JPH06203484A - Device and method for inspecting disk - Google Patents

Abstract

PURPOSE:To attain the error detection with high precision on a widespread error ratio. CONSTITUTION:An error signal with the error ratio A% is sent to a comparator 1 from a variable level error generation circuit 4, and a first reference voltage (a) capable of detecting an error is set by a threshold value voltage variable circuit 6. Then, a second reference voltage (b) corresponding to the error ratio B% is set by b=aX(B/A), and the error ratio B'% error detected is obtained. When the error detection with the error ratio X%, is performed on a regenerative signal 3, the reference voltage is set to a value calculated by a-((a-b)/(A-B'))X(A-X).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk inspection device and a disk inspection method for inspecting the characteristics and the like of a disk which is a recording medium for information signals such as a magnetic disk.

[0002]

2. Description of the Related Art Conventionally, disks such as magnetic disks such as so-called flexible disks, which are recording media for information signals, have been proposed, and disk inspection devices and disks for inspecting the characteristics of such disks. Inspection methods have been proposed.

In inspecting the characteristics of the disk, a sudden pulse component (extra pulse: hereinafter referred to as "EP") as shown in FIG. 1 after all information signals on the disk are erased (DC erase). The presence or absence of (referred to as) is detected.

When inspecting the characteristics of the disk, a sine wave signal (2
When the signal f is written and the signal is read, the dropout component (missing pulse:
Hereinafter, the presence or absence of (MP) will be detected.

In detecting the "EP", as shown in FIG. 3, the signal read from the disk is
The presence or absence of a rectangular wave pulse in the output signal of the comparator 1 is determined by inputting it to a comparator (comparator) 1 serving as a disk inspection device and comparing it with a reference voltage Vr (v) set appropriately. That is, the reference voltage Vr is a threshold voltage for detecting the EP.

To detect the "MP", as shown in FIG. 4, the signal read from the disk is input to the comparator 1 and the reference voltage V set appropriately.
By comparing with r (v), it is determined whether the periodic rectangular wave pulse is missing in the output signal of the comparator 1. That is, the reference voltage Vr is a threshold voltage for detecting the MP.

Regarding "EP", when the reference level of the recording signal on the disc is ± S (v) and the wave height level of "EP" is p (v), p / S
(%) Is called the error rate. For "MP", the reference level of the recording signal on the disc is ± S
(V) and the wave height level of this “MP” is p (v), p / S (%) is called an error ratio.

To determine the reference voltage Vr,
First, a first error signal of "EP" or "MP" having a known error ratio A% is input to the comparator 1,
A first reference voltage a that enables error detection for this error signal is set. Next, when performing error detection on an error signal having an error ratio of X%, the reference voltage is set to Y (v) calculated by Y = a (X / A).

Such a disk inspection device is, for example,
As shown in FIG. 16, an inspection unit 105 including a disk drive device, and a system rack unit 1 to which a signal from the inspection unit 105 is sent via a cable 104.
01 and. In this disc inspection apparatus, the reproduction signal read from the disc in the inspection unit 105 is transmitted via the cable 104 to the measurement control board 103 of the system rack section 101.
Sent to. The measurement control board 103 is provided with a measurement control circuit including the comparator 1 for controlling the inspection unit 105 and performing signal processing on the reproduced signal. In addition, the system rack section 10
1 is a system controller (syscon) board 1 connected to the measurement control board 103 by a dedicated path 106.
02 is provided. The system controller board 102 is provided with a CPU (signal processing unit) for controlling the operation of the measurement control board 103.

[0010]

By the way, in the disk inspection method for determining the reference voltage as described above by using the disk inspection device including the comparator 1 as described above, the error ratio and the reference voltage are If it changes in a linear relationship, accurate error detection can be performed, but if there is an offset in the circuit including the comparator 1,
Accurate error detection cannot be performed.

That is, with respect to an error signal having an error ratio in the vicinity of A% which is the error ratio of the first error signal, substantially accurate error detection can be performed, but as the error ratio deviates from A%, the error signal becomes accurate. Error detection cannot be performed. Therefore, in this disc inspection apparatus and disc inspection method, the range of the error ratio where the error detection result can be trusted, that is, the effective range of the inspection accuracy is narrow.

