CN1983416B - Distinguishing Method of Data Track Pitch of Optical Disc - Google Patents

Abstract

A method for determining the data track pitch of an optical disc comprises the following steps: using a data phase-locked loop or a speed detection device to measure the data transmission frequency value or the bearing speed value, i.e., the characteristic value, at a predetermined data segment position of an optical disc; querying a characteristic value list; and calculating the optical disc track pitch by using an interpolation method or an approximation method.

Description

Distinguishing Method of Data Track Pitch of Optical Disc

technical field

The invention relates to a discriminative method for disc data track pitch, in particular to a discriminative disc data track pitch discriminative method for measuring disc track pitch by using data transmission frequency value or bearing rotational speed value.

Background technique

In some traditional optical discs, the standard track pitch is reduced to increase the storage capacity of the optical disc, in order to avoid misjudgment by the optical drive or selection of the type of optical disc that cannot be judged. The traditional method of measuring the track pitch of an optical disc is to read a fixed data segment length X for an optical disc with an unknown track pitch (assuming that the track pitch is d), then the read data area A=X·d. On the other hand, if the radius of the starting point of the fixed data segment length X is R _S , and the radius of the end point is R _E , then the area of the ring with the fixed data segment length X can be expressed as the data area $A=\mathrm{\π}(R_{\mathrm{E.}}^2-R_S^2)$ , from the aforementioned two equal areas A, deduce the gauge $d=\mathrm{\π}(R_{\mathrm{E.}}^2-R_S^2)/x$ . However, according to the obtained formula, the disc track distance d must be calculated only after detecting the starting radius R _S and the ending radius _RE . The current method of detecting the radius is to use the disk to rotate one circle, detect the data frame number of the disk to convert the circumference of the circle, and then convert it to the corresponding radius length. The disadvantage of this method is that the radius length is not easy to be accurate and easy to obtain, because the correctness of the data frame number depends on the stability of the entire data decoding of the track. Moreover, the acquisition of the track gauge requires a series of conversions, and the accuracy of each conversion will affect the error degree of the track gauge and the computational complexity. Therefore, how to simplify the measurement of the track pitch of optical discs, making the results more direct and accurate, and at the same time more convenient to obtain, will be what the optical drive industry is eagerly looking forward to.

Contents of the invention

The object of the present invention is to provide a method for judging the data track gauge, by establishing a data transmission frequency data or bearing speed value data, measuring the data transmission frequency value or bearing speed value of the optical disc, and calculating it with interpolation or approximation The data track pitch of the optical disc saves the disadvantage of the prior art that the track pitch needs to be obtained by detecting the starting radius R _S and the ending point radius _RE and converting them.

Another object of the present invention is to provide a method for judging the data track pitch, which measures the bearing rotational speed value of the optical disc at the alignment speed, and calculates the optical disc track pitch in conjunction with the bearing rotational speed value data.

Another object of the present invention is to provide a method for judging the track pitch of data, which measures the data transmission frequency value of the optical disc at a constant angular rate, and calculates the track pitch of the optical disc in conjunction with the data transmission frequency data.

In order to achieve the purpose of the aforementioned invention, a method for judging the track pitch of optical disc data includes the following steps: using the existing data phase-locked loop or rotational speed detection device in the optical drive, under the conditions of fixed angular rate and fixed line rate, measure A data transmission frequency value or a bearing rotational speed value of a predetermined data segment position of the optical disc, that is, an eigenvalue, and then query the relationship data between the eigenvalue and the track pitch, and calculate the track pitch of the optical disc with interpolation or approximation.

Description of drawings

Figures 1a and 1b are schematic diagrams of the track pitch and data area of an optical disc according to the present invention.

FIG. 2 is a data diagram corresponding to track gauge value and data transmission frequency in the first embodiment of the present invention.

Fig. 3 is a flow chart of measuring the track pitch of an optical disc at a constant angular velocity according to the first embodiment of the present invention.

Fig. 4 Corresponding data diagram of gauge value and bearing speed in the second embodiment of the present invention

Fig. 5 is a flow chart of the present invention for measuring the track gauge of an optical disc at a fixed line speed.

Description of reference symbols

1a, 1b disc 11, 16 data segments 12, 17 Data segment start radius 13, 18 data segment end point radius Step 21 Start Step 22 Constant angular rate motion Step 23 Jump to the predetermined data segment x position Step 24 The data phase-locked loop detects the data transmission frequency value Step 25 query data transmission frequency list; Utilize interpolation or approximation method to obtain data gauge end of step 26 Step 31 Start Step 32 Set Line Velocity Movement Step 33 Jump to the predetermined data segment x position Step 34 The speed detection device obtains the bearing speed value Step 35 Query the list of bearing speed values; use interpolation or approximation to obtain the data gauge end of step 36

Detailed ways

In order to achieve the above object, the present invention adopts the technical means and its effects, hereby give preferred embodiments, and illustrate as follows in conjunction with the accompanying drawings.

