JPH04238169A - Track jump system - Google Patents

Abstract

PURPOSE:To allow a tracking jump operation with high accuracy by detecting the signal proportional to the reaction of a tracking actuator and using this signal as a compensation signal for a kick signal. CONSTITUTION:This track jump system drives a pickup to an arbitrary track by inputting and amplifying the kick signal and supplying the driving signal to the tracking actuator 3. The reaction component generated in the tracking actuator 3 is detected as a reaction signal and the detected reaction signal is supplied as the compensation signal of the kick signal. A servo amplifier 2 which receives and amplifies the tracking error signal and the kick signal and supplies these signals to the tracking actuator 3 and a feedback circuit which is connected between the output and input of the servo amplifier 2 and detects the reaction component of the tracking actuator 3 as the reaction signal are provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a track jump system, and more particularly to a track jump system that greatly reduces the influence of reaction force.

0002

2. Description of the Related Art Conventionally, a track jump in which a pickup in a CD player or the like jumps and moves to a predetermined tracking position on a disc has been configured as shown in FIG. In FIG. 4, when performing jump control, switch 1 is
is turned off, a kick signal is input to the amplifier (servo amplifier) 2, and the output of the amplifier 2 drives the tracking actuator 3 to move the actuator by the desired number of jumps. Thereafter, switch 1 is switched to supply the tracking error signal to the amplifier and apply the servo.

[0003] FIG. 5 is a diagram illustrating the temporal flow of the operation mode of such a tracking jump. When the switch 1 is OFF, when a kick voltage (V) consisting of a kick part and a brake part as shown in 5A is supplied to the amplifier 2, a driving force (F) as shown in 5B is generated in the tracking actuator 3. do. Due to this driving force 5B, the speed (S) of the tracking actuator 3 gradually increases at first, and gradually decreases after reaching the sign reversal point of the driving force F (
5C). As a result, the amount of movement (P) of the tracking actuator 3 changes as shown in 5D. When moving n tracks, reverse the polarity of the kick voltage (-polarity) when the actuator moves n/2 tracks.
let Then, the brake is activated and the speed becomes 0 after moving further n/2 tracks. At this point, the kick signal is turned off and the servo is applied in response to the tracking error signal to start the tracking operation.

0004

[Problem to be Solved by the Invention] Incidentally, since the tracking actuator constitutes a vibration system consisting of wires, springs, dampers, etc., a reaction force IF is generated which is a force that attempts to return to its mechanical center position. . The reaction force IF is, where k is the spring constant and x is the displacement amount, IF=
kx

It is expressed as (1). In addition, the resonance frequency f, which is one of the pickup characteristics, is f=(1/2π)√(k/m), where m is the equivalent mass of the vibration system.

It is expressed as (2), and in the end, k=m・(2πf)2 =4π2 f2 m

(3) becomes. Here, if 4π2 m=a, then k=
af2, and when substituted into equation (1), IF=af2
x, and in a pickup with a high resonance frequency, the influence of this reaction force cannot be ignored.

The influence of this reaction force will be explained with reference to FIG. When a kick voltage as shown in 6A of FIG. 6 is applied,
The actuator 2 begins to move, but a reaction force (IF) 6B proportional to the amount of movement is generated. The driving force (F) applied to the tracking actuator 3 due to this reaction force is 6C
The change is as shown in FIG. 5, and is not constant as shown in 5B of FIG. As a result, the speed (S) of the tracking actuator 3 becomes nonlinear as shown in 6D, and its movement amount (P) becomes as shown in 6E.

That is, when the kick voltage is reversed after moving by n/2 tracks, the braking force and the reaction force are in the same direction, so a large braking force is generated (6D), and the speed becomes 0 at time x. At this time, since the tracking actuator has not moved to the n/2 track, the brake pulse continues to be applied, and the speed is applied in the opposite direction to the kicking direction. Therefore, as shown at 6E, the moving direction of the tracking actuator is reversed, and the brake pulse continues to be applied until n/2 tracks are counted. As a result, even though n tracks have been jumped, almost no jumps have been made. Also, as shown in 6D of Fig. 6, the brake pulse is OFF.
When this happens, the speed of the actuator is not zero, and even if the servo is turned on, the pickup will move further in the kicking direction until stable tracking starts, resulting in a problem that it takes time.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a track jump method that greatly reduces the influence of reaction force, speeds up the settling of the tracking actuator after a track jump, and enables highly accurate track jumps. .

[0008]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the track jump method according to the present invention inputs a kick signal, amplifies it, and supplies a drive signal to a tracking actuator to move a pickup to an arbitrary track. In the track jump method, a reaction force component generated in the tracking actuator is detected as a reaction force signal, and the detected reaction force signal is supplied as a compensation signal for the kick signal. Also, a servo amplifier that receives a tracking error signal or a kick signal, amplifies it and supplies it to the tracking actuator, and a feedback circuit that is connected between the output and input of the servo amplifier and detects the reaction force component of the tracking actuator as a reaction force signal. It is configured with a circuit.

