Patent Publication Number: US-7911902-B2

Title: Optical disc, method and apparatus for recording signal thereon

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a recordable optical disc such as a DVD-R (a digital versatile disc recordable) or a DVD-RW (a digital versatile disc rewritable). In addition, this invention relates to a method and an apparatus for recording a signal on an optical disc. Furthermore, this invention relates to a recording method and a recording apparatus designed so that a desired level of the recording power of a light beam scanning an optical disc is decided during test recording and reproduction, and then the light beam power is controlled at the desired level during main-data recording which follows the test recording and reproduction. 
     2. Description of the Related Art 
     There are recordable optical discs designed to be scanned by a light beam at a constant linear velocity (CLV). Typical examples of such recordable optical discs are a CD-R (a compact disc recordable) and a CD-RW (a compact disc rewritable). It is known that a recordable optical disc is driven while being scanned by a light beam at a linear velocity higher than the standard value. 
     In the case of CLV-based drive of an optical disc, the rotational speed of the optical disc is increased as a portion of the optical disc which is currently scanned by a light beam radially moves from the outermost position of the optical disc to the innermost position thereof. 
     As disclosed in Japanese patent application publication number P2001-331940A, in the case of CLV-based drive of an optical disc at a 16-fold linear velocity which means a linear velocity equal to 16 times the standard value, the rotational speed of the optical disc is increased to 8,000 rpm or above when the innermost position of the optical disc is scanned by a light beam. Spontaneous vibration of an optical disc is greater as the rotational speed thereof is higher. Spontaneous vibration of an optical disc is pronounced if the center of gravity of the optical disc is geometrically off-centered. 
     Generally, a recordable optical disc has a power calibration area (PCA) in addition to a data recording area. The power calibration area is also referred to as the test recording area. The power calibration area is located in the innermost portion of the optical disc. The data recording area extends outward of the power calibration area. 
     A conventional CLV drive apparatus for a recordable optical disc is designed to subject a light beam to optimum power control (OPC). The conventional drive apparatus implements test recording and reproduction before main-data recording. During the test recording and reproduction, the conventional drive apparatus records a test signal on the power calibration area of the optical disc and reproduces the test signal therefrom while applying the light beam to the power calibration area. The conventional drive apparatus evaluates the reproduced test signal, and decides a desired level (an optimum level) of the recording power of the light beam on the basis of the evaluation result. During the main-data recording, the conventional drive apparatus carries out the recording of main data on the data recording area of the optical disc while controlling the recording power of the light beam at the desired level (the optimum level). In this way, the OPC is carried out. Since the power calibration area is located in the innermost portion of the optical disc, the rotational speed of the optical disc is relatively high during the test recording and reproduction. In the case of high CLV drive, the rotational speed of the optical disc is very high during the test recording and reproduction. The very-high-speed rotation of the optical disc causes considerably great spontaneous vibration thereof which makes unstable the recording and reproduction of the test signal. As a result of the unstable recording and reproduction of the test signal, the decided level of the desired recording power (the optimum recording power) of the light beam is inaccurate so that the OPC is unreliable. In the case of high CLV drive, when an inner portion of the data recording area of the optical disc is scanned by the light beam during the main-data recording, the rotational speed of the optical disc is relatively high and hence great spontaneous vibration of the optical disc occurs. The great spontaneous vibration of the optical disc causes the formation of pits in the optical disc to be unstable. 
     An on-the-fly writing procedure is designed so that image data is written into a CD-R from a CD-ROM (a compact disc read only memory) without making an image file in a hard disc. According to a known way of implementing the on-the-fly writing procedure at a high speed, image data is reproduced from a CD-ROM while the CD-ROM is scanned by a light beam at a high constant angular velocity (a high CAV), and the reproduced image data is recorded on a CD-R while the CD-R is scanned by a light beam at a high CLV. In this case, when the outermost portion of the data recording area of the CD-ROM is scanned by the light beam, the linear velocity of the CD-ROM relative to the related light beam is equal to about a 32-fold value. On the other hand, when the innermost portion of the data recording area of the CD-ROM is scanned by the light beam, the linear velocity of the CD-ROM relative to the related light beam is equal to about a 16-fold value. Thus, when the innermost portion of the data recording area of the CD-ROM is scanned by the light beam, the image data is reproduced therefrom at an insufficient rate so that buffer under-run tends to occur and hence the writing of the image data into the CD-R tends to be unsuccessful. 
     Japanese patent application P2001-331940A discloses that during the recording of a signal on a CD-R (or a CD-RW), an inner part of the CD-R is scanned by a light beam on a CAV basis while an outer part thereof is scanned by the light beam on a CLV basis. For example, the CAV recording of the signal on the CD-R is started from the innermost position of a program recording area (a data recording area) in the CD-R under conditions where the linear velocity of the innermost position of the program recording area relative to the light beam is equal to a 12-fold value. When the linear velocity of the currently scanned portion of the CD-R relative to the light beam reaches a 16-fold value, the CAV recording is replaced by the CLV recording. Then, the CLV recording which corresponds to a 16-fold linear velocity is continued. The change between the CAV recording and the CLV recording reduces the maximum rotational speed of the CD-R, and hence suppresses spontaneous vibration of the CD-R. In the case of an on-the-fly writing procedure, the suppression of the spontaneous vibration of the CD-R prevents the writing of the signal into the CD-R from being unsuccessful. 
     A drive apparatus for the CD-R which can implement the above-mentioned change between the CAV recording and the CLV recording is explained below. During the CAV recording, the linear velocity of the currently scanned portion of the CD-R relative to the light beam varies in time domain, and the optimum recording power of the light beam varies accordingly. Thus, the drive apparatus carries out test recording and reproduction to decide desired recording powers of the light beam for the initial linear velocity (the minimum linear velocity) and the final linear velocity (the maximum linear velocity) regarding the CAV recording. During the CAV recording which follows the test recording and reproduction, a desired recording power of the light beam is decided on the basis of the linear velocity of the currently scanned portion of the CD-R relative to the light beam through interpolation responsive to the desired recording powers of the light beam for the initial linear velocity and the final linear velocity, and the actual recording power of the light beam is controlled at the desired one. During the CLV recording which follows the CAV recording, the actual recording power of the light beam is controlled at the desired recording power for the final linear velocity. The test recording and reproduction use a power calibration area (PCA) located at the innermost position of the CD-R. Since the power calibration area is located at the innermost position of the CD-R, the CD-R is rotated at a very high speed during a stage of the test recording and reproduction which decides a desired recording power of the light beam for the final linear velocity regarding the CAV recording. The very-high-speed rotation of the CD-R causes problems similar to the previously-mentioned ones. 
     Japanese patent application P2001-331940A discloses a PCA-inner/outer optical disc having a program recording area, an inner power calibration area (an inner test recording area) which extends inward of the program recording area, and an outer power calibration area (an outer test recording area) which extends outward of the program recording area. Japanese patent application P2001-331940A also discloses an optical-disc recorder for a PCA-inner/outer optical disc. The optical-disc recorder in Japanese patent application P2001-331940A implements CAV-based drive of the optical disc when an inner part of the program recording area is scanned by a light beam, and implements CLV-based drive of the optical disc when an outer part of the program recording area is scanned by the light beam. The optical-disc recorder can also implement test recording and reproduction using the inner and outer power calibration areas of the optical disc. Japanese patent application P2001-331940A discloses that examples of the PCA-inner/outer optical disc are a CD-R, a CD-RW, and a DVD-R. 
     In the PCA-inner/outer optical disc of Japanese patent application P2001-331940A, each of the inner and outer power calibration areas has a test area and a count area. During test recording and reproduction, each time the test area is subjected to OPC test recording (that is, each time the test area is loaded with a test signal), an EFM signal having a quantity of one sub-code frame is recorded on the count area. The EFM signals recorded on the count area represent the boundary between a used portion and a usable portion in the test area. Before new OPC is carried out, a detection is given of the position up to which EFM signals have already been recorded in the count area. Then, on the basis of the detected position, a decision is made as to the position from which test recording in the new OPC should be started in the test area. 
     In the case of drive of a DVD-R at a constant linear velocity higher than the standard value, a required rotational speed of the DVD-R is excessively high when an innermost portion of the DVD-R is scanned by a light beam. Accordingly, it is basically undesirable to implement test recording and reproduction using the inner power calibration area of the DVD-R. Thus, in this case, it is desirable to carry out only test recording and reproduction using the outer power calibration. 
