JPH01204277A - Search method in optical disk player - Google Patents

Abstract

PURPOSE:To reduce the number of track jumps and to shorten a time, which is needed for the search of the heading of music, etc., by exactly calculating the number of remaining tracks up to a target position and executing thread- sending extremely near the target position. CONSTITUTION:When the thread-sending is executed, based on the output pulse signal of a revolving sensor 2a, a present revolving number n/m per unit time of a CD 1 is obtained and relation between a linear velocity v0 of the CD 1 and a radius (r) can be obtained from this revolving number n/m. Accordingly, a remaining track number N up to a target position Pb can be exactly calculated and the thread-sending can be executed to a position P1, which is extremely near the target position Pb. Thus, the number of the tracks jumps in following operation is reduced and the time to be needed for the search of the heading of the music, etc., can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical disc player such as a CD (compact disc) player, and particularly relates to a search method that can quickly locate the beginning of a song. .

``Prior Art'' Conventionally, when a CD player performs a song search by moving its optical pickup from the inner circumferential side to the outer circumferential side of the CD, the operating procedure is as shown in FIG.

In this figure, RIA is the lead-in area provided on the innermost side of the CD, MA is the music area where musical tone information is recorded, ROA is the lead-out area, Pa is the current position, and Pb is the target position. There is.

First, at startup, the absolute time information of the start point of each side (information indicating the elapsed time from the start point at which the first song begins) is read from the CD track-in area (R) A, and is stored in the RAM (random access memory). ). Next, when a song search is commanded, the number of tracks N to move to the target position Pb is calculated from the absolute time ta of the current position Pa and the absolute time tb of the target position Pb as follows.

In other words, the linear velocity of the disc is vo, the track pitch is P1, the innermost radius at the base of the disc (the starting point of the first song) is ro, the radius to be determined is r, the elapsed time is t, and the number of tracks is N. Then, by transforming equation (1), we get r−(r,”+ P −vo4/
rr)""...The following equation (2) is obtained.

The absolute time ta of the current position Pa and the absolute time tb of the target position pb are substituted into the elapsed time t of the above equation (2) to obtain the radius ra of the current position Pa and the radius rb of the target position Pb. By substituting the radii ra and rb thus obtained into the following equation, the number N of tracks is calculated.

Based on the number N of tracks calculated in this manner, the pickup is moved according to the operating procedure of steps ① to ② shown below, and a song search is performed.

(2) By feeding the thread, the pickup is moved in the outer circumferential direction to a position P1' near the target position pb.

■Read the absolute time information from the current position P1', and if the target position Pb has not been reached, wait 100 tracks in the outer circumferential direction until the target position Pb is passed.
0 track movement) is repeated. In the illustrated example, until passing the target position Pb, P,'→P,
′ ,P,′ →P3′ ,P,′−P,′ and 100
The track jump is repeated three times.

(2) Once the target position Pb has been passed, a lO track jump is performed in the opposite direction (inner circumferential direction).

In the illustrated example, until passing the target position Pb,
P4' → P, ', P5' → P e', P e' → P
He repeated the 7' and 10 track jumps three times.

■When it passes the target position Pb, it moves in the outer circumferential direction with one track jump, and thereby the target position P
Reach b.

"Problem to be Solved by the Invention" By the way, in the conventional song search method described above, when feeding the thread, it is assumed that the value of the linear velocity VO of the disk is always constant, and the number of tracks N to the destination position Pb is was calculated. However, in reality, the linear velocity v0 of this disc is 1.2 to 1.4 m/s according to the CD standard.
The number of tracks after 60 minutes from the innermost circumference of the disc is (2). = 1.2 m/s, 17595 tracks v
, = 1.3 m/s, 18656) rack v,
= 1.4 rn/s, it changes according to the value of linear velocity v0, such as 19685 tracks.

