1. A method to control an FOD (flying on demand) voltage of a hard disk drive apparatus using a TA (thermal asperity) signal, the method comprising:
providing at least one protrusion having a predetermined height on a disk, moving a magnetic head to a position of the protrusion, and applying an FOD voltage for a test to the magnetic head;
detecting the TA signal generated when the magnetic head touches the protrusion by the applied FOD voltage for a test; and
determining the maximum FOD voltage applied to the magnetic head based on the detected TA signal and determining an FOD voltage to control the FH (flying height) of the magnetic head based on the maximum FOD voltage.
2. The method of claim 1, wherein the at least one protrusion comprises;
one protrusion and the height of the protrusion is lower than the FH of the magnetic head with respect to the disk when the FOD voltage for a test is not applied.
3. The method of claim 1, wherein the at least one protrusion comprises:
two protrusions having predetermined different heights at different positions on a surface of the disk.
4. The method of claim 3, wherein, in the determining of the maximum FOD voltage applied to the magnetic head based on the detected TA signal and the determining of an FOD voltage to control the FH (flying height) of the magnetic head based on the maximum FOD voltage, an FOD voltage applied when the magnetic head touches a first protrusion having a lower height of the two protrusions is used as a first FOD voltage that corresponds to the maximum FOD voltage to control the FH of the magnetic head, and an FOD voltage applied when the magnetic head touches a second protrusion is used as a second FOD voltage to control the FH of the magnetic head, and an FOD voltage to control the FH of the magnetic head is determined based on a relationship between the first and second FOD voltages.
5. The method of claim 1, wherein the at least one protrusion is provided at a remaining area except for a data zone on the surface of the disk.
6. The method of claim 5, wherein the at least one protrusion comprises:
a bump protruding from the surface of the disk by a laser process.
7. The method of claim 6, wherein the at least one protrusion comprises:
a pad formed on the surface of the disk in a lithography method.
8. A computer-readable recording medium having embodied thereon a computer program to execute a method, wherein the method comprises:
providing at least one protrusion having a predetermined height on a disk, moving a magnetic head to a position of the protrusion, and applying an FOD voltage for a test to the magnetic head;
detecting a thermal asperity (TA) signal generated when the magnetic head touches the protrusion by the applied FOD voltage for a test; and
determining the maximum FOD voltage applied to the magnetic head based on the detected TA signal and determining an FOD voltage to control the FH (flying height) of the magnetic head based on the maximum FOD voltage.
9. A hard disk drive apparatus, comprising:
a disk on which at least one protrusion having a predetermined height is provided on a surface thereof;
a magnetic head to record data on the disk or to reproduce the recorded data;
a controller to control moving the magnetic head to a position of the protrusion, to apply an FOD (flying on demand) voltage for a test to the magnetic head, to detect a TA (thermal asperity) signal generated when the magnetic head touches the protrusion by the applied FOD voltage for a test, to determine a maximum FOD voltage applied to the magnetic head based on the detected TA signal, and to determine an FOD voltage to control the FH (flying height) of the magnetic head based on the maximum FOD voltage.
10. The hard disk drive apparatus of claim 9, wherein the at least one protrusion comprises:
one protrusion and the height of the protrusion is lower than the FH of the magnetic head with respect to the disk when the FOD voltage for a test is not applied.
11. The hard disk drive apparatus of claim 9, wherein the at least one protrusion comprises:
two protrusions having predetermined different heights at different positions on the surface of the disk.
12. The hard disk drive apparatus of claim 11, wherein an FOD voltage applied when the magnetic head touches a first protrusion having a lower height of the two protrusions is used as a first FOD voltage that corresponds to the maximum FOD voltage to control the FH of the magnetic head, and an FOD voltage applied when the magnetic head touches a second protrusion is used as a second FOD voltage to control the FH of the magnetic head, and an FOD voltage to control the FH of the magnetic head is determined based on a relationship between the first and second FOD voltages.
13. The hard disk drive apparatus of claim 9, wherein the at least one protrusion is provided at a remaining area except for a data zone on the surface of the disk.
14. The hard disk drive apparatus of claim 13, wherein the at least one protrusion comprises:
a bump protruding from the surface of the disk by a laser process.
15. The hard disk drive of claim 13, wherein the at least one protrusion comprises:
a pad formed on the surface of the disk in a lithography method.
16. A hard disk drive apparatus, comprising:
one or more disks;
a magnetic head to record data to or reproduce data from the one or more disks; and
a controller to actively control a flying height of the magnetic head with respect to a respective disk to increase reliability of at least one of a read operation and a write operation based on a thermal asperity (TA) signal:
wherein the controller controls the flying height of the magnetic head based on the thermal asperity signal by moving the magnetic head to a position of the respective disk and applying an FOD voltage for a test to the magnetic head detecting the TA signal generated when the magnetic head contacts the respective disk by the applied FOD voltage, determining the maximum FOD voltage applied to the magnetic head based on the detected TA signal and determining an FOD voltage to control the FH (flying height) of the magnetic head based on the maximum FOD voltage.
