JPH04251474A - Recording system for alignment media - Google Patents

Abstract

PURPOSE:To improve accuracy for tracking adjustment and to shorten time for adjustment by using the two signals of various frequencies for signals showing that a magnetic head is set at a reference position, and writing the two signals separately on the inside and outside of a reference position center. CONSTITUTION:Signals A and B of various frequencies are used for the two signals showing that the magnetic head is set at the reference position of a magnetic medium 1, and the signals A and B are written separately on the inside and outside of a reference position center (a). In this case, assuming that the frequency of the signal A is f1 and that of the signal B is f2, output voltages V1 and V2 of the signals A and B are V1=sin2pif1X(a) and V2=sin2pif2X(b) ((a) and (b) are overlapped width between the magnetic head and the track). This output voltage is passed through the band pass filter of a prescribed circuit and split into two frequency components, and the respective output values are compared. Thus, in the FDD assembly of various OA equipments, accuracy for tracking adjustment is improved and time for adjustment is shortened.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a floppy disk drive (hereinafter referred to as FDD) of so-called office automation equipment such as a personal computer or a word processor.
The present invention relates to a recording method for alignment media that can be implemented in the following manner.

0002

[Background Art] When assembling FDDs used in the above-mentioned office automation equipment, etc., in order to maintain compatibility of the FDDs, it is necessary to adjust the position of the magnetic head so that it is at the same track position for all FDDs. . For this reason, as shown in FIG. 4, a predetermined signal 2 indicating a reference position is written in advance on a magnetic medium (alignment media, floppy disk as an example) 1, which is a circular magnetic recording medium, and this signal is read. The amount of deviation between the magnetic head and the reference position is determined by measuring the output of the magnetic head.

There are mainly the following methods for writing signals indicating this reference position. That is, (a)
Analog cat's eye alignment method (b) in which the center position of the magnetic media is intentionally eccentric for writing; Digital burst alignment method in which the track is divided into outer and inner tracks relative to the reference position, and temporally divided into multiple blocks. To explain this using a diagram, as shown in FIG. 4, a signal 2 indicating the head position is written on the magnetic medium 1, and this is read. In this case, in the method (a), the head position is The two reference signals A signal and B signal for signal 2 indicating It is rotated in the direction shown and read with a magnetic head. When the output voltage of the magnetic head is measured in this manner, two peaks appear during one rotation, as shown in FIG. The off-track amount is calculated from the amplitudes of these two peaks. This calculation is
The amount of positional deviation can be determined by the formula: B/A×k (k is a constant).

The system shown in FIG. 6 is the method (b). In this case, a plurality of blocks (n blocks) are arranged alternately outside and inside the center point a of the magnetic medium 1, with the signal 2 indicating the head position as the boundary, and are also divided in time. Then, one pair is made of the outer one and one inner one. The output voltage during reading by this method is as shown in FIG. The advantage of this method is that off-track can be determined, and the amount of eccentricity, which was impossible with method (a), can also be determined. The amount of positional deviation in this method can be obtained by summing the ratios of each pair, dividing this by the total number n, and multiplying this by a constant k.

The conventional method described above has the following drawbacks. The method (a) lacks accuracy because there is only one pair per rotation. On the other hand, in the method (b), although it is possible to increase the number of pairs, the head position is not measured simultaneously, but is estimated from two positions.

[0006] In both types, the amplitude obtained during readout is susceptible to disturbances from other sources. For example, there is a problem in that the peak value fluctuates due to external noise, media modulation, termination when the write current is turned off, etc., and the accuracy deteriorates.

Furthermore, both methods (a) and (b) start from the index and end when a specified number of readings have been made, so one or more rotations are required for one measurement. It becomes necessary. Thereby, there is a limit to the reduction in adjustment inspection time.

[0008]

[Problem to be solved by the invention] As explained above,
Determining the amount of misalignment of the magnetic head using the above two methods requires comparison at a specific point, which makes it difficult to obtain the amount of misalignment with high precision.Also, since the comparison is based on the amplitude of the signal indicating the reference position, it is difficult to obtain the amount of misalignment with high accuracy. , it has the disadvantage of being easily influenced by noise and the like. The present invention has been made in view of the above-mentioned circumstances of conventional methods, and an object of the present invention is to provide an alignment media recording method that can improve track adjustment accuracy and at the same time shorten adjustment time. With the goal.

[0009]

[Means for Solving the Problems] As a means for solving the above-mentioned problems, the present invention has a magnetic head for writing and reading information on a circular magnetic recording medium, and moves the magnetic head to create a magnetic recording medium. In a magnetic recording device equipped with a mechanism for matching the position of the magnetic head with the track of the recording medium, two signals with different frequencies are used to indicate that the magnetic head is at the reference position, and these two signals are used as the reference position. A recording method for alignment media is obtained which is characterized in that writing is performed separately on the outside and inside from the center of the position.

According to the present invention configured in this manner, the magnetic head reads two signals written at different frequencies. Therefore, by taking the ratio of the magnitudes of these two signals, the current position of the magnetic head can be specified.

