JPH052816A - Compact disk reproducing device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of large sound volume of unusual sound at the time of the changeover of a track by deciding the classification of recording data every track and storing the result at the time of reading TOC information. CONSTITUTION:The decision of the classification of recording data of a track in reproduction is performed based on the classification information on recording data stored in a storage means at the time of reading TOC information. As a result of the decision, a muting control signal is outputted from a CPU 49 to a mute circuit 48 when the track is not a sound track or the data is not sound data. By this, a mute-on processing is to be performed. When sound data is decided, a mute-off processing is performed for a muting circuit 48 by a mute control signal outputted to the mute circuit 48 from the CPU 49. Thus, a reproduced sound outputted from a LPF 47 is to be outputted through the mute circuit 48.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compact disc reproducing apparatus suitable for reproducing an in-vehicle compact disc.

[0002]

2. Description of the Related Art A compact disc (hereinafter referred to as a disc) has a voice signal recorded thereon, a CD-ROM.
There are some types in which only a data signal is recorded as described above, and some types in which a sound signal and a data signal are recorded in a mixed manner such as a game disc.

In a compact disc reproducing apparatus (hereinafter referred to as a player) whose main purpose is to reproduce an audio signal, when the data signal area is reproduced, an uncomfortable and loud sound is output. To prevent
In this area, it is common to mute the audio signal output.

First, here, the subcode and the TOC
(Table Off Content: Table of Content) will be described. The subcode is a signal recorded on the disc together with the main recording signal, and includes P, Q, R, S,
It consists of 8 channels of T, U, V, and W, and the player uses the Q channel code of these to perform control display and the like. The R to W channels are not used in currently marketed discs.

FIG. 5 shows the subcode Q in the program area.
The structure of channels (hereinafter referred to as subcode Q) is shown, and a control 71 (hereinafter referred to as control) including a synchronization signal 70 for controlling the rotation of the disk, the number of channels, main recording data type, and the like, An address 72 indicating data contents, a track number 73, an index 74 (hereinafter referred to as an index) indicating in-track subdivision information, an in-track elapsed time 75, a zero 76 in which all data is 00, an in-disk elapsed time 77, The error correction parity 78 is 98 bits in total.

Further, the track number 73 of the subcode Q
The data of 00 indicates the lead-in area. At this time, the start track number, the last track number, the last track end time, and each track are determined by the data of the control 71, the index 74, and the disc elapsed time 77. The information such as the recording start time and the recording data type can be obtained, and the information in this area is called TOC information.

FIG. 6 shows the timing related to the muting process when the track number changes. Figure 6
6A is a track number, FIG. 6B is a recording data type, and FIG. 6C is a subcode Q reading start position (time).
And appears 75 times a second. Further, FIG. 6D shows the control state of the mute signal, where “0” indicates mute off and “1” indicates mute on. FIG. 6E shows the actual output state of reproduced sound.

Next, a part of a general reproducing process procedure in the conventional disc reproducing apparatus will be described with reference to the flowchart of FIG.

When the disc 7 is reproduced, the control of the subcode Q read intermittently at each timing of FIG. 6C controls the recorded data type of the current reproduction position in step S15 to output the reproduced sound. Decide whether to accept.

According to the determination in step S15,
Branch to step S16 and step S17,
The mute operation is being performed on the playback sound output.

That is, when the reproduced sound in step S15 is not output, the process proceeds from the N side of step S15 to step S16, and the mute-on process is performed in this step S16.

If the reproduced sound is output in step S15, the process proceeds from the Y side of step S15 to step S17 to perform the mute-on process operation.

The track number shown in FIG. 6A is "N".
Focus on the part that shifts from "N + 1" to. Now, FIG.
It is assumed that the data reading of the track number "N + 1" is started at "t1" shown in (e).

On the other hand, since it takes some time to read the subcode Q, the subcode Q is read and the determination of the data type is completed at "t2" shown in FIG. The timing is later than

Therefore, assuming that the track "N" is a music signal and the track "N + 1" is a data signal, FIG.
In the period from "t1" to "t2" in (e), the data signal is output as a reproduced sound.

