JPH06176305A - Data readout mechanism for disk device - Google Patents

Abstract

PURPOSE:To obtain a read data pulse with high certainty in a data area and a sector servo area by reading out data in a recording medium and a head positioning signal, and outputting them through an LPF and a differentiation circuit controlled by a control signal and a pulser. CONSTITUTION:The data in the recording medium 1 and head positioning information are read out by a head 2, and are differentiated by the differentiation circuit 5 through an AMP 3, the LPF 4, and the reproduced data and the positioning information (d) are outputted through the PLS (pulser) 6. On the other hand, the index detection hole of a spindle motor is detected by a detector 7. The detected signal (g) is inputted to an index pulse generator(IPG) 8, and an outputted index pulse (h) becomes H only for a period when the head positioning area of an initial sector in each track is read out by the head 2. By a timer 9 in a control signal generation circuit 20, a data area count signal (i) is outputted to the timer 9 from the pulse (h) and an area identification signal (j) between an information area and the data area and a CLK. The signal (j) is sent to a drive circuit 11 from the timer 10, and the control signals (e), (f) are outputted to the circuits 4, 5 by the circuit 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data reading mechanism of a disk device, and more particularly to data recorded on a magnetic recording medium in the multi-zone recording (MZR) format.
And a data read mechanism for faithfully reproducing sector servo information.

[0002]

2. Description of the Related Art Conventionally, in a disk device, for example, a magnetic disk device using a sector servo system, each track on a magnetic recording medium is divided into a plurality of sectors, and positioning information in which magnetic head positioning information is written in each sector. An area and a data area in which recording data is written are provided. In this magnetic disk device, the magnetic head positioning information is recorded at a recording frequency lower than that of the data, but when the magnetic head positioning information and the data are read from the magnetic recording medium, the data written in the data area is read. The magnetic head positioning information and data are reproduced by using a low-pass filter and a differentiating circuit adjusted to the optimum frequency characteristic.

[0003]

However, in the multi-zone recording method, since the bit recording densities on the inner and outer circumferences of the magnetic recording medium are set to the same value to improve the recording efficiency, it is possible to read at a stage read by the head. The data recording frequency on the outer circumference of the recording medium is higher than the data recording frequency on the inner circumference of the recording medium. on the other hand,
The recording frequency in the magnetic head positioning information amount region is constant regardless of the position of the recording medium. Therefore, in the multi-zone recording method, the recording frequency of the data area and the recording frequency of the head positioning information area may differ greatly.

When the recording frequency in the data area and the recording frequency in the positioning information area are significantly different from each other, the read margin of the magnetic head positioning information reproduced by the low pass filter and the differentiating circuit adjusted to the recording frequency in the data area. Is reduced. As a result, in the worst case, a read error may occur in the magnetic head positioning information, which makes it difficult to position the magnetic head.

[0005]

According to the present invention, the head positioning information area and the data area are positioned based on a signal read by a head from a recording medium written in a sector formed by dividing a track. A data read-out mechanism of a disk device for reproducing information and the data, which is a signal read out from the recording medium, is an input signal, which is subjected to low-pass filtering and differential processing, and is waveform-shaped to output a waveform-shaped signal. Waveform shaping means that has at least two input / output transfer characteristics, these input / output transfer characteristics are selected based on a control signal, and the selected input / output transfer characteristics are given to the input signal.
Index pulse generating means for detecting and outputting an index pulse indicating a reference position of each track from a spindle motor equipped with the recording medium; a head positioning information area in which a head is in a sector on the recording medium based on the index pulse, And a control signal generating means for generating the control signal indicating which one of the data areas is being read.

[0006]

1 is a block diagram showing a first embodiment of the present invention. The first embodiment of the present invention includes an amplifier 3 for amplifying a read signal including magnetic head positioning information and data read from the magnetic recording medium 1 by the magnetic head 2, and a high frequency noise included in the output of the amplifier 3. Low pass filter (LPF) 4 for removing the noise, and low pass circuit output (b)
Of the magnetic head positioning information and data (d)
And a pulsar for playing.