     There is a DVD-R which can be driven at a constant linear velocity changeable among a 1-fold value (the standard value), a 2-fold value, a 4-fold value, a 6-fold value, and an 8-fold value. An 8-fold-speed optical-disc recorder drives such a DVD-R at the 8-fold value. In this case, a required rotation speed of the DVD-R is excessively high when an innermost portion of the DVD-R is scanned by a light beam. Accordingly, it is undesirable to implement test recording and reproduction using the inner power calibration area of the DVD-R. Thus, in this case, it is desirable to carry out only test recording and reproduction using the outer power calibration area of the DVD-R. On the other hand, a 2-fold-speed optical-disc recorder drives the DVD-R at the 2-fold value. In this case, a required rotation speed of the DVD-R remains acceptable even when an innermost portion of the DVD-R is scanned by a light beam. Thus, in this case, it is acceptable to carry out test recording and reproduction using both the inner and outer power calibration areas of the DVD-R. As understood from the above explanation, the speed performance of an optical-disc recorder decides whether or not the inner power calibration area of the DVD-R should be used for test recording and reproduction. 
     The sizes of the inner and outer power calibration areas of a DVD-R are finite. Therefore, under some recording conditions, one of the inner and outer power calibration areas has been fully used for test recording and reproduction, and can not be used any more. Especially, in the case of high-speed drive of a DVD-R, the strategy (the recording light waveform) is complicated and the margin for jitter is small so that a wide area is used for test recording and reproduction. Thus, in this case, one of the inner and outer power calibration areas of the DVD-R has been fully used for test recording and reproduction, and only the other can be used for further test recording and reproduction. 
     Generally, it is difficult to equalize the recording characteristics of the inner and outer power calibration areas of a DVD-R. In the case where an organic dye film is formed by spin coat during the fabrication of a DVD-R, a recording film in the outer power calibration area is thicker than that in the inner power calibration area. In the case where a resin layer of a polycarbonate substrate for a DVD-R is formed by injection molding from an inner side gate, it is difficult to make uniform the birefringence characteristics throughout a disc surface. Surface vibration and tilt in the outer power calibration area of a DVD-R are greater than those in the inner power calibration area thereof. The outer power calibration area of a DVD-R tends to scratch and be given fingerprints. Therefore, the physical characteristics of the inner power calibration area of a DVD-R differ from those of the outer power calibration area thereof. Thus, it is difficult to obtain exactly equal results of test recording and reproduction using the inner power calibration area of a DVD-R and test recording and reproduction using the outer power calibration area thereof. 
     There is an 8-fold-speed optical-disc recorder which can operate at either an 8-fold speed or a 4-fold speed during the drive of an optical disc. When surface vibration of the optical disc is great so that control of a spindle motor is unstable or when a recorder temperature exceeds a reference value, the 8-fold-speed optical-disc recorder operates at the 4-fold speed. When surface vibration of the optical disc is small or when the recorder temperature drops below the reference value, the 8-fold-speed optical-disc recorder operates at the 8-fold speed. 
     SUMMARY OF THE INVENTION 
     It is a first object of this invention to provide an improved optical disc having a data recording area, an inner test recording area (an inner power calibration area) which extends inward of the data recording area, and an outer test recording area (an outer power calibration area) which extends outward of the data recording area. 
     It is a second object of this invention to provide a method of recording a signal on an optical disc which can properly control the recording power of a light beam. 
     It is a third object of this invention to provide an apparatus for recording a signal on an optical disc which can properly control the recording power of a light beam. 
     A first aspect of this invention provides an optical disc comprising a data area; a first test recording area extending inward of the data area and having a portion which has undergone test recording; a second test recording area extending outward of the data area and having a portion which has undergone test recording; and a recording information management area including an address information area storing an address of the portion of the first test recording area and an address of the portion of the second test recording area. 
     A second aspect of this invention is based on the first aspect thereof, and provides an optical disc wherein the recording information management area further includes a recording condition information area storing information representing a condition of the test recording the portion of the first test recording area has undergone and information representing a condition of the test recording the portion of the second test recording area has undergone. 
     A third aspect of this invention provides a method of recording a signal on an optical disc having a data area, a first test recording area extending inward of the data area, a second test recording area extending outward of the data area, and a recording information management area. The method comprises the steps of deciding a desired integral multiple of the standard linear velocity; selecting one from the first test recording area and the second test recording area as a selection-result test recording area in response to the decided desired integral multiple of the standard linear velocity; recording a test signal on a portion of the selection-result test recording area while varying a power of the recording of the test signal and scanning the portion of the selection-resultant test recording area at a linear velocity equal to the decided desired integral multiple of the standard linear velocity; reproducing the recorded test signal from the portion of the selection-result test recording area; deciding an optimum recording power for the decided desired integral multiple of the standard linear velocity on the basis of the reproduced test signal; generating address information representing an address of the portion of the selection-resultant test recording area; and recording the generated address information on the recording information management area. 
     A fourth aspect of this invention is based on the third aspect thereof, and provides a method further comprising the steps of generating condition information representing a condition of the recording of the test signal, and recording the generated condition information on the recording information management area. 
     A fifth aspect of this invention provides an apparatus for recording a signal on an optical disc having a data area, a first test recording area extending inward of the data area, a second test recording area extending outward of the data area, and a recording information management area. The apparatus comprises first means for deciding a desired integral multiple of the standard linear velocity; second means for selecting one from the first test recording area and the second test recording area as a selection-result test recording area in response to the desired integral multiple of the standard linear velocity which is decided by the first means; third means for recording a test signal on a portion of the selection-result test recording area while varying a power of the recording of the test signal and scanning the portion of the selection-resultant test recording area at a linear velocity equal to the desired integral multiple of the standard linear velocity; fourth means for reproducing the recorded test signal from the portion of the selection-result test recording area; fifth means for deciding an optimum recording power for the decided desired integral multiple of the standard linear velocity on the basis of the test signal reproduced by the fourth means; sixth means for generating address information representing an address of the portion of the selection-resultant test recording area; and seventh means for recording the address information generated by the sixth means on the recording information management area. 
     A sixth aspect of this invention is based on the fifth aspect thereof, and provides an apparatus further comprising eighth means for generating condition information representing a condition of the recording of the test signal by the third means, and ninth means for recording the condition information generated by the eighth means on the recording information management area. 
     This invention has the following advantages. An optical disc of this invention is scanned by a light beam. The optical disc has a data area, a first test recording area, a second test recording area, and a recording information management area. The first test recording area extends inward of the data area, and has a portion storing a first test signal. The second test recording area extends outward of the data area, and has a portion storing a second test signal. The recording information management area includes an address information area storing an address of the portion of the first test recording area and an address of the portion of the second test recording area. Thus, by referring to the address information, it is possible to manage the address of the portion of the first test recording area which stores the first test signal and the address of the portion of the second test recording area which stores the second test signal. The first test signal and the second test signal are reproduced. It is possible to accurately decide an optimum recording power of the light beam on the basis of each of the reproduced first test signal and the reproduced second test signal. It is possible to record information on the data area at a high quality by using the decided optimum recording power of the light beam. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a sectional view of an optical disc according to a first embodiment of this invention. 
         FIG. 2  is a block diagram of an optical-disc recording apparatus according to a second embodiment of this invention. 
         FIG. 3  is a diagram of the relation among the radial position of a currently scanned portion of an optical disc, the linear velocity at which the optical disc is scanned, and the rotational speed of the optical disc (the rotational speed of a spindle motor). 
         FIG. 4  is a flowchart of an OPC segment of a control program for a system control circuit in  FIG. 2 . 
         FIG. 5  is a diagram of the relation between the recording power of a laser beam and the address of a currently scanned portion of an optical disc. 
         FIG. 6  is a block diagram of an optical-disc recording apparatus according to a third embodiment of this invention. 
         FIG. 7  is a flowchart of an OPC segment of a control program for a system control circuit in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment 
       FIG. 1  shows an optical disc  10  according to a first embodiment of this invention. Preferably, the optical disc  10  is designed to be scanned at a constant linear velocity (CLV). The optical disc  10  may be designed to be scanned at a velocity changed between a CLV-based value and a CAV-based value. Here, CAV is short for constant angular velocity. In general, CAV and CLV are terms referring to the velocity or speed of the scanning of the optical disc  10 , that is, the velocity or speed of the optical disc  10  relative to an applied laser beam. 
     The optical disc  10  has an information area  16  which basically conforms with the known optical disc standards such as the DVD-R (digital versatile disc recordable) standards or the DVD-RW (digital versatile disc rewritable) standards. 
     An inner portion of the information area  16  includes an inner power calibration area (an inner PCA)  12   a . An outer portion of the information area  16  includes an outer power calibration area (an outer PCA)  22 . The inner and outer power calibration areas  12   a  and  22  are also referred to as the inner and outer test recording areas  12   a  and  22 . 
     A portion of the optical disc  10  whose diameter is in the rage of 44 mm to 48 mm is assigned to a lead-in area  12 . The inner PCA  12   a  and a recording management data area (an RMD area)  12   b  constitute the lead-in area  12 . The RMD area  12   b  extends outward of the inner PCA  12   a . The RMD area  12   b  is located in the information area  16 . 
