JPS61199279A - Tracking device for signal detector - Google Patents

Abstract

PURPOSE:To obtain a tracking device of a signal detector that can make positioning at maximum step of output of a magnetic head by providing a controlling circuit that controls a driving mechanism to stop the detector at a position where output of an information detector becomes maximum. CONSTITUTION:When a display part indicating section 18 designate a track to be sent to a microcomputer 16, a driving circuit 19 rotates a motor 2 based on sequence stored in a ROM 17. When the motor 2 passed a point before designated track, output from a head 4 becomes an envelope signal 28 through a head amplifier 12 and an envelope detector circuit 13, and simple held in a sample and hold circuit 14 by PG pulse from a rotation system 11. The output signal 30 is inputted to a peak detector circuit 15, and a pulse 31 is inputted to the microcomputer 16 at a point where the signal becomes maximum, and the step motor 2 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a tracking device for a signal detector.

[Conventional technology]

Figure 6 (al and (bl) represent the head positioning mechanism in a still image magnetic disk device, which is a conventional device of this type. In Figure 6 fa), ■ is a lead screw, and 2 is this head positioning mechanism. A step motor for rotating the lead screw 1, 3 a head arm that moves in the direction of the arrow in the figure as the lead screw 1 rotates, 4 a head attached to the upper part of the navel arm 3, 5 a magnetic recording device, etc. This is a disk on which image information and the like are recorded, and can be written and read by the head 4.

Also, in FIG. 6 (bl), 6 is a first pulley rotated by the step motor 2, 7 is a second pulley that rotates about the shaft 8, and 9 is the first pulley 6 and the second pulley.
Steel belt hung between Boo U 7, 10
is a head moving table which is connected to a steel belt 9 and has a head 4 attached to its upper part and is movable in the direction of the arrow.

Next, the operation will be explained. In FIG. 6 (al), when the step motor 2 rotates, the lead screw 1 rotates by the rotation angle of the step motor 2, and the female head arm 3 moves a predetermined amount. The moving amount l of the head arm 3 is β=t/(θ/360) (mm), where the rotation angle of the step motor 2 is θ [d e g) and the pitch of the lead screw 1 is t (mm). becomes. Thereby, when mounting the step motor 2, head positioning is performed according to the rotation angle.

Also in FIG. 6 (bl), when the step motor 2 rotates, the first and second pulleys 6.7 rotate, and the head moving table 10 moves according to the rotation angle of the step motor 2 as the steel heald 9 moves. Moving.

The head feeding mechanism shown in FIGS. 6(a) and 6(bl) is configured to prevent rotation angle error of the step motor 2 and lead screw 1 or steel heald 9 at a predetermined position.
Positioning is possible within the error range of

[Problem that the invention seeks to solve]

Conventional head positioning devices are configured as described above, so they can only stop the head at a predetermined position and cannot deal with track misalignment. There are problems such as errors caused by screws or steel belts, and errors caused by temperature and humidity of the recording medium.

The present invention was made to eliminate the problems of the conventional apparatus as described above, and an object of the present invention is to obtain a tracking device for a signal detector capable of positioning at the maximum head output step.

[Means for solving problems]

A tracking device for a signal detector according to the present invention includes a maximum value detection circuit that detects the maximum value of the head output, and a head feed control circuit including a microcomputer that receives the detection signal as input, and drives the control system in a closed loop. It is something.

[Effect]

In this invention, the head drive mechanism detects the maximum point of the head output using envelope detection that extracts only the amplitude component of the head output, a peak detector that detects the maximum amplitude of the signal, etc., and stops the head at this position. control.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram of a servo system in an embodiment of the present invention. In the figure, 1) is a rotation system for rotating the disk 5, 12 is a head amplifier for amplifying the head output, and 13 is a hesoad amplifier 12. 14 is a sample hold circuit for converting the envelope output into information for each rotation of the disk; 15 is a sample hold circuit 14
16 is a microcomputer (hereinafter referred to as microcomputer) for driving the step motor 2 in a predetermined sequence; 17 is a ROM for storing the sequence; , 18 is a display section for displaying the track position and the like, and an instruction section for issuing a command to move the track. 19 is a drive circuit for driving the step motor 2.

FIG. 2 shows a general configuration example of the peak detector circuit 15. In the figure, 21 is a comparator, 22 is a diode, 23 is a hold capacitor, 24 is a voltage follower, 25 is a reset switch, 26 is a monostable circuit, C is human power, and D is a peak detector output.

FIG. 3 shows the output of the head-up 12 versus time on the horizontal axis, where B represents the head amplifier output and A represents the period of one revolution of the disk. FIG. 4 shows a timing chart in this embodiment, where 27 is the output of the head amplifier 12, 28 is the output of the envelope detection circuit 13, and 29 is the PC from the rotating system 1) which is input to the sample and hold circuit 14.
Pulse, 30 is the output of the sample and hold circuit 14, 31
is the output of the peak detector circuit 15, which is 1゛.

. . , 13°, 14°, . . . are the number of steps of the step motor 2, E is the designated track range, and F is the stop step 7 position.

Figure 5 shows an example of a head feed sequence. In the figure, ■ indicates the previous track, I-J indicates an acceleration section, J- indicates a constant speed section, and K-
L is the deceleration section, LM is the closed loop operation section, M
is the designated track.