Further, the first embodiment of the present invention comprises a detector 7 for detecting the reference position of a track from the magnetic recording medium 1,
An index pulse generator 8 for generating an index pulse (g) from a detection signal of the detector 7, and a low pass filter 4 based on the index pulse and a clock pulse (CLK) supplied from a clock source (not shown).
Output the control signals (e, f) for controlling the low-pass characteristics of and the differential characteristics of the differentiating circuit 5,
Further provided is a control signal generating circuit 20 which supplies the differentiating circuit 5.

Next, the operation of this embodiment will be described.
The data written in each sector in the magnetic recording medium 1 and the magnetic head positioning information for each sector are read by the magnetic head 2 and input to the amplifier (AMP) 3 to be amplified. The read signal amplified by the read amplifier 3 is input to the LPF 4 via the signal line a and high frequency noise is removed.

The frequency band of the LPF 4 is set to a frequency band corresponding to the data recording frequency in the data area by the control signal sent from the control signal generating circuit 207 via the control signal line e, and the magnetic head positioning information is set. Is passed, the wave number band is set to match the recording frequency of the magnetic head positioning information recorded at a frequency lower than the data recording frequency. Details of the LPF 4 will be described later with reference to FIG.

The read signal from which the high-frequency noise has been removed by the LPF 4 in the bands corresponding to the recording frequencies of the data and the magnetic head positioning information is supplied to the differentiating circuit 5 via the signal line b.

At this time, the frequency band of the differentiating circuit 5 is set to a frequency band of a differential characteristic matching the data recording frequency in the data area by the control signal sent from the control signal generating circuit 20 through the control signal line 5. Then, when differentiating the magnetic head positioning information, the frequency band of the differential characteristic is set to match the recording frequency of the magnetic head positioning information recorded at a frequency lower than the data recording frequency. Details of the differentiating circuit 5 will be described later with reference to FIG.

The read signal differentiated by the differentiating circuit 5 in the band corresponding to each recording wave number of the data and the magnetic head positioning information is passed through the signal line c to the pulsar (P
LS) 6 and the reproduced data and magnetic head positioning information d are output.

The detector 7 is a magnetic sensor and detects the index detection hole of the spindle motor to which the magnetic recording medium is attached. The index detection hole is about 3m in diameter provided on the rotor of the spindle motor.
It is a small hole having a depth of m and a depth of about 1 mm, and the detector 7 detects a magnetic change caused by the small hole passing through the front surface of the detector 7. By the way, at the time of formatting the magnetic recording medium, the start position of the first sector of each track is determined when this small hole is detected. Therefore, the fact that the detector 7 has detected a small hole when reading the magnetic recording medium means that the magnetic head has started reading the magnetic head positioning information area of the first sector of the track.

The detection signal g of the detector 7 is sent to the index pulse generation period (IPG) 8 to generate the index pulse h. This index pulse has a high level only during a period in which the magnetic head reads the magnetic head positioning area of the first sector of each track.

Next, the structure and operation of the control signal generating circuit 20 will be described. As shown in FIG. 1, the control signal generation circuit 20 includes an index pulse g, an area identification signal j indicating the magnetic head position information area and a data area, and a clock (C) supplied from a clock source (not shown).
LK) and the first to output the data area count signal i from
And a second timer for generating the area identification signal j from the data area count signal i and the clock, and a control signal for switching the characteristics of the low pass filter 4 and the differentiating circuit 5 based on the area identification signal j. and a drive circuit 11 for generating e and f.

The operation of the control circuit 20 will be described with reference to the timing chart of FIG. In FIG. 2, (a) shows the magnetic head read from the magnetic head.
A positioning area (hatched portion in the figure) and a data area are shown. (B) shows the index pulse h, (c)
Is an area identification signal, and (d) is a data area count signal i.
Is shown.