Further, in the disk inspection apparatus having the inspection unit 105 and the system rack section 101 as described above, the cable 10 for sending an analog signal between the inspection unit 105 and the system rack section 101.
Since the connection is made by means of No. 4, there is a possibility that the reliability of the inspection may be reduced. That is, in this disc inspection apparatus, there is a possibility that the S / N ratio of the reproduced signal may be reduced due to the external noise in the cable 104, the control speed performed through the cable 104 may be reduced, and the like.

Since this disc inspection apparatus is constructed by having the system rack section 101, it is difficult to change the system form and it is difficult to make it compact.

Therefore, the present invention is proposed in view of the above circumstances, and an object thereof is to provide a disk inspection apparatus and a disk inspection method capable of highly accurate error detection for a wide range of error ratios. To do.

It is another object of the present invention to provide a disk inspection apparatus that can improve the reliability of inspection results and speed up control while facilitating system configuration changes and downsizing.

[0016]

In order to solve the above problems and achieve the above objects, a disk inspection apparatus according to the present invention includes a disk drive unit for reading an information signal from a disk under inspection, and this disk drive. And a measurement control circuit section for controlling an information signal sent from the disk drive section, and an interface unit for bidirectional communication between the measurement control circuit section and an external device. .

The disk inspection method according to the present invention is
A variable level error generating circuit for generating an error signal of a predetermined error ratio, a disk drive unit for reading an information signal from a disk under test and transmitting a read signal, and the error signal and the read signal are selected via a switch. And a threshold voltage variable circuit for supplying a reference voltage for judging the level of the error signal or the read signal selected by the switch to the comparator.

The disk inspection method according to the present invention uses the disk inspection apparatus to generate a first error signal having a known error ratio A% by the variable level error generation circuit and send the first error signal to the comparator. , The first reference voltage a is set by the threshold voltage variable circuit so that the output signal of the comparator becomes a signal obtained by error detection of the first error signal, and then the error is detected by the threshold voltage variable circuit. The second reference voltage b is used as a reference voltage for detecting an error in the second error signal of the ratio B%,
b = a.multidot. (B / A) is established, the error ratio B '% of the error signal detected at this time is determined, and a read signal is sent from the disk drive unit to the above comparator to calculate the error ratio X. When performing error detection for%, the threshold voltage variable circuit changes the reference voltage to Y =
It is set to Y calculated by a-{(ab) / (AB ')} · (AX).

[0019]

In the disk inspection apparatus according to the present invention, the measurement control circuit section for controlling the disk drive section for reading the information signal from the disk to be inspected and for processing the information signal sent from the disk drive section is the interface. Two-way communication can be performed with an external device via the unit.

Further, the disk inspection apparatus according to the present invention is
A variable level error generating circuit for generating an error signal of a predetermined error ratio, a disk drive unit for reading an information signal from a disk under test and transmitting a read signal, and the error signal and the read signal are selected via a switch. Of the reference voltage for supplying the reference voltage for judging the level of the error signal or the read signal selected by the switch to the comparator. Can be adjusted according to the error rate.

Further, in the disk inspection method according to the present invention, the variable level error generating circuit generates a first error signal having a known error ratio A% and sends it to the comparator, and the output of the comparator. The first reference voltage a is set by the threshold voltage variable circuit so that the signal becomes an error-detected signal for the first error signal, and then the error ratio B% is set by the threshold voltage variable circuit.
The second reference voltage b is set as a reference voltage for detecting an error with respect to the second error signal of 1) so that b = a · (B / A) holds, and the error of the error signal detected at this time is When the ratio B '% is obtained, a read signal is sent from the disk drive unit to the comparator, and error detection is performed for the error ratio X%, the threshold voltage variable circuit sets the reference voltage to Y = a-{(a- b) / (A-
B ′)} · (A−X) is set to Y, so that highly accurate error detection can be performed for a wide range of error ratios.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. The disc inspection apparatus according to the present invention,
As shown in FIG. 5, it has a comparator (comparator) 1. To the comparator 1, a reproduction signal generation source, that is, a read signal transmitted from the disc drive unit 3 for reading the information signal recorded on the disc to be inspected, and a variable level error generation path 4 are transmitted. An error signal is selectively sent via the switch 5.

