JPH0896561A - Time display device for disk player - Google Patents

Abstract

PURPOSE: To display a reproducing time without disturbance even though the reproducing time is prolonged by displaying a time obtained by subtracting the capacity time of a digital signal stored in a memory circuit from the time data of the signal to be written in the memory circuit. CONSTITUTION: The writing operation of audio data in a second memory circuit 9 is performed by control operations of a system control circuit 7 and a memory control circuit 10. At this time, time data T are detected from positional index information at the time the audio data are written in the second memory 9. When the capacity time of the digital signal being audio data stored in the second memory circuit 9 is defined as (t), the time AT of a signal being actually reproduced at present is expressed as (T-t). The time of a music being actually reproduced is displayed by displaying (T-t) on an indicator 8. Even in the case where the digital signal to be stored in the second memory circuit 9 is only audio data, the reproducing time of a music being actually reproduced is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention writes a digital signal read from a disc on which information data is recorded by a digital signal into a memory circuit and reads a signal stored in the memory circuit to perform a reproducing operation. The present invention relates to a time display device for a disc player configured as described above.

[0002]

2. Description of the Related Art Disc players are widely used which perform a reproducing operation by reading a signal from a disc on which information data such as music is recorded by a digital signal by using an optical pickup. Such a disc player is generally configured to reproduce the information data at a constant speed by once writing a digital signal read from the disc into a memory circuit and then reading it out with a read clock, which is a typical example of such a disc player. A CD player is known as such.

As is well known, such a CD type disc has a main data signal of music information and the like, and 1 /
A sub-data signal called a sub-coding signal that completes one block in a cycle of 75 seconds is recorded. Such a sub-coding signal is composed of 8 P, Q to W channels.
The P channel includes position index information indicating the position of the beginning of the song, and the Q channel includes the absolute elapsed time from the start point of the signal track, the elapsed time for each song, and the song number. Is included in the position index information. Therefore, the CD player can perform a search operation by using the position index information, and can perform a reproduction operation of a designated music piece and a repeat reproduction operation of a designated section.

In addition, a CIRC disc has a CIRC.
Since a digital signal to which an error correction code referred to as is added is recorded and an error detection code referred to as CRC is added to the Q channel of the sub-coding signal, such signal is used in a CD player. The error correction operation and the error detection operation of the information data read out by utilizing can be performed.

[0005]

Among the above-mentioned CD players, there is a portable type player configured to listen to a reproduced sound by using headphones. However, such a portable type CD player is Since it is used while being carried, it is often subject to external shock. When such an impact is received, it is possible to perform a tracking control operation that causes the light beam of the optical pickup to correctly follow the signal track in order to read the signal recorded on the disc, and a focusing control operation that focuses the signal surface correctly. There is a problem that the sound cannot be reproduced and the reproduced sound is interrupted.

As a method for solving such a problem, a signal reading operation from a disk is performed faster than a reproducing speed, the read signal is temporarily stored in a memory circuit, and then the signal is reproduced at a normal reproducing speed. A technique for performing a read operation has been developed.

The time display of the reproduced tune in the disc player incorporating such a function is performed based on the position index information stored in the memory circuit. According to such a configuration, since the position index information is stored in the memory circuit together with the main data signal such as music information,
There is a problem that the time of the main data signal stored in the memory circuit becomes short.

If only the main data signal is stored in the memory circuit, the time of the main data signal stored in the memory circuit can be lengthened, but there is a problem that the time of the reproduced music cannot be displayed. .

The present invention is intended to provide a time display device which solves such a problem.

[0010]

The time display device of the present invention comprises a reading means for reading a digital signal from the disk at a speed higher than the reading speed of the digital signal stored in the memory circuit, and a signal to the memory circuit. Memory control circuit for controlling the writing operation and the reading operation from the memory circuit, and controlling the operation of the reading means according to the capacity of the digital signal stored in the memory circuit, and the display operation of the display unit. It is composed of a system control circuit for controlling.

[0011]

According to the present invention, the display unit displays the time obtained by subtracting the capacitance time of the digital signal stored in the memory circuit from the time data of the signal written in the memory circuit.

[0012]

FIG. 1 is a block circuit diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an optical pickup in which a light beam is projected onto a CD type disc (not shown), and a photodetector for receiving the light beam reflected by the signal surface of the disc is incorporated. An RF amplifier circuit 3 that amplifies an RF signal obtained from the photodetector of the pickup 1 and shapes the waveform is provided. The focusing control operation for focusing and the tracking control operation for causing the light beam to follow the signal track on the signal surface are performed, and the pickup 1
This is a servo signal processing circuit that controls the entire feeding operation.

