JP2009004091A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recording power-determining method for an optical disk device which determines optimum recording power information for an optical disk which rotates at a high speed. <P>SOLUTION: Amplitudes of push-pull signals at two positions in the radius direction of an optical disk are acquired prior to recording. Then, on the basis of the acquired amplitudes of the push-pull signals, optimum recording power to radius positions across the whole disk recording area is found by linear approximation computation, and a result thus acquired is determined to be the optimum recording power information to the disk radius positions (201, 202). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a recording power determination method and a recording power control method for an optical disc apparatus that optimally sets a recording power at the time of recording in the optical disc apparatus.

  In a recordable optical disk device such as a CD-R / RW drive or a DVD-R / RW drive, test data is written on the PCA area of the optical disk with various laser powers, and the reproduction quality such as β value is the target value. The OPC (Optimum Power Control) for calculating the laser power and the laser so that the B value indicating the return light amount after recording bit formation is kept constant regardless of the recording film coating unevenness in the optical disk surface and the inclination of the optical disk. Recording quality is ensured by ROPC (Running Optimum Power Control) for feedback control of power.

  Since this ROPC corrects a state in which various factors of the optical disk are mixed, optimization of recording quality is not necessarily realized, and various improvements have been attempted.

  For example, in order to make the β value constant with respect to the tilt of the optical disc, laser power control is performed so that the ratio (ΔB / ΔP) of the fluctuation of the return light amount and the fluctuation of the laser power in ROPC is constant (for example, patent It is known to perform laser power control with Bm / Pn = constant (provided that m <n) (for example, see Patent Document 2).

  Further, in a phase change recording type optical disk such as a CD-RW, when overwriting a recorded area, it is difficult to ensure recording quality by ROPC due to the influence of the previous recording state. The light is divided into a main beam of 0th order diffracted light and two subbeams of + 1st order diffracted light and −1st order diffracted light, and recording is performed by irradiating the main beam to the groove track, while two sub beams are placed on both sides of the groove track. An example of running OPC that eliminates the influence of overwriting by irradiating adjacent land tracks, and performing main beam power control using the return light of the land tracks that are not affected by recording (for example, Patent Document 3) See).

  Also, in an optical disk apparatus, normally, an optical pickup that collects laser light and irradiates a track of the optical disk with a light spot to record information on the optical disk in a direction perpendicular to the track crossing direction and the track crossing direction of the light spot. An arranged divided light receiving unit is provided, and focus information and tracking information are obtained from a detection signal from the divided light receiving unit.

  Then, a push-pull signal (PP signal) is obtained by subtracting the detection signal from the divided light receiving unit in the cross-track direction of the light spot, and the phase comparison of the detection signal from the divided light receiving unit is performed. It is known to obtain a differential phase detection signal (DPD signal) from the two signals and detect the tilt angle of the optical disk from these signals (see, for example, Patent Document 4).

JP 2003-16645 A (Claim 1, 0023) JP 2003-248929 A (Claim 1, Claim 3, 0024, 0026) JP 2003-173533 A (summary, claim 1, disclosure of invention) JP 2001-307359 A (Claim 1, Claim 2, 0023-0028, etc.)

  However, the demand for shortening the recording time has been increasing year by year, and it has become necessary to rotate the optical disc at high speed along with the speeding up of recording, and it has become strict to obtain the return light amount detection accuracy of ROPC that is performed to ensure recording quality. Yes.

  An object of the present invention is to provide a recording power determination method for an optical disc apparatus capable of determining optimum recording power information of the optical disc at high speed rotation of the optical disc.

  Another object of the present invention is to provide a recording power control method for an optical disc apparatus that controls laser power using predetermined optimum recording power information of the optical disc during recording.

  Still another object of the present invention is to determine an optimum recording power information of an optical disk prior to recording at high speed rotation of the optical disk, and to use this determined optimum recording power information to control laser power during recording. Is to provide a recording power control method.

  According to a first aspect of the present invention, there is provided a recording power determination method for an optical disc apparatus, wherein push-pull signal amplitudes at at least two measurement positions in the radial direction of the optical disc are acquired prior to recording, and the acquired push-pull signal amplitudes are obtained. Based on this, the optimum recording power for the radial position over the entire recording area of the disc is calculated and obtained, and the obtained result is determined as the optimum recording power information for the disc radial position.