The above-mentioned disk is a disk which is a recording medium for information signals such as a magnetic disk such as a so-called flexible disk. Variable level error generating circuit 4
Is an error signal which is “EP” (extra pulse) as shown in FIG. 1 or “MP” as shown in FIG.
It is a circuit that generates and outputs an error signal that is (missing pulse). This variable level error generating circuit 4 is
The error ratio of the generated error signal can be a predetermined known error ratio.

The comparator 1 is supplied with a reference voltage serving as a reference for comparison for discriminating the level of the read signal or the error signal. This reference voltage is supplied by the threshold voltage variable circuit. The threshold voltage variable circuit includes a numerical value setting switch 10, an input port 9 for reading the numerical value set in the numerical value setting switch 10, and a CPU (signal processing unit) for inputting a numerical value through the input port 9. 8, a D / A converter 7 controlled by the CPU 8, and a variom 6 for varying the output voltage of the D / A converter 7. The voltage output from the D / A converter 7 is supplied to the comparator 1 as a reference voltage via the variom 6.

The output signal of the comparator 1 is sent to the recognition circuit 2. When the error signal is "EP" in the output signal of the comparator 1, the recognition circuit 2 determines the presence or absence of a rectangular wave pulse as shown in FIG. 3, and the error signal is "MP". If it is, it is determined whether or not the rectangular wave pulse is missing, as shown in FIG.

In this disk inspection apparatus, the reference voltage can be set appropriately by setting the numerical value with the numerical setting switch 10 and adjusting the variom 6.

The disc inspection method according to the present invention is performed using the disc inspection device according to the present invention configured as described above. That is, in this disc inspection method, first, the switch 5 is switched to the variable level error generating circuit 4 side, and the variable level error generating circuit 4 generates a first error signal having a known error ratio A%. , And sends the first error signal to the comparator 1.

Then, the variohm 6 is adjusted to detect the first error signal in the output signal of the comparator 1 by the first reference voltage a.
Set (v).

Next, the second reference voltage b (v) is used as the reference voltage output from the D / A converter 7 as a reference voltage for error detection of the second error signal having the error ratio B%. Set to. This second reference voltage b (v)
Is set so that b = a · (B / A) ····· (Equation 1) holds.

Then, the error ratio B '% of the error signal which is actually error-detected when the second reference voltage b (v) is set is obtained. This B '% is numerically set in the numerical setting switch 10.

In this state, the switch 5 is switched to the disk drive unit 3 side. Then, the read signal is sent from the disk drive unit 3 to the comparator 1. Then, the CPU 8 reads the numerical value set in the numerical setting switch 10 via the input port 9 and controls the D / A converter 7 when detecting an error with respect to an arbitrary error ratio X%. Therefore, the reference voltage is calculated by Y = a-{(ab) / (AB ′)} · (AX) ······ (Equation 2) Set to Y. The CPU 8 has an error ratio A% of the first error signal, an arbitrary error ratio X%, the first and second reference voltages a (v),
b (v) is input prior to performing the control based on Equation 2 above.

When the reference voltage is set in this way,
Even if there is an offset in the circuit that constitutes this disk inspection apparatus, this offset is corrected, so that highly accurate error detection can be performed for a wide range of error ratios.

Then, the above-mentioned disc inspection apparatus is shown in FIG.
It can be integrally configured as shown in FIGS.

That is, this disc inspection apparatus is shown in FIG.
As shown in FIG.
A front panel 22, a power supply control board 23, a digital board 24, an analog board 25, and a disk drive unit 12 are provided on the top. The power control board 23, the digital board 24, and the analog board 25.
Are supported by a substrate rack 26 arranged on the chassis 21.