Reference numeral 4 denotes a digital signal processing circuit for performing digital signal processing of an output signal (serial digital signal) output from the RF amplification circuit 2 and demodulating operation of various signals. Reference numeral 5 denotes the digital signal processing circuit 4. A first memory circuit that temporarily stores data for rearranging data when performing demodulation of various signals, 6 is an operation switch incorporating a changeover switch such as a reproduction operation switch, and 7 is the digital signal processing This is a system control circuit that displays a reproduction time and the like on the display 8 using a sub-coding signal that is position index information demodulated by the circuit 4 and controls various operations according to the operation of the operation switch 6.

Reference numeral 9 denotes a second memory circuit in which a digital (parallel) signal output from the digital signal processing circuit 4 is written, and 10 denotes a signal writing operation to the second memory circuit 9 and the second memory circuit 9 A memory control circuit for controlling the read operation of stored signals, 1
Reference numeral 1 is a comparison circuit which compares the digital signal stored in the second memory circuit 9 with the digital signal output from the digital signal processing circuit 4 and supplies the comparison output to the memory control circuit 10.

Reference numeral 12 is an error detection circuit for detecting an error in the Q channel data of the sub-coding signal demodulated by the digital signal processing circuit 4 and supplying the detection output to the system control circuit 7, and 13 is the second memory circuit. A parallel-serial conversion circuit for converting a parallel digital signal read from 9 into a serial digital signal, and 14 is input with the serial digital signal output from the parallel-serial conversion circuit 13 and converts the signal into an analog signal. It is a D / A converter for conversion.

In the CD player configured as described above, the speed at which the pickup 1 traces the disc is higher than the standard trace speed of the disc in a normal CD player (for example, twice) (higher than the rated linear velocity). The disk rotation driving device is configured to rotate the disk.), And the signal writing speed and the signal reading speed to the first memory circuit 5 are made high in accordance with the disk tracing speed. Also, the second
The writing speed of the signal to the memory circuit 9 is set to be high in accordance with the reading speed from the first memory circuit 5, but the reading speed is set to a standard speed which is slower than the writing speed. It is configured. The signal written in the second memory circuit 9 is
The main data in the signal read from the disc, that is, only the audio data, is constituted.

The memory control circuit 10 provided to control the operation of the second memory circuit 9 is
When the capacity of the digital signal stored in the second memory circuit 9 reaches the first predetermined amount near the overflow, a signal to that effect is supplied to the system control circuit 7. When the system control circuit 7 receives such a signal, the system control circuit 7 picks up the pickup 1
Is configured to output a signal for controlling the operation of the servo signal processing circuit 3 so as to repeatedly trace the same signal track of the disk.

When such an operation is performed, the second memory circuit 9 is operated by the operation of the memory control circuit 10.
The writing operation of the digital signal to the second memory circuit 9 is interrupted, and only the reading operation from the second memory circuit 9 is performed. Then, the signal stored in the second memory circuit 9 decreases with the read operation, and when the capacity of the digital signal stored in the second memory circuit 9 becomes equal to or less than the second predetermined amount, the memory control circuit. It is set so that the signal from 10 is supplied to the system control circuit 7. When the system control circuit 7 receives such a signal, the system control circuit 7 outputs a signal for controlling the operation of the servo signal processing circuit 3 so as to advance the trace position of the disc by the pickup 1. It is configured.

Further, the system control circuit 7 controls the servo signal processing circuit 3 in accordance with the detection output from the error detection circuit 12, and the error detection circuit 12 causes the error of the Q channel data of the sub-coding signal to occur several times. When continuously detected, the audio data of the digital signal portion including the Q channel data having an error is prevented from being written in the second memory circuit 9 by the operation of the memory control circuit 10 and the disc by the pickup 1 is prevented. Is configured to retract the trace position of.

The error in the Q channel data of the sub-coding signal can be detected by the CRC error detection code included in the Q channel data.
If there is an error in the Q channel data, there is a possibility that an error has occurred in the audio data in the digital signal read in 1/75 seconds until one block of the Q channel data is completed. It can be judged to be large. Therefore, if the Q-channel data is erroneous several times in succession, it is very likely that the audio data in the digital signal during that time is erroneous. still,
Since the CD system audio data is subjected to an error correction process called CIRC, some audio data errors can be corrected, but large audio data errors can be corrected. Absent.

The error detection circuit 12 also supplies a signal to the system control circuit 7 indicating that the Q channel data itself, which is generated when the pickup 1 cannot read the signal, cannot be detected. The audio signal is prevented from being written in the second memory circuit 9, and the trace position of the disc of the pickup 1 is retracted by the operation of the servo signal processing circuit 3.