17. The apparatus of claim 16, wherein the respective disk comprises:
a plurality of protrusions in which the FOD voltage can be determined based on the plurality of protrusions.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A game call comprising:
a) a main body forming a resonant chamber having a whistle vent and at least one opening adapted to be closed and opened by finger contact;
b) a mouthpiece at one end of said resonant chamber and in fluid communication therewith;
c) a roller suspended within said resonant chamber and aligned transverse to the longitudinal axis of said mouthpiece, said roller having first and second ends thereof and adapted to freely rotate about its longitudinal axis;
d) a resonant chamber volume adjuster, said volume adjuster is adapted to selectively change the volume of said resonant chamber during use whereby the oscillation rate of said roller may be varied to control the sound emitted by the game call; and
e) a roller support, said roller support comprising a pair of opposed conical sections between which said roller is disposed, said conical sections extend transverse to the longitudinal axis of said resonant chamber and each provided with a shoulder portion configured to receive a separate one of said roller first and second ends.
2. A game call as in claim 1 and wherein said resonant chamber volume adjuster is a piston operatively associated with said resonant chamber and aligned along the longitudinal axis thereof and adapted to be selectively extended therein and retracted therefrom so that said resonant chamber may be correspondingly decreased and increased in volume.
3. A game call as in claim 2 and further including:
a) a resonant chamber extended portion, said resonant chamber extended portion in fluid communication with said resonant chamber and extending transverse to said roller, said piston is operatively associated with said resonant chamber extended portion so that the interior volume thereof may be selectively adjusted in size.
4. A game call as in claim 3 and wherein said mouthpiece and said resonant chamber extended portion are aligned along a common longitudinal axis.
5. A game call as in claim 2 and wherein said piston is provided with a seal for sealing engagement between said resonant chamber and said piston.
6. A game call as in claim 2 and wherein said piston provided with a stop means for limiting the range of motion of said piston.
7. A game call as in claim 1 and wherein said at least one opening adapted to be opened and closed by finger contact comprises a pair of side vents extending from said main body and in fluid communication with said resonant chamber, said roller extends between said pair of side vents and is coaxially aligned therewith.
8. A game call as in claim 1 and wherein said roller contains a ballast material within the interior thereof.
9. A game call comprising:
a) a main body forming a resonant chamber having a whistle vent and at least one opening adapted to be closed and opened by finger contact;
b) a mouthpiece at one end of said resonant chamber and in fluid communication therewith;
c) a roller suspended within said resonant chamber and aligned transverse to the longitudinal axis of said mouthpiece, said roller is adapted to freely rotate about its longitudinal axis and includes an insert formed from a ballast material;
d) a roller support, said roller support adapted to suspend said roller within said resonant chamber wherein said roller support comprises a pair of opposed conical sections between which said roller is disposed, said conical sections extend transverse to the longitudinal axis of said resonant chamber, said roller having first and second ends thereof, each of said conical sections is provided with a shoulder portion configured to receive a separate one of said first and second end of said roller; and
e) a resonant chamber volume adjuster, said volume adjuster is adapted to selectively change the volume of said resonant chamber during use whereby the oscillation rate of said roller may be varied to control the sound emitted by the game call.
10. A game call comprising:
a) a main body forming a resonant chamber and having a whistle vent and a pair of side openings adapted to be closed and opened by finger contact, said pair of side openings coaxially aligned along a central axis;
b) a mouthpiece at one end of said resonant chamber and in fluid communication therewith;
c) a roller member having first and second ends, said roller member disposed within said resonant chamber and coaxially aligned with the central axis of said pair of side openings whereby said roller is suspended within said resonant chamber at each of said first and second end thereof and is adapted to freely rotate about its longitudinal axis as air is blown into said mouthpiece; and
d) a resonant chamber volume adjuster, said volume adjusted is operatively associated with said resonant chamber and located at an opposite end thereof from said mouthpiece, said volume adjuster is adapted to selectively vary the interior volume of said resonant chamber during use whereby the oscillation rate of said roller may be varied to control the sound emitted by the game call wherein each of said pair of side openings provided with a conical section each of which is adapted to receive a separate one of said roller first and second and thereby support said roller in its suspended position and each of said conical sections provided with a shoulder portion configured to receive a separate one of said roller first and second ends.
11. A game call as in claim 10 and wherein said resonant chamber volume adjuster is a piston operatively associated with said resonant chamber and aligned along the longitudinal axis thereof and adapted to be selectively extended therein and retracted therefrom so that said resonant chamber may be correspondingly decreased and increased in volume.
12. A game call as in claim 11 and wherein said resonant chamber including an extended portion, said resonant chamber extended portion in fluid communication with said resonant chamber and extending transverse to said roller, said piston is operatively associated with said resonant chamber extended portion so that the interior volume thereof may be selectively adjusted in size.
13. A game call as in claim 10 and wherein said roller is a tube containing a ballast material.
14. A game call as in claim 10 and wherein said mouthpiece, said resonant chamber and said resonant chamber extended portion are aligned along a common longitudinal axis.
15. A game call as in claim 10 and wherein said roller is a solid rod.