     The inner PCA  12   a  is subjected to test recording and reproduction for optimum power control (OPC). During one test recording and reproduction procedure, a test signal including an 8-16 modulation-resultant signal and having a predetermined quantity such as one frame is recorded on the inner PCA  12   a  twenty six times while the recording power of a light beam is sequentially changed among twenty six different levels. Thus, one test recording and reproduction procedure is composed of twenty six stages each assigned to the once recording of a 1-frame test signal and one recording power level of the laser beam. The inner PCA  12   a  has a capacity corresponding to 100 test recording and reproduction procedures or 2,600 frames. Before a new test recording and reproduction procedure is started, recording address information about the inner PCA  12   a  is read out from the RMD area  12   b . The read-out recording address information is used to detect the boundary within the inner PCA  12   a  between a usable portion and a used portion occupied by test signals recorded by the last and previous test recording and reproduction procedures. The detected boundary is used to decide a position within the inner PCA  12   a  from which the recording of a test signal should be started during the new test recording and reproduction procedure. 
     The information area  16  includes a data area  18  extending outward of the lead-in area  12 . The data area  18  is used to store general data (general information). A possible outermost position  18   e  is given for the data area  18 . The information area  16  further includes a reserved area or a surplus area  20  extending adjacently outward of the possible outermost position  18   e  for the data area  18 . 
     The information area  16  has a track (a pre-groove) extending over the whole thereof. Land pre-pit information (LPP information) is recorded on a wobble of the track as address information. The LPP information represents a value (an address value) indicative of the address of a related position in the optical disc  10 . At the starting position of the data area  18 , that is, at the inner edge of the data area  18 , the address value represented by the LPP information is equal to a predetermined reference value. The address value represented by the LPP information monotonically increases from the predetermined reference value as the related point in the information area  16  moves from the starting position of the data area  18  to the outer edge of the information area  16 . The address value represented by the LPP information monotonically decreases from the predetermined reference value as the related point in the information area  16  moves from the starting position of the data area  18  to the inner edge of the information area  16 . The address value represented by the LPP information may monotonically decrease from the predetermined reference value as the related point in the information area  16  moves from the starting position of the data area  18  to the outer edge of the information area  16 . In this case, the address value represented by the LPP information monotonically increases from the predetermined reference value as the related point in the information area  16  moves from the starting position of the data area  18  to the inner edge of the information area  16 . 
     Preferably, the LPP information contains not only the address information but also recording control information. For example, the recording control information includes at least one among a piece representing integral multiples of the standard linear velocity which are equal to linear velocities at which the optical disc  10  can be driven and scanned, a piece representing a basic optimum recording power (a recommended optimum recording power) of the laser beam, a piece representing a basic optimum erasing power of the laser beam, a piece representing the type of the recording strategy, a piece representing an optimal parameter for the recording strategy, a piece representing the name of the manufacturer of the optical disc  10  (or the name of the manufacturer of a related recording apparatus), a piece representing the ID number of the related recording apparatus, a piece representing the lot number of the related recording apparatus, and a piece representing the serial number of the related recording apparatus. 
     The information area  16  includes a lead-out area  22   a  which is formed immediately after signal recording on the data area  18  is closed, that is, immediately after an actual outer edge of the data area  18  is provided. In the case where the actual outer edge of the data area  18  is near the possible outermost position  18   e  therefor, the lead-out area  22   a  enters the reserved area  20  extending outward of the data area  18 . Preferably, the lead-out area  22   a  has a capacity corresponding to 1.5 frames or more. The reserved area  20  except the lead-out area  22   a  is used as the outer PCA  22 . Preferably, the reserved area  20  has a physical width of about 0.2 mm so that the outer PCA  22  can be surely provided. 
     The optical disc  10  may use a DVD-R, a DVD-RW, or another optical disc formed with a lead-in area  12  and an outer PCA  22 . 
     The outer PCA  22  is subjected to test recording and reproduction for optimum power control (OPC). During one test recording and reproduction procedure, a test signal including an 8-16 modulation-resultant signal and having a predetermined quantity such as one frame is recorded on the outer PCA  22  one hundred and four times while the recording power of a light beam is sequentially changed among twenty six different levels. Thus, one test recording and reproduction procedure is composed of twenty six stages each assigned to the four-times recording of a 1-frame test signal and one recording power level of the laser beam. The outer PCA  22  has a capacity corresponding to 100 test recording and reproduction procedures or 10,400 frames. Before a new test recording and reproduction procedure is started, recording address information about the outer PCA  22  is read out from the RMD area  12   b . The read-out recording address information is used to detect the boundary within the outer PCA  22  between a usable portion and a used portion occupied by test signals recorded by the last and previous test recording and reproduction procedures. The detected boundary is used to decide a position within the outer PCA  22  from which the recording of a test signal should be started during the new test recording and reproduction procedure. 
     The RMD area  12   b  stores at least one of the following information pieces (a), (b), (c), (d), and (e) composing RMD information:
     (a) an information piece representing addresses of a portion of the inner PCA  12   a  which has been used or occupied, and an information piece representing addresses of a portion of the outer PCA  22  which has been used or occupied;   (b) an information piece representing at least one integral multiple of the standard linear velocity which is equal to a linear velocity at which test recording and reproduction have been carried out, an information piece representing the results of the evaluation of a reproduced test signal (for example, an information piece representing a jitter value, an error rate, and a modulation degree of the reproduced test signal);   (c) an information piece representing which of the inner PCA  12   a  and the outer PCA  22  has been used by test recording and reproduction;   (d) an information piece representing recording conditions including at least one optimum recording power of the laser beam, at least one optimum erasing power of the laser beam, the type of the recording strategy (the recording laser beam waveform), at least one optimum parameter for the recording strategy, and the date (year, month, day, and time) of related test recording and reproduction, an information piece representing environmental conditions including a disc temperature, a disc vibration, and a disc surface vibration, and an information piece representing the name of the manufacturer of the optical disc  10 ; and   (e) an information piece representing items of a recording apparatus such as the name of the manufacturer of the recording apparatus, the ID number of the recording apparatus, the lot number of the recording apparatus, and the serial number of the recording apparatus.   

     Preferably, the RMD area  12   b  has an address management section which stores the information piece representing the addresses of the portion of the inner PCA  12   a  which has been used or occupied, and the information piece representing the addresses of the portion of the outer PCA  22  which has been used or occupied. These address-related information pieces can be used for management of the inner PCA  12   a  and the outer PCA  22 . Thus, these address-related information pieces are also referred to as the PCA management information pieces. 
     Preferably, the RMD area  12   b  has a recording condition information area which stores the information piece representing recording conditions including at least one optimum recording power of the laser beam, at least one optimum erasing power of the laser beam, the type of the recording strategy (the recording laser beam waveform), at least one optimum parameter for the recording strategy, and the date (year, month, day, and time) of related test recording and reproduction. 
     Second Embodiment 
       FIG. 2  shows an optical-disc recording apparatus or an optical-disc recording/reproducing apparatus according to a second embodiment of this invention. The optical-disc recording apparatus (the optical-disc recording/reproducing apparatus) can be operated in one selected from various modes including a normal recording mode, a test recording mode, and a reproducing mode or a playback mode. 
     The optical-disc recording apparatus of  FIG. 2  includes a spindle motor  24 , a frequency generator  26 , an optical pickup (an optical head)  28 , an RF amplifier  30 , an address detection circuit  32 , a β detection circuit  34 , a decoder  38 , a servo circuit  40 , a laser driver  42 , an optical power control circuit  44 , an encoder  46 , a strategy circuit  48 , and a system control circuit  50 . 
     The spindle motor  24  serves to rotate the optical disc  10  same as that in  FIG. 1 . The spindle motor  24  is connected with the servo circuit  40 . The frequency generator  26  is associated with the spindle motor  24 . The frequency generator  26  is connected with the servo circuit  40 . The optical pickup  28  serves to apply a laser beam (a light beam) to the optical disc  10 . The optical pickup  28  also serves to receive a laser beam returned from the optical disc  10 . The return laser beam occurs during all the normal recording mode, the test recording mode, and the reproducing mode (the playback mode) of operation of the optical-disc recording apparatus. The optical pickup  28  is connected with the RF amplifier  30 , the servo circuit  40 , and the laser driver  42 . The RF amplifier  30  is connected with the address detection circuit  32 , the β detection circuit  34 , the decoder  38 , and the servo circuit  40 . The address detection circuit  32 , the β detection circuit  34 , and the decoder  38  are connected with the system control circuit  50 . The servo circuit  40  is connected with the system control circuit  50 . The laser driver  42  is connected with the optical power control circuit  44  and the strategy circuit  48 . The optical power control circuit  44  is connected with the system control circuit  50 . The encoder  46  is connected with the strategy circuit  48  and the system control circuit  50 . 