[0016]

The muting process for the reproduced sound of the conventional disc reproducing apparatus is performed based on the recorded data type information which can be judged from the control of the read subcode Q.

For this reason, there is a time difference between the reproduced sound output of the main recording data read from the disc and the control of the sub code Q, and the mute processing performed by the determination.

Therefore, when the audio signal track is switched to the data signal track during the reproduction of the disc, a large volume of abnormal sound is instantaneously generated by the reproduction of the subsequent data signal and the main memory data of the track. However, there was a problem that it occurred.

The present invention has been made in order to solve the above problems, and even when reproducing a disc in which an audio signal and a data signal are mixedly recorded, a large volume difference occurs at the time of track switching. An object of the present invention is to obtain a compact disc reproducing device capable of preventing the generation of sound.

[0020]

A compact disc reproducing apparatus according to the present invention determines a recording data type for each track recorded on a compact disc from TOC information of the compact disc and stores the determination result. And reproducing the audio output of the succeeding track from a specific position in the pause period immediately before the main recording data area of the succeeding track when the reproducing position is transferred to the succeeding track according to the information stored in the storing means. A central processing unit for setting the output level is provided.

[0021]

According to the present invention, by using the recording data type information for each track stored by the storage means during the TOC information reading operation, the following main recording data is recorded in the pause period during the track switching. The type can be determined, and the playback level setting process such as mute processing or attenuation processing for the playback sound is performed before the playback position enters the main recording data area, and the disk playback position shifts from the audio signal track to the data signal track. Also in this case, the following data signal area acts so as to prevent the reproduced sound from being output as a loud sound.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of a compact disc reproducing apparatus of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment.

Reference numeral 1 in the figure denotes a disc, and disc 40
Is rotated by a disc motor 41 at a predetermined speed. Data is read from the optical pickup 42 from the recording signal surface of the disk 1, and the read data is output to the RF amplifier 43.

The output of the RF amplifier 43 is output to the digital signal processing circuit 44. The output signal of the RF amplifier 43 sent to the digital signal processing circuit 44 is subjected to signal processing such as FM demodulation, subcode demodulation and error correction.

The output of the digital signal processing circuit 44 is output to the central processing unit (hereinafter referred to as CPU) 49 and the digital filter 45. Of these, the CPU 49 uses the demodulated subcode information to cause the display circuit 50 to display.

The main recording signal demodulated by the digital signal processing circuit is passed through a digital filter 45 and a digital / analog (hereinafter referred to as D / A) converter 46.
Sent to. The D / A converter 46 converts the digital data into an analog signal, and outputs the left and right channel audio signals to the muting circuit 48 via the low pass filter 47.

A muting control signal is output from the CPU 49 to the muting circuit 48. The muting control signal causes the muting circuit 48 to output the left and right channel audio signals output from the low-pass filter 47. On the other hand, mute processing is performed as necessary.

When the mute processing is not performed by the mute circuit 48, the audio signals of the left and right channels are output as audio output from the mute circuit 48.

Next, the operation will be described. FIG. 2 shows a data map of a recording data type information memory as a storage means necessary for the embodiment of the present invention, and shows that 99 tracks are prepared. This is equal to the maximum number of recording tracks defined by the disc standard.

Next, the processing procedure will be described with reference to the flowchart of FIG. In FIG. 3, the CP at step S1
U49 outputs TO from the output of the digital signal processing circuit 44.
It is determined whether or not the C information has been read, and the branch of the process is determined.

If the result of this determination is that TOC information has not been read, the process branches from the N side in step S1 to step S2. In this step S2, TO
At the same time that the C information reading process is performed, the recording data type information for each track is recorded in a storage means (not shown),
Go to step S3.

In the step S1, the TOC
If it is determined that the information has been read, Y in step S1.
The process branches from the side to step S3, and this step S3
Then, the subcode Q is used to determine the current reproduction position. If the pause period is in progress, from the Y side of step S3 to step S3.
The process moves to 4.

In step S4, the recording data type of the currently reproduced track is determined based on the recording data type information stored in the storage means when the TOC information is read, and the branch is determined.

As a result of the determination, if the recorded data type of the currently reproduced track is not an audio track, the process moves from the N side of step S4 to step S6, and if it is an audio track, the Y side of step S4. To Step S5.

As a result of the determination in step S3, even if the pause period is not in progress, from the N side of step S3 to step S3.
Branch to 5. In step S5, the recording data type is determined from the control of the subcode Q read at the current reproduction position, and the branch of the process is determined.

If the result of this determination is that the recording data type is voice data, the process branches from the Y side in step S5, and the process proceeds to step S7. If it is not voice data, the process branches from the N side in step S5. Then, the process proceeds to step S6.

In step S6, if it is not the audio track that is the result of the determination in step S4 and if it is not the audio data that is the result of the determination in step S5, the CPU 49
Outputs a muting control signal to the mute circuit 48. As a result, mute-on processing is performed, and no output is made from the mute circuit 48.

In step S7, step S
When the audio data is discriminated in 5, the muting control signal output from the CPU 49 to the mute circuit 48 is applied to the muting circuit 48 to perform the mute off process. As a result, the reproduced audio outputs of the left and right channels output from the low pass filter 47 are output through the mute circuit 48.

Here, the above processing routine will be further described. When the CPU 49 determines that the TOC information has been read in step S1 and step S2
At the same time when the TOC information is read, the recording data type that can be determined from the control of the subcode Q is stored in the portion corresponding to the track number of the data type information memory shown in FIG.

For example, processing is performed for all tracks, such as "0" for audio signals and "1" for data signals. When this process is completed, it is determined that the TOC has been read, and the process proceeds to step S3.

In this step S3, the data of the index 74 shown in the internal configuration diagram of the subcode Q channel information of FIG. 5 is "00" during the pause period when the current reproduction position is switched from the read subcode Q. Refers to the state.

If the result of the determination in step S3 is the pause period, the process proceeds to step S4. If it is not the pause period, the process proceeds to step S5, but if the process proceeds to step S4, the TOC of step S2 is performed. By referring to the data type information stored at the time of reading the information, the recorded data type of the currently reproduced track is determined, and branching is performed.

If the result of the judgment is that of the audio signal track, step S5 is executed. If it is of the data signal track,
Go to step S6.

In step S5, the recording data type is determined based on the control information of the subcode Q read at the current reproduction position, and the processing routine is branched according to the result of the determination.

When the result of the judgment is a data signal,
If the signal is a voice signal, the process proceeds to step S7. In step S6, the reproduction sound mute process is performed, and in step S7, the reproduction sound mute process is canceled.

When the reproduction is performed by the above procedure, the timing related to the mute processing in the vicinity of the switching of tracks is as shown in FIG. 4 in the present invention as compared with the case shown in FIG. 5 of the prior art. .. In FIG. 4, FIG.
~ Fig. 4 (e) is Fig. 6 (a) ~ Fig. 6 (e) of the conventional example of Fig. 6.
Is the same as.

In the processing procedure according to the present invention, the pause period is found at the timing "t3" in FIG. 4, and the mute processing determination and operation are performed at a timing earlier than the timing "t1" at which the subsequent data area starts. You will be able to do it.

In the above description, the case where the voice is completely cut off in the data area has been described as an example. However, in the data area, the process of lowering the reproduction output level from the regular level at a constant rate, that is, attenuation is performed. There is also a method of processing, and the present invention can be applied to such a case.

[0049]

As described above, according to the present invention, when the reproduction position is switched from the audio signal track to the data signal track during the disk reproduction, the judgment and operation of the mute process for the subsequent data signal track can be performed. This can be done before the reproduction of the main recording data area. as a result,
A large volume of abnormal noise due to the reproduction of the main recording data area of the subsequent data signal track is eliminated.

[Brief description of drawings]

FIG. 1 is a block diagram of a compact disc reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a data map of a recording data type information memory for explaining the embodiment.

FIG. 3 is a flowchart showing a flow of operations of the above embodiment.

FIG. 4 is a timing chart relating to mute processing when a track is switched in the embodiment.

FIG. 5 is an explanatory diagram of subcode Q channel information of a conventional compact disc reproducing device.

FIG. 6 is a timing chart relating to mute processing when a track is switched in a conventional compact disc reproducing apparatus.

FIG. 7 is a flowchart showing a flow of operations of a conventional compact disc reproducing apparatus.

[Explanation of symbols]

 40 compact disk 41 disk motor 42 optical pickup 43 RF amplifier 44 digital signal processing circuit 45 digital filter 46 D / A converter 47 low-pass filter 48 muting circuit 49 CPU 50 display circuit

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[Procedure amendment]

[Submission date] May 15, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

That is, the determination in step S15 is
If it is not audio data, the process proceeds from the N side of step S15 to step S16, and the mute on process is performed in this step S16.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

In step S15, the voice data is
If it is determined that the mute-off process is performed, the process proceeds from the Y side of step S15 to step S17 to perform a mute-off process .

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

The track number shown in FIG. 6A is "N".
Focus on the part that shifts from "N + 1" to. Now, FIG.
It is assumed that the data reading of the track number "N + 1" is started at "t1" shown in (c) .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

On the other hand, since it takes some time to read the subcode Q, the subcode Q is read and the determination of the data type is completed at "t2" shown in FIG. The timing is later than

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

Therefore, the track "N"Audio signal
Then, assuming that the track “N + 1” is a data signal,Figure 6
(C)During the period from “t1” to “t2”, the data signal is
It will be output as a raw sound.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

Therefore, if there is a changeover from the audio signal track to the data signal track during the reproduction of the disc, at the time of the changeover, the subsequent data is changed.
There is a problem that a loud noise is instantaneously generated due to the reproduction of the main memory data of the signal track .

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Reference numeral 40 in the drawing denotes a disk, and disk 4
0 is rotatably driven by the disc motor 41 at a predetermined speed. Light from the recording signal side of the disk 40
The pickup 42 reads the data and outputs the read data to the RF amplifier 43.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

The output of the RF amplifier 43 is output to the digital signal processing circuit 44. The output signal of the RF amplifier 43 sent to the digital signal processing circuit 44 is subjected to signal processing such as EFM demodulation , subcode demodulation and error correction.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0030

[Correction method] Change

[Correction content]

Next, the processing procedure will be described with reference to the flowchart of FIG. In FIG. 3, in step S1, TO
It is determined whether or not the C information has been read , and the branch of the process is determined.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

As a result of this judgment, the recording of the currently reproduced track is performed.
If the data type is not an audio track, step S
The process moves from the N side of 4 to step S6, and in the case of an audio track, the process moves from the Y side of step S4 to step S5.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Name of item to be corrected] 0037

[Correction method] Change

[Correction content]

In step S6, if it is not the audio track that is the result of the determination in step S4 and if it is not the audio data that is the result of the determination in step S5, the CPU 49
Outputs a muting control signal to the mute circuit 48. As a result, the mute on process is performed, and the output level of the reproduced sound is set by the mute circuit 48.
To be done.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

Here, the above processing routine will be further described. TOC information read in step S1
Otherwise, if the CPU 49 makes the determination, step S2
At the same time when the TOC information is read, the recording data type that can be determined from the control of the subcode Q is stored in the portion corresponding to the track number of the data type information memory shown in FIG.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0041

[Correction method] Change

[Correction content]

In this step S3, it is judged from the read sub-code Q whether or not the current reproduction position is in the pause period for track switching . The pause period indicates a state where the data of the index 74 shown in the internal configuration diagram of the subcode Q channel information of FIG. 5 is “00”.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0042

[Correction method] Change

[Correction content]

[0042] In addition, if the result is pause period of the determination at the step S3, the process proceeds to step S4, if not pause period, the process proceeds to step S5, if the procedure advances to step S4, TOC in step S2 By referring to the data type information stored at the time of reading the information, the recorded data type of the currently reproduced track is determined, and branching is performed.

Claims (1)

Claim: What is claimed is: 1. A reading unit for reading table-off content information of a disc, and a recording type for each track is determined from the table-off content information read by the reading unit. When the reproduction position is stored in the storage means and the reproduction position is changed to the following track according to the information stored in the storage means, the audio of the following track is recorded from a specific position in the pause period immediately before the main recording data area of the following track. A compact disc reproducing apparatus having a central processing unit for setting a reproducing output level for output.