JP3334979B2 - Minidisk inspection apparatus and inspection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a minidisk (MD) inspection device, and more particularly, to a minidisk inspection device and an inspection method for reproducing a minidisk on which information is recorded and inspecting the recorded state. About.

[0002]

2. Description of the Related Art As a method of inspecting the state of the recording surface of an optical disk, there is, for example, a surface inspection apparatus described in Japanese Patent Application Laid-Open No. 1-269037. This is a surface inspection device for a write-once optical disc stamper on which index data is recorded. Further, there is a defect inspection method described in Japanese Patent Application Laid-Open No. 2-307007. This teaches a group defect inspection on a write-once optical disc. In addition, Japanese Patent Application No. 5-138059, filed by the same applicant as the present application, discloses a medium inspection method for an optical disk such as a compact disk (CD) that can be additionally recorded. However, a medium inspection method for a so-called mini disk is not known.

[0003] Mini discs include a read-only type, a recording type, and a hybrid type in which both are combined.
The recording type and the hybrid type use a magneto-optical recording medium for a recordable portion and are configured to be rewritable. The information area of the mini-disc includes a lead-in area, a UTC (User's Table of Contents) area, a program area, and a lead-out area. The recordable area consisting of the UTOC area and the program area is an area that can be used by the user,
Here, data can be rewritably recorded. Data is recorded in cluster units, and one cluster is composed of 36 sectors. There is an area called a gap where no user data is recorded between the clusters.
The gap is used for sub-data or linking for recording, reproduction and management of recording data.
Sectors are allocated.

[0004]

However, when information recorded on such a mini-disc is inspected for recording characteristics such as an error rate while reproducing the information,
If the data is reproduced up to the gap, it is not appropriate for the inspection of the recording characteristics of the information recording portion.

[0005] Further, when recording is performed a plurality of times on one mini-disc, a gap or an overwritten portion of an undefined length tends to be generated particularly at a seam between clusters. After the data is recorded, an uncorrectable error is likely to occur in these portions in a check of the recording state. Whether this error is due to a defect in the disk medium, an error in recorded data, or a seam between clusters,
Indistinguishable. For this reason, even if there is no defective portion in the disk medium or the recorded data, if an uncorrectable error occurs, all data must be re-recorded on a new disk.

SUMMARY OF THE INVENTION The present invention provides a mini-disc inspection apparatus and an inspection method capable of properly inspecting the recording state of a mini-disc on which data is recorded without being affected by errors caused by gaps between clusters. The purpose is to:

[0007]

According to the present invention, there is provided a mini-disc inspection apparatus for reproducing a mini-disc on which information is recorded and inspecting a recording state of the mini-disc. The reproducing means for detecting an error in the information recorded on the mini-disc, the counting means for counting the errors detected by the reproducing means, the reproducing means and the counting means are controlled, and the count value counted by the counting means is taken in. Control means for counting the count value and checking the recording state of the mini-disc, wherein the control means calculates the mini-disc based on the count value counted for an area other than the area including the gap between clusters in the mini-disc. Check the recording status of

According to the present invention, the reproducing means outputs the address of the cluster and the sector in the mini disk being reproduced to the control means, and the control means outputs the address of the cluster and the sector immediately before and after the gap for the cluster. Of the identified sectors, masking the identified sectors, counting the count values obtained from the counting means for the other sectors in cluster units, calculating the average value of the count results for all the inspected clusters, and calculating the average value. Is the error rate of the minidisk.

According to the present invention, there is further provided a mini disc inspection method for reproducing a mini disc on which information is recorded and inspecting a recording state of the mini disc. Detecting
The method includes a step of counting the detected errors, and a step of counting the count values obtained in the counting step for an area other than an area including a gap between clusters in the minidisk and inspecting the recording state of the minidisk.

According to the present invention, the step of reproducing further includes a step of obtaining an address of a cluster and a sector in the reproducing mini-disc, and the step of inspecting the gap of the cluster from the address of the cluster and the sector. Identifying the sector immediately before and after, masking the identified sector, and counting the counts obtained for the other sectors in cluster units;
Calculate the average of the aggregation results for all the clusters examined,
Setting the average value as an error rate of the mini-disc.

