JPH04103080A - Data recording/reproducing device - Google Patents

Abstract

PURPOSE:To make it unnecessary to use an exclusive measuring instrument, to shorten a measuring time and to improve the reliability of this data recording/reproducing device by providing the device with an window shifting means for shifting a window signal by the control of a control means and separating read data pulse string into data pulses and clock pulses based upon the shifted window signal. CONSTITUTION:A controller 27 sets up the window shifting variable of the window shifting circuit 29 to a maximum value on the advance or delay side. In addition, the controller 27 shifts the shifting variable to the delay or advance side in each fixed value, converts the strobe offset of the window signal and checks whether data can be accurately read out or not in each conversion to detect a limit point EARLY or LATE on the advance side or the delay side capable of accurately reading out data. The controller 27 finds out a reading margin from a difference between both the limit points EARLY, LATE. Since the reading margin can be automatically measured without using a measuring instrument to be exclusively used for the reading margin, the measuring time can be shortened and the reliability of the device can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a data recording/reproducing device such as a magnetic disk device suitable for determining a read margin 61.

(Prior Art) As shown in FIG. 5, in a magnetic disk device, a signal read from a disk 11 through a magnetic head 12 is
The read data is converted into binary data through a head amplifier 13 and a peak detector 14. Here, the pulse train of read data read from the disk 11 is a mixture of data pulses and clock pulses by FM or MFM modulation.

The VFO circuit 15 creates a window signal for separating this read data into a data pulse and a clock pulse. By this window signal, the read data is separated into a data pulse and a clock pulse by the data separator 1B.

In FIG. 5, 17 is a controller that controls various circuits of the magnetic disk device, and 18 is a host computer that manages and controls the magnetic disk device.

By the way, when performing read margin measurement in a conventional magnetic disk device, first record a specific pattern at a specific position (for example, the innermost circumference) on the disk 11 using the measuring device 19, and then Read data to measuring device 1
Make it read at 9.

Then, a window signal is created within the measuring device 19, and the strobe offset of the window signal is changed by shifting this window signal forward and backward by a fixed amount (see Figure 4).
By checking whether the data can be read accurately each time, the limit points at which the data can be read accurately are detected on the leading and lagging sides of the window signal. The reading margin is determined from the difference between the limit point on the leading side and the limit point on the delayed side.

(Problem to be Solved by the Invention) As mentioned above, conventionally, when measuring the reading margin,
A dedicated measuring device was required, and the measuring person had to operate the measuring device. For this reason, there were problems such as time-consuming measurement and lack of reliability.

The present invention has been made in view of the above-mentioned points, and provides data that enables reading margin measurement without the need for a dedicated measuring instrument, shortens measurement time, and improves reliability. The purpose is to provide a recording/playback device.

[Structure of the Invention] (Means and Effects for Solving the Problems) A data recording/reproducing device according to the present invention is provided with a window shift means for shifting a window signal under the control of a control means, and a window signal shifted by the window shift means is provided. The read data pulse train is separated into data pulses and clock pulses based on the window signal.

Further, the control means is characterized in that it has a read margin measurement function and controls the shift operation of the window shift means in accordance with the read margin measurement procedure.

According to such a configuration, since the shift amount of the window signal can be changed under the control of the control means, reading margin measurement can be performed without requiring a dedicated measuring device.

(Embodiment) Hereinafter, a data recording and reproducing apparatus according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the circuit configuration of a reading system used in, for example, a magnetic disk device. In Figure 1,
Data is recorded on the disk 21, which is a recording medium, by FM or MFM modulation. The magnetic head 22 moves in the radial direction of the disk 21 and records/reproduces data. The head amplifier 23 amplifies the signal read by the magnetic head 22. peak detector 24
performs differentiation, zero-volt comparator, waveform shaping, etc., and binarizes the read signal from the magnetic head 22.

The VFO circuit 25 generates a window signal in synchronization with the read data to separate the pulse train of the same data into data pulses and clock pulses.

