Servo signal inspecting device and method for inspecting servo signal

1. A servo signal inspecting device for inspecting quality of a timing based servo signal recorded on a magnetic tape comprising:

a servo signal inspecting head for reading the timing based servo signal recorded on the running magnetic tape;

a peak detecting means for detecting pulse peaks from the timing based servo signal;

a time interval measuring means for measuring a time interval of the detected pulse peaks by comparing timing of the pulse peaks with a standard clock signal; and

an inspection means for inspecting quality of the timing based servo signal based on the measured time interval of the pulse peaks,

wherein a period T [s] of the standard clock signal used in the time interval measuring means and a running speed v [m/s] of the magnetic tape at the servo signal inspecting head satisfy the following relationship: T×v<80 nm.

2. The device according to claim 1 , wherein a track pitch of a data signal to be recorded on the magnetic tape for recording the timing based servo signal is 20 μm or less.

3. The device according to claim 1 , wherein, in order to satisfy the relationship: T×v<80 nm, the device further comprises:

a speed control means for adjusting the running speed by adjusting a tape delivery speed of the servo signal inspecting device; and

a clock control means for adjusting clock frequency of the standard clock signal.

4. A method for inspecting servo signal comprising:

reading a timing based servo signal recorded on a running magnetic tape;

measuring a time interval of pulse peaks detected from the timing based servo signal by comparing timing of the pulse peaks with a standard clock signal;

inspecting quality of the timing based servo signal based on the measured time interval of the pulse peaks,

wherein a period T [s] of the standard clock signal and a running speed v [m/s] of the magnetic tape satisfy the following relationship: T×v<80 nm.

5. The method according to claim 4 , wherein the timing based servo signal recorded on the magnetic tape is written on a servo band magnetized by direct current in one direction along a longer side of the servo band with the servo signal being magnetized in a direction opposite to the direction of the servo band.

6. The method according to claim 5 , wherein the timing based servo signal recorded on the magnetic tape comprises at least one unit comprising two non-parallel pairs of servo pattern sets, each pair independently composed of:

a first servo pattern set being formed across a width of the servo band at an angle from 8 to 20 degrees with respect to the width; and

a second servo pattern set being formed across the width of the servo band in non-parallel with the first servo pattern set.

7. The method according to claim 6 , wherein the width corresponds to a longitudinal running direction of the magnetic tape.

8. The method according to claim 4 , wherein, in order to satisfy the relationship: T×v<80 nm, the method further comprises:

adjusting the running speed by adjusting a tape delivery speed of the servo signal inspecting device; and

adjusting clock frequency of the standard clock signal.

9. A servo signal inspecting device for inspecting quality of a timing based servo signal recorded on a magnetic tape comprising:

a servo signal inspecting head for reading the timing based servo signal recorded on the running magnetic tape;

a peak detecting circuit for detecting pulse peaks from the timing based servo signal;

a time interval measuring circuit for measuring a time interval of the detected pulse peaks by comparing timing of the pulse peaks with a standard clock signal; and

an inspection circuit for inspecting quality of the timing based servo signal based on the measured time interval of the pulse peaks,

wherein a period T [s] of the standard clock signal used in the time interval measuring circuit and a running speed v [m/s] of the magnetic tape at the servo signal inspecting head satisfy: T×v<80 nm.

10. The servo signal inspecting device according to claim 9 , wherein a track pitch of a data signal to be recorded on the magnetic tape for recording the timing based servo signal is 20 μm or less.

11. The servo signal inspecting device according to claim 9 , wherein, in order to satisfy the relationship: T×v<80 nm, the device further comprises:

a speed control circuit which adjusts the running speed by adjusting a tape delivery speed of the servo signal inspecting device; and

a clock control means which adjusts clock frequency of the standard clock signal.