[0011]

According to the present invention, the reproducing means reproduces a mini-disc and detects an error in information recorded on the mini-disc. The counting means counts the detected error,
The control means totalizes the count values obtained by the counting means in areas other than the area including the gap between clusters in the mini-disc and checks the recording state of the mini-disc.

More specifically, the control means obtains, from the reproducing means, addresses of clusters and sectors on the mini disc being reproduced, and from these addresses, identifies a sector immediately before and after the gap in the cluster, The identified sectors are masked, and the count values obtained for the other sectors are totaled in cluster units. An average value of the aggregation results is obtained for all the inspected clusters, and this average value is used as the error rate of the minidisk.

Thus, it is possible to exclude an error signal generated in a sector where actual data is not recorded in a region including a gap and measure an error rate not including the error signal.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a mini disk inspection apparatus according to an embodiment of the present invention; Referring to FIG. 1, an embodiment of a mini-disc inspection apparatus according to the present invention includes a mini-disc (MD) player 20 and a connecting line 2 connected thereto.
It includes a computer 30 connected at 02 and a counter 40 connected to both by connections 204 and 302.

In this embodiment, the mini-disc player 20 is a recording-type and hybrid-type mini-disc 10 (FIG. 3).
This is a mini-disc reproducing apparatus for reproducing. FIGS. 3 and 4 show a conceptual configuration of the mini-disc. Mini disc
The 10 information areas are lead-in areas
12, a UTOC (User's Table of Contents) area 14, a program area 16, and a lead-out area 18. The recordable area where the user can record data consists of a UTOC area 14 and a program area 16,
A guide groove 102 called a pre-groove is formed spirally from the inner peripheral side to the outer peripheral side of the disk 10, and new data is recorded along each track along the guide groove 102. One track of the mini disk 10 is defined as one cluster, and one cluster is
It consists of 36 sectors. Data recording is performed in cluster units, and there is a gap between clusters, which corresponds to, for example, four sectors. In the lead-in area 12,
Information on the contents of the information recorded on the disc 10 is recorded in advance, and the lead-out area 18 is
Information indicating the end of 16 is recorded.

The reproduction of the mini-disc 10
This is performed by the mini-disc player 20 based on the cluster address and the sector address. When detecting an uncorrectable error during playback, the mini-disc player 20 outputs an error correction signal to the
Output to 40. The mini-disc player 20 also outputs a cluster address signal and a sector address signal to the computer 30.

The counter 40 has a low level input as an error correction signal from the mini disc player 20.
This is a counting device that counts (L) and high level (H) state signals and outputs a count value of an uncorrectable error. Counter 40
Is connected to the computer 30 by a connection line 302, and the connection line 302 is a GPIB (General-Purpose Inte
rface Bus). A control signal for controlling the operation of the counter 40 is input from the computer 30 to the counter 40 via the bus 302, and the count value is input to the computer 30 from the counter 40. The control signal output from the computer 30 includes starting, stopping, resetting of the counting operation of the counter 40, a count value output instruction, and the like.

The computer 30 includes a connection line 202 from the mini-disc player 20 as a function particularly relevant to the present invention.
This is a processing device that receives a cluster address signal and a sector address signal through the counter 40, receives an error count value from the counter 40 through the bus 302, processes them, and totalizes the error rate. In this embodiment, a personal computer may be used. It has a keyboard (not shown) for inputting various instructions and data such as an instruction to start a test, and a display (not shown) for displaying the state of the system.

The recording of data in the recordable area of the mini-disc 10 is performed in cluster units, and a gap corresponding to four sectors exists between two adjacent clusters. In the present embodiment, when reproducing recording data and inspecting recording characteristics such as an error rate thereof, the reproduction of two sectors before and after this gap, that is, four sectors, is masked, and the number of error corrections occurring in other portions is masked. Tally. Such masking and counting functions are
30 do. In the present embodiment, the number of sectors in the mask portion is the default value “4”, but this size and position can be variably set in the computer 30.

