KR950001872B1 - Trackcounting compensation circuit for optical recording apparatus - Google Patents

Abstract

The circuit protects the track counting error which is caused to variation of motor position. The device includes the slade motor which moves the information of optic-recording media, the RF amplifier which generates the time crossing signal and mirror signal. The device includes the compensation means which has the operational amplifier for amplifying the time crossing signal to the specified gain, and the coupling capacitor which removes the dirrect current components of time zero crossing signal and connects to the inverting input terminal and output terminal of operational amplifier.

Description

Track Counting Compensation Circuit of Optical Recording & Reproducing Equipment

1 is an optical recording and reproducing apparatus having a track counting compensation circuit according to the present invention.

2 is a waveform diagram of each part according to FIG. 1.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording / playback apparatus such as a CD-ROM (Compact Disc-Rom) and CD-I (Compact Disc-Interactive). And a track counting compensation circuit.

Typically, an optical recording / reproducing apparatus includes a servo for rotating a disk, which is an optical recording medium, at a constant speed, a sled servo that moves the entire pickup unit for access to an arbitrary track on the disk, and controlling tracking on the track of the disk. Tracking servo is installed. Among these, the sled servo is very useful when searching for information on a disk where a large amount of information is recorded at high speed.

The servo controls the sled motor moving in the axial direction so that the position of the pickup unit which leads the information on the disc is moved to the target point.

In general, the microcomputer that controls the system as a whole applies data for moving the sled motor to a predetermined position by the servo in response to user command data, thereby continuously checking whether the pickup has reached the corresponding position. do.

The check is made by applying track counting data to the microcomputer indicating how many tracks the servo has moved.

That is, the track counting data is generated by phase comparison of a time zero crossing signal and a mirror signal read from a pickup, and are data output by the servo to the microcomputer.

In such a conventional optical recording / reproducing apparatus, the level of the information read from the pickup moving by the sled motor to a predetermined position on the disc becomes smaller as the high-speed search decreases the frequency characteristic.

Therefore, even though the mirror signal is normally input, the servo cannot output normal track counting data to the microcomputer because the zero crossing signal is abnormally applied.

Therefore, the microcomputer does not control the servo accurately, resulting in the pickup on the disc not reaching the target position.

The zero crossing signal is a signal generated each time the pickup crosses a track on the disc one by one.

Of course, the information read from the pickup is weak, but there is an RF amplification unit that amplifies it. There was no.

Accordingly, an object of the present invention is to provide a track counting compensation circuit capable of preventing a track counting error caused by a change in position of a sled motor during high speed search.

Another object of the present invention is to improve the reliability of the optical recording and reproducing apparatus by preventing track counting errors.

According to an aspect of the present invention for achieving the above object, a sled motor for moving a pickup that leads information on an optical recording medium in a predetermined direction in response to a movement signal applied through a servo line, A sled servo that provides the movement signal for moving the sled motor in response to the movement data and receives the time zero crossing signal and the mirror signal generated from the RF amplifier according to the read of the information and generates track counting data. An optical recording and reproducing apparatus comprising: the sled servo connected between the RF amplifying unit and the sled servo and compensating the time zero crossing signal with a predetermined gain to prevent an occurrence of the track counting data. Compensation means for applying is provided.

Here, the first signal of the compensation means is the time zero crossing signal, and the sled servo provides the track counting data generated by comparing the mirrored signal with the compensated time zero crossing signal to the microcomputer.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is an optical recording and reproducing apparatus having a track counting compensation circuit according to the present invention, wherein a pickup 6 which reads information from a disk rotated at a constant linear speed by the spindle motor 2 signals the read information. The RF amplifier 10 is applied to the RF amplifier 10 through a line SL, and the RF amplifier 10 outputs a time zero crossing signal and a mirror signal to the output terminals 01 and 02, respectively. The first signal, which is the time zero crossing signal of the output terminal 01, is compensated and applied to the sled servo unit 20 through the line A, and the sled servo unit 20 transmits the first signal and the mirror. And outputting the track counting data generated by comparing the signals to the microcomputer 30 through the line L1.

In addition, the microcomputer 30 applies the movement data corresponding to the user's key input to the sled servo unit 20 through the data line DL. Accordingly, the sled servo unit 20 transmits the servo line SV. It is made to control the sled motor (4) through.