Next, the operation will be explained.

First, in the instruction section 18, select the trunk to be sent to the microcomputer 1.
6, the step motor 2 is rotated by the drive circuit 19 based on the sequence stored in the ROM 17. For example, the sequence is as shown in FIG. 5, where ■ is the current stop step and M is the desired stop position. According to the sequence stored in the ROM 17,
Acceleration is performed between I and J, maximum constant speed is performed between J-, and deceleration is performed between K and L, and during these periods, the step motor 2 performs open loop drive according to a sequence.

When the step motor 2 passes the point before the designated track in the sequence, the head amplifier 12 amplifies the output from the head 4 and outputs the FM signal 27 shown in the timing chart of FIG. This is converted by the envelope detection circuit 13 into a signal 28 containing only the envelope component as shown in the figure. This envelope signal 28 includes periodic components as shown in FIG. 3 due to eccentricity of the disk and uneven contact in the head contact each time the disk rotates. For this reason, the sample and hold circuit 14 performs sample and hold using the PG pulse (signal 29 in FIG. 4), which is a reference signal for each rotation generated from the rotation system 1). The output of the sample and hold circuit 14 becomes a signal 30 that does not include fluctuation components within one revolution as shown in FIG. , generates a pulse 31. The output 31 of this peak detector circuit 15 is input to the microcomputer I6, and the step motor 2 is stopped. The stop step at this time is step 14' in the timing chart of Fig. 4.If you want to further ensure the maximum output of the head 2, you can input a command to return one step back to the microcomputer sequence, and the timing chart shows step 14'. It is also possible to stop at step 13''.

In this way, between LM in the sequence of FIG. 5,
The step motor 2 operates in a closed mode, and even when it stops, the head arm mechanism is fed at a low speed so that it can come to a near-vibration-free stop.

Here, the peak detector circuit 15 generally has a configuration as shown in FIG.
Since the potential of the inverting input of C is defined by the potential of the hold capacitor 23, when the potential of the human power C starts to decrease, a pulse is output from the monostable circuit 26. Therefore, after operating the peak detector circuit 15, it is necessary to turn on the reset switch 25 using the microcomputer 16 to reset the peak detector circuit 15.

According to this embodiment, the step motor 2 is driven in a closed loop and is configured to be stopped at the maximum head output step, so it can cope with tracking errors and errors in the head feeding mechanism, and the system is simple. , a system that achieves the same function can be made smaller and more cost-effective.

In the above embodiments, the present invention is applied to a head feeding mechanism using a lead screw, but it goes without saying that the present invention can also be applied to a head feeding mechanism using a steel belt.

〔Effect of the invention〕

As described above, according to the present invention, there is provided a maximum value detection circuit that detects the maximum value of the output of a detector such as a head.

A control circuit for controlling the drive mechanism of the detector is provided to perform closed-loop control of the drive mechanism and stop the detector at the position where its output is maximum, thereby reducing tracking errors and the head feed mechanism. It is possible to deal with errors, etc., and since the system is simple, it has the effect of reducing size and cost.

[Brief explanation of drawings]

1 to 5 are diagrams for explaining one embodiment of the present invention, FIG. 1 is a block diagram of the device, and FIG. 2 is a diagram showing an example of the configuration of a peak detector circuit of the device. , 3rd
The figure shows the output of the hesodon amplifier, FIG. 4 is a timing chart, FIG. 5 is a diagram showing an example of the microcomputer sequence of the device, and FIG. 6 (al (b) is a diagram showing the conventional device. Yes. 1... Lead screw, 2... Stamp motor, 3
... Head arm, 4... Magnetic head, 5... Magnetic disk, 1)... Rotating system, 12... Head amplifier, 13... Envelope detection circuit, 14... Sample hold circuit , 15... peak detector circuit,
16... Macro computer, 17... ROM, 1
8... Display section and instruction section, 19... Drive circuit. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (5)

[Claims] (1) A detector that detects information recorded on a recording medium;
a drive mechanism for moving the detector; a maximum value detection circuit for detecting the maximum value of the output of the detector; and a drive mechanism for stopping the detector at a position where the output of the detector is maximum. A tracking device for a signal detector, comprising: a control circuit for controlling a mechanism. (2) The signal detector tracking device according to claim 1, wherein the recording medium is a magnetic recording medium, and the detector is a magnetic head. (3) The signal according to claim 2, wherein the maximum value detection circuit detects the amplitude of a signal obtained by amplifying the output of the magnetic head, and detects the maximum value thereof. Detector tracking device. (4) The recording medium is a magnetic disk, the detector is a magnetic head for detecting information recorded on the magnetic disk, and the maximum value detection circuit amplifies the output of the magnetic head. an envelope detection circuit that detects the amplitude of a signal that is detected, a sample-hold circuit that samples and holds the detected amplitude using rotational phase information from the rotation system, and a detection circuit that detects the maximum value of the output of the sample-and-hold circuit. A tracking device for a signal detector according to claim 1, characterized in that the tracking device comprises: a tracking device for a signal detector according to claim 1; (5) The control circuit includes a logic circuit that operates based on a sequence determined by an external movement command and an output signal of the maximum value detection circuit, and a drive mechanism that operates according to a drive command from the logic circuit. A tracking device for a signal detector according to claim 4, characterized in that it comprises a drive control circuit.