The first timer 9 outputs a clock (CLK) when at least one of the index pulse h and the area identification signal changes to high level and then changes to low level.
Start counting. Here, the period during which the index pulse and the region identification signal are at high level is as shown in FIG.
As shown in (b) and (c), it coincides with the period during which the magnetic head is reading the magnetic head position information area. When the first timer 9 counts a clock for a time corresponding to a time length required only for the magnetic head to read the data area, the first timer 9 outputs a data area count signal i which becomes a high level for one clock width as shown in FIG. 2D. Output.

When the data area count signal becomes high level, the second timer 10 becomes a high level signal only for the time required for the magnetic head to read the magnetic head position information area, as shown in FIG. 2 (c). , That is, the area identification signal j is output. As described above, this area identification signal is supplied to the drive circuit (DRV) 11, and the drive circuit 11 generates the control signals e and f for switching the frequency characteristics of the low pass filter 4 and the differentiation circuit 5.

Next, with reference to FIG. 3, a configuration example and operation of the low pass filter (LPF) 4 will be described. As shown in FIG. 3, the LPF 4 includes a buffer amplifier 41 to which the operation output a of the amplifier 3 in FIG. 1 is connected, a series connection of inductors L1 to L4 and inductors L5 to L8, and a buffer amplifier 42. It is connected to the. Also, the connection point between the inductors L2 and L3 and the inductors L6 and L7
Capacitors C1 and C2 are included between the connection points.

The LPF 4 has inductors L2, L4 and
The analog switches SW1, SW2, SW3, and SW4, which are connected to the input / output terminals between the terminals L6 and L8 and are supplied with the control signal e at the control input terminals, and one terminal of the capacitor C2 and the inductors L6 and L7. The analog switch SW5 includes an input / output terminal connected between the connection points and a control input terminal supplied with the control signal e.

While the control signal e is low level, that is, while the magnetic head is reading the magnetic head positioning information area in each sector, the analog switches SW1 to SW4 are off and the analog switch SW5 is on.
The circuit 43 in FIG. 3 includes inductors L1 to L8 and a capacitor C.
It operates as a low pass filter consisting of 1 and C2.

Further, when the control signal e is at a high level, that is, when the magnetic head is reading the data area in each sector, the analog switches SW1 to SW4 are turned on and the analog switch SW5 is turned off so that the circuit 43 shown in FIG. , Inductors L1, L3, L5, L7, and a capacitor C1 to operate as a low pass filter. As a result, when the control signal e is low level, that is, when the magnetic head is reading the magnetic head positioning area in each sector, the circuit 4 is
The pass band of 3 becomes narrow.

Next, a configuration example and operation of the differentiating circuit 5 will be described with reference to FIG. As shown in FIG. 4, the differentiating circuit 5 is shown in FIG.
Differential amplifier 51 to which the operation output b of the LPF 4 is connected
And resistors C1, R2 connected in series to the frequency characteristic control terminal of the differential amplifier 51 and the capacitor C connected in parallel between the resistor R2 and the frequency characteristic control terminal of the linear amplifier 51.
3 and C4. Further, an input / output signal is connected to both terminals of the resistor R2, an analog switch SW6 having a control signal input terminal supplied with the control signal f, and one terminal of the capacitor C4 and one terminal of the capacitor C3. It further includes an analog switch SW7 connected to the terminals and having a control input terminal supplied with the control signal f. As this linear amplifier, a differential two-stage video amplifier N manufactured by MOTROLA
E-592 can be used.

When the control signal f is low level, that is, when the magnetic head is reading the magnetic head positioning information area in each sector, the analog switch SW6 is turned off and the analog switch SW7 is turned on so that the circuit 5 of FIG. Differentiating operation is performed in the frequency band defined by R1, R2 and capacitors C3, C4.

Further, when the control signal f is at a high level, that is, when the magnetic head is reading the data area in each sector, the analog switch SW6 is turned on, the analog switch SW7 is turned off, and the circuit 5 of FIG. , Performs differential operation in the frequency band defined by the capacitor C3.

As a result, the frequency band of the circuit 5 becomes narrower when the control signal f is at a low level, that is, when the magnetic head is reading the magnetic head positioning information area of each sector.

In the first embodiment described above, the frequency characteristics of the low pass circuit 4 and the differentiating circuit 5 are simultaneously switched based on the control signals e and f. However, in the present invention, only the frequency characteristic of one circuit can be switched by the control signal, and the frequency characteristic of the other circuit can be fixed. This is the second and third embodiments of the present invention.

FIG. 5 is a block diagram showing a second embodiment of the present invention, and FIG. 6 is a block diagram showing a third embodiment. The difference between the first embodiment and the second embodiment is that the frequency characteristic variable differentiating circuit 5 of the first embodiment is replaced with a frequency characteristic fixed differentiating circuit 5a. The difference between the first embodiment and the third embodiment is that the low-pass filter 4 with variable frequency characteristics of the first embodiment is replaced by a low-pass filter with fixed frequency characteristics. The operation of the other circuits of the second and third embodiments is similar to that of the first embodiment, and will not be repeated here.

Although the embodiment of the present invention has been described above by taking the magnetic disk device as an example, the present invention can be similarly applied to an optical disk and a magneto-optical disk.

[0030]

As described in detail above, the present invention can provide a data read mechanism for a disk device with less read errors even when the recording frequency of the data area and the recording frequency of the head positioning information area are greatly different. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the control circuit 20 of FIG.

FIG. 3 is a circuit diagram showing a configuration example of a low pass filter 4 of FIG.

FIG. 4 is a circuit diagram showing a configuration example of a differentiating circuit 5 in FIG.

FIG. 5 is a block diagram showing a second embodiment of the present invention.

FIG. 6 is a block diagram showing a third embodiment of the present invention.

[Explanation of symbols]

 1 magnetic recording medium 2 magnetic head 3 amplifier 4 low-pass filter 5 differentiating circuit 6 pulser 7 detector 8 index pulse generator 9, 10 timer 11 drive circuit

Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number in the agency FI Technical display location G11B 21/10 E 8425-5D (72) Inventor Osamu Miyazaki 367 Ocha, Sekikan, Makiki-cho, Makabe-gun, Ibaraki 2 Inside Ibaraki NEC Corporation

Claims (4)

[Claims] 1. A head positioning information area and a data area are reproduced from a recording medium written in a sector formed by dividing a track on the basis of a signal read by a head to read head positioning information and data. Is a data read mechanism of the disk device to, the input signal is a signal read from the recording medium,
A waveform shaping unit that outputs a signal whose waveform has been subjected to a low-pass filtering process and a differential process. The waveform shaping unit has two input / output transfer characteristics, and one of the two input / output transfer characteristics is provided. A waveform shaping means which is selected based on a control signal and imparts the selected input / output transfer characteristic to the input signal; an index detection hole provided in a spindle motor having the recording medium mounted thereon is detected, and a reference for each track is detected. Index pulse shaping means for outputting an index pulse indicating a position; generating the control signal indicating whether the head is reading a head positioning information area or a data area in a sector on the recording medium based on the index pulse And a control signal generating means for controlling the data reading mechanism of the disk device. 2. The low-pass filter, which has two input / output characteristics and has one input / output characteristic selected by the control signal, and two input / output characteristics. 2. The disc according to claim 1, further comprising: a differentiating circuit that applies one input / output characteristic selected by the control signal to an output of the low-pass filter and outputs the waveform-shaped signal. Device data read mechanism. 3. The low-pass filter, wherein the waveform shaping means has two input / output characteristics and imparts one input / output characteristic selected by the control signal to the input signal, and the low-pass filter. 2. A data reading mechanism for a disk device according to claim 1, further comprising a differentiating circuit for giving a fixed input / output characteristic to an output and outputting the waveform-shaped signal. 4. The waveform shaping means has a low-pass filter that gives fixed input / output characteristics to the input signal, and two input / output characteristics, and one input / output characteristic selected by the control signal. 2. The data reading mechanism of the disk device according to claim 1, further comprising: a differential circuit for applying the signal to the output of the low pass filter and outputting the waveform-shaped signal.