  According to a second aspect of the present invention, there is provided a recording power control method for an optical disc apparatus which acquires disc position information of an optical pickup at the time of recording, and obtains the disc position information and optimum recording power information for a stored disc radial position. Then, the optimum recording power at the recording position of the optical disc is set, and the laser power of the optical pickup is controlled so as to be the set optimum recording power.

  According to a third aspect of the present invention, there is provided a recording power control method for an optical disc apparatus that acquires push-pull signal amplitudes at at least two positions in the radial direction of the optical disc prior to recording, and based on the acquired push-pull signal amplitudes. In addition, the optimum recording power for the radial position over the entire recording area of the disc is calculated and obtained, and the obtained result is determined and stored as the optimum recording power information for the radial position of the disc, and the optical pickup disc position information is obtained during recording. Then, an optimum recording power at the recording position of the optical disc is set from the obtained disc position information and the optimum recording power information with respect to the stored disc radius position, and the optical pickup is set to the set optimum recording power. It is characterized by controlling the laser power.

According to a fourth aspect of the present invention, there is provided a recording power determination method or a recording power control method for an optical disc apparatus according to the first, second, or third aspect, wherein the optimum recording power information for the disc radial position is the outer circumference for the inner circumference reference measurement position. A recording power determination method or a recording power control method for an optical disc apparatus, wherein PO is calculated or obtained by the following equation, where PO is an optimum recording power at an arbitrary measurement position.
PO = [1 + {(PPI / PPO) -1} * PUP] * PI
Or
PO = [1+ {1- (PPO / PPI)} * PUP] * PI
here,
PPI: Push-pull signal amplitude acquired at the inner circumference reference measurement position or a position in the vicinity thereof,
PPO: Push-pull signal amplitude acquired at the outer circumference arbitrary measurement position,
PUP: Ratio factor of power-up due to disk radius,
PI: Optimal recording power by trial writing of the inner circumference reference measurement position.

According to a fifth aspect of the present invention, there is provided a recording power determination method or a recording power control method for an optical disc apparatus according to the fourth aspect, wherein the optimum recording power at the outer peripheral arbitrary non-measurement position in the optimum recording power information with respect to the disc radial position. Assuming that P, P is obtained or obtained by calculation from the following equation.
P = (PI-PO) / (ri-ro) × r
+ (PO * ri-PI * ro) / (ri-ro)
here,
ri: the disk radius position at the inner circumference reference measurement position or its vicinity,
ro: Disc radius position of the outer peripheral arbitrary measurement position where the PPO of claim 4 is acquired.

According to a sixth aspect of the present invention, there is provided a recording power determination method or a recording power control method for an optical disc apparatus according to the first, second, or third aspect, wherein the optimum recording power information for the disc radial position is the outer circumference relative to the inner circumference reference measurement position. Assuming that the optimum recording power at an arbitrary measurement position is PO, PO is calculated or obtained from the following equation.
PO = [1 + {(PPI / PPO) -1} * PUP] * Pr
Or
PO = [1+ {1- (PPO / PPI)} * PUP] * Pr
here,
PPI: Push-pull signal amplitude acquired at the inner circumference reference measurement position or a position near it
PPO: Push-pull signal amplitude acquired at the outer circumference arbitrary measurement position,
PUP: Ratio factor of power-up due to disk radius,
Pr: Optimum power at the disc radius r at any position on the outer periphery when there is no push-pull amplitude difference between the inner periphery and the outer periphery.

According to a seventh aspect of the present invention, there is provided a recording power determination method or a recording power control method for an optical disc apparatus according to the sixth aspect, wherein the optimum recording power information for the disc radial position is the optimum at an outer peripheral arbitrary position with respect to the inner peripheral reference position. A recording power determination method or a recording power control method for an optical disc apparatus, characterized in that Prb is calculated or obtained by the following equation, where Prb is the recording power.
Prb = PCR × Pr
here,
Pr is the optimum power at the disc radius r at the outer peripheral arbitrary position when there is no push-pull amplitude difference at the inner peripheral position and the outer peripheral position.
PCR is a power control coefficient at the disc radius r at the outer peripheral arbitrary measurement position of the optical pickup,
PCR = {(PCI-PCO) / (ri-ro)} × r
+ {(PCO × ri) − (PCI × ro)} / (ri-ro)
here,
ri is the disk radius at or near the inner circumference reference measurement position,
ro is the radius of the disk at the outer periphery,
PCI: power control coefficient at or near the inner circumference reference measurement position,
PCO: Power control coefficient at the outer periphery arbitrary measurement position,
further,
PCI = 1
PCO = [1 + {(PPI / PPO) -1} × PUP]
Or
PCO = [1+ {1- (PPO / PPI)} * PUP].