When the servo signal processing circuit 3 works to move the trace position of the disk of the pickup 1 back and the digital signal can be read again, the comparison circuit 1
1 compares the audio data output from the digital signal processing circuit 4 with the audio data stored in the second memory circuit 9. In this case, the audio data output from the digital signal processing circuit 4 is sequentially compared with each of the plurality of audio data stored in the second memory circuit 9 in the written order.

When the same audio data is detected several times in succession by the comparison operation, the control operation of the memory control circuit 10 causes the digital signal processing circuit 4 to overlap the storage addresses of the same audio data portion. The writing operation of the output audio data to the second memory circuit 9 is restarted. Therefore, when the signal track of the digital signal portion including the erroneous Q channel data is traced again and the correctly read audio data is output from the digital signal processing circuit 4, the audio data becomes the Q channel data. Is written in a predetermined address of the second memory circuit 9 so as to be correctly continuous with the audio data of the digital signal portion before the error is detected.

Here, the second memory circuit 9 reads the erroneously read digital signal, reads the digital signal from the second memory circuit 9 while processing the digital signal and writing the digital signal into the second memory circuit 9. A device having a storage capacity such that audio data is not lost is used. Therefore, audio data read from the second memory circuit 9 will not be interrupted even if the digital signal read by mistake is read again.

Further, since only the audio data is written in the second memory circuit 9, the position index information is not included in the signal read from the second memory circuit 9. The time of the music being reproduced cannot be displayed on the display 8 based on the signal. Therefore, in the present invention, the time data T is detected from the position index information when the audio data is written in the second memory circuit 9, and the capacity time of the digital signal stored in the second memory circuit 9 at that time is detected. Is set to t, the time TA of the music being reproduced becomes T-t, and the TA time is displayed on the display unit 8 as the time of the music being reproduced.

The present invention is configured as described above, and the operation will be described below. When the signal track formed on the disc is traced by the light beam projected from the optical pickup 1, the signal recorded on the disc is read by the pickup 1 and an RF amplification circuit as an RF signal (high frequency signal). 2 is supplied. The RF signal is amplified by the RF amplifier circuit 2 and waveform-shaped and applied to the digital signal processing circuit 4 as a digital signal.

The digital signal processing circuit 4 demodulates the digital signal output from the RF amplifier circuit 2 and extracts various data signals included in the digital signal. The audio data is extracted by the signal processing operation of the digital signal processing circuit 4, and the audio data is subjected to error correction processing based on the error correction data included in the digital signal. The error correction processing operation is performed by the data rearrangement operation using the first memory circuit 5.

The audio data output from the digital signal processing circuit 4 is written into the second memory circuit 9 and read from the second memory circuit 10 by the control operation of the memory control circuit 10, but the writing operation is performed at high speed. The read operation is performed at a standard speed.

The audio data read from the second memory circuit 9 is a parallel digital signal,
The digital signal is input to the parallel / serial conversion circuit 13 and converted into serial audio data.
The serial audio data output from the parallel / serial conversion circuit 13 is applied to the D / A converter 14 to be converted into an analog signal and separated into left and right channel signals and output. Therefore, if the analog signals of the left and right channels output by the D / A converter 14 are supplied to an audio circuit (not shown) and amplified, the signals such as music recorded on the disc can be reproduced and heard. I can.

When the above-mentioned operation is being performed, the Q channel data of the sub-coding signal extracted by the digital signal processing circuit 4 is in a state of being supplied to the error detecting circuit 12. The error detection circuit 12 checks the CRC included in the Q channel data each time the Q channel data is supplied, detects whether the Q channel data has an error, and detects the error within a certain period. It is detected whether or not the Q channel data itself can be detected. Then, the error detection circuit 12 is read from the disk by detecting an error in the Q channel data a predetermined number of times set in advance or by detecting the absence of the Q channel data within a certain period. It is determined that the digital signal has an error.

When it is determined by the error detection circuit 12 that the digital signal read by the error detection circuit 12 has no error, the audio data stored in the second memory circuit 9 is processed by the memory control circuit 10 and the system control circuit 7. It is detected whether or not the predetermined amount is 1. And the second
If the audio data stored in the memory circuit 9 has not reached the first predetermined amount and the audio data can be newly written in the second memory circuit 9, the trace position by the pickup 1 is advanced as it is, New audio data is continuously written in the second memory circuit 9.

When such an operation is performed, the audio data stored in the second memory circuit 9 exceeds the first predetermined amount, and new audio data cannot be written in the second memory circuit 9. In this state, the trace position by the pickup 1 becomes a state in which the tracing operation of the same signal track is repeatedly performed, and the writing operation of the audio data to the second memory circuit 9 is interrupted. In such a state, when the read operation of the audio data stored in the second memory circuit 9 is performed and the amount becomes smaller than the first predetermined amount, the write operation to the second memory circuit 9 may be performed. Ready to go.

By the way, when the error detection circuit 12 detects that the read digital signal has an error, the audio data stored in the second memory circuit 9 by the system control circuit 7 is second predetermined amount. It is determined whether it is less. Then, the second memory circuit 9
If it is determined that the audio data stored in is less than the second predetermined amount, even if there is an error in the read digital signal, the trace position by the pickup 1 is advanced as it is, and new audio data is transferred to the second memory circuit 9 Continue to write. Therefore, the audio data read from the second memory circuit 9 is not interrupted.

On the other hand, when it is detected that the read digital signal has an error, if it is determined that the audio data stored in the second memory circuit 9 is larger than the second predetermined amount, the Q channel having the error is detected. Second memory circuit 9 for audio data in digital signal including data
To stop writing to the system control circuit 7
The control operation of the servo signal processing circuit 3 is performed and the trace position by the pickup 1 is returned to the rear. Therefore, the portion of the digital signal including the erroneous Q channel data is read again.

As described above, the signal writing operation and the signal reading operation with respect to the second memory circuit 9 of the present embodiment are performed. Next, the operation in a specific situation will be described. The operation of reading the signal recorded on the disc by the pickup 1 is correctly performed, and the error detection circuit 1
When it is determined that 2 has no error in the read digital signal, correct audio data is written in the second memory circuit 9. Since the signal writing speed to the second memory circuit 9 is set higher than the reading speed of the stored signal, the audio data stored in the second memory circuit 9 gradually increases. .

However, when the audio data stored in the second memory circuit 9 becomes equal to or larger than the first predetermined amount, the trace position of the pickup 1 is retracted, and the tracing of the same portion on the disc is repeated. Since the writing operation of the audio data corresponding to the signal of the portion to the second memory circuit 9 is not performed, the second memory circuit 9 does not overflow. Even when the same portion on the disc is repeatedly traced by the pickup 1, the audio data read operation from the second memory circuit 9 is continuously performed, so that the audio data is not interrupted. However, the signal reproducing operation is continuously performed.

On the other hand, when the pickup 1 does not correctly read the signal on the disc due to an external impact or swing and the error detection circuit 12 determines that the read digital signal has an error, the second memory If the audio data stored in the circuit 9 is larger than the second predetermined amount, the trace position on the disc of the pickup 1 is retracted and the digital signal determined to be incorrect is read again. Then, the audio data in the reread digital signal is written so as to be correctly continuous with the audio data stored in the second memory circuit 9. In such a case, the digital signal which is determined to be erroneous is read again, and while the audio data in the digital signal is written in the second memory circuit 9, the audio data read from the second memory circuit 9 may be present. The storage capacity of the audio data in the second memory circuit 9 is controlled. Therefore, the audio data stored in the second memory circuit 9 is read again after the audio data stored in the second memory circuit 9 is read, so that the audio data is not interrupted and the signal reproduction operation is continuously performed. .

As described above, the writing operation and the reading operation of the digital signal to the second memory circuit 9 are performed, but the audio data which is the parallel digital signal read from the second memory circuit 9 is parallel It is input to the serial conversion circuit 13 and converted into serial audio data. The serial audio data output from the parallel / serial conversion circuit 13 is
The signal is applied to the D / A converter 14 and converted into an analog signal, and separated into left and right channel signals and output. Therefore, a signal such as music recorded on the disc can be reproduced and heard at a standard speed.

As described above, the normal reproducing operation in this embodiment is carried out. Next, the reproducing time display operation will be described. As described above, the writing operation of the audio data to the second memory circuit 9 is performed by the control operation of the system control circuit 7 and the memory control circuit 10. However, when such operation is performed, the second memory circuit is The time data T is detected from the position index information at the time when the audio data is written in the memory 9. When the capacity time of the digital signal which is the audio data stored in the second memory circuit 9 at this time is represented by t, the time TA of the signal actually reproduced at present is represented as T-t. Therefore, if this T-t time is displayed on the display unit 8, the time of the song actually being reproduced is displayed.

As described above, even when the digital signal stored in the second memory circuit 9 is only audio data, it is possible to display the reproduction time of the actually reproduced music. However, when the signal is read again from the disc, the signal is not written to the second memory circuit 9, and the reproduction time cannot be displayed on the display unit 8.

In order to solve such a problem, the present invention is constructed as follows. The operation of writing the audio data to the second memory circuit 9 is performed by the control operation of the system control circuit 7 and the memory control circuit 10. When such operation is performed, the audio data is written to the second memory circuit 9. The time data T is detected from the position index information at the time of writing. When the capacity time of the digital signal which is the audio data stored in the second memory circuit 9 at this time is represented by t, the time TA of the signal actually reproduced at present is represented as T-t. Then, at this time, the timer circuit incorporated in the system control circuit 7 is operated, and the time output from the timer circuit is displayed on the display 8 in addition to the T-t time. That is, the actual time of the song can be displayed by using the Tt time as a reference time and adding the time from the timer circuit to this time. By doing so, the time of the reproduced music can be displayed even in a state in which the signal read from the disc is not written into the second memory circuit 9.

However, the digital signal read from the disc may be erroneous, and the digital signal obtained by the reread operation may not be continuous with the signal stored in the second memory circuit 9. In this case, The above-mentioned T-t time does not match the reproduction time of the actually reproduced music. Therefore, in this case, the T-t time measured when the writing operation to the second memory circuit 9 is performed and the reproduction time displayed on the display unit 8 are compared, and based on the comparison output. To correct the timer time of the timer circuit. By performing such a correction operation, even when the digital signal read from the disc has an error and the digital signal obtained by the reread operation and the signal stored in the second memory circuit 9 are not continuous, promptly It is possible to return to the state where the correct time is displayed.

[0043]

Since the present invention is configured to display the time obtained by subtracting the capacitance time of the digital signal stored in the memory circuit from the time data of the signal written in the memory circuit on the display, Even if the reproduction time of the signal stored in the memory circuit is lengthened by writing only the main data signal to the circuit, the reproduction time can be displayed without any trouble.

Even if the writing operation to the memory circuit is interrupted, the reproduction time can be obtained by the time information obtained at the time of writing, the capacity time of the digital signal stored in the memory circuit and the timer time obtained from the timer circuit. Therefore, the time display of the reproduced signal can be continuously performed. Then, the timer time obtained from the timer circuit is corrected by comparing the time obtained by the time information obtained when writing to the memory circuit and the capacitance time of the digital signal stored in the memory circuit with the displayed time. Since the digital signal writing operation to the memory circuit is interrupted and the digital signal obtained by the rereading operation and the signal stored in the memory circuit are not continuous, the correct time is displayed promptly. It can be returned to the state.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of a time display device of the present invention.

[Explanation of symbols]

 1 Optical Pickup 3 Servo Signal Processing Circuit 4 Digital Signal Processing Circuit 5 First Memory Circuit 7 System Control Circuit 8 Display 9 Second Memory Circuit 10 Memory Control Circuit 11 Comparison Circuit 12 Error Detection Circuit

Claims (3)

[Claims] 1. A disc player configured to write a digital signal read from a disc on which information data is recorded by a digital signal into a memory circuit and to read a signal written in the memory circuit to perform a reproducing operation. Reading means for reading a digital signal from the disk at a speed higher than a reading speed of the digital signal stored in the memory circuit, and a memory for controlling a signal writing operation to the memory circuit and a reading operation from the memory circuit It is composed of a control circuit and a system control circuit which controls the operation of the reading means and controls the display operation of the display according to the capacity of the digital signal stored in the memory circuit, and is written in the memory circuit. From the time data of the signal to the memory Time display device of the disc player, wherein a time obtained by subtracting the capacity time of the digital signal stored in the road and to display on said display device. 2. A disc player configured to write a digital signal read from a disc on which information data is recorded by a digital signal to a memory circuit and to read a signal written to the memory circuit to perform a reproducing operation. Reading means for reading a digital signal from the disk at a speed higher than a reading speed of the digital signal stored in the memory circuit, and a memory for controlling a signal writing operation to the memory circuit and a reading operation from the memory circuit It is composed of a control circuit and a system control circuit for controlling the operation of the reading means according to the capacity of the digital signal stored in the memory circuit and for displaying the reproduction time on the display, and is written in the memory circuit. The memory from the time data of the signal The time obtained by subtracting the capacitance time of the digital signal stored in the circuit is used as the reference time, the time of the signal currently being reproduced is obtained from the reference time and the time signal obtained from the timer circuit, and the time is set to the above-mentioned value. A time display device for a disc player characterized by displaying on a display unit. 3. The reference time is the time obtained by subtracting the capacitance time of the digital signal stored in the memory circuit from the time data of the signal written in the memory circuit, and the reference time is displayed on the display. The time display device according to claim 2, wherein the time of the timer circuit is corrected based on the time.