JPS6339179A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To realize the correct positioning of a magnetic head by providing a masking circuit for detecting no track zero cross signal for the prescribed term. CONSTITUTION:A trigger pulse signal (i) is outputted by detecting the rise of the magnetic head moving start signal starting to flow the current for the movement by a one shot multiple circuit 8 at the time when the magnetic head 1 is moved, the one shot multiple circuit 9 is triggered by this signal (i) and the negative logic one shot signal (j) is outputted in the prescribed pulse width. The output signal (k) of the masking circuit 7 is obtd. by taking a logical product of this signal (j) and track zero cross TZC signal d' by an AND circuit 10 and this output signal (k) is counted by a counter 6. Consequently the counting by the counter 6 of the TZC signal d' erroneously due to the displacement of the magnetic head at its moving start time is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and particularly to a magnetic disk device that prevents erroneous detection of track zero cross signals due to positional deviation of the magnetic head at the start of movement of the magnetic head. [Prior Art] FIG. 6 is a schematic diagram of a conventional track position detecting device for a magnetic disk drive disclosed in, for example, Japanese Patent Laid-Open No. 1/7272. (C is a magnetic head for reproducing device signals composed of a magnetic disk;
(3) is generated by this magnetic head ((3) is a position signal generator into which the position signal reproduced by (C) is input, and generates and outputs the input position signal as a position signal. an odd component comparator that compares the absolute value of the output voltage of the odd component of the position signal fa) shown in the reference voltage rv-) and generates a predetermined output when a position signal voltage that is equal to or higher than the reference voltage is detected; The output signal is generated by the position signal generator (2), and the absolute value of the output voltage of the even component of the position signal (al) and the reference voltage (V+
), and generates a predetermined output when detecting a position signal voltage higher than the reference voltage.
j) is the comparator for even components (el
TZC signal that outputs the output signal from the odd component comparator (3) shown in bl and cl (every time cl is output, a TZC position signal is generated below the track zero cross signal c) The generator outputs a VCTZC signal every time the magnetic head (c moves from an even component to an odd component/track, for example). This is a counter that counts the number of moving tracks.

FIG. 7 is a detailed block diagram of the position signal generator shown in FIG. Then, the position signal detected by the magnetic head (c) is converted into an even track position information signal (t) in FIG.
The odd track position information signal (as shown in ml, is output while controlling the gain to obtain a uniform output on the inner and outer circumferences of the recording medium. (/) is output from an AGC amplifier (
An odd component window circuit that determines the width for detecting the odd track component (hereinafter referred to as odd component) of the position signal shown in FIG. 9 obtained from //), (/J)
is a 9-into circuit for even components that determines the width for detecting the even track components (t)c shown in FIG. 9 obtained from the AGC amplifier (//);
) is the position signal (odd component signal of al and reference voltage (V-)
(ts) is the even component comparator that compares the even component signal of the position signal (al and the reference voltage (V+)), (/6) is the odd component comparator (H'). Peak hold the output of
The odd component peak hold circuit inputs the signal (O) to the integrator (/l) as shown in FIG. A peak hold circuit for even components that inputs the signal (nl) to the integrator (/l) as shown in FIG.
/l) converts the respective signals (01, fnl) from the peak hold circuit for odd components (/6) and the peak hold circuit for even components (/7) into a sinusoidal position signal fal as shown in FIG. It is an integrator that converts and generates.Figure 3 shows the output signal waveform of each part in Figure 6.
In this figure, (a) is a position signal, and when the magnetic head (c) is moving, the position signal generator (c)
The comparator output signal for even components (bl is the output signal from the comparator for even components (15), the comparator output signal for odd components (cl is the output signal from the comparator for odd components (/μ), the signal fd
) is the TZC position signal obtained from the TZC signal generator (S). FIG. 9 is an output signal waveform diagram of each part in FIG. 7, in which the signal (17 is an even track position information signal obtained from the A ()
//) Odd track position information signal obtained from signal 1
nl is the even track peak hold output signal obtained from the even number peak hold circuit (/7), signal IO) is the odd track peak hold output signal obtained from the all number peak hold circuit C/6), and the position signal fal is the even track peak hold output signal. It is obtained by integrating the peak hold output signal (nl) and the track peak hold output signal (ol) using an integrator (it). 70-chart diagram of conventional firmware in case (S
(y') is a step of receiving a traveling direction signal of the magnetic head (/l), (Ss) is a step of counting a step signal instructing the number of moving tracks of the magnetic head (/1), (83)
(8*) is the step of counting the TZC signal,
(Sz) is a step of determining whether the number of moving tracks of the magnetic head (c) is remaining/track; (E3a)
is a seek operation step in which the magnetic head (C) is moved at a speed corresponding to the number of moving tracks, and (S) is a seek operation step in which the magnetic head (C) is moved by the last track.