     The optical disc  10  is driven and rotated by the spindle motor  24 . The rotational speed of the shaft of the spindle motor  24 , that is, the rotational speed of the optical disc  10 , is detected by the frequency generator  26 . The frequency generator  26  feeds the servo circuit  40  with a signal representing the detected rotational speed (the actual rotational speed) of the optical disc  10 . 
     During all the normal recording mode, the test recording mode, and the reproducing mode (the playback mode) of operation of the optical-disc recording apparatus, the optical pickup  28  applies the laser beam to the optical disc  10 . The applied laser beam can return from the optical disc  10  to the optical pickup  28 . The return laser beam includes the wobble signal and the LPP information. The optical pickup  28  converts the return laser beam into the corresponding electric signal which includes the wobble signal and the LPP information. The LPP information is propagated from the optical pickup  28  to the system control circuit  50  through the RF amplifier  30  and the address detection circuit  32 . The wobble signal can be propagated from the optical pickup  28  to the servo circuit  40  through the RF amplifier  30 . 
     During the recording of information (data) on the optical disc  10 , the optical pickup  29  modulates the laser beam in accordance with the information, and the optical disc  10  is scanned by the resultant laser beam. 
     During the reproduction of information (data) from the optical disc  10 , the laser beam applied from the optical pickup  28  scans the optical disc  10 , and the optical pickup  28  receives a return laser beam from the optical disc  10  which carries the information recorded on the optical disc  10 . The optical pickup  28  converts the return laser beam into a corresponding reproduced electric signal containing an 8-16 modulation-resultant signal representative of the reproduced information same as the information recorded on the optical disc  10 . The optical pickup  28  feeds the reproduced signal (the reproduced electric signal or the reproduced 8-16 modulation-resultant signal) to the RF amplifier  30 . The RF amplifier  30  passes the reproduced signal (the reproduced 8-16 modulation-resultant signal) to the address detection circuit  32 , the β detection circuit  34 , and the servo circuit  40  while amplifying the reproduced electric signal. The address detection circuit  32  extracts wobble signal components from the reproduced signal, and decodes the extracted wobble signal components into LPP information. The LPP information contains not only information representative of the addresses of different positions on the optical disc  10  but also recording control information. The address detection circuit  32  feeds the LPP information to the system control circuit  50 . Basically, the LPP information currently fed from the address detection circuit  32  to the system control circuit  50  represents the position (the address) of the currently scanned portion of the optical disc  10 . 
     The recording control information is previously recorded on the optical disc  10 . Generally, the recording control information is represented by land pre-pits in the optical disc  10 . The recording control information may be represented by pits in the lead-in area  12  of the optical disc  10 . Preferably, the recording control information includes at least one among a piece representing integral multiples of the standard linear velocity which are equal to linear velocities at which the optical disc  10  can be driven and scanned, a piece representing a basic optimum recording power (a recommended optimum recording power) of the laser beam, a piece representing a basic optimum erasing power of the laser beam, a piece representing the type of the recording strategy, a piece representing an optimal parameter for the recording strategy, a piece representing the name of the manufacturer of the optical disc  10  (or the name of the manufacturer of a related recording apparatus), a piece representing the ID number of the related recording apparatus, a piece representing the lot number of the related recording apparatus, and a piece representing the serial number of the related recording apparatus. 
     The β detection circuit  34  computes a β value, that is, an asymmetry value, from the reproduced 8-16 modulation-resultant signal (the reproduced signal). The β value (the asymmetry value) is a parameter relating to the quality of the reproduced signal. The β value (the asymmetry value) is denoted by a position of a 3T signal in the reproduced 8-16 modulation-resultant signal which corresponds to the shortest mark, where T denotes a channel period. The β detection circuit  34  feeds the system control circuit  50  with a signal representing the computed β value. 
     For example, a 3T signal and a 11T signal are recorded on the optical disc  10  as an 8-16 modulation-resultant signal. In this case, a β value (an asymmetry value) can be computed from the conditions of the reproduced 3T signal or the reproduced 11T signal. 
     Under the control by the system control circuit  50 , the decoder  38  demodulates and decodes the reproduced 8-16 modulation-resultant signal into original data called reproduced data. The decoder  38  outputs the reproduced data to an external device (not shown) and also the system control circuit  50 . The function of the decoder  38  is inverse with respect to that of the encoder  46 . 
     Under the control by the system control circuit  50 , the servo circuit  40  controls the rotation of the spindle motor  24 . Under the control by the system control circuit  50 , the servo circuit  40  drives the optical pickup  28  to implement focusing control, tracking control, and feeding control of the laser beam with respect to the optical disc  10 . Here, “feeding control” means control of the radial position of the laser beam relative to the optical disc  10 . Preferably, the control of the rotation of the spindle motor  24  accords with CLV control. 
     It should be noted that the control of the rotation of the spindle motor  24  may be changed between CAV control and CLV control in accordance with the radial position of the currently scanned portion of the optical disc  10 . For example, the system control circuit  50  detects the radial position of the currently scanned portion of the optical disc  10  in response to the LPP signal fed from the address generation circuit  32 . The system control circuit  50  decides whether the detected radial position of the currently scanned portion of the optical disc  10  is in a predetermined inner range or a predetermined outer range. For example, the predetermined inner range extends inward of the inner PCA  12   a  in the optical disc  10 . The system control circuit  50  generates a control change signal in accordance with the result of the decision. The system control circuit  50  feeds the control change signal to the servo circuit  40 . The servo circuit  40  changes the control of the rotation of the spindle motor  24  between the CAV control and the CLV control in response to the control change signal. The CAV control is carried out when the radial position of the currently scanned portion of the optical disc  10  is decided to be in the predetermined inner range. The CLV control is carried out when the radial position of the currently scanned portion of the optical disc  10  is decided to be in the predetermined outer range. 
     Specifically, the CAV control is implemented as follows. The system control circuit  50  notifies the servo circuit  40  of a setting rotational speed (a desired rotational speed) of the optical disc  10 . The frequency generator  26  notifies the servo circuit  40  of the actual rotational speed of the optical disc  10 . The servo circuit  40  drives the spindle motor  24  in response to the desired rotational speed and the actual rotation speed to equalize the actual rotational speed to the desired rotational speed. 
     Specifically, the CLV control is implemented as follows. The system control circuit  50  notifies the servo circuit  40  of a setting integral multiple (a desired integral multiple) of the standard linear velocity at which the optical disc  10  is scanned by the laser beam. The servo circuit  40  detects a wobble signal in the reproduced 8-16 modulation-resultant signal. The servo circuit  40  drives the spindle motor  24  in response to the desired integral multiple of the standard linear velocity and the detected wobble signal to harmonize the detected wobble signal with the desired integral multiple of the standard linear velocity. 
     Preferably, the CLV control is continuously implemented regardless of whether the radial position of the currently scanned portion of the optical disc  10  is in the predetermined inner range or the predetermined outer range. 
     The optical pickup  28  contains a laser for generating the laser beam. The laser driver  42  drives the laser in the optical pickup  28  while being controlled by the optical power control circuit  44 . The system control circuit  50  feeds the optical power control circuit  44  with optical power control information. During the normal recording mode, the test recording mode, and the reproducing mode of operation of the optical-disc recording apparatus, the optical power control circuit  44  adjusts the laser driver  42  in response to the optical power control information to properly control the power of the laser beam applied to the optical disc  10 . 
     During the normal recording mode of operation of the optical-disc recording apparatus, the encoder  46  receives input data (data to be recorded). Under the control by the system control circuit  50 , the encoder  46  subjects the input data to 8-16 modulation to get 8-16 modulation-resultant data. The encoder  46  outputs the 8-16 modulation-resultant data to the strategy circuit  48 . The function of the encoder  46  is inverse with respect to that of the decoder  38 . The strategy circuit  48  subjects the 8-16 modulation-resultant data to time base correction to get correction-resultant data. The strategy circuit  48  outputs the correction-resultant data to the laser driver  42 . The laser driver  42  generates a laser drive signal, and feeds the laser drive signal to the laser in the optical pickup  28  so that the laser will be actuated in response to the laser drive signal. The laser driver  42  modulates the laser drive signal in accordance with the correction-resultant data. Thus, the laser beam applied to the optical disc  10  is modulated in accordance with the correction-resultant data. The data area  18  in the optical disc  10  is scanned by the laser beam inclusive of the correction-resultant data. As a result, the correction-resultant data (the input data) is recoded on the data area  18  in the optical disc  10 . 