As shown in FIG. 9, the disk drive unit 12 includes a head 27, a head seek motor 29, 00.
A sensor 30, a disk type detection switch 31, a spindle rotation speed switching port 32, and the like are provided. The head 27, via the head harness 28,
It is connected to the analog board 25. The head seek motor 29, via the stepper harness 35,
It is connected to the backplane 37. The 00 sensor 30 is a sensor that detects that the head is at the reference position (00 position), and is connected to the backplane 37 via the 00 sensor harness 34. The disk type detection switch 31 and the spindle rotation speed switching port 32 are connected to the backplane 37 via an auxiliary I / O harness 33. Also,
The disk drive unit 12 is a disk drive I /
It is connected to the backplane 37 via an F (interface) harness 36.

The analog board 25 and the digital board 24 are connected to the backplane 37. A maintenance connector 44 is connected to the analog board 25. The digital board 24 has a GP-I
B (General Perbose Interface Bus: ge
general purp interface b
us)) connector 43 is connected. Further, the power supply control board 23 is connected to the backplane 37 via a power supply secondary harness 38.
A power supply connector 41 is connected to the power supply control board 23 through a power supply primary harness 40, and a power supply switch 42 is connected through a power supply switch harness 39. The power connector 41 and the power switch 42
Are attached to the front panel 22.

As shown in FIG. 10, the analog board 25 has a pair of measuring circuits 49 and 51 which include the comparator 1 and are connected to the backplane 37. , The above measuring circuits 4
9 and 51 include a pair of analog switches 48 and 52, a pair of reproduction amplifiers 47 and 53, and a pair of R / W (read / read).
Write) amplifiers 46 and 54 are sequentially connected in correspondence. One R / W (read / write) amplifier 46 is connected to the head 27 for the first surface (side 0) of the disk. That is, one measuring circuit 49 is a circuit for inspecting the first surface of the disk. The other R / W (read / write) amplifier 54 is connected to the head 27 for the second surface (side 1) of the disk. That is, the other measuring circuit 51 is a circuit for inspecting the second surface of the disk. In addition, the backplane 3 is mounted on the analog substrate 25.
An envelope circuit 50 connected to 7 is provided.

As shown in FIG. 11, the digital boards 24 are connected to the back planes 37, respectively.
Side 0 recognition circuit 55, side 1 recognition circuit 56, reference voltage generating D / A converter 57, A / D converter 5
8. It has a consumption current measuring circuit 59 and a head seek motor drive circuit 60. Each of these circuits is connected to the I / O 61. The I / O 61 is connected to the back plane 37. And this I / O 61
Is connected to the CPU (Z80) 65. This CP
A CTC 62, a ROM (read only memory) 63, a RAM (random access memory) 64, and a GP-IB controller 67 are connected to the U65. This G
The P-IB controller 67 is connected to the GP-IB connector (interface connector) 43.

Then, the power supply control board 23
As shown in FIG. 12, has a surge eliminating circuit 68 and a DC limiting circuit 69 connected to the power source secondary harness 38. The surge eliminating circuit 68 is connected to the power supply connector 41 via a GP-IB address line. The DC limiting circuit 69 is connected to the power connector 41 via a power line. A power supply ON / OFF circuit 70 is connected to the DC limiting circuit 69. The power on / off circuit 70 is connected to the power switch 42.

As shown in FIG. 6, the disc inspection apparatus 11 constructed as described above has the disc drive unit 1 described above.
2 has a measuring circuit 13 and a CPU circuit 14 connected to each other, and a GP-IB interface circuit 15 connected to the CPU circuit 14. Therefore, in this disc inspection device, the CP
The U circuit 14 is the GP-IB interface circuit 1 described above.
5 and the GP-IB cable 17, bidirectional communication can be performed with an external device. In this disc inspection apparatus, a general-purpose input / output circuit 16 is connected to the CPU circuit 14. A power cable 18 is connected to the disk inspection device.