A conventional magnetic disk drive is configured as described above. First, it receives an external interrupt signal to enter a speed control mode in which the magnetic head is moved. Then, the magnetic disk drive starts operating by moving the magnetic head on the recording medium. (Receives a traveling direction signal from the CPU that instructs movement of /1 to the inner or outer circumference side (
Step (Sl)). Thereafter, a step signal indicating the number of tracks to be moved by the magnetic head C force is received from CPTJ (step (SJ)), and movement of the magnetic head (1) is started (step C3J)), and the TZC signal is counted ( Step (S4+)).

It is determined whether the number of moving tracks is /track remaining, that is, whether the difference between the step signal and the TZC signal is l (step (Ss)), and the difference between these step signals and the TZC signal is /. When , the magnetic head C force moves to the last/track only (step "S")). If the number of moving tracks is more than this track, the speed corresponds to the remaining number of moving tracks. Step C (Sb) in which the magnetic head (C) is moved and this operation is repeated until the number of remaining moving tracks reaches /track.
). When the movement of the last track is completed and the magnetic head (c) is positioned, the speed control mode ends.

[Problem that the invention seeks to solve]

In conventional magnetic disk drives such as those mentioned above, when the magnetic head is misaligned from the center of the data track, the position signal is higher than the voltage when the magnetic head is located at the center of the data trunk. When the absolute value of the displacement voltage exceeds the set reference voltage of the comparator, a certain predetermined output signal is obtained from the comparator. The output signal from this comparator is converted into a TZC signal, and a counter detects a falling portion of the TZC signal caused by a positional shift of the magnetic head, resulting in a problem of erroneously detecting the number of moving tracks.

This invention was made to solve this problem, and even if the magnetic head deviates from the center of the data track and generates an erroneous TZC signal, the number of tracks moved due to the erroneous TZC signal will be reduced. An object of the present invention is to provide a magnetic disk device that can accurately position a magnetic head by preventing erroneous detection.

[Means for solving problems]

A magnetic disk device according to the present invention includes a magnetic head that reproduces a position signal recorded on a magnetic disk, a position signal generator that generates a position signal reproduced by the magnetic head, and an output of the position signal generator. an odd and even component comparator that compares each of the odd and even components of the signal with a respective desired reference voltage; A track zero cross signal generator for generating a zero cross signal, a mask circuit for masking the signal generated from the track zero cross signal generator for a predetermined period, and a counter for counting the output signal of the mask circuit. This is what I did.

[For production]

In this invention, the TZC signal that occurs when the magnetic head starts to move is ignored for a predetermined period, and the TZC signal that occurs when the magnetic head is out of position before starting to move is ignored.
This prevents the C signal from being erroneously detected.