  According to the present invention, it is possible to obtain a recording power determination method of an optical disc apparatus that can determine optimum recording power information of an optical disc at high speed rotation of the optical disc. Further, according to the present invention, it is possible to obtain a recording power control method of an optical disc apparatus that controls laser power using predetermined optimum recording power information of an optical disc at the time of recording. Further, according to the present invention, the optimum recording power information of the optical disc is determined prior to recording in the high-speed rotation of the optical disc, and the recording of the optical disc apparatus that controls the laser power at the time of recording using the determined optimum recording power information. A power control method can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a configuration diagram of an embodiment of an optical disc apparatus having a recording power setting method according to the present invention.

  In FIG. 1, the disk motor rotation control means 1 controls the disk motor 3 so that the rotation speed specified by the microcomputer 2 is obtained. The disk motor 3 controls the optical disk 4 to a designated rotational speed.

  The laser power control means 5 controls the laser power of the optical pickup 6 so that it becomes the laser power set by the microcomputer 2.

  The optical pickup 6 focuses the laser beam on the optical disc 4 and performs an information recording operation. Further, the information recorded on the optical disc 4 is detected as optical information and converted into an electrical signal.

  Here, the optical pickup 6 has a divided light receiving portion arranged in a track transverse direction and a direction perpendicular to the track transverse direction of the light spot that condenses the laser light and irradiates the track of the optical disc. The detection signal is output.

  When the servo control means 7 receives a command from the microcomputer 6, it extracts focus information and tracking information information necessary for the disc information groove tracking operation by the optical pickup 6 from the detection signal from the divided light receiving portion of the optical pickup 6. The focus / tracking tracking operation of the optical pickup 6 is performed based on the information.

  The signal processing means 8 reads out the ATIP address information, which is position information recorded on the optical disc 4, from the optical disc 4 by the optical pickup 6, and acquires the position information of the optical pickup 6. Also, media ID information for each optical disc attached to a CD-R optical disc or the like is acquired.

  The push-pull signal amplitude detecting means 9 detects the push-pull signal amplitude by subtraction operation from the detection signal from the divided light receiving unit in the cross-track direction of the light spot among the divided light receiving units of the optical pickup 6.

  The memory 10 stores optimum recording power information for the disk radial position calculated by the microcomputer 2 based on the push-pull signal amplitude from the push-pull signal amplitude detecting means 9.

  At the time of recording, from the position information of the optical pickup 6 acquired by the signal processing means 8 by the microcomputer 2 and the optimum recording power information with respect to the disk radius position stored in the memory 10, the recording radius position of the optical pickup 6 is obtained. The optimum recording power is set, and the laser power control means 5 is instructed to set the optimum recording power, and the laser power control means 5 sets the laser power of the optical pickup 6 according to the instruction of the microcomputer 2. Control to be power.

  FIG. 2 is a diagram showing a flow of the entire operation relating to recording in FIG.

  In FIG. 2, step 210 and step 202 are steps performed prior to recording.

  In step 201, the microcomputer 2 moves the optical pickup 6 to two positions in the radial direction of the optical disk 4, that is, an inner peripheral position (for example, a radius of 23 mm from the inner side) and an outer peripheral position (for example, a radius of 50 mm from the inner side). Are acquired from the push-pull signal acquisition means 9.

  In step 202, the microcomputer 2 obtains a linear approximation calculation of the optimum recording power with respect to the radial position over the entire recording area of the disc based on the push-pull signal amplitude information acquired at the inner and outer circumferential positions in step 201, and the obtained result. Is stored in the memory 10 as the optimum recording power information for the disk radial position.

  In step 203, during recording, the microcomputer 2 moves the optical pickup 6 to the recording start position in the radial direction of the optical disk 4.

  In step 204, an actual recording operation is performed by the optical pickup 6.

  FIG. 3 is a diagram showing an example of the detailed content flow of step 201 in FIG.