Please refer to FIG. 1 a , which is a schematic diagram of the track pitch and data area of an optical disc according to the present invention. The track pitch of the optical disc 1a is d1, which contains a data segment 11 of length x (expanded as the data segment 11 of length x in the figure). The starting point radius 12 of the data segment 11 is Rs, which is the data stipulated in the optical disc specification The radius of the inner edge of the area, and the length of the end radius 13 of the data segment 11 is R1, and the data segment 11 forms a data segment area A1. Since the area A1 of the data segment 11 is the length x of the data segment 11 multiplied by the track pitch d1 of the optical disc, that is, A1=x·d1. Simultaneously, if the starting radius length Rs and the end radius length R1 of the data segment 11 of the optical disc are used for calculation, the area A1 of the data segment is π(R1 ² −Rs ² ), that is, the area A1=x·d1=π(R1 ² −Rs ² ), the gauge d1=π(R1 ² −Rs ² )/x is obtained. Similarly, in Fig. 1b, the track pitch of the optical disc 1b is d2, which contains a data segment 16 of length x (expand the data segment 16 of length x in the figure), and the radius 17 of the starting point of the data segment 16 has a length of Rs, namely The radius of the inner edge of the data area stipulated in the optical disc specification, and the length of the radius 18 at the end of the data segment 16 is R2, forming a data segment area A2, and its data segment area A2=x·d2=π(R2 ² −Rs ² ), we get Gauge d2=π(R2 ² −Rs ² )/x.

Therefore, when comparing the optical disc 1a with the optical disc 1b, when the lengths of the data segments 11 and 16 of the two groups of optical discs are the same as x, and the starting radius Rs is the same as the radius of the inner edge of the data area stipulated in the optical disc specification, because the data segment area A1 is (x·d1), the data segment area A2 is (x·d2), if the gauge d1 is greater than the gauge d2, then the data segment area A1 is greater than the data segment area A2, that is, π(R1 ² -Rs ² )>π( R2 ² -Rs ² ). Since the starting radii 12 and 17 of the data segments 11 and 16 have the same length as Rs, R1>R2 is deduced; so two optical discs with different data track gauges have different radii at the same data segment x position, and the optical disc with the larger track gauge corresponds to a larger Radius, a disc with a small track pitch corresponds to a smaller radius.

In the first embodiment of the present invention, the optical drive is used in the constant angular velocity (Constant AngularVelocity, CAV) operating mode, that is, the optical drive rotates the optical disc at the same speed, and the optical disc with a larger track gauge corresponds to the same data segment x position. The longer the radius, the higher the line rate. When the read head of the optical drive reads the optical disc data recording signal, the data phase-locked loop will generate a clock synchronous with the optical disc data recording signal read by the read head. The data recording signal read by the optical drive per unit time represents the arc length of the optical disc read by the optical drive per unit time, and also represents the linear velocity of the optical disc at the read point. The linear velocity can be obtained by measuring the data transmission frequency value at this position. Therefore, the size of its frequency value can reflect the change of line speed. Therefore, using some optical discs with known track pitches, at a predetermined position of the same data segment x, in the constant angular velocity (CAV) mode, the data transmission frequency value can be recorded, as shown in Figure 2, made with a track pitch The value to index the data transfer frequency data.

For an optical disc with an unknown track gauge, by measuring the characteristic value of the x position of the predetermined data segment, that is, the data transmission frequency value F at a constant angular rate, the data corresponding to the track gauge value and the data transmission frequency is used to query the data transmission frequency data, and then cooperate with the internal The gauge size D can be obtained by interpolation or approximation.

Please refer to FIG. 3 , the flow chart of measuring the track gauge of an optical disc at an equiangular velocity in this embodiment, and its steps are described as follows:

Step 21: Start the operation of the optical disc drive;

Step 22: The optical drive moves at a fixed angular rate;

Step 23: The read head jumps to the position x of the data segment scheduled for detection;

Step 24: Utilize the data phase-locked loop to detect the data transmission frequency value of the data segment x position scheduled to be detected; Step 25: Compare the data transmission frequency value obtained in step 24 with a data transmission frequency data, and use interpolation or Approximation method to obtain data gauge; step 26: end

Therefore, the present invention uses a data transmission frequency data established by an optical disc with a known track gauge, and uses the data phase-locked loop of the optical drive to provide a simple identification method without increasing the cost. The interpolation and approximation methods are used to calculate the Disc track pitch. Moreover, the accuracy of the data phase-locked loop is no less than that of detecting the number of disc data frames, but the computational complexity and cost are very low. In the same way, the data of a data transmission frequency established above can also be made into a list of data transmission frequency and track pitch, and the track pitch of the optical disc can be calculated by interpolation and approximation.