The data separator 26 separates the read data pulse train into data pulses and clock pulses based on the window signal. The controller 27 controls various circuits of the magnetic disk drive, has a read margin measurement function, and executes the read margin measurement process as shown in FIG. The host computer 28 is
It manages and controls the magnetic disk device, and here it outputs a test command that instructs reading margin measurement. The window shift circuit 29 is connected to the controller 2
7, the window signal (the phase) created by the VFO circuit 25 is quantitatively shifted to the leading side or the lagging side.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG.

When measuring the reading margin, first, a test command instructing the measurement is transferred from the host computer 28 (step Sl). When the controller 27 decodes this test command, the controller 27 writes a specific pattern (for example, a random pattern) for measuring the read margin at a specific position (for example, the innermost circumference) of the disk 21 through the magnetic head 22 using the FM or MFM modulation method ( Step S
2).

Next, the data recorded at that specific location is read. The data read by the magnetic head 22 is binarized through a head amplifier 23 and a peak detector 24 (this disulfurized data is hereinafter referred to as read data). Here, as shown in FIG. 3, the VFO circuit 25
A window signal synchronized with the read data is created,
In the data separator 26, the read data pulse train is separated into data pulses D and clock pulses C. At this time, the controller 27 controls the shift operation of the window shift circuit 29 in the following procedure. 4
control and measure the read margin.

That is, as shown in FIG. 4, the controller 27
First, the window shift amount of the window shift circuit 29 is set to the maximum on the advance side (step S3). and,
The controller 27 changes the strobe offset of the window signal by shifting the shift amount in the opposite direction, that is, to the delay side, every fixed amount, and each time, the controller 27 changes the strobe offset of the window signal by a predetermined amount (for example, 107
By reading the data pattern (bit) and checking whether it can be read accurately, a limit point EARLY on the advance side at which the data can be read accurately is detected (steps 84 to S8).

Note that the strobe offset is the interval from the center of the window signal to the data pulse.

Next, the controller 27 controls the window shift circuit 29
The window shift amount is set to the maximum on the lag side (step 510), and similarly to the above, the shift amount is shifted to the advance side by a fixed amount, and each time, by checking whether the data can be read accurately. , a limit point LATE on the delayed side at which the data can be accurately read is detected (steps S11 to S516).

In this way, the limit point EA on the advancing side of the window signal
When RLY and the late limit point LATE are detected, the controller 27 calculates a reading margin from the difference between the limit point EARLY and the limit point LATE, and sends the result to the host computer 28 (step 517).

In this manner, by providing the window shift circuit 29 that shifts the window signal under the control of the controller 27, the strobe offset of the window signal can be changed in response to a command from the controller 27. therefore,
The reading margin can be automatically measured through internal processing of the device, without using a dedicated measuring device for the reading margin as in the past. Thereby, measurement time can be shortened and reliability can be improved.

In the above embodiment, the reading margin measurement is executed by a command, but the reading margin measurement may be executed automatically, for example, when the apparatus is powered on.

[Effects of the Invention] As described above, according to the present invention, since the shift amount of the window signal can be changed under the control of the controller, reading margin measurement can be performed without requiring a dedicated measuring device. This makes it possible to shorten measurement time and improve reliability.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, FIG. 2 is a flowchart for explaining the operation of the embodiment, and FIGS. 3 and 4 show the reading margin measurement of the embodiment. A timing chart for explanation and FIG. 5 is a block diagram showing a conventional configuration. 21...Disk, 22...Magnetic head, 23...
・Head amplifier, 24...Peak detector, 25・
・VFO circuit, 2B...data separator, 27...
Controller, 28... Host computer, 29.
...Window shift circuit.

Claims (2)

[Claims] (1) Binarization means that reads data recorded on a recording medium using a predetermined modulation method and binarizes the data, and converts the pulse train of the data binarized by the binarization means into data pulses and clock pulses. a window signal creation means for creating a window signal for separating into two; a window shift means for shifting the window signal created by the window signal creation means; 1. A data recording and reproducing apparatus comprising: data separating means for separating a pulse train of binarized data into data pulses and clock pulses; and control means for controlling the shifting operation of the window shifting means. (2) The data recording and reproducing apparatus according to claim 1, wherein the control means has a read margin measurement function and controls the shift operation of the window shift means in accordance with the read margin measurement procedure.