JPH03141086A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To prevent a fact that data recorded in other area than a servo- detection area is brought to erroneous detection as servo-detection data by using unused frequency data in a data area and setting it as the servo-detection data. CONSTITUTION:On a head part of a servo-area 12, a pre-0.5f part 14, a pre-erase part 15, a 0.5f part 16, and an erase part 17 are provided. The pre-0.5f part 14 records a prescribed number of continuous data by a frequency of 0.5f being an unused frequency in data area 11, 13. The pre-erase part 15 is a non- magnetization inversion area, and records erase data. In the same way, in the 0.5f part 16, continuous data of a frequency of 0.5f and of a smaller number than the number of data recorded in the pre-0.5f part 14 are recorded, and also, area length of the erase part 17 is set shorter than the erase part 15. By detecting the 0.5f data and the erase data, servo-data is detected exactly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a data surface servo type magnetic recording/reproducing device.

(Prior Art) For example, in a hard disk drive, positioning control of a magnetic head is performed based on servo data recorded in advance on a disk. Positioning control methods (servo methods) for this magnetic head include a servo surface servo method and a data surface servo method.

The data surface servo method is called embedded servo, in which servo data is intermittently recorded on the data surface (for example, for each sector).

By the way, in the data surface servo method, since servo data is recorded on the data surface as described above, it is necessary to separate the data area and the servo area. Therefore, conventionally, a servo detection area for detecting servo data was provided at the beginning of the servo area to separate the data area and the servo area.

(Problem to be Solved by the Invention) However, conventionally, as servo detection data recorded in the servo detection area, for example, in the MFM recording method shown in FIG. 4, when the reference frequency is f, 1f or 2
A combination of frequency data used in data areas such as f and erase data was used. Therefore, there is a possibility that data recorded in an area other than the servo detection area may be mistakenly detected as servo detection data, and there is a problem that the data area and the servo area cannot be accurately separated.

The present invention has been made in view of the above points, and an object of the present invention is to provide a magnetic recording/reproducing apparatus that can accurately separate a data area and a servo area in a data surface servo system.

[Structure of the Invention] (Means and Effects for Solving the Problems) That is, the data surface servo type magnetic recording/reproducing device according to the present invention uses, for example, the MFM recording type as the servo detection data recorded in the servo detection area. When the fundamental frequency is f, by using frequency data of 0 and 5f, which are unused frequencies in the data area, data recorded in areas other than the servo detection area is not mistakenly detected as servo detection data. Second, the servo detection data is accurately detected.

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

FIG. 1 is a diagram showing the data structure of a recording medium in the data surface servo system. A servo area 12 is provided in a predetermined area of each sector, and servo data for head positioning control is recorded in this servo area I2.

Here, at the beginning of this servo area 12, there is a burr of 0.5
A servo detection area consisting of an f section 14, a blank erase section 15.0.5fm18, and an erase section 17 is provided.

In the 0.5f section 14, in the MFM recording method, a predetermined number of consecutive data are recorded at frequencies of 0 and 5f, which are unused frequencies in the data area 11.13, where f is the fundamental frequency. has been done. The pre-erase section 15 is a non-magnetization reversal area, and erase data is recorded therein. Similarly, continuous data is recorded in the 0.5f section 16 at a frequency of 0.5f and is smaller than the number of data recorded in the 0.5f section 14, and erased data is recorded in the erase section 17. has been done. Further, the area length of the erase section 17 is shorter than that of the pre-erase section 15.

In this way, in the same embodiment, the servo detection area includes:
As the servo detection data, a combination of 0.5f frequency data and erase data is used.

FIG. 2 is a block diagram showing the configuration of the servo detection circuit of the same embodiment. In FIG. 2, a recording medium 21 has the data structure shown in FIG. The magnetic head 22 is a read/write device for recording/reproducing data on the recording medium 21.
It's a light head. The amplifier 23 amplifies the head reproduction output. The binarization circuit 24 binarizes the head reproduction data from the amplifier 23 using a window comparator.

The 0.5f detection circuit 25 detects the 0.5f data recorded in the 0.5f section 14 or the 0,5f data recorded in the 0.5f section 16 from the output data of the binarization circuit 24. . Similarly, the erase detection circuit 26 detects the erase data recorded in the pre-erase section 15 or the erase data recorded in the erase section 17 from the output data of the binarization circuit 24. AND circuit 27
is the yellow 0.5f output from the 0.5f detection circuit 25.
The detection signal a and the erase detection signal S output from the erase detection circuit 26 are ANDed, and the resultant enable signal EN is output.

Counter 28 starts counting in response to enable signal EN, and outputs the count signal to decoder 29. The decoder 29 decodes the count signal and outputs an enable signal e that enables the count result within a specified value. The AND circuit 27 uses this enable signal e and the 0, 5f output from the 0.5f detection circuit 25.
The detection signal c1 and the erase detection signal d output from the erase detection circuit 26 are ANDed, and the resulting detection signal OK is output to a control section (not shown).

