JP2951147B2 - How to search for a disc player - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for searching a disk player which reads a signal recorded on a disk rotating at a constant linear velocity by an optical pickup.

[0002]

2. Description of the Related Art Disk players which perform a reproducing operation by reading out a signal from a disk on which information data such as music is recorded by a digital signal using an optical pickup have become widespread. One of them is a CD player.

As is well known, a disc used in such a CD player is called a sub-coding signal in which one block is completed at a period of 1/75 second in addition to a main data signal such as music information. A sub data signal is recorded. Such subcoding signals are P, Q to W
The P channel includes position index information indicating the position of the beginning of the song, and the Q channel includes the absolute elapsed time from the start of the signal track, the elapsed time for each song, and the Q channel. Position index information indicating a song number or the like is included.

Therefore, the CD player can perform an operation of detecting a position where a desired music or the like is recorded and starting a reproducing operation, that is, an operation called a search, by using the position index information. It is configured.

[0005] Such a search operation is performed by moving the optical pickup in the radial direction of the disk. The movement operation involves moving the pickup main body to a target position at a high speed and an object constituting the optical pickup. The operation is performed by displacing the lens.

[0006]

The conventional search method is as follows.
The number of tracks to the target position is calculated from the absolute time of the current position and the absolute time of the target position, and the optical pickup is moved in accordance with the number of tracks. This is done by counting the number of signal tracks traversed using the resulting signal.

The higher the moving speed of the optical pickup body in order to increase the search speed, the longer the time required from the application of the brake signal to the optical pickup to the stop is. Therefore, when the target position is close to the position of the outermost signal recorded on the disk, there is a problem that the optical pickup jumps out to a position where no signal is recorded, that is, a mirror area.

An object of the present invention is to provide a disk player search method which solves the above problem.

[0009]

According to the present invention, the absolute time of the current position, the absolute time of the target position, the number of tracks (A) to the target position are calculated, and the position of the outermost signal recorded on the disk and the target position are calculated. The number of tracks (B) between them is calculated, and when the number of tracks (B) is smaller than a predetermined value, the number of search tracks (S) is set to AK (K is a constant).

[0010]

FIG. 1 is a flowchart showing a search method according to the present invention, and FIG. 2 is a block circuit diagram of a disc player according to the present invention.

In FIG. 2, reference numeral 1 denotes an optical pickup having a photodetector for projecting a light beam on a CD type disc and receiving a light beam reflected on a signal surface of the disc;
Reference numeral 2 denotes an RF amplifier circuit that amplifies an RF signal obtained from the photodetector of the pickup 1 and shapes the waveform, and 3 denotes a light beam of the optical pickup 1 based on a signal obtained through the RF amplifier circuit 2. Servo signal for performing focusing control for focusing on the signal surface of the disk and tracking control for causing the light beam to follow a signal track on the signal surface, and for controlling track jump by displacing an objective lens constituting the optical pickup. It is a processing circuit.

Reference numeral 4 denotes a digital signal processing circuit for performing digital signal processing of signals output from the RF amplifier circuit 2 and demodulating various signals, and reference numeral 5 denotes a digital signal digitally processed by the digital signal processing circuit 4. And a D / A converter 6 for converting the signal into an analog signal, and an amplifier 6 for receiving the left and right channel audio signals converted into the analog signal by the D / A converter 5 and amplifying the signal. Circuit.

Reference numeral 7 denotes a system control circuit which receives a signal demodulated by the digital signal processing circuit 4 and performs various operation controls in accordance with the operation of an operation switch 8. Reference numeral 9 denotes a track jump control circuit whose operation is controlled by the system control circuit 7, which has an operation of controlling the track jump operation of the optical pickup 1 by the servo signal processing circuit 3. Reference numeral 10 denotes a pickup feed control circuit whose operation is controlled by the system control circuit 7, and has an operation of controlling a drive operation of an electric motor (not shown) for moving the main body of the optical pickup 1.

In such a circuit configuration, the number of tracks jumped by the optical pickup 1 based on the control operation of the track jump control circuit 9 is determined by the difference between the absolute time of the current position read from the disk and the absolute time of the target position. Although determined according to the difference, the number of track jumps is set to a smaller value as approaching the target position. The optical pickup 1 is controlled by the pickup feed control circuit 10.
Is performed by displacing the main body of the optical pickup 1 at a high speed, and such a displacing operation is based on a known change in the signal obtained with the feeding operation of the main body of the optical pickup 1. This is done by technology, i.e., by counting signals that change each time they cross a signal track.

