JPH0679423B2 - Search method for disc player - Google Patents

Description

TECHNICAL FIELD The present invention relates to a search method for a disc player in consideration of search error prevention.

"Prior Art" FIG. 3 is a block diagram showing a configuration of a disc player.

In the figure, 1 is a compact disc (hereinafter referred to as CD),
Reference numeral 2 is a spindle motor for rotationally driving the CD 1, 3 is an optical pickup for reading digital pit information on the recording surface of the CD 1, and 4 is a feed motor for moving the optical pickup 3. Digital audio information, TOC information, and the like are recorded on the CD1. Of these, TOC
The information is recorded on the innermost track of CD1, the total playing time (that is, the total playing time of digital audio information) is Tt minutes, and the first song is played after Ts minutes have passed from the current track position. Contents information including contents such as the beginning and the end of the whole performance after Te minutes, the performance (playback) time of the first song is T ₁ minute, the performance time of the second song is T ₂ minutes, and so on. Is. The optical pickup 3 includes a semiconductor laser, an objective lens, an optical sensor, a focus actuator (focus adjustment mechanism), a tracking actuator (tracking adjustment mechanism), and the like. 5 is an RF amplifier that amplifies the read signal output from the optical pickup 3, 6 is a signal processing circuit that demodulates the amplified read signal, corrects and corrects code errors, and 7 is a digital read signal that is an analog audio signal A DA converter for converting to an audio circuit, an audio circuit 8 for amplifying an audio signal, and the like, and an output terminal 9 for the audio circuit. Further, a servo controller 10 and a servo circuit 11 are provided to control the spindle motor 2, the optical pickup 3, and the feed motor 4. The servo controller 10 includes a CPU (central processing unit), a ROM in which a control program is recorded, a RAM for data recording, and an I / O port, and creates various control signals to generate a servo circuit 11 and the like. Send to. In addition, the servo circuit 11 is based on various control signals supplied from the servo controller 10, and starts up the spindle motor 2 and CLV servo control (constant linear velocity control), focus servo control of the optical pickup 3, and tracking.・ Perform servo control.

When the disc player having the above structure is used, a so-called high-speed search is conventionally used to move the optical pickup 3 at high speed from the current track position to the track position where the target music start is recorded (target track position). Is taken.

This method is as follows.

From the above TOC information, the time required for performance from the current track position to the target track position is known, and performance processing is performed using this time and linear velocity (relative track traveling speed of the optical pickup) to determine the time from the current track position. Calculate the number of tracks to the target track position. Next, while the number of jump tracks is being measured by high-speed thread feeding, the number of tracks is moved until the measured value of the number of tracks reaches the calculated value. By such a method, the optical pickup 3 is moved at high speed near the target track position.

"Problems to be solved by the invention" By the way, the linear velocity varies depending on various CDs (1.2 m / s to 1.4 m
/ s), the number of tracks from the current track position to the target track position calculated by the above method includes an error. Therefore, according to the above conventional search method, a feed error may occur due to the high-speed thread feed, and the optical pickup may overrun in the outer peripheral direction of the CD. In this case, the movement range of the optical pickup is set according to the diameter (12 cm) of a normal CD, so this does not cause much trouble when using a normal CD, but a single CD (8 cm diameter) Or CDV
The following problems have been problems when using (CD with video). That is, in the case of a CD single with a small outer diameter, the optical pickup sometimes went out of the CD and went out of control. Also, in the case of CDV, the maximum length of the digital audio recording area is 20 minutes, so an optical pickup may have entered the video track, causing a runaway.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a search method for a disc player in which a means for preventing runaway of a high speed pickup during a high speed search is provided.

"Means for Solving the Problem" The present invention relates to a search method in a disc player for moving an optical pickup from a current track position to a target track position, and based on the index information recorded at a predetermined position of a CD, all the digital information is recorded. If it is determined that the reproduction time is longer than or equal to a predetermined time, and as a result, it is determined that the reproduction time is longer than or equal to the predetermined time, the optical pickup is initially moved to the vicinity of the target track position by high-speed feed, and then, The above problem is solved by performing the search by pulse feeding and, on the other hand, by performing the search only by pulse feeding when it is determined that the total reproduction time is less than or equal to the predetermined time.

[Operation] According to the present invention, the total reproduction time of the digital information is determined, and when the total reproduction time is equal to or longer than the predetermined time, the search including the high-speed feed is performed, while the total reproduction time is equal to or shorter than the predetermined time. If so, only the search by pulse feed is performed.