     During the test recording mode of operation of the optical-disc recording apparatus, the system control circuit  50  generates a basic test signal, and outputs the generated basic test signal to the encoder  46 . Under the control by the system control circuit  50 , the encoder  46  subjects the basic test signal to 8-16 modulation to get an 8-16 modulation-resultant test signal. The encoder  46  outputs the 8-16 modulation-resultant test signal to the strategy circuit  48 . The strategy circuit  48  subjects the 8-16 modulation-resultant test signal to time base correction to get a correction-resultant test signal. The strategy circuit  48  outputs the correction-resultant test signal to the laser driver  42 . The laser driver  42  generates a laser drive signal, and feeds the laser drive signal to the laser in the optical pickup  28  so that the laser will be actuated in response to the laser drive signal. The laser driver  42  modulates the laser drive signal in accordance with the correction-resultant test signal. Thus, the laser beam applied to the optical disc  10  is modulated in accordance with the correction-resultant test signal. The inner PCA  12   a  or the outer PCA  22  in the optical disc  10  is scanned by the laser beam inclusive of the correction-resultant test signal. As a result, the correction-resultant test signal is recoded on the inner PCA  12   a  or the outer PCA  22  in the optical disc  10 . 
     During the recording of the correction-resultant test signal on the inner PCA  12   a  or the outer PCA  22  in the optical disc  10 , the system control circuit  50  adjusts the optical power control circuit  44  so that the recording power of the laser beam applied to the optical disc  10  will be varied stepwise among different levels (for example, 26 different levels) each assigned to one frame. Thus, the recorded test signal has segments which correspond to the different recording power levels respectively. 
     During the test recording mode of operation of the optical-disc recording apparatus, the optical pickup  28  reproduces the recorded test signal from the inner PCA  12   a  or the outer PCA  22  in the optical disc  10 . The reproduced test signal is sent from the optical pickup  28  to the β detection circuit  34  via the RF amplifier  30 . The β detection circuit  34  computes a β value, that is, an asymmetry value, from the reproduced test signal for each of the different recording power levels. The computed β values for the respective recording power levels are the results of the evaluation of the reproduced test signal or the parameters relating to the quality of the reproduced test signal. The β detection circuit  34  notifies the system control circuit  50  of the computed β values for the respective recording power levels. 
     During the reproducing mode of operation of the optical-disc recording apparatus, the optical power control circuit  44  adjusts the laser driver  42  to control the power of the laser beam at a desired level represented by the optical power control information fed from the system control circuit  50 . 
     The system control circuit  50  includes a CPU having a combination of an input/output port, a processing section, a ROM, and a RAM. The system control circuit  50  (the CPU) operates in accordance with a control program stored in the ROM. The control program is designed to enable the system control circuit  50  to implement the previously-mentioned operation steps and also later-mentioned operation steps. 
     The system control circuit  50  can adjust the radial position of the optical pickup  30  relative to the optical disc  10  through the servo circuit  32 . Therefore, the system control circuit  50  can operate to move the laser beam radially with respect to the optical disc  10 . The system control circuit  50  detects the position of the currently scanned portion of the optical disc  10  from the LPP information given by the address detection circuit  32 . The system control circuit  50  can implement feedback control for moving the optical pickup  28  or the laser beam to a desired position relative to the optical disc  10  while referring to the detected position of the currently scanned portion of the optical disc  10 . 
     When the optical-disc recording apparatus operates in the normal recording mode, information or data is recorded on the data area  18  (see  FIG. 1 ) in the optical disc  10 . During the recording of information on the data area  18 , the rotation of the optical disc  10  is controlled on a CLV basis. Specifically, the CLV control is implemented as follows. The system control circuit  50  notifies the servo circuit  40  of a setting integral multiple (a desired integral multiple) of the standard linear velocity at which the optical disc  10  is scanned by the laser beam. The servo circuit  40  detects a wobble signal in the reproduced 8-16 modulation-resultant signal. The servo circuit  40  drives the spindle motor  24  in response to the desired integral multiple of the standard linear velocity and the detected wobble signal to harmonize the detected wobble signal with the desired integral multiple of the standard linear velocity. 
     As shown in  FIG. 3 , there is a predetermined reference position RP for the radial position of the currently scanned portion of the optical disc  10 . The predetermined reference position RP exists in the data area  18  of the optical disc  10 . When the radial position of the currently scanned portion of the optical disc  10  coincides with the inner circumferential edge of the data area  18 , the linear velocity of the optical disc  10  relative to the laser beam is controlled at a 6-fold value which means a linear velocity equal to 6 times the standard value. When the radial position of the currently scanned portion of the optical disc  10  is between the inner circumferential edge of the data area  18  and the predetermined reference position RP, the linear velocity of the optical disc  10  relative to the laser beam remains controlled at the 6-fold value. In this case, the rotational speed of the optical disc  10  (the rotational speed of the spindle motor  24 ) is monotonically decreased as the radial position of the currently scanned portion of the optical disc  10  moves from the inner circumferential edge of the data area  18  to the predetermined reference position RP. When the radial position of the currently scanned portion of the optical disc  10  reaches the predetermined reference position RP, the linear velocity of the optical disc  10  relative to the laser beam is increased from the 6-fold value to an 8-fold value and is then controlled at the 8-fold value. At the same time, the rotational speed of the optical disc  10  (the rotational speed of the spindle motor  24 ) is increased accordingly. When the radial position of the currently scanned portion of the optical disc  10  is between the predetermined reference position RP and the outer circumferential edge of the lead-out area  22   a , the linear velocity of the optical disc  10  relative to the laser beam remains controlled at the 8-fold value. In this case, the rotational speed of the optical disc  10  (the rotational speed of the spindle motor  24 ) is monotonically decreased as the radial position of the currently scanned portion of the optical disc  10  moves from the predetermined reference position RP to the outer circumferential edge of the lead-out area  22   a.    
     Before test recording and reproduction is carried out, the LPP information is reproduced from the optical disc  10 . The recording control information which includes a piece representing the basic optimum recording power (the recommended optimum recording power) of the laser beam is derived from the reproduced LPP information. The basic optimum recording power of the laser beam is used by test recording and reproduction as an initial value for a final optimum recording power of the laser beam. During test recording and reproduction, the initial optimum recording power value is referred to, and optimum levels (final optimum levels) of the recording power of the laser beam applied to the optical disc  10  are decided for the 6-fold linear velocity and the 8-fold linear velocity, respectively. During the normal recording mode of operation of the optical-disc recording apparatus which follows the test recording and reproduction, or during next test recording and reproduction, the actual recording power of the laser beam is controlled as follows. When the optical disc  10  is scanned by the laser beam at the 6-fold linear velocity, the actual recording power of the laser beam is controlled at the optimum level for the 6-fold linear velocity. When the optical disc  10  is scanned by the laser beam at the 8-fold linear velocity, the actual recording power of the laser beam is controlled at the optimum level for the 8-fold linear velocity. 
     The optical-disc recording apparatus is of a stationary type or a portable type. Preferably, the optical-disc recording apparatus of the stationary type is designed to implement CLV control which can be changed between a 6-fold speed state and an 8-fold speed state as previously mentioned. 
     Preferably, the optical-disc recording apparatus of the portable type is designed to implement CLV control continuously fixed at a 4-fold speed state. In this case, as shown in  FIG. 3 , the linear velocity of the optical disc  10  relative to the laser beam remains controlled at a 4-fold value independent of the radial position of the currently scanned portion of the optical disc  10 . On the other hand, the rotational speed of the optical disc  10  (the rotational speed of the spindle motor  24 ) is monotonically decreased as the radial position of the currently scanned portion of the optical disc  10  moves from the inner circumferential edge of the data area  18  to the outer circumferential edge of the lead-out area  22   a . The 4-fold linear velocity is advantageous over the 6-fold linear velocity and the 8-fold linear velocity in reducing the size of the spindle motor  24  or decreasing the rate of the heat generation from the spindle motor  24 . 
     In the case where the optical-disc recording apparatus implements CLV recording at an 8-fold speed, the rotational speed of the optical disc  10  exceeds 10,000 rpm and reaches an unduly great value when the inner PCA  12   a  in the optical disc  10  is scanned. Thus, it is preferable that during the CLV recording at the 8-fold speed, test recording and reproduction are carried out by using the outer PCA  22  in the optical disc  10 . The values of the optimum recording power of the laser beam are decided on the basis of the results of the evaluation of the reproduced test signals in the test recording and reproduction. In the case where the optical-disc recording apparatus implements CLV recording at a 6-fold speed, it is preferable that test recording and reproduction are carried out by using the inner PCA  12   a  or the outer PCA  22  in the optical disc  10 . The values of the optimum recording power of the laser beam are decided on the basis of the results of the evaluation of the reproduced test signals in the test recording and reproduction. Generally, the outer PCA  22  is lower in reliability than the inner PCA  12   a . Therefore, it is preferable to use only the inner PCA  12   a  for the test recording and reproduction during the CLV recording at the 6-fold speed. 