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

The signal reproduced by the magnetic head 22 is amplified by an amplifier 23 and then converted into digital data by a binarization circuit 24. The output data of this binarization circuit 24 is sent to a 0.5f detection circuit 25 and an erase detection circuit 2B.

Here, the 0.5f detection circuit 25 detects the 0.5f data recorded in the 0.5f section 14 or the 0.5f data recorded in the 0.5f section 18 from the output data of the binarization circuit 24. 5f data is detected, and a flashing 0.5f detection signal a or flashing 0.5f detection signal S is output according to the detection result. This detection is performed by the 0.5f part 14 and the
．． This is done by detecting the number of data recorded in the 5f section 16.

That is, the 0.5f detection circuit 25 detects the 0.5f portion 1
The number of continuous data of 0 and 5f frequencies, which are the frequencies of the data recorded in the 4 and 0.5f section IB, is counted. As a result, when the 0.5f detection circuit 25 detects a predetermined number of data continuously recorded at a frequency of 0.5f, it outputs a blurring 0.5f detection signal a to the AND circuit 27,
In addition, if data continuously recorded at a frequency of 0.5f, which is smaller than the predetermined number of data, is detected, 0.5f is detected.
The f detection signal C is output to the AND circuit 30.

Note that here, the number of data recorded in 0.5fl14 is greater than the number of data recorded in 0.5f*1B, but the reverse may be used.

On the other hand, the erase detection circuit 2B detects the data length of the pre-erase section 15 or the erase section 17, and outputs the pre-erase detection signal d to the AND circuit 27 or the erase detection signal d to the AND circuit 30 according to the detection result. do.

As shown in FIG. 3, each of the detection signals a to d is output with a delay from when each data is actually read. This is because there is a detection period for each data as described above.

Here, when the flash 0.5f detection signal a and the pre-erase detection signal a are both in the enabled state (“H” level state), the enable signal EN is outputted to the counter 28 through the AND circuit 27. The counter 28 starts counting at the input timing of this enable signal EN.

By decoding the count signal of the counter 28, the decoder 29 sends an enable signal e to the AND circuit 80 when the count result reaches the lower limit of the specified value, until the count result reaches the upper limit of the specified value. Output. As a result, the enable signal e, the 0.5f detection signal C, and the erase detection signal d are all enabled!
! (rHJ level state), the AND circuit 30
A detection signal OK is outputted to the control section through.

In addition, the lower limit and upper limit of the above count result are
．． The timing to open the gate of the AND circuit 30 is at a sufficient point in time after the detection of the 5f detection signal a and the pre-erase detection signal S and the detection of the two signals of the 0.5f detection signal C and the erase detection signal d. and a numerical value provided to determine the time interval during which the gate of the AND circuit 30 is opened.

That is, when all of the data constituting the servo detection data within the servo detection area are correctly detected, the detection signal OK is output to the control section. In this case, since 0 and 5f data, which are frequencies other than those used in data areas 11 and 12, are used as servo detection data, data in other areas cannot be mistakenly detected as servo detection data. do not have. Therefore, in the control section,
Based on this detection signal OK, the data area and the servo area can be accurately separated, and thereafter, head positioning control can be performed reliably using the servo data in the servo area 12.

In addition, in this embodiment, the servo detection data is 0.5
Although the frequency data of f is used, the present invention is not limited to this, and any unused frequency data in the data area may be used. However, since there is a problem that the S/N ratio decreases in high frequency data of, for example, 2f or more, approximately 0.5f is optimal.

C Effect of the Invention] As described above, according to the present invention, since servo detection data is used as servo detection data by using unused frequency data in the data area, it is not possible to record it in an area other than the servo detection area. It is possible to prevent erroneously detecting data that has been detected as servo detection data, and thereby it is possible to accurately separate the data area and the servo area.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing the data structure of a recording medium according to an embodiment of the present invention, FIG. 2 is a block diagram showing the circuit configuration of the embodiment, and FIG. 3 is for explaining the operation of the embodiment. FIG. 4 is a diagram for explaining conventional servo detection data. 11 and 13...data area, 12...servo area, 14...buri 0.5f section, 15...pre-erase section, 1B...0.5f section, 17...erase section,
21... Recording medium, 22... Magnetic head, 23...
・Amplifier, 24...Binarization circuit, 25...0.5f
Detection circuit, 26... Erase detection circuit, 27 and 3
0...AND circuit, 28...Counter, 29...
decoder. Data 1 1f data (a) Data f data (b)

Claims (1)

[Claims] In a magnetic recording/reproducing device that records/reproduces data using a magnetic head whose positioning is controlled by a data surface servo method, for detecting the servo data at the beginning of a servo area where the servo data is recorded. A servo detection area is provided, and this servo detection area includes at least a recording medium in which servo detection data consisting of unused frequency data in a data area is recorded in advance, and a recording medium recorded in the servo detection area of this recording medium. 1. A magnetic recording and reproducing apparatus comprising: a detection means for detecting the servo detection data.