The error rate (error rate) of data recorded on the mini-disc 10 is 1 in this embodiment.
Number of error corrections per second (frames / second)
Is defined by The number of error corrections occurring in the cluster of cluster number k (natural number) is represented by Σk.
The number of sectors to be reproduced in the unit time by the mini-disc player 20 of the embodiment is 75 sectors / second. The inspection starts from the cluster number a, and the cluster number n (a and n are a natural numbers a
Check for a series of clusters up to ≤n). The unit of one error rate aggregation is generally 25 clusters, but this value can be variably set in the computer 30. In this embodiment, two sectors before and after the gap, that is, four sectors are masked for one cluster, and the number of error corrections of 32 sectors is counted. Computer 30
Monitors the sector address from the mini-disc player 20, and causes the counter 40 to count the number of error corrections from when the third cluster is identified for one cluster to when the sector address # 34 is identified by the sector address. . When this is performed for a series of clusters from the cluster number a for starting the inspection to the cluster number n for ending (both a and n are natural numbers), the error rate Er for these clusters is expressed by equation (1).

[0021]

(Equation 1) In this way, by not counting the number of error corrections before and after the gap in the mini-disc 10, for example, two sectors, that is, a total of four sectors, the mini-disc 10 is not counted.
It is possible to realize an appropriate inspection of the recording state of the image.

Referring to the flowchart of FIG. 2, first, the mini disc 10 to be measured is set on the mini disc player 20 (step S12). In the computer 30, the number or number of clusters to be inspected is set. As described above, in the default state, the unit of one error rate aggregation is 25 clusters. This may be changed by operating the keyboard of the computer 30. In the case of 25 clusters, the error rate Er by the equation (1) from the total number of error collections Δk is Er = 3 · Δk / 32 (2).

When an instruction to start inspection is input from the keyboard of the computer 30 (step S14), the computer 30
Command the counter 40 via the GPIB bus 302 to initialize the counter 40 and stand by for measurement. Further, the reproduction start is instructed to the mini-disc player 20 (step S16).
The mini-disc player 20 starts playing the recordable area of the mini-disc 10 in order from the inner circumference to the outer circumference. At the same time, the mini-disc player 20 outputs the cluster address signal and the sector address signal to the computer 30 via the connection line 202, and outputs an error correction signal to the counter 40 every time an error occurs. Computer 30
Captures the cluster and sector addresses from the mini-disc player 20 and monitors the arrival of the inspection start sector of the cluster to be inspected (step S18). When the inspection start sector is reached, the computer 30 instructs the counter 40 to start counting the error correction signal (step S20).
). In response to this, the counter 40 starts counting the error correction signal input every time an error occurs.

The computer 30 fetches the sector address from the player 20, and monitors the inspection end sector (step S22). When the inspection end sector is reached, that is, when the sexter address reaches “34”, the computer 30 instructs the counter 40 to stop counting. Computer 20
The count value of the counter 40 at this time via the GPIB bus 302
Then, a count reset command signal is output to the counter 40 (step S24). Thus,
As for one cluster in the mini disk 10, the total value of the error correction signal in which each of the two sectors immediately before and after the gap between the cluster and the adjacent cluster is masked is obtained. In this embodiment, the error correction signal is counted and integrated by the counter 40 for one cluster, and the integrated value is taken into the computer 30. However, the error correction signal is collected by the counter 40 for each sector. Counting signals and computer 30
, And the computer 30 may be configured to perform integration for one cluster.

In any case, when the inspection for one cluster is completed, the existence of the next cluster to be inspected is checked in step S26, and it is checked whether the inspection has been completed for all specified clusters. If unchecked sectors remain, the process returns to step S18, and the same check is performed for the next cluster.

When the inspection has been completed for all the designated clusters, the process proceeds to step S28, where the error rate
Executes the counting operation of Er. The computer 30 calculates the number of error collections per cluster of the mini disk 10 to be measuredΣ
k is added for all the clusters, and the error rate Er of all 25 clusters is calculated from the addition result に よ り k by the equation (2). The error rate per disk obtained in this way is compared with a specified value in step S30, and the quality of the disk 10 is determined.

