Magnetooptical disk unit capable of recording or reproducing signals having different domain lengths under the same conditions, signal recording method and signal reproducing method

A magnetooptical disk unit recording a recorded signal having a signal of n bits consisting of is and a signal of m bits consisting of 0s arranged in a prescribed system in a magnetooptical recording medium, said magnetooptical disk unit including:

• a magnetic head applying a magnetic field to said magnetooptical recording medium;
• a signal conversion circuit converting each of first to n−1-th 1s forming said signal of n bits to (1,0) having a unit bit length when said n is at least 2, and
• converting each of first to m−1-th 0s forming said signal of m bits to (0,1) having a unit bit length when said m is at least 2;
• and
• a drive signal generation circuit generating a drive signal for driving said magnetic head in response to an output signal from said signal conversion circuit.

A magnetooptical disk unit recording a recorded signal having a signal of n bits consisting of 1s and a signal of m bits consisting of 0s arranged in a prescribed system in a magnetooptical recording medium, said magnetooptical disk unit including:

• a magnetic head applying a magnetic field to said magnetooptical recording medium;
• a detection circuit detecting 1 or 0 from said recorded signal and outputting a first detection signal corresponding to 1 and a second detection signal corresponding to 0;
• a signal conversion circuit converting each of first to n−1-th 1s forming said signal of n bits to (1,0) having a unit bit length when said detection circuit continuously outputs said first detection signal n times (n≧2), and
• converting each of first to n−1-th 0s forming said signal of m bits to (0,1) having a unit bit length when said detection circuit continuously outputs said second detection signal m times (m≧2);
• and
• a drive signal generation circuit generating a drive signal for driving said magnetic head in response to an output signal from said signal conversion circuit.

A magnetooptical disk unit recording a recorded signal having a signal of n bits consisting of 1s and a signal of m bits consisting of 0s arranged in a prescribed system in a magnetooptical recording medium, said magnetooptical disk unit including:

• a magnetic head applying a magnetic field to said magnetooptical recording medium;
• an external synchronizing signal generation circuit generating an external synchronizing signal on the basis of a shape formed on said magnetooptical recording medium;
• a timing signal generation circuit generating a first timing signal synchronous with said external synchronizing signal generated by said external synchronizing signal generation circuit and a second timing signal formed by delaying the phase of said external synchronizing signal by a prescribed cycle;
• a detection circuit detecting 1 or 0 from said recorded signal in synchronization with said first timing signal generated by said timing signal generation circuit and outputting a first detection signal corresponding to 1 and a second detection signal corresponding to 0;
• a signal conversion circuit converting each of first to n−1-th 1s forming said signal of n bits to (1,0) having a unit bit length in synchronization with said second timing signal from said timing signal generation circuit when said detection circuit continuously outputs said first detection signal n times (n≧2), and
• converting each of first to m−1-th 0s forming said signal of m bits to (0,1) having a unit bit length in synchronization with said second timing signal from said timing signal generation circuit when said detection circuit continuously outputs said second detection signal m times (m≧2);
• and
• a drive signal generation circuit generating a drive signal for driving said magnetic head in response to an output signal from said signal conversion circuit.

A magnetooptical disk unit recording a recorded signal having a signal of n bits consisting of 1s and a signal of m bits consisting of 0s arranged in a prescribed system in a magnetooptical recording medium, said magnetooptical disk unit including:

• an optical pickup irradiating said magnetooptical recording medium with a pulse beam;
• a magnetic head applying a magnetic field to said magnetooptical recording medium;
• an external synchronizing signal generation circuit generating an external synchronizing signal on the basis of a shape formed on said magnetooptical recording medium;
• a timing signal generation circuit generating a first timing signal synchronous with said external synchronizing signal generated by said external synchronizing signal generation circuit and a second timing signal formed by delaying the phase of said external synchronizing signal by a prescribed cycle;
• a detection circuit detecting 1 or 0 from said recorded signal in synchronization with said first timing signal generated by said timing signal generation circuit and outputting a first detection signal corresponding to 1 and a second detection signal corresponding to 0;
• a signal conversion circuit converting each of first to n−1-th 1s forming said signal of n bits to (1,0) having a unit bit length in synchronization with said second timing signal from said timing signal generation circuit when said detection circuit continuously outputs said first detection signal n times (n≧2) , and
• converting each of first to m−1-th 0s forming said signal of m bits to (0,1) having a unit bit length in synchronization with said second timing signal from said timing signal generation circuit when said detection circuit continuously outputs said second detection signal m times (m≧2);
• and
• a drive signal generation circuit generating a drive signal for driving said magnetic head in response to an output signal from said signal conversion circuit and generating a second drive signal for emitting said pulse beam from said optical pickup.

A magnetooptical disk unit reproducing a signal from a magnetooptical recording medium recording a recorded signal having a signal of n bits consisting of 1s and a signal of m bits consisting of 0s arranged in a prescribed system

• by converting each of first to n−1-th 1s forming said signal of n bits to (1,0) having a unit bit length when said n is at least 2, and
• converting each of first to m−1-th 0s forming said signal of m bits to (0,1) having a unit bit length when said m is at least 2, said magnetooptical disk unit including:
• a magnetic head applying an alternating magnetic field at least including a magnetic field component along the in-plane direction of said magnetooptical recording medium to said magnetooptical recording medium;
• and
• a drive signal generation circuit generating a drive signal for applying said alternating magnetic field around a boundary between domains formed on said magnetooptical recording medium on the basis of said recorded signal.