CPU circuit 1 of the disk inspection device 11
Since 4 can perform bidirectional communication with an external device through the interface circuit, as shown in FIG. 7, when a disk inspection system is constructed by using a plurality of the disk inspection apparatuses 11, these disk inspection apparatuses 11 are used. Each CP
The U circuit 14 can be connected to one system controller 19 via a single GP-IB cable 17 in what is called a daisy chain. Each of these disk inspection devices 11 can be independently controlled by the system controller 19. In addition, each of the disk inspection devices 11 includes one power supply device 2
From 0, power can be supplied in parallel.

That is, the disk inspection device 11 is
As shown in FIGS. 14 and 15, a so-called VME (Versa Module European) bus system is used as a system controller, and a disk inspection system for inspecting a large number of disks using a plurality of GP-IB boards 92 is used. Can be configured. In this disc inspection system, the plurality of disc drive units 12 are connected to the rack 81.
FDC (disk controller) board 8
8 is connected to a VME bus 89 to which a main CPU (signal processing unit) 91 is connected. This VM
An operation unit 79 is connected to the E-bus 89 via the EGS-1 board 84. A display 80 is connected to the operation unit 79. This display 80
Are attached to the rack 81. Also, the above V
The ME bus 89 includes a plurality of memory devices 83 and dual I
/ O (DIO) board 85, PIA (peripheral interface adapter: peripheral inte
An rface adapter) board 86, a SIO board 87, etc. are connected.

The main CPU 91 has an I /
An O channel bus 90 is connected. A plurality of GP-IB boards 92 and a plurality of PPMC boards 93 are connected to the I / O channel bus 90. Each of the above-mentioned disk inspection devices 1 is provided on each of the above-mentioned GP-IB boards 92.
One CPU 95, 96, 99 is correspondingly connected. A plurality of motors 98 are connected to the PPMC boards 93 via motor drivers 97. These motors 98 are motors for carrying and supplying the discs to be inspected to the disc inspection devices 11. That is, in the vicinity of the rack 81,
A robot arm 74 for conveying the disc to be inspected and supplying it to each disc inspection device 11 and a belt conveyor device 77 for conveying the disc to be inspected are arranged. Each of the motors 98 has the robot arm 74.
And a motor for driving the belt conveyor device 77. A disc stocker 82 for stacking and supporting a plurality of discs to be inspected is provided on the belt conveyor 77.
Is provided.

Further, the disk inspection device 11 according to the present invention.
As shown in FIG. 13, a so-called personal computer 19 can be used as a controller to configure a disc inspection system. That is, the personal computer 19 is connected to the disc inspection device 11 having the disc drive unit 12 via the GP-IB cable 17. This disk inspection device 11
The power is supplied from the power supply device 20 to the power source. In this disc inspection system, various control information can be input by the keyboard unit 72 connected to the personal computer 19, and various inspection results can be displayed by the display 71 connected to the personal computer 19.

[0045]

As described above, in the disc inspection apparatus according to the present invention, the disc drive unit for reading the information signal from the disc to be inspected is controlled and the information signal sent from the disc drive unit is processed. The measurement control circuit section, via the interface unit,
It is possible to perform bidirectional communication with an external device.

Therefore, in this disk inspection apparatus, it is possible to improve the reliability of the inspection result and speed up the control while facilitating the change of the system form and downsizing.

Further, the disk inspection apparatus according to the present invention is
A variable level error generating circuit for generating an error signal of a predetermined error ratio, a disk drive unit for reading an information signal from a disk under test and transmitting a read signal, and the error signal and the read signal are selected via a switch. And a threshold voltage variable circuit for supplying the comparator with a reference voltage for judging the level of the error signal or the read signal selected by the switch. Therefore, in this disc inspection apparatus, the reference voltage can be adjusted according to the error ratio.

