laser power;

determining the width of the impulse response at the set laser power according to a method according to claim 3;

modifying the laser power until the width of the impulse response has reached its minimum.

7. A system for determining an optimum readout laser power for a non-diffraction-limited optical storage medium, the system comprising means configured to carry out the method of claim 6.