JPS62183065A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To obtain reproduced information without noise or intermission by writing reproduced data from a disk in a memory and restoring the pickup position at the discrimination of generation of track jump so as to use a write address at the arrival of the position of track jump as the next write address into the memory. CONSTITUTION:A reproduced output from the disk 1 by a pickup 3 is written in a memory 13 accessed by a write address counter 10 counting a recovered clock. At the time of the discontinuity of a time code of the reproduced output is detected at the same time, a track jump detection circuit 8 decides the track jump, a gate 19 is controlled by a control circuit 9 and the address of the counter 10 for the case is stored in a memory 20. Then the pickup 3 is restored to a position before the occurrence of track jump by the circuit 9 and when the pickup 3 reaches the position of the occurrence of track jump, a gate 18 is controlled by the circuit 9 via a counter 17 and a memory 16 and the address in the memory 20 is set in the counter 10. Thus, the reproduced information without noise at track jump or intermission is obtained via the memory 13.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a disc playback device, and particularly to a disc playback device suitable for playing back information from a disc on which time information is recorded together with main information such as a digital audio disc. Regarding equipment.

[Conventional technology]

As an example in which main information and time information are recorded on a screw track of a disk, as described in Japanese Patent Laid-Open No. 60-43270, a digital audio signal is optically recorded as the main information. There are compact discs (CDs) that are recorded in a readable manner. Regarding the CD recording format, as stated in the above publication,
It is continuous and constitutes a predetermined small frame unit, each small frame has a period of about 136 μs, and each small frame includes a small frame synchronization information part, a subcode information part, and main information music information. It consists of the data part that is The subcode information portion consists of 98 small frames, and includes time address information and the like in units of large frames with a period of approximately 13.3771 seconds.

In this way, when reproducing signals from a disc on which digital signal information is recorded by optical means or other means, the reading position on the disc by the information reading means is likely to be moved by external force, etc. In some cases, reproduction information may be missing or mm may occur. For this reason, in the above publication, if the information reading means is accidentally moved by an external force, the position of the information reading means and the rotational speed of the disk are controlled to move the information reading means to the original playback position. It became.

[Problem that the invention seeks to solve]

In the above conventional technology, when the information reading means is accidentally moved by an external force or the like, the position of the information reading means is controlled to the normal reading position on the disc, so no omission or duplication of reproduced information occurs. Is there noise in the reproduced information after the information reading means is accidentally moved until it returns to its normal position? There has been a problem that an abnormal playback state such as a temporary interruption of playback occurs.An object of the present invention is to solve the above problem, that is, to prevent the information reading means from being accidentally moved until it returns to its normal position. It is an object of the present invention to provide a disk playback device that suppresses abnormal playback conditions such as noise and temporary interruption of playback, improves vibration resistance, and operates stably without being adversely affected by scratches on the disk.

[Means for solving interpolation points]

The above objective can be achieved as follows. That's right,
First, the data played from the disc is written to memory. If a track jump occurs, it is determined, the pickup is moved to the position before the track jump, and data is reproduced from the disc. When the reproduced data from the disk reaches the location where the track skip occurs, the data continuity on the memory is eliminated by setting the memory write address to the next value of the write address at the location where the track skip occurred. Data is read from the memory at a constant period of the sampling frequency.

[Effect]

Since the memory that stores playback data from the disk stores playback data for a certain period of time, the time taken to move the pickup position from the time when track skipping occurs, and the data read from the memory is based on this accumulated data. Yomita. As a result, data subjected to digital/analog conversion does not become discontinuous and can be reproduced continuously.

〔Example〕

An embodiment of the present invention will be described below with reference to FIG.