〔Example〕

FIG. 1-a is a schematic diagram of a track position detection device for a magnetic disk device according to an embodiment of the present invention.
6) is the same as the conventional one. (ri) is a mask circuit which masks the TZC signal (a') as shown in FIG. 3 generated by the TZC' signal generator 1sl for a predetermined period. FIG. 1-b is a detailed configuration diagram of the mask circuit (71) in the above embodiment, in which (71 detects the start of movement of the magnetic head (C) and sends a trigger pulse signal (S1).
The one-shot multi-circuit that generates (?) is the trigger pulse signal (1), so it is a negative logic one-shot signal f
One-shot multi-circuit that outputs j+, (10) is T
This is an AND circuit that takes the logical product of the ZC signal (a') and the one-shot word (jl). Figure 1 shows the case where the magnetic head (c) starts moving without any positional deviation from the center of the data track. FIG. 1-a is an output signal waveform diagram of each part in FIG.
The ZC signal fdl is the output signal 1al of each part in Figure 1-a.
, fbl, icl, and fdl. Figure 3 shows the first-fi position when the magnetic head (C) starts moving with its position shifted from the center of the data track.
It is an output signal waveform diagram of each part in the figure, and the position signal (a')
, comparator output signal for even components (b'), comparator output signal for odd components (C'), TZC' signal (a'
) is the output signal (a')+(bi) of each part in Fig. 1-a.

(c'): Corresponds to each of (d'). FIG. 9 is an output signal waveform diagram of each part in FIG. 1-a and FIG. c')
, TZC signal (a'), trigger pulse signal (1) when detecting the start of movement of the magnetic head, negative logic one-shot signal (j), output signal of the mask circuit (7) (kl 1st-a Output signals (a') of each part in the figure and FIG. 1-b.

(bi), (c'), (d'1. (1), (j), (k
).

In a magnetic disk device configured as above,
In Fig. 3, if a positional deviation occurs when the magnetic head (C) starts moving, an output signal having a displacement voltage corresponding to the positional deviation of the magnetic head, such as the position signal (a') in Fig. 3, will be an odd number, for example. It is applied to the comparator for components (3) and compared with the reference voltage (V-), and if the displacement voltage exceeds the reference voltage (V-) of the comparator for odd components (jl), T
Since the ZC signal (rf) is output at the same time as the magnetic head (c) starts moving and is added to the counter (6), the TZC
The falling edge of the signal is erroneously counted and the number of tracks actually moved is counted by an amount greater than the number of tracks actually moved, but the mask circuit (7) operates to prevent this erroneous counting. The operation of this mask circuit (7) is as follows. When moving the magnetic head (c), the one-shot multi-circuit ffl detects the rise of the magnetic head movement start signal that starts flowing the current to move the magnetic head (c), outputs a trigger pulse signal (1), and outputs this output signal. The one-shot multi-circuit (9) is triggered by (1), and a one-shot signal fjl of negative logic is output with a predetermined pulse width.This one-shot signal fjl and the TZC signal (d''
) by the AND circuit (IO'J), the output signal (kl) of the mask circuit (7) is obtained, and by counting this output signal [kl with the counter (6), the output signal (kl) of the magnetic head (h) is obtained. TZ C41M (a') due to the positional shift at the start of the transfer vljJ was mistakenly placed (6
) will no longer be counted.

FIG. Sa is a schematic diagram of a track position detecting device for a magnetic disk drive according to another embodiment of the present invention.
(6) is the same as that in Fig. 1-a.

(19) is firmware, which is a control function unit that controls the counter (6) not to count the falling edge of the TZC signal for a predetermined period. FIGS. s-b are exemplary diagrams illustrating the operation of the firmware (/q) that prevents the detection of the TZC signal for a predetermined period at the same time that the magnetic head (c) starts moving; ~(St') correspond to each of conventional steps (Sl) to (S7) in FIG. 70. Step (St) is a step in which the TZC signal is not counted for a predetermined period from the start of movement of the magnetic head. In other words, this is a step in which the counting of TZC signals is delayed by providing a waiting time to prevent false detection of TZC signals even if the magnetic head (c) starts moving in a state where it is out of position.

