JPH05174514A - Head positioning controller for data recorder/ reproducer - Google Patents

Abstract

PURPOSE:To enhance the positioning accuracy of a head by making it possible to obtain an accurate amplitude value of burst data at all times in head positioning control employing address code information and servo information containing burst data. CONSTITUTION:A control signal S1 is delivered from a servo control circuit 22 to a pulsation circuit 20 under position control mode. Consequently, the pulsation circuit 20 is disabled when an amplitude value detecting circuit 21 is detecting the amplitude value of burst data and thereby the amplitude value detecting circuit 21 is protected against the adverse effect of operational noise(ON/OFF switching noise at the time of pulsation of burst data).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a magnetic disk device (H
The present invention relates to a head positioning control device used in a data recording / reproducing device such as DD).

[0002]

2. Description of the Related Art Conventionally, for example, in a magnetic disk device of a sector servo system, head positioning control is performed based on servo information previously recorded for each sector on a disk which is a recording medium. The servo information is composed of address code information indicating a track (cylinder) number and burst data alternately recorded at a position shifted by a half track in the radial direction of the disk with respect to the center position of the track. Of these, the address code information is used to detect which track (cylinder) the head is currently on, and is used to detect how much the burst data deviates from the center position of the track. ..

That is, the head positioning control is roughly classified into a speed control mode and a position control mode. In the speed control mode, the head moving speed is detected by detecting the current position of the head using the address code information of the servo information, and speed control is performed to correct the error between the detected speed and the target speed. To be done. In the position control mode, when the head moves to the target position in the speed control mode described above, the shift amount of the head with respect to the center of the target position is detected by using the burst data of the servo information, and the shift amount is detected. Position control for correction is executed.

By the way, when the head positioning control based on such servo information is realized, the data reproducing system is
It is necessary to provide a circuit for pulsing the address code information and a circuit for detecting the amplitude value of the burst data. In this case, since the address code information and the burst data are serially read from the disk as servo information, they are input to both circuits. Therefore, in the speed control mode (when address code information is required), the output of the amplitude value detection circuit is ignored, and conversely, in the position control mode (when burst data is required) I try to ignore the output.

[0005]

However, in the conventional reproducing system, the pulsing circuit is always in operation regardless of the control modes of the speed control mode and the position control mode. Therefore, in the position control mode, even if the processing target is switched from the pulse conversion circuit to the amplitude value detection circuit and the output of the pulse conversion circuit is ignored, the operation noise of the pulse conversion circuit (burst data is pulsed) The on / off switching noise) adversely affects the amplitude value detection circuit, and an accurate amplitude value may not be obtained.

The present invention has been made in view of the above points, and when servo information including address code information and burst data is used, an accurate amplitude value of burst data can always be obtained. It is an object of the present invention to provide a head positioning control device for a data recording / reproducing device that can improve the head positioning accuracy.

[0007]

DISCLOSURE OF THE INVENTION The present invention is a data recording / reproducing device provided with a pulsing device for pulsing servo information composed of address code information and burst data and an amplitude value detecting device for detecting an amplitude value of the servo information. In the head positioning control device of the apparatus, the pulsing operation of the pulsing means is prohibited when the amplitude value of the servo information is detected by the amplitude value detecting means.

[0008]

According to the above construction, when the amplitude value detecting means is detecting the amplitude value of the burst data, the pulsing means is in a stopped state, and its operation noise (burst data is pulsed as in the prior art). The on / off switching noise) is prevented from adversely affecting the amplitude value detecting means.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A head positioning control device for a data recording / reproducing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the construction of a sector servo type magnetic disk device, for example. In FIG. 1, a disk 11 is a recording medium and is rotated by driving a spindle motor 12. Servo information is recorded in advance on the disk 11 for each sector. The servo information is position information for head positioning control, and is recorded alternately at address code information indicating a track (cylinder) number and a position shifted by a half track in the radial direction of the disk 11 with respect to the center position of the track. It consists of burst data. Of these, the address code information is used when detecting on which track (cylinder) the magnetic head 13 is currently located, and when detecting how much the burst data deviates from the center position of the track. Used.

The magnetic head 13 reads / writes data from / to the disk 11, and is moved in the radial direction of the disk 11 via an actuator 14 by driving a voice coil motor (hereinafter referred to as VCM) 15. Here, the information recorded on the disk 11 is read as an analog signal by the magnetic head 13, amplified by the head amplifier (AMP) 16, and further, by the gain set by the AGC control circuit 18 in the AGC amplifier 17. Is amplified according to. Here, since the read waveform has high-frequency noise, a low-pass filter (LP
F) Remove this at 19.

The read signal of the magnetic head 13 that has passed through the low-pass filter 19 is input to the pulse conversion circuit 20 and the amplitude value detection circuit 21. The pulsing circuit 20 is a circuit that pulsates a read signal that is an analog signal,
For example, it comprises a differentiating circuit and a zero-cross comparator. Here, the control signal S1 from the servo control circuit 22 is
The operation of the pulsing circuit 20 is controlled by. On the other hand, the amplitude value detection circuit 21 is a circuit that detects the amplitude value of the read signal, and includes, for example, a sample / hold circuit and an A / D converter.