The configuration of FIG. 1 takes a compact disc player as an example. 1 is a compact disc, 2 is a motor that rotates the disc, 3 is a pickup that optically reads out the signal on the disc, and 4 is a pickup that amplifies the signal from the pink-up, and outputs the playback signal from the disc as well as track and focus error signals. 5 is a servo circuit for servo-controlling the pink-up 3 and motor 2 based on the track and focus error signals from the preamplifier and the speed detection signal of the motor 2 obtained from the digital signal processing circuit 6;
After capturing the playback signal from the disc, it performs EFM demodulation, error detection and correction, and error correction processing according to the recording format, and data with a quantization bit number of 16 bits and a sampling frequency of 44.1KH2 is transferred to two channels (L,
A digital signal processing circuit 7 consists of a timing circuit for alternately outputting R channel), obtaining a speed detection signal for the motor 2 from the frequency fluctuation of the synchronization signal reproduced from the disk 1, and performing these operations. an oscillator that generates a reference clock for the digital signal processing circuit 6;
8 is recorded on the disk 1, and a track skipping detection ffl [0 circuit, 9 receives a signal from the track jump detection circuit 8 to control the memory 16 reading counter 17, and compares the time information with the contents of the memory 16 and the counter 17, and a write address counter 10.
10 is a write address counter, which is input from the digital signal processing circuit 6. Counts in synchronization with data or with σtsuku. Further, reference numeral 11 denotes a read address counter which performs a counting operation using a clock synchronized with the data output from the digital signal processing circuit 6.

12 is a switch for changing the output of counters 1υ and 11, which is controlled by the digital signal processing circuit 6 and outputs from memory 1.
When writing to counter 10. At the time of reading, the field of the counter 11 is selected, and this switching is controlled in synchronization with the output data of the digital signal processing circuit 6. 13 is a memory; 14 is a DA converter that converts the output data of the memory 13 into digital/analog; 15 is a sample and hold circuit that samples and holds the output of the DA converter 14 to obtain a 2-channel audio signal; A memory 17 is a counter that stores time information immediately before the signal is detected. Simultaneously with the memory 16, the time information immediately before the track jump signal is detected is set, and the information is obtained from the digital signal processing circuit 6. The signal is counted in synchronization with the clock provided by the clock and is used as a reference signal to be compared with time information.

18 and 19 are gates, and 2o is a memory. When a track skip signal is detected, the control circuit 9 sends a signal to the gate 19 to store the address of the write address counter 1° in the memory 2o. And the contents of memory 16,
When the pickup moves to the position before the track jump and the time information of the data to be reproduced matches, the control circuit 9
sends a signal to gate 1B to set the contents of memory 20 in write address counter 10. 21 is a clock signal, and 22 is a time information signal error detection signal, which is output when it is detected that there is an error in the time information.

The operation shown in FIG. 1 will be explained below.

A signal detected by a pickup 5 from a track of the disk 1 is amplified by a preamplifier 4 and applied to a digital signal processing circuit 6. The digital signal processing circuit 6 separates the time information and transmits the time information to the track jump detection circuit 8 through the signal line 8S.

Further, the digital signal processing circuit 6 samples the 2-channel binary encoded 16-bit audio data at a sampling frequency of 44.5 kHz using the clock oscillated by the oscillator 7 as a reference.
1 KH2 is alternately output to the memory 13, and a clock 21 synchronized therewith is supplied to the control circuit 9, write address counter 10, and read address counter 11.

Here, the operations of the track jump detection circuit 8 and the control circuit 9 will be explained with reference to the timing diagram of FIG. FIG. 2 is a timing diagram when track skipping occurs.

The time information from the digital signal processing circuit 6 is shown in FIG.
It consists of minutes, seconds, and frames as shown in , and a frame is in units of E seconds. When the pickup 3 is accurately tracing the tracks of the disc 1, the minutes, seconds, and frames change continuously, but if a track jump occurs, the values become discontinuous. Here, the time information indicated by the x mark in FIG. 2 is determined to have an error by the error detection signal 22, and is naturally discontinuous. This discontinuity is determined by the track jump detection circuit 6, and the track jump signal 8Tfl-
This is generated as shown in FIG. 2 and is input to the control circuit 9.