The feed operation of the main body of the optical pickup 1 is performed at a high speed, and the number of moving tracks is calculated from the absolute time of the current position and the absolute time of the target position. The number of moving tracks is set to a small value because the track is not immediately stopped even after the execution.

The disk player according to the present invention is configured as described above. Next, the operation of the present embodiment will be described. When the user operates a playback operation switch (not shown) among the operation switches 8, the control operation by the system control circuit 7 is performed and the reproduction operation of the disc player is started.

The optical pickup 1 performs a focusing control operation and a tracking control operation by the servo signal processing circuit 3 and a feed control operation of the pickup 1 main body by the pickup feed control circuit 10 to read a signal recorded on the disk. Perform the operation. The signal read by the optical pickup 1 is input to an RF amplifier circuit 2 where it is amplified, waveform-shaped, and applied to a digital signal processing circuit 4 as a digital signal. The digital signal processing circuit 4 demodulates a digital signal output from the RF amplifier circuit 2 and extracts various data signals included in the digital signal.

When signal processing is performed by the digital signal processing circuit 4 to extract information data (audio data), the information data is applied to a D / A converter 5 after signal processing such as error correction is performed. You. The digital signal applied to the D / A converter 5 is converted into an analog signal, then separated into left and right stereo signals and input to the amplifier circuit 6. Therefore, the user can play and listen to signals such as music recorded on the disc.

As described above, the reproducing operation in the present embodiment is performed. Next, a search method which is the gist of the present invention will be described with reference to the flowchart shown in FIG.

When the user performs an operation for reproducing a desired music, that is, a music selection operation, the absolute time of the current position, the absolute time of the target position, and the number of tracks (A) from the target position are calculated. (Step A).

The number of tracks (B) between the position of the outermost signal recorded on the disk and the target position is calculated (step B). In a state where the optical pickup 1 is moved at a high speed by the control operation of the pickup feed control circuit 10, when the brake operation is performed, the optical pickup 1 is provided on the disc by the operation of moving until the optical pickup 1 stops. Let C be the number of tracks in the dangerous area that enters the mirror area (step C).

The number of tracks (C) and the number of tracks (B)
Is determined (step D). If C ≧ B, it is determined that the target position is within the dangerous area, so the search track number (S) is set to S = AK (K is a constant) (step E). The high-speed search operation for counting the AK tracks, which is the number of search tracks (S) set in this way, is started (step F).

If it is determined in step D that C <B, it is determined that the target position is not within the dangerous area, so the number of search tracks (S) is set to S = A (step G). Then, a high-speed search operation for counting the A track, which is the number of search tracks (S) set in this way, is started (step F).

The high-speed search operation is started by the above-described method. In the high-speed search operation state, when the count operation of the number of search tracks (S) is performed, a brake is applied to the motor that moves the optical pickup 1 body. A signal is provided. Such an operation stops the moving operation of the main body of the optical pickup 1, but the stop position is shifted from the position where the brake signal is supplied, that is, the position where the search track number (S) is counted.

Therefore, the count number (P) counted during the high-speed search operation is determined by the number of tracks shifted after braking by Q
Then, it suffices to set P = SQ. Further, the number of tracks (A) calculated in step A can be set in consideration of the number of tracks that are shifted after braking. Then, in step E, the value of the set constant K is set to be larger than C.

[0026]

According to the search method of the present invention, the absolute time of the current position, the absolute time of the target position and the number of tracks to the target position are calculated, and the position of the outermost signal where the target position is recorded on the disk is calculated. The number of tracks counted at the time of the high-speed search is set by determining whether or not the optical pickup is close to the optical disk. Therefore, it is possible to prevent the optical pickup from jumping out of the mirror area.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a search method of the present invention.

FIG. 2 is a block circuit diagram of a disc player according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical pickup 3 Servo signal processing circuit 4 Digital signal processing circuit 7 System control circuit 9 Track jump control circuit 10 Pickup feed control circuit

Claims (1)

(57) [Claims] 1. A disk player configured to perform a search operation by reading out a signal recorded on a disk rotating at a constant linear velocity by an optical pickup and counting the number of tracks.
The absolute time of the current position, the absolute time of the target position and the number of tracks (A) to the target position are calculated, and the number of tracks between the position of the outermost signal recorded on the disk and the target position (B) Is calculated, and when the track number (B) is smaller than a predetermined value, the search track number (S) is set to AK
(K is a constant). A method of searching for a disc player.