Next, one embodiment of the present invention will be described with reference to FIG. In the present invention, signals A and B having different frequencies are used as two signals indicating that the magnetic head on the magnetic medium 1 is at the reference position, and these two signals A and B are moved from the center of the reference position. It is designed to write separately on the outside and inside. In the illustrated example, the signal A is recorded on the outer circumferential side of the magnetic medium 1, and the signal B is recorded on the inner circumferential side of the magnetic medium 1. Here, if the frequency of signal A is f1 and the frequency of signal B is f2, the output of the magnetic head that reads this signal is V1 = sin2πf1 where the output voltage of signal A is V1 and the output voltage of signal B is V2. ×a (a: overlap width between magnetic head and track) V2 = sin2πf2 ×b (b
: overlap width between the magnetic head and the track). From this, the output voltage of the magnetic head is V=V1 +V2
Then, V=V1 +V2 = sin2πf1 ×a+sin2
πf2×b.

The output voltage of the magnetic head obtained in this manner is separated into two frequency components f1 and f2 by passing through a band-pass filter in a circuit to be described later, and the two frequency components are passed through an envelope detection circuit to determine the respective output values. By comparing the values, the position of the magnetic head can be determined. That is, if the center of the magnetic head is now at the reference position, a=b, and the f1 and f2 components are equal, and if the center of the magnetic head shifts inward, a<
At b, the f1 component becomes smaller than the f2 component, and if the center of the magnetic head shifts outward, then a>b, and the f1 component becomes larger than the f2 component.

FIG. 3 is a circuit diagram of a circuit that processes the output voltage of the magnetic head. In this figure, the reference numeral 4 is a magnetic head, which reads information written on the magnetic medium 1. This magnetic head 4 is connected to two systems A and B via an amplifier 5. A bandpass filter 6, a detection circuit 7, and an envelope circuit (low-pass filter) 8 are sequentially connected to the system A, and a bandpass filter 9, a detection circuit 10, and an envelope circuit (low-pass filter) 11 are similarly connected to the system B. It is connected. The output terminals 12 and 13 of these two systems are connected to the differential amplifier 1.
4, and an indicator 15 for displaying the position of the magnetic head 4 is connected to the output side of the differential amplifier 14.

The circuit of FIG. 3 operates as follows. Assuming that the magnetic head 4 is located at the position shown in FIG. 1 on the magnetic medium 1, the signals A and B of the magnetic medium 1 are read simultaneously. That is, the magnetic head 4 reads signals of two frequencies f1 and f2, amplifies them, and inputs them to two systems of bandpass filters 6 and 9. At this point, the high and low frequencies of both signals are cut and stable operation is achieved, and the signals are detected by the detection circuits 7 and 10 and enveloped by the envelope circuit 8.
, 11 and the differential amplifier 14
The display meter 15 displays the position of the magnetic head 4 in real time based on the ratio of both signals. In addition, the display on the display meter 15 indicates that a=b when the value is plus or minus 0.
It turns out that.

When operating as described above, the two frequencies f1 and f2 used can be any frequency as long as the following constraints are met. (a) f1 and f2 are not the same value. (b) Both frequencies f1 and f2 are within the frequency band of the magnetic head. (c) The output voltage of the magnetic head is at both frequencies f1 and f2.
and should be as similar as possible. (d) Separation is possible with bandpass filters 6 and 9. Furthermore, the bandpass filters 6 and 9 must have a bandwidth that is not affected by fluctuations in frequencies f1 and f2 due to rotational fluctuations of the magnetic medium 1.

[0016]

[Effects of the Invention] The present invention is constructed as described above,
Because this is the recording method of the operating alignment media,
The drawbacks of the conventional method can be solved as follows. (1) Both frequencies f1 and f2 are written over the entire circumference of the magnetic media.Since the two frequencies are always output to the same head position, no matter how you divide them, the values cannot be changed. You will be able to ask for it. (2) Also, external noise etc. has a frequency of f1 or f2.
If the frequency is the same, it cannot be prevented, but if the frequency is different, it will not be affected by this noise. (3) Furthermore, since the signal is written at any position (rotation angle) of the magnetic medium, it is not necessary to measure the entire rotation, which simplifies the measurement. (4) From the above, it is possible to improve the drawbacks of conventional methods such as lack of accuracy and long measurement time, and it is possible to improve quality and reduce costs.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of one embodiment of the present invention.

FIG. 2 is a graph showing the characteristics of FIG. 1;

FIG. 3 is a circuit diagram of a signal processing circuit according to the present invention.

FIG. 4 is an explanatory diagram of an example of a conventional technique.

FIG. 5 is a graph showing the characteristics of those in FIG. 4;

FIG. 6 is an explanatory diagram of another example of the prior art.

FIG. 7 is a graph showing the characteristics of those in FIG. 6;

[Explanation of symbols]

1 Magnetic media 2 Signal indicating head position 4 Magnetic head

Claims (1)

[Claims] Claim 1: Writing information on a circular magnetic recording medium;
A signal indicating that the magnetic head is at a reference position in a magnetic recording device having a magnetic head for reading and a mechanism for moving the magnetic head to match the position of the magnetic head with a track on a magnetic recording medium. An alignment media recording method characterized in that two signals with different frequencies are used for recording, and the two signals are written separately on the outside and inside from the center of a reference position.