The control circuit 9 uses the track skip signal 8T to set data in the memory 6 and counter 7 immediately before the track skip signal 8T is obtained. In Fig. 2, it is (minutes, seconds, frames) - (1°11,1). At the same time, the control circuit 9 also sends a signal to the gate 19, and stores in the memory 20 the address at which the track jump signal 8T- was obtained. In FIG. 2, 8 is the address. After this,
The counter 17 counts in synchronization with the clock 21 as shown in FIG. Then, the time information 8S and the contents of the counter 17 are compared every clock. However, when an error is detected in the time information 8S, there is no need to compare, so the comparison may be omitted. If there is no error detected in the time information 8S and the contents of the counter 17 and the time information 8S are different, it is known that a track jump has occurred. In Figure 2, the time information 8S is (1, 15, 5
>, there are 17 counters (1, 11, 4), which is different. Although only one piece of time information is compared here, it is also possible to compare multiple pieces of time information and determine whether or not the time information 8S is continuous based on the result. It was found that the contents of time information 8S and counter 17 were different, and a track skip occurred.
The control circuit 9 provides the servo circuit 5 with a signal that generates a jump pulse for returning the trace position of the pickup 3. At this time, the contents of the counter 17 and the time information BS
By comparing the , it is possible to determine whether the pickup 3 has flown forward or backward by comparing it with the original position. 9B.

Or, either the jump direction or the previous pulse 9F is output compared with the original time information. By this operation, the position of the pink-up 3 traces the track before the occurrence of track jump, and the time information changes as shown in FIG. 2 88. As a result, when the content of the memory 16 and the time information 8S match, that is, when the position of the pickup 3 reaches the position before track skipping occurs, the control circuit 9 outputs the address gate pulse 9G and the information is stored in the memory 20. The address that was previously stored is set in the write address counter 10.

As can be seen from FIG. 2, by controlling the write address in this manner, the data in the memory 1 can be made continuous.

Next, the timing diagram shown in FIG. 6 will be explained. 6th
The timing diagram shown in the figure shows a case where the time information 8S becomes partially discontinuous due to a scratch on the disk 1, or a partial error is detected. Therefore, the data input to the memory 13 is not normal. be. In this case as well, as shown in FIG. 2, the time information 8S becomes discontinuous at the location shown in FIG. 3, so the track jump detection circuit 8 circles the track jump signal BT as shown in FIG. . Hereinafter, as in the case of FIG. 2, the memory 16. Counter 17. memory 20
Information is stored in each of the counters 17 and 2.
Count in synchronization with 1. Then, the time information 8S and the contents of the counter 17 are compared, but unlike the case in Fig. 2,
In FIG. 3, the time information 8S and the contents of the counter 17 match ((1, 11, 4) in FIG. 3). In this case, jump nozzle 9B or 9F does not occur, that is, it is determined that the time information is continuous and no track jump occurs. As a result, the write address of memory 13 is not changed.

As described above, with the configuration shown in FIG. 1, it is possible to distinguish between track skips and simple scratches, and the influence of scratches can be reduced.

Next, consider the operation of the memory 13. The output data from the digital signal processing circuit 6 is 16-bit data converted into two brigadiers, and two channels are output alternately.

This output data is not written according to the value of the write address counter 10.

As mentioned earlier, even if a track jump occurs and a discontinuous signal is stored in the memory 13, the value of the write address counter 10 will be the same as that in the memory 13 when the pick amplifier returns to its original position and reproduces the correct signal. The data is set to a value that makes it continuous, and is eventually stored in the memory 13 while erasing discontinuous signals. Therefore, memory 1
3 stores continuous signals.

The read address counter 11 is configured to read data with a certain difference behind the value of the write address counter 10. This difference corresponds to the allowable value of the stop period of the write address counter 10. Therefore, the amount of difference is determined by taking into consideration the time required to return the pickup 3 to its original position, and can be increased by increasing the capacity of the memory filter.

In this way, the stored contents of the memory 3 can be continuous data, and by adding these data to the sequential readout DA converter 14, continuous sound can be reproduced even when a track jump occurs. .