  In step 301, the microcomputer 2 moves the optical pickup 6 to two positions in the radial direction of the optical disk 4, that is, to the outer peripheral position of the inner peripheral position and the outer peripheral position.

  In step 302, the microcomputer 2 acquires the push-pull signal amplitude at the outer peripheral position from the push-pull signal acquisition unit 9.

  In step 303, the microcomputer 2 moves the optical pickup 6 to two positions in the radial direction of the optical disc 4, that is, to an inner peripheral position of the inner peripheral position and the outer peripheral position.

  In step 304, the microcomputer 2 acquires the push-pull signal amplitude at the inner peripheral position from the push-pull signal acquisition unit 9.

  The above is the detailed content flow of step 201 in FIG.

  In this embodiment, the amplitude of the inner peripheral position is acquired after the outer peripheral position, but may be performed first from the inner peripheral position. The flow at that time is step 303, then step 304, then step 301, and then step 302.

  Here, when acquiring the push-pull signal amplitude in step 302 and step 304, first, the tracking-off operation sets a state in which the signal change in the track crossing direction (transverse direction) of the optical disc can be measured as the push-pull amplitude.

  The actual push-pull amplitude measurement is then measured and obtained. Finally, tracking is turned on again.

  If necessary, a WAIT process such as waiting for rotation speed stabilization may be provided at an arbitrary position before actual measurement and acquisition.

  Since the amount of warpage of the disk changes depending on the rotation speed of the optical disk, it is desirable to use the push-pull amplitude when the rotation speed is the same as the recording speed.

  FIG. 4 is a diagram showing an example of the detailed content flow of step 204 in FIG.

  In step 401, recording is started at the recording start position in the radial direction of the optical disc 4.

  In step 402, the microcomputer 2 obtains ATIP address information from the signal processing means 8 and obtains disk radius position information.

  In step 403, the microcomputer 2 determines the optimum recording power at the recording radius position of the optical disk 4 from the disk radius position information detected in step 402 and the optimum recording power information for the disk radius position stored in the memory 10. The laser power control unit 5 is instructed to set the optimum recording power, and the laser power control unit 5 is controlled so that the laser power of the optical pickup 6 is set to the optimum recording power according to the instruction of the microcomputer 2. To do.

  In step 404, the microcomputer 2 determines whether it is the recording end position from the position information of the optical pickup 6 acquired by the signal processing means 8. If it is not the recording end position, the microcomputer 2 returns to step 402 to continue recording. If it is the recording end position, a recording end operation 405 is performed.

  Next, detailed contents of step 202 in FIG. 2 will be described.

First, when recording the entire surface of the optical disk at the same speed (CLV recording), the optimal recording power information for the disk radial position is PO, where the optimal recording power at the outer peripheral arbitrary position with respect to the inner peripheral reference position is PO.
PO = [1 + {(PPI / PPO) -1} × PUP] × PI (1)
Or
PO = [1+ {1- (PPO / PPI)} × PUP] × PI (Expression 2)
It shows.
here,
PPI: Push-pull signal amplitude acquired near the inner circumference reference position,
PPO: Push-pull signal amplitude acquired at an arbitrary position on the outer periphery,
PUP: Ratio factor of power-up due to disk radius,
PI: The optimum recording power by trial writing of the inner circumference reference position.

  Note that it is preferable that the optimum value of the power-up ratio coefficient according to the disk radius of the PUP is checked in advance for each medium.

  Moreover, it is good also as a mechanism which preserve | saves the result investigated about the said PUP for every media in the memory 10, and reads it from the memory 10 before actual calculation.

Here, when the optimum recording power at the outer periphery arbitrary position is defined as P, the disk radius at the outer periphery arbitrary position is defined as r, the disk radius at the inner periphery reference acquisition position is defined as ri, and the disk radius position at the outer periphery arbitrary acquisition position is defined as ro. As shown in FIG. 5, by assuming that P and r can be approximated by a linear expression, they can be expressed as follows.
P = (PI-PO) / (ri-ro) × r
+ (PO × ri · PI × ro) / (ri-ro) (Formula 3)
Therefore, the optimum laser power P corresponding to the arbitrary radius r is obtained by substituting (Equation 1) or (Equation 2) into (Equation 3).