The servo control circuit 22 controls the entire apparatus, and is composed of, for example, a CPU, obtains servo information consisting of address code information and burst data through the pulsing circuit 20 and the amplitude value detection circuit 21, and outputs the servo information. Positioning control of the magnetic head 13 is performed based on the servo information. The VCM driver 23 and the motor driver 24 drive the voice coil motor 15 and the spindle motor 12, respectively, under the control of the servo control circuit 22.

Further, the read circuit 25 is the pulse conversion circuit 2
0 is a circuit for generating read data based on a read pulse signal obtained by 0, for example, a phase synchronization circuit (P
LL) and the like. The read circuit 25 operates based on the read gate signal S2 from the servo control circuit 22. HDC (hard disk controller) 26
Is an interface with the host system, and transfers read data obtained by the read circuit 25 to the host system, for example. Next, the operation of the embodiment will be described.

When the target track is designated by the host system, the magnetic head 13 seeks on the disk 11 toward the target track under the control of the servo control circuit 22. At this time, the information recorded on the disk 11 is read through the magnetic head 13. In this case, as shown in FIG. 2, since servo information including address code information and burst data is recorded in advance on the disk 11 for each sector, the seek of the magnetic head 13 causes
The servo information is read out intermittently. The read signal of the magnetic head 13 at this time is amplified by the head amplifier 16 and then amplified by the AGC amplifier 17 and the low-pass filter 19.
Through pulse generator 20 and amplitude value detector 21.

The pulsing circuit 20 pulsates a read signal which is an analog signal and outputs the read pulse signal to the servo control circuit 22 and the read circuit 25. On the other hand, the amplitude value detection circuit 21 detects the amplitude value of the read signal and outputs the amplitude value signal obtained by digitizing the amplitude value to the servo control circuit 22. The servo control circuit 22 selectively inputs the read pulse signal from the pulsing circuit 20 or the amplitude value signal from the amplitude value detection circuit 21 according to the control mode at that time. That is, the servo control circuit 2
2 ignores the amplitude value signal output from the amplitude value detection circuit 21 and inputs the read pulse signal from the pulse conversion circuit 20 in the speed control mode (when address code information is required). In the position control mode (when burst data is required), the amplitude value signal from the amplitude value detection circuit 21 is input.

In this embodiment, in the position control mode, the control signal S1 shown in FIG. 2 is output from the servo control circuit 22 to the pulse forming circuit 20. This control signal S1 is a signal for controlling the pulsing operation of the pulsing circuit 20, and becomes "L" level when the burst data is being read from the servo area, and the pulsing circuit 20 is pulsed. Prohibit operation. As a result, in the position control mode, the amplitude value detection circuit 2
When 1 is detecting the amplitude value of the burst data, the pulsing circuit 20 is in a stopped state, and its operation noise (on / off switching noise when the burst data is pulsed) as in the conventional case. It is prevented that the amplitude value detection circuit 21 is adversely affected. Therefore,
The servo control circuit 22 can always obtain an accurate amplitude value of burst data, and can accurately position the magnetic head 13 at the center of a target track based on the amplitude value.

The read pulse signal pulsed by the pulse conversion circuit 20 is also given to the read circuit 25. The pulsing circuit 20 outputs the read gate signal S2 from the servo control circuit 22, that is, the read pulse signal in the read mode (in this case, normal data read from the magnetic head 13 through the magnetic head 13). Pulsed signal), and read data is generated based on the signal.

[0019]

As described above, according to the present invention, in the head positioning control using the servo information including the address code information and the burst data, the pulse operation is prohibited when the amplitude value of the burst data is detected. Therefore, it is possible to prevent the adverse effect of the operation noise. Therefore, it is possible to always obtain an accurate amplitude value of the burst data, and it is possible to improve the head positioning accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the embodiment.

[Explanation of symbols]

11 ... Disk, 12 ... Spindle motor, 13 ... Magnetic head, 14 ... Actuator, 15 ... Voice coil motor, 16 ... Head amplifier, 17 ... AGC amplifier, 18
... AGC control circuit, 19 ... Low pass filter, 20 ... Pulsing circuit, 21 ... Amplitude value detection circuit, 22 ... Servo control circuit, 23 ... VCM driver, 24 ... Motor driver,
S1 ... Control signal, S2 ... Read gate signal.

Claims (3)

[Claims] 1. A head positioning control device of a data recording / reproducing device for performing head positioning control based on servo information consisting of address code information and burst data recorded in advance on a recording medium, a pulse for pulsing the servo information. Converting means, amplitude value detecting means for detecting the amplitude value of the servo information, and control for prohibiting the pulsing operation of the pulsing means when the amplitude value of the servo information is detected by the amplitude value detecting means. And a head positioning control device for a data recording / reproducing device. 2. A head positioning control device of a data recording / reproducing device for performing head positioning control based on servo information composed of address code information and burst data recorded in advance on a recording medium, and a pulse for pulsing the servo information. Converting means, an amplitude value detecting means for detecting an amplitude value of the servo information, and when the servo information is pulsed by the pulsing means, the output of the amplitude value detecting means is ignored and the amplitude value is A head positioning control device for a data recording / reproducing apparatus, comprising: a control means for prohibiting the pulsing operation of the pulsing means when the amplitude value of the servo information is detected by the detecting means. 3. The data recording / reproducing apparatus according to claim 1 or 2, wherein the pulsing means pulsates the servo information and normal data read from the recording medium through the head. Head positioning control device.