     In the case where the optical-disc recording apparatus implements CLV recording at a 4-fold speed, it is preferable that test recording and reproduction are carried out by using the inner PCA  12   a  or the outer PCA  22  in the optical disc  10 . The values of the optimum recording power of the laser beam are decided on the basis of the results of the evaluation of the reproduced test signals in the test recording and reproduction. Since the outer PCA  22  is lower in reliability than the inner PCA  12   a  as previously mentioned, it is preferable to use only the inner PCA  12   a  for the test recording and reproduction. The inner PCA  12   a  has a limited capacity, and hence there occur conditions where the inner PCA  12   a  is fully used or occupied. When the inner PCA  12   a  falls into a fully-used state, further test recording and reproduction are carried out by using the outer PCA  22 . The values of the optimum recording power of the laser beam are decided on the basis of the results of the evaluation of the reproduced test signals in the test recording and reproduction. 
     The optical-disc recording apparatus generates an information piece representing at least one optimum recording power of the laser beam, an information piece representing which of the inner PCA  12   a  and the outer PCA  22  has been used by test recording and reproduction to decide the optimum recording power of the laser beam, an information piece representing at least one integral multiple of the standard linear velocity which is equal to a linear velocity at which test recording and reproduction have been carried out, an information piece representing addresses of a portion of the inner PCA  12   a  which has been used or occupied, and an information piece representing addresses of a portion of the outer PCA  22  which has been used or occupied. The optical-disc recording apparatus records the generated information pieces on the RMD area  12   b  in the optical disc  10  as portions of RMD information. 
     Preferably, the information piece representing the addresses of the portion of the inner PCA  12   a  which has been used or occupied, and the information piece representing the addresses of the portion of the outer PCA  22  which has been used or occupied are assigned to the address management section in the RMD area  12   b.    
     In addition, the optical-disc recording apparatus generates an information piece representing the name of the manufacturer of the apparatus, the ID number of the apparatus, the lot number of the apparatus, and the serial number of the apparatus. The optical-disc recording apparatus records the generated information piece on the RMD area  12   b  in the optical disc  10  as a portion of RMD information. 
     Generally, the normal recording mode of operation of the optical-disc recording apparatus is preceded by the test recording mode of operation thereof in which test recording and reproduction is carried out for OPC. During the test recording and reproduction for OPC, the optical-disc recording apparatus reproduces RMD information from the RMD area  12   b  in the optical disc  10 , and decides whether or not usable portions exist in both the inner PCA  12   a  and the outer PCA  22  on the basis of the reproduced RMD information. When it is decided that usable portions exist in both the inner PCA  12   a  and the outer PCA  22 , the optical-disc recording apparatus carries out a first main stage of the test recording and reproduction by using the inner PCA  12   a  to decide an optimum laser-beam recording power value P6× for a 6-fold linear velocity. Then, the optical-disc recording apparatus carries out a second main stage of the test recording and reproduction by using the outer PCA  22  to decide an optimum laser-beam recording power value P8× for an 8-fold linear velocity. It should be noted that the decision of the optimum laser-beam recording power value P8× for the 8-fold linear velocity may be prior to the decision of the optimum laser-beam recording power value P6× for the 6-fold linear velocity. 
     Steps of basic operation of the optical-disc recording apparatus are as follows.
     (1) The optical-disc recording apparatus reproduces, from the address management section in the RMD area  12   b  of the optical disc  10 , the information piece representing the addresses of the portion of the inner PCA  12   a  which has been used or occupied and also the information piece representing the addresses of the portion of the outer PCA  22  which has been used or occupied. The optical-disc recording apparatus detects which of the inner PCA  12   a  and the outer PCA  22  has been used on the basis of the reproduced address-related information pieces (the reproduced PCA management information pieces). The optical-disc recording apparatus may reproduce, from the RMD area  12   b  of the optical disc  10 , the information piece representing which of the inner PCA  12   a  and the outer PCA  22  has been used by test recording and reproduction. In this case, the optical-disc recording apparatus detects which of the inner PCA  12   a  and the outer PCA  22  has been used by referring to the reproduced information piece.   (2) The optical-disc recording apparatus decides whether or not the address-related information pieces for both the inner PCA  12   a  and the outer PCA  22  are absent from the RMD area  12   b . When it is decided that the address-related information pieces for both the inner PCA  12   a  and the outer PCA  22  are absent from the RMD area  12   b , the optical-disc recording apparatus selects desired one from the inner PCA  12   a  and the outer PCA  22 . Then, the optical-disc recording apparatus carries out test recording and reproduction by using the desired PCA, and subsequently records RMD information pieces (corresponding to the previously-mentioned ones) about the test recording and reproduction on the RMD area  12   b.      (3A) The optical-disc recording apparatus decides whether or not the address-related information pieces for both the inner PCA  12   a  and the outer PCA  22  are present in the RMD area  12   b . In the case where it is decided that the address-related information pieces for both the inner PCA  12   a  and the outer PCA  22  are present in the RMD area  12   b , the optical-disc recording apparatus further decides whether or not new test recording and reproduction for a low linear velocity (a 6-fold linear velocity) should be carried out by using the inner PCA  12   a . When the result of the decision is positive, the optical-disc recording apparatus carries out the low-velocity test recording and reproduction by using the inner PCA  12   a . Subsequently, the optical-disc recording apparatus records RMD information pieces (corresponding to the previously-mentioned ones) about the low-velocity test recording and reproduction on the RMD area  12   b.      (3B) In the case where it is decided that the address-related information pieces for both the inner PCA  12   a  and the outer PCA  22  are present in the RMD area  12   b , the optical-disc recording apparatus further decides whether or not new test recording and reproduction for a high linear velocity (an 8-fold linear velocity) should be carried out by using the outer PCA  22 . When the result of the decision is positive, the optical-disc recording apparatus carries out the high-velocity test recording and reproduction by using the outer PCA  22 . Subsequently, the optical-disc recording apparatus records RMD information pieces (corresponding to the previously-mentioned ones) about the high-velocity test recording and reproduction on the RMD area  12   b.      (3C) In the case where it is decided that the address-related information pieces for both the inner PCA  12   a  and the outer PCA  22  are present in the RMD area  12   b , the optical-disc recording apparatus reproduces, from the RMD area  12   b , the RMD information including the information piece representing at least one integral multiple of the standard linear velocity which is equal to a linear velocity at which test recording and reproduction have been carried out. Then, the optical-disc recording apparatus decides whether the integral multiple of the standard linear velocity which is represented by the reproduced RMD information is necessary or unnecessary to the apparatus. When it is decided that the integral multiple of the standard linear velocity is unnecessary, the optical-disc recording apparatus carries out new test recording and reproduction at a linear velocity equal to a necessary integral multiple of the standard linear velocity by using one of the inner PCA  12   a  and the outer PCA  22 . Subsequently, the optical-disc recording apparatus records RMD information pieces (corresponding to the previously-mentioned ones) about the new test recording and reproduction on the RMD area  12   b.      (3D) In the case where it is decided that the address-related information pieces for both the inner PCA  12   a  and the outer PCA  22  are present in the RMD area  12   b , the optical-disc recording apparatus further decides whether or not the inner PCA  12   a  has been fully used on the basis of the address-related information piece for the inner PCA  12   a . When it is decided that the inner PCA  12   a  has been fully used, the optical-disc recording apparatus carries out test recording and reproduction under changed recording conditions by using the outer PCA  22 . Subsequently, the optical-disc recording apparatus records RMD information pieces (corresponding to the previously-mentioned ones) about the test recording and reproduction on the RMD area  12   b.      (4) The optical-disc recording apparatus reproduces the RMD information from the RMD area  12   b  in the optical disc  10 . Then, the optical-disc recording apparatus decides whether the reproduced RMD information is effective or ineffective. When it is decided that the reproduced RMD information is effective, the optical-disc recording apparatus detects the recording conditions such as the optimum recording power or powers of the laser beam from the reproduced RMD information.   

     As explained above, one of the inner PCA  12   a  and the outer PCA  22  is adaptively and selectively used for test recording and reproduction on the basis of the address-related information pieces reproduced from the RMD area  12   b . Thereby, the test recording and reproduction can decide at least one optimum recording power of the laser beam. 
     As previously mentioned, the system control circuit  50  (the CPU) operates in accordance with the control program stored in the internal ROM. The control program has a routine or a segment for OPC. 
       FIG. 4  is a flowchart of the OPC segment of the control program. With reference to  FIG. 4 , a first step S 1  of the program segment sets an initial integral multiple of the standard linear velocity to a value corresponding to a 6-fold linear velocity. In addition, the step S 1  sets a final integral multiple of the standard linear velocity to a value corresponding to an 8-fold linear velocity. 