As a result, it is possible to avoid a runaway accident of the optical pickup at the time of search, which is caused by different types of CDs.

[Examples] Examples of the present invention will be described below with reference to the drawings.

1 and 2 are explanatory diagrams for explaining the operation of the search method in the disc player according to the embodiment of the present invention. The search operation in the disc player according to this embodiment is performed by the following procedure.

In this embodiment, it is judged from the read TOC information whether or not the required reproduction time of the digital audio portion, that is, the required trace time from the innermost track a to the outermost track b exceeds 20 minutes. It Depending on the result, the subsequent search method is different.

(B) "Required playback time exceeds 20 minutes" An example of this case will be described with reference to FIG. This is the case when using a regular CD with a maximum of 74 minutes of digital audio.

In this case, the number of tracks from the current track position c to the target track position d is calculated from the required time and the like by the same method as the conventional example. Using this result, a predetermined track position e before the target track position d
Up to this point, the feed motor 4 performs the search by the high-speed thread feed of the optical pickup 3, and after reaching the predetermined track position e, the search is switched to the pulse feed search. In the above-mentioned search by pulse feed,
A search is performed by a 1-pulse 100-track jump of a step, a 1-pulse 10-track jump of a second step, and a 1-pulse 1-track jump of a third step. That is, in the first step, the optical pickup 3 is jumped 100 tracks each time one pulse of the drive command signal is applied to the feed motor 4. As a result, the optical pickup 3 further approaches the target track position d, and after reaching the track position f, a search is performed by 10 track jumps every time one pulse of the second stage is applied. As a result, after reaching the track position g which is closest to the target track position d, the optical pickup 3 is moved by one track for each pulse in the third stage. In this way, the optical pickup 3 can be moved to the target track position d at high speed.

(B) When the required playback time does not exceed 20 minutes This case applies when using a CD single or CDV with a maximum of 20 minutes for digital audio.

In this case, the search by the high-speed thread feed described in (a) above is not performed. Then, as shown in FIG. 2, only the search by pulse feeding is performed.
That is, from the current track position c to the target track position d
Up to the predetermined track position h before the target track position d after the number of tracks up to is calculated by the same method as above.
The first-step 1-pulse 100-track jump search is performed, then the second-step 1-pulse 10-track jump search is performed to the track position i that is closest to the target track position d, and finally the target track Position d
Up to the third stage, the search is performed by the one-pulse one-track jump.

It should be noted that the above example is generally applied to a disc player for reproducing normal music, but the present invention is not limited to this, and a CD-RO
It can also be applied to playback devices such as M, CD-I (compact disc interactive media), CD-V (compact disc video), and LD (laser disc).

[Advantages of the Invention] As described above, according to the search method in the disc player of the present invention, when the total reproduction time of the digital information is the predetermined time or more, the search including the high speed feed is performed, while When the total playback time is less than the specified time, only the pulse feed search is performed, so even when the target track position is overrun, the runaway accident of the optical pickup is avoided regardless of the CD type. be able to. That is, in the case of a CD whose total playback time is a predetermined time or more, even if an overrun occurs due to high-speed feed, since it is the part where the same type of digital information is still recorded, runaway can be avoided and the total playback time In the case of CD for a predetermined time or less, since only the search by pulse feed is performed, overrun does not occur and therefore runaway can be avoided. In the latter case, since the maximum movement distance of the optical pickup is relatively short, the relatively slow search speed does not substantially cause a problem.

[Brief description of drawings]

1 and 2 are explanatory views for explaining the operation of the search method in the disc player according to the embodiment of the present invention, and FIG. 3 relates to the embodiment of FIGS. 1 and 2. The block diagram which shows the electric constitution of a disc player. 1 ... Compact disc (CD), 3 ... Optical pickup, 4 ... Feed motor, a ... Innermost track position, b ... Outermost track position, c ... Current track position, d ... Purpose Track position, e, f, g, h, i ...
Other intermediate track positions.

Claims (1)

[Claims] 1. A search method in a disk player for moving an optical pickup from a current track position to a target track position, wherein a total reproduction time of digital information is a predetermined time or more based on table of contents information recorded at a predetermined position of a disk. If, as a result, it is determined that the time is longer than the predetermined time, the optical pickup is initially moved close to the target track position by high-speed feed, and then a search is performed by pulse feed. A search method in a disc player, characterized in that, when it is determined that the total reproduction time is shorter than a predetermined time, the search is performed only by pulse feeding.