JPS6030030B2 - Positioning information recording position test method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for testing the recording position of positioning information on a magnetic disk.

Conventionally, as a method of testing the recording position of positioning information, the head is positioned using a servo system in a disk device that uses positioning information as a servo signal, and the movement of the head is measured using a high-precision measuring device such as a laser extender. This was done by measuring. Figures 1 and 2 are explanatory diagrams showing the relationship between positioning information and the reading head. Figure 1 shows when the recording position of position information is in an ideal state, and Figure 2 shows when the recording position is shifted. ing. In Fig. 1, 1 is an information track on which position information 3 and 4 are written, and a reading head 2 is located in the middle of the information track.
The read output when is positioned is 5. 1st
As shown in the figure, when the recording position of each information is ideal, the waveforms of the read output 5 corresponding to the position information 3 and 4 have the same peak value as 6 and 7, and the difference in the peak value becomes zero. In a disk device, this principle is used to control the head position so that the difference in peak values becomes zero, and to position the head at an intermediate position of each layer information track 1. On the other hand, if the recording position of the positional information deviates from the ideal state as shown in Figure 2, if the reading head 2 is in a fixed position, the reading output 5 will have a peak value for each layer information 3 and 4 as shown in the figure. If you take the difference, you get 8.

Therefore, the recording position can be tested by monitoring the difference signal 8 of the position information read output. FIG. 3 shows an example of a circuit according to the conventional method.

9 is an amplifier that amplifies the output of the Kendori head 2, and position information for each track spanning one or two rivers (6 in Figure 1) is used.
, 7), 11 is an error signal creation circuit that creates a voltage difference between the position information 6 and 7, 12 is a power amplifier that drives the voice coil motor 13, and 14 is a laser lengthener that lengthens the head position. It is.

In this circuit, the head is positioned by a servo system that creates a difference between position information outputs 6 and 7 using an error signal generation circuit 11, and drives a voice coil motor 13 through a power amplifier 12 so as to make the difference voltage zero. . The recording position test was performed by lengthening the movement of the head at this time using a laser lengthening device 14. Therefore, the head positioning itself is greatly influenced by the characteristics of the servo system used, and if the servo system is different from the servo system actually used, problems will arise in test accuracy. Therefore, it has the disadvantage that it is not general enough to test the recording position. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a general test method for testing recording positions with high accuracy.

In order to achieve the above object, the present invention fixes the positioning information discussion head at a predetermined position in advance and then tests the output voltage of the positioning information there, thereby eliminating the influence of the servo system in the conventional method and improving generality. It is something that I have.

The means includes a means for reading positioning information of the magnetic disk, a means for averaging the read output and generating maximum and minimum test voltages from that value, and a means for comparing the read output with the maximum and minimum test voltages. There is. Specific examples of the present invention will be explained below with reference to the drawings.

FIG. 4 is an example of a circuit embodying the present invention. In the figure, 17
1 is an AGC amplifier for making the average output constant from the readout output amplified through the amplifier 16 from the read head 2; 18 is a circuit for calculating the average value of the readout output and creating an AGC voltage; 19 is an AGC voltage 23 is a circuit that creates a dark value for error determination; 20 is a circuit that compares the output of the AGC amplifier 17 with the reference voltage; and 21 is a circuit that ORs the error upper and lower limit check outputs.

In a test using this circuit, first, the reading head 2 is positioned in advance at a predetermined position using a laser extender 14 or the like.

The output voltage 5 of the position information measured at that position is the AGC
The voltage is averaged by the voltage generation circuit 18, and the comparison circuit 20 compares it with the maximum and minimum check levels 24 and 25 generated by the error judgment function value generation circuit 19 based on the average value, thereby making it possible to perform the test. As described above, according to the present invention, external factors such as the positioning servo system can be eliminated, and a highly accurate and general testing method can be obtained.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams showing the relationship between position information and heads, FIG. 3 is an example of a circuit according to a conventional system, and FIG. 4 is an example of a circuit according to an embodiment of the present invention. 2...reading head, 5...reading output, 6...output of position information 1, 7...output of position information 2, 16...amplifier , 17...A
GC amplifier, 18...AGC voltage generation circuit, 1
9...Error judgment threshold value creation circuit, 20...
・Comparison circuit, 21...OR circuit, 22...
...Error output, 23...AGC signal, 24...
...Maximum check level, 25...Maximum 4 check level. O / Fig. Z Fig. O Fig. 3 Fig. 4

Claims (1)

[Claims] 1. It has a means for reading the positioning information of the magnetic disk, a means for averaging the read output and generating the maximum and minimum test voltages from that value, and a means for comparing the read output with the maximum and minimum test voltage, A positioning information recording position test characterized by fixing the information reading head at a predetermined position in advance, then measuring the output voltage of the positional information at that position and testing whether the value is within an allowable range. method.