     A step S 2  following the step S 1  controls the servo circuit  40  in response to the LPP information to move the optical pickup  28  to a position corresponding to the RMD area  12   b  in the lead-in area  12  of the optical disc  10 . The step S 2  adjusts the optical pickup  28  via the servo circuit  40  so that the RMD area  12   b  will be scanned by the laser beam, and the RMD information including the PCA management information pieces (the address-related information pieces) will be reproduced therefrom. The reproduced PCA management information pieces are sent from the optical pickup  28  to the system control circuit  50  via the RF amplifier  30  and the decoder  38 . The step S 2  detects the boundary within the inner PCA  12   a  between a usable portion and a used portion from the reproduced PCA management information pieces. On the basis of the detected boundary, the step S 2  decides a position within the inner PCA  12   a  from which the recording of a test signal should be started during the present test recording and reproduction. The decided position is referred to as the test-recording start position. 
     A step S 3  subsequent to the step S 2  controls the servo circuit  40  in response to the LPP information to move the optical pickup  28  to a position corresponding to the test-recording start position within the inner PCA  12   a . The step S 3  notifies the servo circuit  40  of the initial integral multiple of the standard linear velocity (the 6-fold linear velocity) at which the optical disc  10  is scanned by the laser beam. The step S 3  controls the servo circuit  40  to detect a wobble signal in the reproduced 8-16 modulation-resultant signal, and to drive the spindle motor  24  in response to the initial integral multiple of the standard linear velocity and the detected wobble signal to harmonize the detected wobble signal with the initial integral multiple of the standard linear velocity. Thus, the step S 3  controls the actual linear velocity at the initial integral multiple of the standard linear velocity. The step S 3  starts recording a test signal on the inner PCA  12   a  from the test-recording start position while holding the optical disc  10  scanned by the laser beam at a linear velocity equal to the initial integral multiple of the standard linear velocity (the 6-fold linear velocity). 
     Specifically, the step S 3  generates a basic test signal. The step S 3  outputs the basic test signal to the encoder  46 . The encoder  46  converts the basic test signal into an 8-16 modulation-resultant test signal. The 8-16 modulation-resultant test signal is sent from the encoder  46  to the laser driver  42  via the strategy circuit  48  before being recorded on the inner PCA  12   a  only once. During the recording of the 8-16 modulation-resultant test signal on the inner PCA  12   a , the step S 3  adjusts the optical power control circuit  44  to vary the recording power of the laser beam among different levels (for example, 26 different levels) on a stepwise basis. Each of the different levels is assigned to one frame. Thus, the recorded test signal has 1-frame segments which correspond to the different recording power levels respectively. For example, as shown in  FIG. 5 , the recording power of the laser beam is varied stepwise from the maximum level to the minimum level through the intermediate levels. Since the address of the currently scanned portion of the optical disc  10  is updated and incremented (or decremented) in accordance with the lapse of time, the recording power of the laser beam is varied as a function of the address in  FIG. 5 . It should be noted that the recording power of the laser beam may be varied stepwise from the minimum level to the maximum level through the intermediate levels. 
     A step S 4  following the step S 3  controls the servo circuit  40  in response to the LPP information to return the optical pickup  28  to a position corresponding to the test-recording start position within the inner PCA  12   a . The step S 4  adjusts the optical pickup  28  via the servo circuit  40  so that a related portion of the inner PCA  12   a  will be scanned by the laser beam, and the latest recorded 8-16 modulation-resultant test signal will be reproduced therefrom. The reproduced 8-16 modulation-resultant test signal is sent from the optical pickup  28  to the β detection circuit  34  through the RF amplifier  30 . The β detection circuit  34  computes a β value, that is, an asymmetry value, from the reproduced 8-16 modulation-resultant test signal for each of the different recording power levels. Specifically, the computed β value is given by the following equation.
 
β=( a+b )/( a−b )
 
where “a” denotes the peak level of the waveform of the corresponding-1-frame segment of the reproduced 8-16 modulation-resultant test signal, and “b” denotes the bottom level thereof. The peak level “a” has a positive sign “+” while the bottom level “b” has a negative sign “−”. The step S 4  is notified of the computed β values for the respective recording power levels. The step S 4  selects one from the computed β values which is the closest to a predetermined optimum β value. The step S 4  detects one among the different recording power levels which corresponds to the selected β value. The step S 4  designates the detected recording power level as an optimum laser-beam recording power value P6× for the 6-fold linear velocity.
 
     It should be noted that the optimum laser-beam recording power value P6× for the 6-fold linear velocity may be decided as follows. A laser-beam recording power value corresponding to the predetermined optimum β value is estimated from at least two among the different recoding power levels through interpolation responsive to at least two among the computed β values. The estimated laser-beam recording power value is designated as the optimum laser-beam recording power value P6× for the 6-fold linear velocity. 
     A step S 5  subsequent to the step S 4  refers to the reproduced PCA management information pieces given by the step S 2 . The step S 5  detects the boundary within the outer PCA  22  between a usable portion and a used portion from the reproduced PCA management information pieces. On the basis of the detected boundary, the step S 5  decides a position within the outer PCA  22  from which the recording of a test signal should be started during the present test recording and reproduction. The decided position is referred to as the test-recording start position. The step S 5  controls the servo circuit  40  in response to the LPP information to move the optical pickup  28  to a position corresponding to the test-recording start position within the outer PCA  22 . 
     A step S 6  following the step S 5  notifies the servo circuit  40  of the final integral multiple of the standard linear velocity (the 8-fold linear velocity) at which the optical disc  10  is scanned by the laser beam. The step S 6  controls the servo circuit  40  to detect a wobble signal in the reproduced 8-16 modulation-resultant signal, and to drive the spindle motor  24  in response to the final integral multiple of the standard linear velocity and the detected wobble signal to harmonize the detected wobble signal with the final integral multiple of the standard linear velocity. Thus, the step S 6  controls the actual linear velocity at the final integral multiple of the standard linear velocity. The step S 6  starts recording a test signal on the outer PCA  22  from the test-recording start position while holding the optical disc  10  scanned by the laser beam at a linear velocity equal to the final integral multiple of the standard linear velocity (the 8-fold linear velocity). 
     Specifically, the step S 6  generates a basic test signal. The step S 3  outputs the basic test signal to the encoder  46 . The encoder  46  converts the basic test signal into an 8-16 modulation-resultant test signal. The 8-16 modulation-resultant test signal is sent from the encoder  46  to the laser driver  42  via the strategy circuit  48  before being recorded on the outer PCA  22 . During the recording of the 8-16 modulation-resultant test signal on the outer PCA  22 , the step S 6  adjusts the optical power control circuit  44  to vary the recording power of the laser beam among different levels (for example, 26 different levels) on a stepwise basis. Each of the different levels is assigned to one frame. Thus, the recorded test signal has 1-frame segments which correspond to the different recording power levels respectively. For example, as shown in  FIG. 5 , the recording power of the laser beam is varied stepwise from the maximum level to the minimum level through the intermediate levels. The recording power of the laser beam may be varied stepwise from the minimum level to the maximum level through the intermediate levels. The step S 6  repeats the above-mentioned test recording procedure four times. Thus, the first, second, third, and fourth 8-16 modulation-resultant signals each having 1-frame segments are recorded on the outer PCA  22 . 
     A step S 7  subsequent to the step S 6  controls the servo circuit  40  in response to the LPP information to return the optical pickup  28  to the position corresponding to the test-recording start position within the outer PCA  22 . The step S 7  adjusts the optical pickup  28  via the servo circuit  40  so that a related portion of the outer PCA  22  will be scanned by the laser beam, and the latest recorded first, second, third, and fourth 8-16 modulation-resultant test signals will be reproduced therefrom. The reproduced first, second, third, and fourth 8-16 modulation-resultant test signals are sent from the optical pickup  28  to the β detection circuit  34  through the RF amplifier  30 . The β detection circuit  34  responds to each of the reproduced first, second, third, and fourth 8-16 modulation-resultant test signals as follows. The β detection circuit  34  computes a β value, that is, an asymmetry value, from the reproduced 8-16 modulation-resultant test signal for each of the different recording power levels in the same way as the previously-mentioned one. Regarding each of the first, second, third, and fourth 8-16 modulation-resultant test signals, the step S 7  is notified of the computed β values for the respective recording power levels. For each of the first, second, third, and fourth 8-16 modulation-resultant test signals, the step S 7  selects one from the computed β values which is the closest to a predetermined optimum β value. The step S 7  detects one among the different recording power levels which corresponds to the selected β value. There are the detected recording power levels for the first, second, third, and fourth 8-16 modulation-resultant test signals respectively. The step S 7  decides an optimum laser-beam recording power value P8× for the 8-fold linear velocity on the basis of the detected recording power levels. For example, the step S 7  discards one or ones among the detected recording power levels which are at least a given value apart from an expected level. The step S 7  averages the remaining detected recording power levels to get the optimum laser-beam recording power value P8× for the 8-fold linear velocity. Alternatively, the step S 7  may designate the minimum one among the remaining detected recording power levels as the optimum laser-beam recording power value P8× for the 8-fold linear velocity. 