Another embodiment of the present invention is shown in FIG. The circuit of FIG. 4 is the same as the circuit of FIG. 1 except that the time f'# signal detection signal is removed. The operation in FIG. 4 is almost the same as the operation in FIG. 1, so only the different parts will be explained. In FIG. 4, the time information 8S and the contents of the counter 17 are compared for a while after the track skip signal BT is output. and,
Looking at the degree of agreement between the two contents, Honsho determines whether the discontinuity is due to a skipped track, or whether it is simply a scratch. The reliability of the system determines how many samples to use and how much they match. In the case of the embodiment shown in FIG. 4, it is possible to eliminate errors in determining the effects of track skipping and scratches due to errors in detection of time information.

All of the above embodiments have been explained using the subcode Q channel, which is one of the recording formats of compact discs. The Q channel is designed to be completed in 98 frames, and since this is π seconds, no more detailed control is possible. However, the present invention is applicable not only to this format, but also to a device that reproduces an address Mn in each frame Dn as shown in FIG. In a device that reproduces a signal DnA in which a large address Mn is assigned to each frame and then an address NA is assigned within that frame, it is possible to perform track control down to even finer time.

Although not specifically explained in the present invention, the time information and the main data are configured to be completely synchronized, and for example, to achieve this, the time information generation circuit and the main data generation circuit may be synchronized using an oscillator. Take it and move it.

〔Effect of the invention〕

According to the present invention, writing playback data using a memory,
In addition, since information discontinuities are monitored for a relatively long period of time when track skips occur, it is possible to distinguish between discontinuities due to track skips and discontinuities due to scratches, etc. By detecting track skipping without receiving any signal and changing the memory write address,
This has the effect of allowing continuous playback even if track skips occur.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
FIG. 3 is a diagram showing the timing of the operation of the track jump detection circuit 8 and control circuit 9. FIG. 3 is another diagram showing the timing of the operation of the track jump detection circuit 8 and control circuit 9. is a block diagram showing another embodiment of the present invention, and FIG. 5 is a signal format (signal format) to which the present invention can be applied.
It is l. 8... Track jump detection circuit, 9... Control circuit, 1
0: Write address counter, 11: Read address counter, 13: Memory, 17: Counter. 1st 76′! 20th Atsushi 30th Address Skate Igusu 9Q Invitation 4/6/'7

Claims (1)

[Scope of Claims] 1. A rotating means for rotating a disk on which digitized information data and a time code based on the recording start end of the information data are recorded in a spiral or concentric manner and have a recording track; A disc playback device comprising an information reading means for reading information from the disc, a storage means for storing the information data obtained by the information reading means, a control means for controlling a write/read address of the storage means, and a storage means for storing the information data obtained by the information reading means; Discontinuity detection means for detecting discontinuity in the time code obtained by the information reading means, storage means for storing the time code when the discontinuity occurs, and a time code counter for counting the time since the discontinuity occurs. and storage means for storing the write address at which the discontinuity has occurred, the discontinuity detecting means stores the time code of the discontinuity occurrence part in the time code storage means, and the write address is stored in the address storage means. The time code counter is counted in synchronization with the time code, track jumps are detected by comparing the time code counter and the time code, and the read position on the disk before the discontinuity of the time code occurs. and when the information reading means is moved to the read position on the disk before the time code discontinuity occurs using the time code storage means, the write address is changed to the contents of the write address storage means. A disc playback device that eliminates discontinuity of information data by writing and prevents discontinuity of information data when skipping tracks by reading the storage means at regular time intervals. 2. In the disc playback device according to claim 1, when a time code discontinuity occurs and the time code is compared with the time code, a time code error detection signal is used to detect the time code discontinuity. A disc playback device characterized in that only discontinuities caused by track skips are extracted, excluding discontinuities caused by causes other than track skips. 3. In the disc playback device according to claim 1, when a discontinuity occurs in the time code and the time code counter is compared with the time code, the comparison is continued for a relatively long time and the time code counter and the time code are compared. A disc playback device characterized in that a track skip signal is obtained depending on the degree of coincidence of values, and only discontinuities caused by track skips are extracted.