  Next, the case of CAV recording on the entire surface of the optical disk will be described. In the case of CAV, the double speed changes depending on the radial position. Also, the optimum recording power changes according to the double speed. Therefore, the optimum power for each double speed (each radial position) is further corrected by push-pull amplitude difference information.

If the power control coefficient at the inner circumference reference position is PC1, and the power control coefficient at the outer circumference measurement position is PCO,
PC1 = 1 (Equation 4)
PCO = [1 + {(PPI / PPO) -1} × PUP] ... (Formula 5)
Or
PCO = [1+ {1- (PPO / PPI)} * PUP]] (Formula 6)
It is.

  (Expression 5) and (Expression 6) are the coefficient terms themselves of (Expression 1) and (Expression 2), respectively. Actually, the calculation is performed using any one of (Equation 5) and (Equation 6).

  Next, the power control coefficient PCR at an arbitrary radius r is calculated using (Expression 4) and (Expression 5) or (Expression 6).

According to the linear approximation as shown in FIG.
PCR = {(PCI-PCO) / (ri-ro)} × r
+ {(PCO × ri) · PCI × ro} / (ri-ro) (Equation 7)
It shows.

  Therefore, the power control coefficient PCR corresponding to the arbitrary radius r is obtained by substituting (Equation 4) and (Equation 5) or (Equation 6) into (Equation 7).

  The optimum power at an arbitrary radius r when there is no difference in push-pull amplitude between the inner and outer circumferences is defined as Pr. Since the CAV control is used, the speed is changed by r and the optimum power is changed accordingly. Therefore, Pr becomes a different value for every r.

  It should be noted that Pr may be defined as the optimum recording power at each reproduction position (each reproduction speed) obtained by using other known OPC and ROPC other than the present invention for Pr different for each double speed. good.

Here, if the optimum recording power after performing power correction according to this patent is defined as Prb with respect to Pr, the following relationship is established between Prb and Pr.
Prb = PCR × Pr (Equation 8)
here,
PCR = {(PCI-PCO) / (ri-ro)} × r
+ {(PCO × ri) · PCI × ro} / (ri-ro) (Equation 7)
Pr is the optimum power at an arbitrary radius r when there is no difference in push-pull amplitude between the inner and outer circumferences.

In addition, (Formula 8) is applicable not only to CAV but the above-mentioned CLV, ZCLV, etc.
Further, by using (Equation 8), it is possible to further correct the optimum power obtained by power control by ROPC or the like other than the present invention.

  As described above, according to the embodiment of the present invention, it is possible to obtain a recording power determination method of an optical disc apparatus that can determine the optimum recording power information of the optical disc at high speed rotation of the optical disc.

  In addition, according to the embodiment of the present invention, it is possible to obtain a recording power control method for an optical disc apparatus that controls laser power using predetermined optimum recording power information of an optical disc during recording.

  According to the embodiment of the present invention, the optimum recording power information of the optical disk is determined prior to recording in the high-speed rotation of the optical disk, and the laser power is controlled at the time of recording using the determined optimum recording power information. A recording power control method for an optical disc apparatus can be obtained.

1 is a configuration diagram of an embodiment of an optical disc apparatus having a recording power setting method according to the present invention. FIG. It is a figure which shows the flow of the whole operation | movement regarding the recording in FIG. It is a figure which shows the example of the flow of the detailed content of step 201 in FIG. It is a figure which shows the example of the flow of the detailed content of step 204 in FIG. FIG. 3 is a diagram showing a relationship between a recording power and a disk radius at CLV in step 202 in FIG. 2. FIG. 3 is a diagram showing a relationship between a power control coefficient PCR and a disk radius at CAV in step 202 in FIG. 2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Disk motor rotation control means, 2 ... Microcomputer, 3 ... Disk motor, 4 ... Optical disk, 5 ... Laser power control means, 6 ... Optical pick-up, 7 ... Servo control means, 8 ... Signal processing means, 9 ... Push pull signal Amplitude detection means, 10... Memory.

