Medium storage device and medium rotation synchronization processing method for medium storage device

1. A medium storage device comprising:

a head for either reading or writing data on a track of a storage medium where servo information, including servo synchronization marks, is written on one track with a predetermined interval;

an actuator for positioning said head on a desired track of said storage medium which is rotating;

a controller for controlling reading or writing data on said storage medium by said head at a timing synchronizing the rotation of said storage medium; and

a processing unit for correcting the synchronization timing of said controller from an interval of said servo synchronization marks detected by said controller,

wherein said processing unit judges the normalcy of the detection of said servo synchronization marks, calculates said interval of the servo synchronization marks if the judgment result is normal, and corrects a frequency of the synchronization timing of said controller based on said calculated interval,

and wherein, if said judgment result is not normal, said processing unit calculates a space of said servo synchronization marks which is estimated by interpolation processing of the space of said servo synchronization marks in the past, and corrects the frequency of the synchronization timing of said controller based on said estimated servo synchronization marks.

2. The medium storage device according to claim 1 , wherein said processing unit judges the normalcy of the detection of said servo synchronization marks based on the servo information other than said servo synchronization mark, which comes after said servo synchronization mark.

3. The medium storage device according to claim 1 , wherein, if said judgment result is normal, said processing unit performs low pass filter processing for the interval of said servo synchronization marks and corrects the synchronization timing of said controller based on the interval of said servo synchronization marks of the processing result.

4. The medium storage device according to claim 1 , wherein said controller comprises:

a clock source for generating clocks; and

a timing generation circuit for generating the rotation synchronization timing signals from said clock,

and wherein said processing unit calculates a frequency correction value of said clock of said timing generation circuit, and sets the calculated value in said controller.

5. The medium storage device according to claim 1 , wherein said processing unit starts said synchronization timing correction processing according to a servo gate signal synchronizing the rotation of said storage medium.

6. The medium storage device according to claim 4 , wherein said controller further comprises a counter for counting the servo synchronization mark detection time based on the clock of said clock source,

and said processing unit reads a count value of said counter according to a servo gate signal synchronizing the rotation of said storage medium, and executes said synchronization timing correction processing.

7. The medium storage device according to claim 4 , wherein the timing generation circuit of said controller comprises:

a servo timing generation circuit for generating a servo timing signal from said clock;

a data timing generation circuit for generating a data timing signal from said clock; and

a write timing generation circuit for generating a write timing signal from said clock.

8. The medium storage device according to claim 7 , wherein said controller further comprises a gate signal generation circuit for generating a servo gate signal, a read gate signal and a write gate signal according to said servo timing signal of said servo timing generation circuit.

9. The medium storage device according to claim 7 , wherein said controller further comprises a detection circuit for outputting said servo information and read data from a read signal of said head according to said servo timing signal and said data timing signal.

10. A medium rotation synchronization processing method for a medium storage device comprising the steps of:

writing or reading data on a track of a storage medium where servo information, including servo synchronization marks, is written on one track with a predetermined interval at a timing synchronizing the rotation of said storage medium with a head;

judging the normalcy of detection of said servo synchronization marks detected from a read signal of said head;

calculating said interval of the servo synchronization marks if the judgment result is normal; and

correcting a frequency of said synchronization timing based on the interval of said servo synchronization marks if the judgment result is normal; and

calculating a space of said servo synchronization marks which is estimated by interpolation processing of the space of said servo synchronization marks in the past if said judgment result is not normal, and correcting a frequency of the synchronization timing of said controller based on said estimated servo synchronization marks.

11. The medium rotation synchronization processing method for a medium storage device according to claim 10 , wherein said judgment step comprises a step ofjudging the normalcy of the detection of said servo synchronization marks based on the servo information other than said servo synchronization mark which comes after said servo synchronization mark.

12. The medium rotation synchronization processing method for a medium storage device according to claim 10 , wherein said correction step comprises:

a step of performing low pass filter processing for the interval of said servo synchronization marks if said judgment result is normal; and

a step of correcting the synchronization timing of said controller based on the interval of said servo synchronization marks of said processing result.

13. The medium rotation synchronization processing method for a medium storage device according to claim 10 , wherein said correction step further comprises a step of calculating a frequency correction value of a clock of a timing generation circuit for generating the rotation synchronization timing signal from said clock from a clock source.

14. The medium rotation synchronization processing method for a medium storage device according to claim 10 , wherein said normalcy judgment step further comprises a step of judging the normalcy of said servo synchronization mark detection according to the servo gate signal synchronizing the rotation of said storage medium.

15. The medium rotation synchronization processing method for a medium storage device according to claim 13 , wherein said correction step further comprises a step of executing said synchronization timing correction processing by reading a count value of a counter for counting the servo synchronization mark detection time based on the clock of said clock source according to the servo gate signal synchronizing the rotation of said storage medium.

16. The medium rotation synchronization processing method for a medium storage device according to claim 13 , wherein said correction step further comprises a step of performing frequency correction of said clock of a servo timing generation circuit for generating a servo timing signal from said clock, a data timing generation circuit for generating a data timing signal from said clock, and a write timing generation circuit for generating a write timing signal from said clock.

17. The medium rotation synchronization processing method for a medium storage device according to claim 16 , further comprising a step of generating a servo gate signal a read gate signal and a write gate signal according to said servo timing signal of said servo timing generation circuit.

18. The medium rotation synchronization processing method for a medium storage device according to claim 16 , further comprising a step of detecting said servo information and read data from the read signal of said head according to said servo timing signal and said data timing signal.