As described above, in the present embodiment, the reproduction inspection (error rate, jitter, etc.) of the recording area of the mini disk 10 is a non-recorded area and masks the gap between clusters which is not appropriate for the reproduction inspection. Can be performed appropriately.

Although the above embodiment is a preferred embodiment of the present invention, the present invention is not limited to this embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the illustrated embodiment, the inspection is masked by stopping the counting operation of the counter 40 in the region including the gap.
Always counts the error correction signal for each sector and outputs the count value to the computer 30.
In 30, the count value near the gap area obtained from the counter 40 may be discarded, and only the other count values may be used for calculating the error rate. Further, in the embodiment, the mini-disc inspection apparatus is configured by a combination of three devices, but is not limited to this configuration. Further, the number of sectors and clusters is merely an example.

[0029]

As is apparent from the above description, the minidisk inspection apparatus of the present invention performs reproduction inspection by masking an area including a gap between clusters in a minidisk on which data is recorded. The recording state of the disc can be properly inspected without being affected by errors caused by the gap. Therefore, an effective error rate can be obtained for the portion where the actual data is recorded.

[Brief description of the drawings]

FIG. 1 is a functional configuration diagram showing an embodiment of a minidisk inspection apparatus according to the present invention.

FIG. 2 is a diagram showing an example of an inspection flow of a mini disk in the embodiment shown in FIG.

FIG. 3 is a plan view showing a configuration example of a mini disk used in the embodiment.

FIG. 4 is a conceptual sectional view taken along a dashed line IV of the mini-disc shown in FIG.

[Explanation of symbols]

 10 Minidisc 20 Minidisc player 30 Computer 40 Counter

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 20 / 18,20 / 10

Claims (5)

(57) [Claims] 1. A mini-disc inspection apparatus for reproducing a mini-disc on which information is repeatedly recorded and inspecting a recording state of the mini-disc, wherein the apparatus reproduces the mini-disc and outputs information recorded on the mini-disc. A reproducing means for detecting an error of the reproducing means, a counting means for counting the errors detected by the reproducing means, controlling the reproducing means and the counting means, taking in the count value counted by the counting means, and totalizing the counted value. Control means for inspecting the recording state of the mini-disc, the control means including detection means for detecting a gap between clusters in the mini-disc from information reproduced by the reproduction means, The counting values counted by the counting means are counted for the region excluding the gap and the predetermined region adjacent to the gap, and the mini-data is calculated based on the counting result. Mini disk inspection apparatus characterized by checking the recording state of the disk. 2. The inspection apparatus according to claim 1, wherein the reproducing unit outputs an address of a cluster and a sector in a mini disk being reproduced to the control unit, and the control unit outputs the address of the cluster and the sector. From the address, the sector immediately before and after the gap is identified for the cluster, the identified sector is masked, and the count values obtained from the counting means for the other sectors are totaled in cluster units. A mini-disc inspection apparatus, wherein an average value of the aggregation results is obtained, and the average value is used as an error rate of the mini-disc. 3. The inspection apparatus according to claim 1, wherein the cluster includes 36 sectors and is adjacent to the gap .
The predetermined area corresponds to two clusters before and two clusters after the gap. 4. A mini-disc inspection method for reproducing a mini-disc on which information is repeatedly recorded and inspecting a recording state of the mini-disc, the method comprising: reproducing the mini-disc; Detecting an error in the detected information; counting the detected error; and detecting a gap between clusters in the mini-disc from the information reproduced in the reproducing step, wherein the gap between the clusters is included. And counting the count values obtained in the counting step for the area excluding the predetermined area adjacent to the gap, and inspecting the recording state of the mini-disc based on the counted result. And mini disk inspection method. 5. The inspection method according to claim 4, wherein the reproducing step includes a step of obtaining an address of a cluster and a sector on the mini disk being reproduced, and the inspecting step includes the step of obtaining the cluster and the sector. Identifying the sector immediately before and after the gap in the cluster from the address, masking the identified sector, and counting the counts obtained for the other sectors in cluster units; Find the average value of the aggregation results,
Using the average value as the error rate of the mini-disc.