Claims (7)

  Prior to recording, the push-pull signal amplitude at at least two measurement positions in the radial direction of the optical disk is acquired, and the optimum recording power for the radial position over the entire recording area of the disk is calculated based on the acquired push-pull signal amplitude. A recording power determination method for an optical disc apparatus, wherein the determination result is determined as optimum recording power information for a disc radial position.   The disk position information of the optical pickup is acquired at the time of recording, and the optimum recording power at the recording position of the optical disk is set and set from the obtained disk position information and the optimum recording power information with respect to the stored disk radius position. A recording power control method for an optical disc apparatus, wherein the laser power of the optical pickup is controlled so that the optimum recording power is obtained.   Prior to recording, the push-pull signal amplitude at at least two positions in the radial direction of the optical disk is acquired, and the optimum recording power for the radial position over the entire recording area of the disk is calculated based on the acquired push-pull signal amplitude. Determine the optimum recording power information for the disk radial position and store the obtained result, obtain the disk position information of the optical pickup at the time of recording, and obtain the obtained disk position information and the stored disk radius position Recording power control for an optical disc apparatus, wherein optimum recording power at the recording position of the optical disc is set from the optimum recording power information, and the laser power of the optical pickup is controlled to be the set optimum recording power Method. 4. The optimum recording power information for the disk radial position according to claim 1, wherein if the optimum recording power at the outer peripheral arbitrary measurement position with respect to the inner peripheral reference measurement position is PO, PO is calculated from the following equation. A recording power determination method or a recording power control method for an optical disc apparatus, characterized by:
PO = [1 + {(PPI / PPO) -1} * PUP] * PI
Or
PO = [1+ {1- (PPO / PPI)} * PUP] * PI
here,
PPI: Push-pull signal amplitude acquired at the inner circumference reference measurement position or a position in the vicinity thereof,
PPO: Push-pull signal amplitude acquired at the outer circumference arbitrary measurement position,
PUP: Ratio factor of power-up due to disk radius,
PI: Optimal recording power by trial writing of the inner circumference reference measurement position. 5. In the optimum recording power information with respect to the disk radial position according to claim 4, wherein P is an optimum recording power at an outer peripheral arbitrary non-measurement position, and P is calculated or obtained from the following equation. A recording power determination method or a recording power control method for an optical disc apparatus.
P = (PI-PO) / (ri-ro) × r
+ (PO * ri-PI * ro) / (ri-ro)
here,
ri: the disk radius position at the inner circumference reference measurement position or its vicinity,
ro: Disc radius position of the outer peripheral arbitrary measurement position where the PPO of claim 4 is acquired. 4. The optimum recording power information for the disk radial position according to claim 1, wherein if the optimum recording power at the outer peripheral arbitrary measurement position with respect to the inner peripheral reference measurement position is PO, PO is calculated from the following equation. A recording power determination method or a recording power control method for an optical disc apparatus, characterized by:
PO = [1 + {(PPI / PPO) -1} * PUP] * Pr
Or
PO = [1+ {1- (PPO / PPI)} * PUP] * Pr
here,
PPI: Push-pull signal amplitude acquired at the inner circumference reference measurement position or a position in the vicinity thereof,
PPO: Push-pull signal amplitude acquired at the outer circumference arbitrary measurement position,
PUP: Ratio factor of power-up due to disk radius,
Pr: Optimum power at the disc radius r at any position on the outer periphery when there is no push-pull amplitude difference between the inner periphery and the outer periphery. 7. The optimum recording power information for the disk radial position according to claim 6, wherein Prb is calculated or obtained from the following equation, where Prb is the optimum recording power at the outer peripheral arbitrary position with respect to the inner peripheral reference position. A recording power determination method or a recording power control method for an optical disc apparatus, comprising:
Prb = PCR × Pr
here,
Pr is the optimum power at the disc radius r at the outer peripheral arbitrary position when there is no push-pull amplitude difference at the inner peripheral position and the outer peripheral position.
PCR is a power control coefficient at the disc radius r at the outer peripheral arbitrary measurement position of the optical pickup,
PCR = {(PCI-PCO) / (ri-ro)} × r
+ {(PCO × ri) − (PCI × ro)} / (ri-ro)
here,
ri is the disk radius at or near the inner circumference reference measurement position,
ro is the radius of the disk at the outer periphery,
PCI: power control coefficient at or near the inner circumference reference measurement position,
PCO: Power control coefficient at the outer periphery arbitrary measurement position,
further,
PCI = 1
PCO = [1 + {(PPI / PPO) -1} × PUP]
Or
PCO = [1+ {1- (PPO / PPI)} * PUP].

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