〔Effect of the invention〕

As explained above, this invention is configured to provide a mask circuit or firmware so that the TZC signal is not detected for a predetermined period of time due to τ, so that the number of moving tracks of the magnetic head can be detected correctly and the positioning of the magnetic head can be performed. It has an effect if done correctly.

[Brief explanation of drawings]

Figure 1-a is a schematic diagram of a track position detection device for a magnetic disk drive according to an embodiment of the present invention, Figure 1-b is a detailed configuration diagram of a mask circuit (W) in the above embodiment, and Figure 2 is a magnetic Figure 3 shows the output signal waveform diagram of each part in Figure 1-a when the head (C) starts moving with no displacement from the center of the data track. Figure 1-a is the output signal waveform diagram of each part when movement is started in the state, and Figure 1-a is the output signal waveform diagram of each part when movement is started in the state.
fi figure and output signal waveform diagram of each part of figure 1-1), j
Fig. -a is a schematic diagram of a track position detecting device for a magnetic disk device according to another embodiment of the present invention, and Fig. S-b is a schematic diagram of a track position detection device for a magnetic disk device according to another embodiment of the present invention. FIG. 6 is a schematic diagram of a track position detecting device of a conventional magnetic disk drive, and FIG. 7 is a diagram of a position signal generator of FIG. 6. Detailed block diagram, Figure 2 is an output signal waveform diagram of each part in Figure 6, Figure 2 is an output signal waveform diagram of each part in Figure 7, and Figure 70 is a magnetic head (
FIG. 3 is a flowchart illustrating a conventional operation when moving a vehicle to a target track. In the figure, (c...magnetic head, (2)...position signal generator, (3)
)... Comparator for odd components, (Comparator for read/even components, (jl@@TZC signal generator, (61**
Counter, [ri l-mask circuit, 171, 1? )
...One-shot multi circuit, (10)...AND circuit, (//)...AGC circuit, (t2)...window circuit for odd components. (/3)...Window circuit for even components, (/u) ΦHun comparator for odd components, r/j) 66 comparator for even components, (16)...Peak hold circuit for odd components, (/ri)・Peak hold circuit for even components, (
/r)...Integrator, (/9")...Firmware. In each figure, the same reference numerals indicate the same or equivalent parts. Figure 8 Figure 9 Figure 10 Procedure amendment "Voluntary ” Showa 61. ”'11.Monday 5th

Claims (3)

[Claims] (1) A magnetic head that reproduces a position signal recorded on a magnetic disk, a position signal generator that generates the position signal reproduced by the magnetic head, and odd and even components of the output signal of the position signal generator. Odd component and even component comparators for comparing each of the components with respective desired reference voltages; and a track generating a track zero cross signal each time the respective output signals of the odd and even component comparators are generated. A magnetic disk device comprising a zero-crossing signal generator, a masking circuit for masking a signal generated from the track zero-crossing signal generator for a predetermined period, and a counter for counting output signals of the masking circuit. . (2) The mask circuit includes a first one-shot multi-circuit that detects a movement start signal of the magnetic head and generates a trigger pulse signal, and a second one-shot multi-circuit that outputs a negative logic one-shot signal in response to the trigger pulse signal. 2. The magnetic disk drive according to claim 1, comprising a shot multi-circuit and an AND circuit that performs a logical product of the one-shot signal and the track zero-crossing signal. (3) A magnetic head that reproduces a position signal recorded on a magnetic disk, a position signal generator that generates the position signal reproduced by the magnetic head, and odd and even components of the output signal of the position signal generator. comparators for odd and even components that compare each of the components with their respective desired reference voltages; and generating a track zero cross signal each time the respective output signals of the comparators for odd and even components are generated. A magnetic device comprising: a track zero-crossing signal generator; a counter that counts output signals of the track zero-crossing signal generator; and firmware that controls the counter so as not to count track zero-crossing signals for a predetermined period. disk device.