[0009]

[Operation] In this invention, the reaction force component generated in the tracking actuator is detected as a reaction force signal, and the detected reaction force signal is supplied as a compensation signal for the kick signal, thereby greatly reducing the influence of reaction force and tracking This speeds up the settling of the tracking actuator after a jump, enabling highly accurate track jumps. The reaction force signal can be detected by an integrating means, such as an integrating amplifier, connected to the tracking actuator. The loop gain of the feedback circuit consisting of this integrating amplifier is adjusted by a variable resistor. Further, a configuration in which the feedback circuit is disconnected by a switch can also be adopted.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram showing an example of a structure for implementing the track jump method according to the present invention. In FIG. 1, components denoted by the same reference numerals as those in FIG. 4 indicate the same components as in FIG. In this embodiment, the output and input of the amplifier 2 are connected through a feedback path, and a reaction force signal obtained by detecting a reaction force component generated in the tracking actuator is used as a compensation signal (cancellation signal).

In the embodiment of FIG. 1, the feedback path consists of an integrator 4 consisting of a semi-fixed resistor RV, an amplifier 4 having a resistor R1 and a capacitor C1 connected between its input and output. FIG. 3 shows a diagram similar to FIGS. 5 and 6 for explaining the operation of the components shown in FIG. 1. In FIG. 3, kick voltage V (3A) is input to amplifier 2. A reaction force IF as shown in 3B is generated in the tracking actuator 3, and a voltage VIF proportional to the reaction force IF (3B) is generated at the output of the amplifier 4 having an integrator configuration. When this voltage VIF is superimposed on the kick pulse (3A) by the amplifier 2, a constant amount of driving force F (3D) is obtained. Therefore, the moving speed S of the tracking actuator changes as shown in FIG. 3E, similar to 5C in FIG. 5, and the moving amount P of the tracking actuator also becomes approximately ideal.

Here, the semi-fixed resistor RV is an adjustment resistor for setting the loop gain constituted by the amplifiers 2, 4, etc. in FIG. 1 to 1. Further, when the servo operation is turned on and tracking is performed, the loop is operated and a voltage corresponding to the actuator position is constantly supplied to the tracking actuator 3, which is useful for preventing sound skips due to disturbances such as scratches.

FIG. 2 is a block diagram of another embodiment of the tracking jump method according to the present invention. In the embodiment shown in FIG. 2, except for the semi-fixed resistor RV in the embodiment shown in FIG.
It is controlled by F. In other words, the above loop gain is set to approximately 1, a control signal is input to the switch 5 until the tracking actuator operation stabilizes after the kick pulse is applied, and the switch 5 is turned OFF after the servo turns ON. ing. According to the embodiment of FIG. 2, the same effect as the embodiment of FIG. 1 can be obtained without adjustment. In the above embodiment, the reaction force detection means can be constructed by omitting the reaction force detection amplifier and connecting a simple integrator made of a resistor and a capacitor to the non-inverting input of the amplifier 2.

[0014]

As explained above, the tracking jump method according to the present invention detects a signal proportional to the displacement amount (reaction force) of the tracking actuator and uses this detection signal as a compensation signal for the kick signal, so it is stable. and enables highly accurate tracking jump operation. Therefore, it is possible to prevent a failure in the track jump operation due to the reaction force of the tracking actuator, to reach a desired track at high speed, and to realize an optical disc reproducing device with a short search time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a configuration for realizing a tracking jump method according to the present invention.

FIG. 2 is a block diagram showing another configuration example for realizing the tracking jump method according to the present invention.

FIG. 3 is a time chart diagram illustrating the operation of the embodiment shown in FIG. 1;

FIG. 4 is a block diagram showing an example of a configuration adopted in a conventional track jump method.

FIG. 5 is a time chart diagram illustrating the operation of the configuration shown in FIG. 4;

FIG. 6 is a time chart diagram for explaining the problems of the conventional track jump method.

[Explanation of symbols]

1, 5 Switch 2,4 Amplifier

Claims (5)

[Claims] 1. A track jump method in which a kick signal is input, amplified and a drive signal is supplied to a tracking actuator to move the pickup to a desired track, wherein a reaction force component generated on the tracking actuator is used as a reaction force signal. A track jump method characterized by detecting a reaction force signal and supplying the detected reaction force signal as a compensation signal for the kick signal. 2. The track jump method according to claim 1, wherein the reaction force signal is detected by an integrating means connected to the tracking actuator. 3. A servo amplifier that receives a tracking error signal or a kick signal, amplifies the signal, and supplies the amplified signal to a tracking actuator; and a servo amplifier connected between an output and an input of the servo amplifier, which converts a reaction force component of the tracking actuator into a reaction force signal. A track jump method characterized by comprising a feedback circuit for detecting. 4. The track jump method according to claim 3, wherein the feedback circuit is an integral amplifier that performs an integral operation, and includes the variable resistor that adjusts a loop gain formed by the servo amplifier and the integral amplifier. . 5. The track jump method according to claim 3, wherein said feedback circuit is an integral amplifier that performs an integral operation, and has a switch for disconnecting the feedback circuit from said servo amplifier.