Therefore, if the sled is fed based on the calculation result of the number of tracks N described above, an error will occur and the sled will be fed to a position away from the target position Pb, resulting in an increase in the number of subsequent track jumps (from In the worst case, the number of times each track jump is required (in the worst case, each track jump is nine times).Therefore, there is a problem in that it takes a long time to reach the target position pb by track jump, that is, it takes a long time to search for a song.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a search method for an optical disc player that can reduce the time required for searches such as finding the beginning of a song.

"Means for Solving the Problem" The present invention moves an optical pickup to the vicinity of a target position by thread feeding, and then reads absolute time information from a reference position recorded in each part of a disk by the optical pickup. In a search method for an optical disc player that searches for a target position by jumping, when thread-feeding the pickup, the number of rotations per unit time of the disc is detected, and absolute time information of the current position is read from the disc. , Then, based on the rotation speed, absolute time information of the current position, and absolute time information of the target position,
The present invention is characterized in that the number of remaining tracks to the target position is calculated, and based on the result of this calculation, the pickup is sled-fed to the vicinity of the target position.

"Operation" According to the above search method, when feeding the thread, the current number of revolutions per unit time of the disk is detected, and based on this number of revolutions, etc., the number of remaining tracks to the target position is accurately determined. As a result, the thread can be sent very close to the target position, and as a result, the number of subsequent track jumps can be reduced, and the time required for searches such as finding the beginning of a song can be shortened.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a CD player to which an embodiment of the present invention is applied. In this figure, l is a CD, 2 is a spindle motor that rotationally drives the CDI, and 2 is a spindle motor that rotationally drives the CDI.
a is an optical or magnetic rotation sensor that is connected to the shaft of the spindle motor 2 and detects the number of rotations of the spindle motor 2 and CDI per unit time, and generates a pulse signal of m pulses every time the CDI rotates once. Output. 3
4 is an optical pickup that reads digital information recorded by pits on the CDI, and 4 is a feeding mechanism that moves the pickup 3 in the radial direction of the CD. The pickup 3 is composed of a semiconductor laser, a lens, an optical sensor, a focus/tracking adjustment mechanism, etc. The read signal output from the pickup 3 is amplified by an RF amplifier 5 and then sent to a signal processing circuit 6. , demodulation, code error correction and compensation, and is converted into an analog audio signal by a D/A (digital/analog) converter 7.

The audio signal output from the D/A converter 7 is subjected to processing such as amplification in the audio circuit 8, and then output to an external speaker or the like via an output terminal 9.

Further, IO is a servo circuit, which controls the rotation of the spindle motor 2 (constant linear velocity control), the focus/tracking control of the pickup 3, and the feed mechanism 4 based on control signals supplied from the microcomputer 11, which will be described later.
The movement of the robot is controlled.

In this case, for constant linear velocity control of the spindle motor 2,
A pulse signal output from the rotation sensor 2a is also used. 11 is a microcomputer that controls the operation of each part of the CD player, and includes a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores programs used by the CPU, and an RA that temporarily stores various data.
M, and an l10 (input/output) boat that exchanges data with the outside. This microcomputer 1
1 is supplied with jump information corresponding to the number of hyperactive tracks of the pickup 3 from the RF amplifier 5, and absolute time information read from each part of the CDI is supplied from the signal processing circuit 6. CD from sensor 2a
A pulse signal corresponding to the rotation speed of I is supplied. Reference numeral 12 designates an operation button for giving various operation commands to the microcomputer 11, and reference numeral 13 represents a display device that performs various displays based on display commands supplied from the microcomputer 11.

Next, the operation procedure when performing a song search in the above-described configuration will be explained with reference to FIG.

First, at startup, the microcomputer 11
The absolute time information of the start point of each part is read from the lead-in area RIA of the DI, and this absolute time information is written into the internal RAM.

Next, when the operation button 12 is operated and a song search is commanded, the number of rotations per unit time of the CDI at the current position Pa is detected based on the pulse signal output from the rotation sensor 2a, and this number of rotations is detected. From, CDI linear velocity V. and the radius r corresponding to the amount of displacement of the pickup 3 from the center of the CDI. That is, if the number of pulses per second output by the rotation sensor 2a is n, the number of pulses output from the rotation sensor 2a every time CD 1 h < 1 rotation is m, so 1 of the current CDI
The number of rotations per second is n/I++, and therefore, the following equation (4) holds true.

v0=2・π・r・(n/m)...
...(4) Substituting this equation (4) into the above-mentioned equation (2), the absolute time La of the current position Pa is determined by the elapsed time of the equation.
and the absolute time tb of the target position Pb, respectively, to obtain the radius ra of the current position Pa and the radius rb of the target position Pb.