In the disk inspection method according to the present invention, the variable level error generating circuit generates a first error signal having a known error ratio A% and sends it to the comparator, and the output of the comparator is generated. The first reference voltage a is set by the threshold voltage variable circuit so that the signal becomes an error-detected signal for the first error signal, and then the error ratio B% is set by the threshold voltage variable circuit.
The second reference voltage b is set as a reference voltage for detecting an error with respect to the second error signal of 1) so that b = a · (B / A) holds, and the error of the error signal detected at this time is When the ratio B '% is obtained, a read signal is sent from the disk drive unit to the comparator, and error detection is performed for the error ratio X%, the threshold voltage variable circuit sets the reference voltage to Y = a-{(a- b) / (A-
B ′)} · (AX) is set to Y.

Therefore, in this disk inspection method, highly accurate error detection can be performed for a wide range of error ratios.

That is, the present invention can provide a disk inspection apparatus and a disk inspection method capable of highly accurate error detection over a wide range of error ratios.

[Brief description of drawings]

FIG. 1 is a waveform diagram showing an extra pulse used in a disc inspection.

FIG. 2 is a waveform diagram showing a missing pulse used in disc inspection.

FIG. 3 is a circuit diagram showing a configuration of a main part of a disk inspection device for detecting the extra pulse and a waveform diagram showing a signal waveform on this circuit.

FIG. 4 is a circuit diagram showing a configuration of a main part of a disk inspection device for detecting the missing pulse and a waveform diagram showing a signal waveform on this circuit.

FIG. 5 is a block circuit diagram showing a configuration of a disk inspection device according to the present invention.

FIG. 6 is a block diagram showing a configuration around a disc drive unit of the disc inspection apparatus.

FIG. 7 is a block diagram showing a disk inspection system configured to have a plurality of disk drive units of the disk inspection apparatus.

FIG. 8 is a side view schematically showing the configuration of the disc inspection device.

FIG. 9 is a plan view schematically showing the configuration of the disc inspection device.

FIG. 10 is a plan view schematically showing a configuration of an analog substrate of the disc inspection device.

FIG. 11 is a plan view schematically showing a configuration of a digital substrate of the disc inspection device.

FIG. 12 is a plan view schematically showing a configuration of a power supply control board of the disk inspection device.

FIG. 13 is a front view showing the configuration of the disc inspection device.

FIG. 14 is a perspective view showing a disk inspection system including a plurality of disk drive units of the disk inspection apparatus.

FIG. 15 is a block diagram showing a configuration of the disc inspection system.

FIG. 16 is a block diagram showing a configuration of a conventional disk inspection device.

[Explanation of symbols]

 1 --- Comparator 3 --- Disk drive section 4--Variable level error generation circuit 5・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Switch 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Variom 7 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ D / A converter 8 ・ ・ ・ ・・ ・ ・ ・ ・ ・ ・ ・ CPU 9 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Input port 10 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Numeric setting switch

Claims (3)

[Claims] 1. A disk drive section for reading an information signal from a disk to be inspected, a measurement control circuit section for controlling the disk drive section and processing an information signal sent from the disk drive section, and the measurement. A disk inspection apparatus comprising: an interface unit that performs bidirectional communication between a control circuit unit and an external device. 2. A variable level error generating circuit for generating an error signal having a predetermined error ratio, a disk drive section for reading an information signal from a disk under test and transmitting a read signal, the error signal and the read signal. , A comparator selectively sent through the switch, and a threshold voltage variable circuit for supplying the comparator with a reference voltage for judging the level of the error signal or the read signal selected by the switch. A disk inspection device equipped. 3. The disk inspection apparatus according to claim 2, wherein a variable level error generation circuit has a known error ratio A%.
Generating a first error signal and transmitting the first error signal to the comparator, and the first reference voltage is changed by the threshold voltage variable circuit so that the output signal of the comparator becomes a signal obtained by error detection of the first error signal. a is set, and then the second reference voltage b is set as a reference voltage for detecting an error with respect to the second error signal having the error ratio B% by the threshold voltage variable circuit, b = a · (B / A) is set so that the error ratio B ′% of the error signal detected at this time is obtained, and a read signal is sent from the disk drive unit to the comparator,
When error detection is performed for the error ratio X%, the threshold voltage variable circuit sets the reference voltage to Y = a-
A disk inspection method in which Y is calculated by {(a-b) / (A-B ')}-(A-X).