The second embodiment of the present invention is to use the constant linear velocity (Constant Liniar Velocity, CLV) operation mode, that is, the optical drive rotates the optical disc at a changing speed, so that each data point of the optical disc has the same linear velocity, then the same At the position x of the data segment, the optical disc with a larger track gauge has a smaller angular velocity, that is, the rotational speed of the optical drive is smaller; and the rotational speed detection device of the optical drive uses electromagnetic induction or the light-and-dark method of the optical path, so that the bearing of the optical drive rotates once and a signal will be emitted. Predetermining a plurality of pulse signals is used to measure the rotation speed of the optical drive bearing to reflect the change of the angular rate. Therefore, as shown in Figure 4, using some optical discs with known track gauges, at a predetermined position x of the same data segment, in the alignment velocity (CLV) mode, record the bearing speed values respectively, and make the track gauge value Indexed bearing speed value data.

For an optical disc with an unknown track gauge, by measuring the characteristic value of the x position of the predetermined data segment, that is, the bearing speed value R at the alignment speed, query the bearing speed value from the data corresponding to the track gauge value and the bearing speed, and then cooperate with the interpolation method or The gauge size D can be obtained by approximate method.

Please refer to Fig. 5, the flow chart of measuring disc track gauge under the equilinear velocity of the present invention, its steps are described as follows:

Step 31: Start the operation of the optical disc drive;

Step 32: The CD-ROM drives at a fixed speed;

Step 33: The read head jumps to the predetermined data segment x position;

Step 34: Use the rotational speed detection device to detect the rotational speed value of the bearing at the predetermined data position, which is equivalent to detecting the angular velocity at this position;

Step 35: comparing the bearing speed value obtained in step 34 with a list of bearing speed values, and obtaining the data gauge by interpolation or approximation;

Step 36: End.

Therefore, this embodiment provides a simple identification method without increasing the cost by utilizing the necessary data phase-locked loop and rotational speed detection device of the optical drive. The accuracy of the data phase-locked loop is no less than that of detecting the number of disc data frames, but the computational complexity and cost are very low. Also, by using a list of bearing rotational speed values established by an optical disc with a known track gauge and measuring the bearing rotational speed of an optical disc with an unknown track gauge, the track gauge of the optical disc can be calculated by an interpolation method and an approximation method. In the face of discs with non-specified gauges, the present invention provides a fast disc judging mechanism, so that the research and development personnel can use this method to improve the performance of this special disc. Therefore, the present invention really possesses the novelty, advancement and industrial applicability required by the invention patent, so the application is filed according to the law.

The above are only preferred embodiments for conveniently illustrating the present invention, and the scope of the present invention is not limited to these preferred embodiments. Any changes made according to the present invention will not depart from the spirit of the present invention. , all belong to the scope of the patent application of the present invention.

Claims (10)

1. A discriminant method for disc data track pitch, comprising the following steps: measuring a characteristic value of a position of a predetermined data segment of an optical disc; Query the relationship data between a feature value and the gauge; and The disc track pitch is calculated in conjunction with an interpolation method or an approximation method. 2. The method for judging the data track pitch of an optical disc according to claim 1, wherein the characteristic value is a data transmission frequency value. 3. The method for judging the data track pitch of an optical disc as claimed in claim 2, wherein the data transmission frequency value is detected by a data phase-locked loop. 4. The discriminative method of a kind of optical disc data track pitch as claimed in claim 2, wherein, the relational data of this characteristic value and track pitch is to utilize the optical disc of known track pitch, at a same predetermined data section position, in fixed In the angular rate mode, record the data transmission frequency value respectively, and make the data transmission frequency data indexed by the gauge value. 5. The method for judging the track pitch of optical disc data according to claim 1, wherein the characteristic value is a rotational speed value of a bearing. 6. The method for judging the track pitch of optical disc data according to claim 5, wherein the rotational speed value of the bearing is detected by a rotational speed detection device. 7. A method for discriminating the track pitch of optical disc data as claimed in claim 5, wherein, the relational data of the feature value and the track pitch is to use an optical disc with a known track pitch, at a same predetermined data segment position, at a fixed In the linear velocity mode, record the bearing speed value separately, and make the bearing speed value data indexed by the track gauge value. 8 . The method for judging the track pitch of optical disc data according to claim 1 , wherein the relationship data between the characteristic value and the track pitch is a list including data corresponding to the track pitch and the data transmission frequency. 9. The method for judging the track pitch of optical disc data according to claim 1, wherein the relationship data between the feature value and the track pitch is a list including data corresponding to the track pitch and the rotational speed value of the bearing. 10. The method for judging the data track pitch of an optical disc according to claim 1, wherein the starting point of the measured position of the predetermined data segment of the optical disc is the inner edge of the data area stipulated in the optical disc specification.

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