The radii ra and rb obtained by this are as described above (3)
By substituting into the equation, the accurate number of tracks N to the target position pb is calculated. Based on the number N of tracks calculated in this way, the pickup 3 is thread-fed to the vicinity of the target position Pb.

From then on, 100 track jumps will be made as before.

Perform a song search by controlling the 10 track jump and 1 track jump.

That is, reading absolute time information from the current position P1,
If the target position Pb has not been reached, this target position pb
Carry out a 100 track jump toward the outer circumference until you pass . In the illustrated example, one 100 track jump is performed with P+=Pt until the target position pb is passed. Next, when the vehicle passes the target position Pb, a 10-track jump is performed in the opposite direction. In the illustrated example, P until the target position Pb is passed.

→P3. The IO track jump is repeated three times: P3→P,,P,→P. Next, when the pickup 3 passes the target position Pb, the pickup 3 moves in the outer circumferential direction by l-track jump, and thereby the pickup 3 reaches the target position Pb.

According to the embodiment described above, when feeding the thread, the current CD is detected based on the output pulse signal of the rotation sensor 2a.
The rotation speed n/m per unit time of I is obtained, and from this rotation speed n/m, the linear velocity V of CDI is obtained.

Since the relationship between and the radius r can be obtained, it is possible to accurately calculate the number N of remaining tracks to the target position Pb, and thereby the thread can be sent to a position P1 extremely close to the target position Pb. As a result, the number of subsequent track jumps is reduced compared to the conventional method.

In the embodiment described above, after the thread is fed, the track jump is repeated a plurality of times to move to the target position Pb. The number of remaining tracks to the target position pb may be calculated based on this calculation result, and the vehicle may be moved to the target position Pb in one track jump. In addition, in the above-mentioned embodiment, the case where the application is applied to a CD player for normal music playback and the beginning of a song is explained was explained. , CD-V (compact disc video), LD (laser disc), etc., and may be used to cue various data and videos.

"Effects of the Invention" As explained above, according to the present invention, when thread-feeding the pickup, the number of rotations per unit time of the disk is detected, the absolute time information of the current position is read from the disk, and then , calculates the number of remaining tracks to the target position based on the rotation speed, the absolute time information of the current position, and the absolute time information of the target position, and moves the pickup to the vicinity of the target position based on the calculation result. Since the sled is fed, the number of remaining tracks to the target position can be accurately calculated when the sled is fed, and this allows the sled to be fed extremely close to the target position. The number of track jumps required is reduced, and the time required for searches such as finding the beginning of a song can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a CD player to which a search method according to an embodiment of the present invention is applied, FIG. 2 is a diagram for explaining the operating procedure of the search method according to the embodiment, and FIG. FIG. 2 is a diagram for explaining the operating procedure of a conventional search method. l...CD, 2...spindle motor,
2a... Rotation sensor, 3... Optical pickup, 4... Feeding mechanism, 5...
...RF amplifier, 6...signal processing circuit, I
O... Surho circuit, II... Microcomputer.

Claims (1)

[Claims] After an optical pickup is moved to the vicinity of the target position by thread feeding, the target position is searched by track jump while reading absolute time information from a reference position recorded on each part of the disk by the pickup. In a search method for an optical disc player, when thread-feeding the pickup, the number of revolutions per unit time of the disc is detected, absolute time information of the current position is read from the disc, and then the number of revolutions and the number of revolutions are read from the disc. , calculates the number of remaining tracks to the target position based on the absolute time information of the current position and the absolute time information of the target position, and based on this calculation result, threads the pickup to the vicinity of the target position. A search method in an optical disc player, characterized in that: