JPH04214202A - Pulse-width narrowing apparatus and hard disk apparatus using this apparatus - Google Patents

Abstract

PURPOSE: To enlarge data storage density by narrowing widths of pulses outputted from a hard disk device via plural amplifiers whose amplifying actions are adjusted and a delay line. CONSTITUTION: Pulses read out from a hard disk device 10 are passed through a filter 14 to be supplied to amplifier circuits consisting of amplifiers 16∼20. Amplifying actions of amplifiers 16∼20 are adjusted by a microprocessor 30. When the output of the filter 14 is of the polarity of one side, the output is supplied to the amplifier 18 and when it is of an opposite polarity, the output is respectively supplied to amplifiers 16, 17 19, 20. Outputs of the amplifiers 16∼20 are respectively supplied to a delay line 22 via taps 35∼39. The output signal of the delay line 22 is made to be pulses which are subtracted from original pulses and rising parts and falling parts of the pulses supplied to the central tap 37 and added by attenuated pulses to be supplied to taps 34, 36, 38, 39 of both sides of the tap 37.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse width narrowing device, particularly a means for narrowing the pulse width generated when data is read from a storage disk of a hard disk drive, and a hard disk drive using the same. Regarding.

0002

BACKGROUND OF THE INVENTION In the digital storage technology of hard disk drives, when a write current pulse information signal passes through a write head, it induces a corresponding magnetic pattern on the hard disk moving beneath the head.

Hard disks maintain a magnetized state of stored digital information. Reading is the reverse process, where the magnetization state on the disk (platter) induces a variable current in the read head.

Computer programs require a huge amount of storage, so the density of data to be stored on each disk, or platter, in the hard disk drive and the speed at which information is stored and read are important. , must be made larger. As storage densities and data rates increase, pulse-to-pulse interference and other related issues become increasingly worse.

[0005] There is a US patent that changes the spectral contour of the signal after it is read from a hard disk to compensate for changes due to temperature changes in the environment in which the hard disk drive is operating.

A device of this type is disclosed in US Pat. No. 4,479,152 to Chi, issued October 23, 1984. Accordingly, a single delay and amplitude correction signal is subtracted from the original signal to compensate for changes due to temperature, pressure, or other conditions. The amount of delay and amplitude modification is varied within a fixed selection setting based on the physical conditions under which the hard disk drive is being operated.

[0007]

However, with such a simple device, the improvement in performance is not very significant. There is a need for high performance devices that can more effectively narrow data pulses, thereby allowing for greater storage densities and higher data rates.

[0008] An object of the present invention is to provide a device that narrows the width of pulses read from a hard disk drive, thereby increasing the density of data storage and increasing the read speed. It is.

[0009]

According to the present invention, a delay line having a plurality of input taps along the longitudinal direction is provided,
Means is provided for delivering pulses from the magnetic medium to intermediate points along the delay line. The same pulse is also applied to the taps of the delay line on either side of the midpoint, with opposite polarity.

The attenuation or weighting of the pulses applied on either side of the midpoint on the delay line is varied by a control circuit. The control circuit varies the weight of the pulses applied on either side of the midpoint by various factors based on, for example, the platters and tracks on which the pulses are generated.

The signal provided at the "back end" of the midpoint is subtracted from the falling pulse applied at the midpoint along the delay line. The signal provided at the "leading edge" of the midpoint is subtracted from the rising signal applied at the midpoint. Therefore, the signal resulting from the delay line will be narrower than the pulse read from the disk.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a detailed description of preferred embodiments of the present invention with reference to the accompanying drawings, and other objects, features, and advantages of the present invention than those described above will become clear.

As shown in FIG. 1, the circuit according to the invention comprises:
Receives a signal from a hard disk device (H.D.A.) (10). H. D. A. (10) includes a plurality of hard disks, a head positioning device, and a magnetic head attached to the outer end of a head positioning arm.

Pulses are read from the hard disk by a magnetic head, and the pulses or signals are sent to an amplifier (12) located at the base of each head's positioning arm. The pulse is then applied to the filter (14).

The circuit configuration for supplying a pulse of one polarity to a midpoint along the delay line (22) and supplying the same pulse of opposite polarity to points on the delay line on both sides of the midpoint is as follows: , is as follows.

The pulses are fed from the filter (14) to an amplifier circuit. The amplifier circuit shown in FIG. 1 includes a plurality of amplifiers (16) to (20). In the case of one polarity, the pulse is sent to the central amplifier, i.e. amplifier (18);
And in the case of opposite polarity, the remaining amplifiers (16) (17)
(19) and (20), respectively. The signals are sent to the delay line (22) at taps (35)-(39).

The microprocessor (30) adjusts the amplification action of the amplifiers (16)-(20) according to various factors. For example, the pulse height varies depending on the disk track on which the pulse is generated and also on the characteristics of the associated read head.

[0018] The microprocessor controls each amplifier (16)
“Current setting (I-set)” (24) for ~(20)
) to (28). I-set (24) ~
(28) generates a control current according to a control signal from the microprocessor. The level of control current from each I-set determines the output level from the associated amplifier.

FIG. 2 is an equivalent circuit diagram according to an embodiment of the present invention at a certain point at a certain time.

The output from filter (14) (see FIG. 1) is applied to input voltages (V-IN) with polarities shown as (52), (54), and (56). Input (5
The signals associated with 2) are supplied with one polarity. The inputs (54) and (56), the signals associated with the inputs marked with a negative (-), are also connected to a differential or balanced delay line (57) (with an inherent impedance at each end), with opposite polarity. Z0) is represented by a capacitive-inductive network with Z0).

The total delay of the delay line from the input (54) to the end of the delay line is denoted by d. For the input (52) located in the center of the delay line, the delay from the input (52) to the output of the delay line is 1/2·d. The delay of the signal associated with the input (54) is 1/2·d with respect to the signal associated with the input (52).

Considering the output of the delay line (57),
The signal associated with input (56) leads the signal associated with input (52) by 1/2·d.

FIG. 3 shows a single pulse; the narrow output pulse (58) shown in dashed lines is at the output voltage (V-out) of FIG. Solid line pulse (4
0) represents the signal associated with the input (52) shown in FIG. The negative solid line pulse (43) represents the signal associated with the input (54), and the negative pulse (43) represents the signal associated with the input (54).
5) represents the signal associated with the input (56).

[0024] Upon input, these signals are sent to an amplifier (60), as shown in FIG. The amplifier (60) is
It works as a buffer. The resulting output signal (V
-out) is indicated by a wavy line (58). As shown in FIG. 3, the resulting pulse is narrower than the original pulse.

Narrow pulses produce more pulses per unit time. In this way, by narrowing the pulse width, it is possible to increase the data read speed and to increase the storage density on the disk.

FIG. 4 is an equivalent circuit diagram showing another embodiment of the present invention at a certain point in time.

The output from the filter (14) shown in FIG. 1 is applied to the input voltage (V(-)IN) with the polarity indicated.

Resistors (R1)-(R5) determine the weight, or attenuation, of each pulse applied to the delay line. FIG. 4 is shown as a system of capacitors and inductors with a unique impedance (Z0) at each end. Circuit elements located downstream of the resistors (R1) to (R5) are biased.

The signal associated with the resistor (R3) is supplied with one polarity and the resistor (R1) which is the subtracting element
The signals associated with (R2) (R4) (R5) are fed to the delay line with opposite polarity.

The attenuated signals associated with resistors (R1) (R2) are delayed with respect to the signals associated with resistors (R3), and the signals associated with resistors (R4) (R5) are delayed relative to the signals associated with resistors (R4) (R5). (R3) and related signals. Figure 4
The embodiment shown in FIG. 2 is more complex than that of FIG. 2, but allows for superior pulse narrowing.

[0031] In the hard disk device, data is
Usually, information is recorded more densely on the inner tracks of a disc than on the outer tracks.

In carrying out the invention, the microprocessor (30) (see FIG. 1) selects taps (35), (36), (38), and (39) depending on the track from which data is being read.
) (subtraction element) can be changed.

The weight of the subtraction element is increased when an inner track that is densely packed with data is being read because its data pulses are more closely spaced. Therefore, in order to eliminate interference between pulses and improve pulse detection accuracy, it is necessary to further narrow the width.

When reading outer tracks that are not tightly packed, the weight of the subtraction element is reduced because the data pulses are spaced apart. There is almost no interference between pulses, and pulse detection accuracy is improved. Therefore, there is no need to narrow the width.

[0035] The appropriate weight for the subtraction element in each track is predetermined. These values are utilized by the microprocessor when reading data from a particular track.

Similarly, changing characteristics of the read head can also be compensated for by varying the weights of the subtraction elements. Also, other factors that affect the data pulses, such as temperature and humidity, can also be compensated for by the present invention.

The invention is not limited to the embodiments described above. The invention can be practiced by making various modifications to the embodiments described above without departing from the concept of the invention.

Attenuation of the subtractive element can be performed using various electronic means. Multiple taps on the delay line or means for supplying pulses to the delay line may be used. Multiple inputs to the delay line can be controlled by a single amplifier. Instead of attenuating the subtraction element, it is possible to amplify the pulse applied in the middle, or to use a combination of attenuation and amplification.

The invention is amenable to all types of modifications that may occur to those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a pulse narrowing device according to a preferred embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram according to an embodiment of the present invention at a certain point in time.

FIG. 3 is a waveform diagram showing a pulse before modification and a pulse after width narrowing.

FIG. 4 is an equivalent circuit diagram according to another embodiment of the present invention at a certain point in time;

[Explanation of symbols]

(1) Hard disk device (H.D.A.) (12) Amplifier
(14) Filters (16) to (20) Amplifiers
(22) Delay line (24
) ~ (28) Current setting (I-set)
(30) Microprocessor (35) to (39) Tap
(40) Pulse (43) Pulse
(45) Pulse (52) (54) (56) Input (V(-)IN)
(57) Delay line (58) Output pulse
(60) Amplifier (R1) to (R5) Resistor
(V-out) Output voltage (Z0) Impedance

Claims (20)

[Claims] 1. A high-density hard disk drive for storing digital data, comprising: a hard disk drive; means for receiving pulses from a disk of the hard disk drive; a delay line; a pulse of one polarity is applied at an intermediate point along said delay line, and a pulse of opposite polarity and reduced amplitude is applied at points along the delay line on either side of said intermediate point to A hard disk device comprising: means for narrowing the width; and means for detecting a narrowing pulse generated on the output side of the delay line. 2. The hard disk drive according to claim 1, further comprising a circuit element for changing the relative level of the pulse applied to the delay line. 3. A hard disk drive according to claim 2, further comprising control means responsive to the state of the hard disk drive to control the circuit elements, thereby being adapted to vary the narrowing of the pulses. . 4. The hard disk device according to claim 3, wherein the control means comprises a microprocessor. 5. The pulse is supplied to three successive points along the delay line, consisting of a first point, a second point as an intermediate point, and a third point, The hard disk drive according to claim 1, wherein the first and third points are located on both sides of the intermediate point. 6. The pulse is located at the first and second points along the delay line, at the third point which is an intermediate point, and at the fourth and fifth points along the delay line.
and the first and second points are on one side of the intermediate point, and the fourth and fifth points are The hard disk device according to claim 1, wherein the hard disk device is located on the other side of the intermediate point. 7. A hard disk drive, a delay line having a plurality of longitudinal input taps, means for transmitting pulses from the hard disk drive to intermediate taps along the delay line, and means for transmitting pulses from the hard disk drive to intermediate taps along the delay line; to taps on either side of said intermediate tap with opposite polarity; amplifying means for controllably modifying the amplitude of each pulse applied to said delay line; and controlling the amplitude modification by said amplifying means. 1. A pulse narrowing device comprising: a microprocessor for controlling the pulse width; 8. The pulse narrowing device of claim 7, wherein the microprocessor is adapted to control the amplitude modification by the amplifying means in response to the platters and tracks on which the pulses are generated. 9. Amplifying means includes a plurality of amplifiers associated with each tap, control means for sending a bias signal to each amplifier to establish a gain for each of said amplifiers, and a signal from a microprocessor for transmitting a signal from said microprocessor to said each amplifier. coupled to a control means;
8. A pulse narrowing device according to claim 7, further comprising means for thereby establishing the gain of each amplifier. 10. Pulses are provided to three successive points along the delay line consisting of a first point, a second intermediate point, and a third point, and 8. The pulse narrowing device according to claim 7, wherein the points No. 3 are located on both sides of the intermediate point. 11. The pulses are supplied to five consecutive points along the delay line, consisting of the first and second points, a third point that is an intermediate point, and a fourth and fifth point. 8. The pulse narrower according to claim 7, wherein the first and second points are located on one side of the midpoint, and the fourth and fifth points are located on the other side of the midpoint. Widthening device. 12. A delay line having a magnetic storage medium and a plurality of input taps in the longitudinal direction, directing pulses from the magnetic storage medium with one polarity to an intermediate tap in the delay line, and means for narrowing the width of the pulse by sending the pulse with opposite polarity to taps of a delay line on either side of the intermediate tap;
and means for detecting a narrowing pulse occurring at the output from the delay line. 13. The pulse narrowing device of claim 12, wherein the means for sending the pulses comprises amplifying means for varying the level of the pulses before feeding them to the delay line. 14. The pulse width narrowing device according to claim 12, further comprising control means for controlling the amplification means and thereby changing the degree of width narrowing of the pulse. 15. The pulse narrowing device of claim 14, wherein the control means is responsive to conditions that act on the pulse from the magnetic medium and are capable of varying the amount of amplification of the amplification means. 16. Pulses are provided at three successive points along the delay line, consisting of a first point, a second intermediate point, and a third point, and 16. The pulse narrowing device according to claim 15, wherein the points No. 3 are located on both sides of the midpoint. 17. Pulses are provided at five successive points along the delay line, consisting of the first and second points, a third point that is an intermediate point, and a fourth and fifth point, 16. The first and second points are located on one side of the midpoint, and the fourth and fifth points are located on the other side of the midpoint. pulse narrowing device. 18. The pulse narrowing device according to claim 14, wherein the control means comprises a microprocessor. 19. The pulse narrowing device of claim 12, wherein the magnetic storage medium comprises a hard disk drive. 20. The hard disk device according to claim 1, wherein the delay line is a differential type or a balanced type delay line.