A magnetooptical disk unit reproducing a signal from a magnetooptical recording medium recording a recorded signal having a signal of n bits consisting of 1s and a signal of m bits consisting of 0s arranged in a prescribed system

• by converting each of first to n−1-th 1s forming said signal of n bits to (1,0) having a unit bit length when said n is at least 2, and
• converting each of first to m−1-th 0s forming said signal of m bits to (0,1) having a unit bit length when said m is at least 2, said magnetooptical disk unit including:
• a magnetic head applying an alternating magnetic field at least including a magnetic field component along the in-plane direction of said magnetooptical recording medium to said magnetooptical recording medium;
• an external synchronizing signal generation circuit generating an external synchronizing signal on the basis of a shape formed on said magnetooptical recording medium;
• a drive signal generation circuit generating n drive signals for forming said alternating magnetic field varied in phase difference with respect to said external synchronizing signal on the basis of said external synchronizing signal from said external synchronizing signal generation circuit;
• and
• a control circuit deciding an optimum drive signal from a reproduced signal reproduced by said magnetic head by applying said alternating magnetic field to said magnetooptical recording medium on the basis of said n drive signals from said drive signal generation circuit for generating said alternating magnetic field minimizing an error rate of said reproduced signal.

A signal recording method of recording a recorded signal having a signal of n bits consisting of 1s and a signal of m bits consisting of 0s arranged in a prescribed system in a magnetooptical recording medium, including:

• a first step of converting each of first to n−1-th 1s forming said signal of n bits to (1,0) having a unit bit length when said n is at least 2, and
• converting each of first to m−1-th 0s forming said signal of m bits to (0,1) having a unit bit length when said m is at least 2;
• and
• a second step of driving a magnetic head applying a magnetic field to said magnetooptical recording medium on the basis of said recorded signal converted in said first step.

A signal reproducing method of reproducing a signal from a magnetooptical recording medium recording a recorded signal having a signal of n bits consisting of 1s and a signal of m bits consisting of 0s arranged in a prescribed system

• by converting each of first to n−1-th 1s forming said signal of n bits to (1,0) having a unit bit length when said n is at least 2, and
• converting each of first to m−1-th 0s forming said signal of m bits to (0,1) having a unit bit length when said m is at least 2, said signal reproducing method including:
• a first step of generating a drive signal for applying an alternating magnetic field at least including a magnetic field component along the in-plane direction of said magnetooptical recording medium around a boundary between domains formed on said magnetooptical recording medium on the basis of said recorded signal;
• and
• second step of applying said alternating magnetic field to said magnetooptical recording medium on the basis of said drive signal generated in said first step.

A signal reproducing method of reproducing a signal from a magnetooptical recording medium recording a recorded signal having a signal of n bits consisting of 1s and a signal of m bits consisting of 0s arranged in a prescribed system

• by converting each of first to n−1-th 1s forming said signal of n bits to (1,0) having a unit bit length when said n is at least 2, and
• converting each of first to m−1-th 0s forming said signal of m bits to (0,1) having a unit bit length when said m is at least 2, said signal reproducing method including:
• a first step of generating an external synchronizing signal on the basis of a shape formed on said magnetooptical recording medium;
• a second step of generating n drive signals for applying an alternating magnetic field at least including a magnetic field component along the in-plane direction of said magnetooptical recording medium by varying the phase of said external synchronizing signal generated in said first step;
• and
• a third step of deciding an optimum drive signal from a reproduced signal reproduced by said magnetic head by applying said alternating magnetic field to said magnetooptical recording medium on the basis of said n drive signals generated in said second step for generating said alternating magnetic field minimizing an error rate of said reproduced signal,
• for applying said alternating magnetic field to said magnetooptical recording medium on the basis of said optimum drive signal decided in said third step thereby reproducing said signal.

A magnetooptical disk unit reproducing a signal from a magnetooptical recording medium recording a recorded signal having a signal of n bits consisting of 1s and a signal of m bits consisting of 0s arranged in a prescribed system

• by converting each of first to n−1-th 1s forming said signal of n bits (1,0) having a unit bit length when said n is at least 2, and
• converting each of first to m−1-th 0s forming said signal of m bits to (0,1) having a unit bit length when said m is at least 2, said magnetooptical disk unit including:
• a magnetic head applying an alternating magnetic field having a prescribed angle θ with respect to the normal direction of said magnetooptical recording medium to said magnetooptical recording medium;
• a drive signal generation circuit generating a drive signal for applying said alternating magnetic field around a boundary between domains formed on said magnetooptical recording medium on the basis of said recorded signal;
• and
• a magnetic head moving mechanism moving said magnetic head to the track direction of said magnetooptical recording medium so that said angle θ of said alternating magnetic field is in the range of 32 to 46°.