Here, the compensation unit 100 corresponds to the compensation means, an operational amplifier OP1 for amplifying the first signal with a predetermined gain, a bias resistor R3, and an amplification resistor R1 and R2. And capacitors C1 and C2 for coupling the DC component of the first signal to the front and rear ends of the operational amplifier OP1.

2 is a waveform diagram of each part according to FIG. 1, wherein waveform B is a waveform appearing in the line B, waveform A is a waveform appearing in the line A, and a waveform CO is shown in the line L1. The waveforms are shown separately.

Hereinafter, the operation and effect according to the embodiment of the present invention will be described in detail based on the operation alc.

First, referring to FIG. 1, the microcomputer 30 applies movement data corresponding thereto to the sled servo unit 20 through the data line DL in response to a user's key manipulation during a high-speed search.

The movement data output by the microcomputer 30 indicates how much (by how many tracks) the microcomputer 30 should move the pickup 6 in the circumferential direction or the inner circumferential direction to the track point on the disc currently located. Data to represent.

Accordingly, the sled servo unit 20 applies a signal for controlling the sled motor 4 to the servo line SV in response to the applied movement data.

As the movement of the sled motor 4 starts, the microcomputer 30 continuously counts the track counting data applied to the line L1, and if the pickup 6 moves to the target track, the stop command is issued. It must be applied to the data line DL.

That is, it can be seen that the stop command is closely related to the track counting data.

As the sled motor 4 moves, the pickup 6 moves the position on the disk at a high speed. In this case, the RF amplifier unit converts the information, which is an RF signal read from the disk, through a signal line SL. Output as (10). Therefore, the RF amplifier 10 amplifies the information by a predetermined amount and outputs the time zero crossing signal and the mirror signal to the output terminals 01 and 02.

Here, the mirror signal is shown as waveform B of FIG. 2, but the time zero crossing signal is not the same as waveform A. FIG.

In other words, during the high-speed search, the first signal, which is the time zero crossing signal, does not appear like the waveform A, but appears as a sine wave in the vicinity of the reference voltage ref.

Therefore, the track counting data without error can be provided to the microcomputer 30 only by compensating the signal, that is, the first signal, as the waveform A of the second signal, to the output terminal 01 of the RF amplifier 10. will be.

Therefore, in order to compensate the first signal as shown in the waveform A of FIG. 2, the compensation unit 100 is provided between the output terminal 01 and the input terminal TZC of the sled servo unit 20.

In this case, the voltage at the output voltage point V0 of the compensator 100 is expressed by the following equation.

Therefore, when the resistors R1 and R2 are appropriately selected according to the input voltage Vi during the high-speed search, the reference voltage ref can be made at the center position of the first signal as shown in the waveform A of FIG. There will be.

Accordingly, the sled servo unit 20 inputs waveforms A and B of FIG. 2 to compare phases, and then generates track counting data similar to the waveform CO.

The waveform CO is applied to the microcomputer 30 through the line L1.

Accordingly, the microcomputer 30 may accurately search for a desired track even at a high speed search by counting the track counting data in which no error occurs.

Here, the sled servo unit 20 is well known, and is usually embedded in a Sony CXA 1082BQ LSI chip.

As described above, the present invention has an advantage of preventing a track counting error caused by a change in the position of the sled motor during high-speed search, thereby improving reliability of the system.

Claims (3)

A sled motor for moving a pickup that leads information on the optical recording medium in a predetermined direction in response to a movement signal applied through a servo line, and a movement of the sled motor in response to movement data applied from the outside; An optical recording and reproducing apparatus including a time zero crossing signal generated from an RF amplifying unit and a sled servo for generating track counting data in advance in response to a read of the information. Track counting is connected between the unit and the sled servo and comprises a compensation means for compensating the time zero crossing signal with a predetermined gain and applying it to the sled servo in order to prevent the occurrence of the track counting data. Compensation circuit. The track counting compensation circuit according to claim 1, wherein said compensation means has an operational amplifier for inputting said time zero crossing signal to an inverting input terminal and amplifying said predetermined gain. 3. The track counting compensation circuit according to claim 2, further comprising a coupling capacitor connected to the inverting input terminal and the output terminal of the operational amplifier and for removing a DC component of the time zero crossing signal.