     It should be noted that the optimum laser-beam recording power value P8× for the 8-fold linear velocity may be decided as follows. For each of the first, second, third, and fourth 8-16 modulation-resultant test signals, a laser-beam recording power value corresponding to the predetermined optimum β value is estimated from at least two among the different recoding power levels through interpolation responsive to at least two among the computed β values. There are the estimated recording power levels for the first, second, third, and fourth 8-16 modulation-resultant test signals respectively. The optimum laser-beam recording power value P8× for the 8-fold linear velocity is decided on the basis of the estimated recording power levels. For example, the step S 7  discards one or ones among the estimated recording power levels which are at least a given value apart from an expected level. The step S 7  averages the remaining estimated recording power levels to get the optimum laser-beam recording power value P8× for the 8-fold linear velocity. Alternatively, the step S 7  may designate the minimum one among the remaining estimated recording power levels as the optimum laser-beam recording power value P8× for the 8-fold linear velocity. 
     A step S 8  following the step S 7  generates an information piece representing addresses of the portion of the inner PCA  12   a  on which the latest 8-16 modulation-resultant test signal has been recorded. In addition, the step S 8  generates an information piece representing the optimum laser-beam recording power value P6× for the 6-fold linear velocity. Furthermore, the step S 8  generates an information piece representing addresses of the portion of the outer PCA  22  on which the latest first, second, third, and fourth 8-16 modulation-resultant test signals have been recorded. In addition, the step S 8  generates an information piece representing the optimum laser-beam recording power value P8× for the 8-fold linear velocity. The step S 8  outputs the generated information pieces (the address-related information pieces and the optimum-power-related information pieces) to the encoder  46 . The information pieces are propagated from the encoder  46  to the optical pickup  28  through the strategy circuit  48  and the laser driver  42 . The step S 8  controls the servo circuit  40  in response to the LPP information to move the optical pickup  28  to a position corresponding to the RMD area  12   b  in the lead-in area  12  of the optical disc  10 . The step S 8  adjusts the optical pickup  28  via the servo circuit  40  so that the RMD area  12   b  will be scanned by the laser beam, and the previously-indicated information pieces (the address-related information pieces and the optimum-power-related information pieces) will be recorded thereon. After the step S 8 , the current execution cycle of the program segment ends. 
     It should be noted that the step S 8  may be omitted from the program segment in  FIG. 4 . In this case, the step S 4  generates an information piece representing addresses of the portion of the inner PCA  12   a  on which the latest 8-16 modulation-resultant test signal has been recorded. In addition, the step S 4  generates an information piece representing the optimum laser-beam recording power value P6× for the 6-fold linear velocity. The step S 4  outputs the generated information pieces (the address-related information piece and the optimum-power-related information piece) to the encoder  46 . The information pieces are propagated from the encoder  46  to the optical pickup  28  through the strategy circuit  48  and the laser driver  42 . The step S 4  controls the servo circuit  40  in response to the LPP information to move the optical pickup  28  to a position corresponding to the RMD area  12   b  in the lead-in area  12  of the optical disc  10 . The step S 4  adjusts the optical pickup  28  via the servo circuit  40  so that the RMD area  12   b  will be scanned by the laser beam, and the previously-indicated information pieces (the address-related information piece and the optimum-power-related information piece) will be recorded thereon. Similarly, the step S 7  generates an information piece representing addresses of the portion of the outer PCA  22  on which the latest first, second, third, and fourth 8-16 modulation-resultant test signals have been recorded. In addition, the step S 7  generates an information piece representing the optimum laser-beam recording power value P8× for the 8-fold linear velocity. The step S 7  outputs the generated information pieces (the address-related information piece and the optimum-power-related information piece) to the encoder  46 . The information pieces are propagated from the encoder  46  to the optical pickup  28  through the strategy circuit  48  and the laser driver  42 . The step S 7  controls the servo circuit  40  to move the optical pickup  28  to a position corresponding to the RMD area  12   b  in the lead-in area  12  of the optical disc  10 . The step S 7  adjusts the optical pickup  28  via the servo circuit  40  so that the RMD area  12   b  will be scanned by the laser beam, and the previously-indicated information pieces (the address-related information piece and the optimum-power-related information piece) will be recorded thereon. 
     During the normal recording mode of operation of the optical-disc recording apparatus, when the radial position of the currently scanned portion of the optical disc  10  is inward of the predetermined reference position RP, the linear velocity of the optical disc  10  relative to the laser beam remains controlled at the 6-fold value on a CLV basis. In this case, the recording power and recording strategy (recording waveform) of the laser beam are controlled at the optimum ones corresponding to the 6-fold linear velocity. On the other hand, when the radial position of the currently scanned portion of the optical disc  10  is outward of the predetermined reference position RP, the linear velocity of the optical disc  10  relative to the laser beam remains controlled at the 8-fold value on a CLV basis. In this case, the recording power and recording strategy (recording waveform) of the laser beam are controlled at the optimum ones corresponding to the 8-fold linear velocity. 
     Third Embodiment 
       FIG. 6  shows an optical-disc recording apparatus or an optical-disc recording/reproducing apparatus according to a third embodiment of this invention. The optical-disc recording apparatus in  FIG. 6  is similar to that in  FIG. 2  except for design changes mentioned hereafter. 
     The optical-disc recording apparatus in  FIG. 6  includes an envelope detection circuit  36  and a system control circuit  50 A. The envelope detection circuit  36  is connected between the RF amplifier  30  and the system control circuit  50 A. The system control circuit  50 A replaces the system control circuit  50  in  FIG. 2 . 
     Basically, the optical-disc recording apparatus in  FIG. 6  uses the envelope detection circuit  36  for the evaluation of a reproduced 8-16 modulation-resultant test signal during test recording and reproduction. Thus, the β detection circuit  34  may be omitted from the optical-disc recording apparatus in  FIG. 6 . 
     During the reproduction of information (data) from the optical disc  10 , the RF amplifier  30  passes the reproduced signal (the reproduced 8-16 modulation-resultant signal) to the address detection circuit  32 , the β detection circuit  34 , the envelope detection circuit  36 , and the servo circuit  40  while amplifying the reproduced electric signal. The envelope detection circuit  36  detects the envelope of the reproduced 8-16 modulation-resultant signal which relates to the degree of the modulation thereof. The envelope detection circuit  36  feeds the system control circuit  50 A with a signal representing the detected envelope. The system control circuit  50 A uses the detected envelope to decide an optimum recording power of the laser beam in response to the degree of the modulation of the reproduced 8-16 modulation-resultant signal. 
       FIG. 7  is a flowchart of an OPC segment of a control program for the system control circuit  50 A. The program segment in  FIG. 7  is similar to that in  FIG. 4  except for design changes mentioned below. The program segment in  FIG. 7  includes steps S 4 A and S 7 A instead of the steps S 4  and S 7  in  FIG. 4 . 
     The step S 4 A is a modification of the step S 4  (see  FIG. 4 ). The step S 4 A refers to the detected envelope of the reproduced 8-16 modulation-resultant test signal which is notified by the envelope detection circuit  36 . The detected envelope relates to the degree of the modulation of the reproduced 8-16 modulation-resultant test signal. The step S 4 A uses the detected envelope to decide an optimum laser-beam recording power value P6× for the 6-fold linear velocity in response to the degree of the modulation of the reproduced 8-16 modulation-resultant test signal. 
     The step S 7 A is a modification of the step S 7  (see  FIG. 4 ). The step S 7 A refers to the detected envelopes of the first, second, third, and fourth 8-16 reproduced 8-16 modulation-resultant test signals which are notified by the envelope detection circuit  36 . The detected envelopes relate to the degrees of the modulation of the first, second, third, and fourth reproduced 8-16 modulation-resultant test signals. The step S 7 A uses the detected envelopes to decide an optimum laser-beam recording power value P8× for the 8-fold linear velocity in response to the degrees of the modulation of the first, second, third, and fourth reproduced 8-16 modulation-resultant test signals. 
     Fourth Embodiment 
     A fourth embodiment of this invention is similar to the first and second embodiments thereof except that the optical disc  10  uses a Blu-ray Disc or one of another type. 
     Fifth Embodiment 
     A fifth embodiment of this invention is similar to the first and second embodiments thereof except that the parameter relating to the quality of the reproduced signal includes the degree of modulation, the value obtained by a γ method of differentiating the modulation degree, the error rate, or the jitter.