JPS62150560A - Disc reproducing device - Google Patents

Abstract

PURPOSE:To improve the vibration resistance by stopping the write of a data in a memory while a pickup is moved to a position prior to track jump after track jump takes place and reading the data from the memory for a prescribed period of a sampling frequency to suppress the abnormal reproducing state such as noise or temporary intermission of reproduction. CONSTITUTION:When a pickup 3 traces a track of a disc 1 accurately, a minute/ second frame is changed sequentially and continuously, but when any track jump takes place, the frame is discontinuous. When the pickup 3 jumps the preceding track, since the time is discontinuous in the increasing direction, a signal 8B generating a jump pulse to restore the pickup 3 to the trace position is fed to a servo circuit 5. The pickup 3 traces a track before the occurrence of track jump, the time information is changed as shown in figure 8S, the output of a track jump detection circuit 8 generates a pulse shown in figure 8G until the pickup 3 restores to the home position at the occurrence of track jump. Thus, even any track jump takes place, the data is continuously reproduced.

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]

An example of main information and 1-hour information recorded on the wl and family tracks of a disc is JP-A No. 60-43270.
As stated in the publication.

The main information is the digitized audio signal,
There are compact discs (CDs) that are recorded in an optically readable manner. Regarding the CD recording format,
As stated in the above publication, a predetermined small frame unit is formed and is continuous, and the small frame is approximately 136
Each small frame has a period of microseconds, and each small frame consists of a small frame synchronization information part, a subcode information part, and a data part containing music information of the main information.

The subcode information portion consists of 98 small frames and includes time address information and the like in units of large frames of 9 cycles and approximately 13.3 msec.

In this way, when reproducing signals from a disc on which digital signal information has been 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 or the like, and may be moved accidentally. If it is set, omission or duplication of reproduction information may occur. Therefore, 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 so that the information reading means returns to its original playback position. It was configured to move.

[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. After the information reading means is accidentally moved until it is returned to the normal playback position, if the information read by the information reading means is played back, noise may be generated in the reproduced information until the information reading means returns to the normal position. There has been a problem in that abnormal playback conditions such as playback or temporary interruption of playback occur.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, such as noise and temporary interruption of reproduction after the information reading means is accidentally moved until it returns to its normal position. It is an object of the present invention to provide a disc playback device which suppresses abnormal playback conditions and improves vibration resistance.

[Means for solving problems]

The above purpose is to write the data reproduced from the disc to the memory, stop writing the data reproduced from the disc to the memory from the time when the track jump occurs, while moving the pickup to the position before the track jump, This is achieved by reading 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 the track jump occurs, the data read from the memory is based on this accumulated data. read out. As a result, data subjected to digital-to-analog conversion can be reproduced continuously without becoming discontinuous.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIG. 1, taking a compact disc brake as an example.

In Figure 1, 1 is a compact disc.

2 is a motor that rotates the disk, and 3 is a pickup that optically reads out signals on the disk.

4 is a preamplifier circuit that amplifies the signal from the pickup 3 and obtains a playback signal from the disk and a track/focus error signal; 5 is a preamplifier circuit that amplifies the signal from the pickup 3 and obtains the track/focus error signal from the preamplifier circuit 4 and the speed of the motor 2 from the digital signal processing circuit 6; Pick up by detection signal 3. A servo circuit 6 that servo-controls the motor 2 takes in the playback signal from the disk, performs EFM demodulation error detection and correction processing according to the recording format, and converts the number of quantization bits to 1.
6-bit data is output at a sampling frequency of 44.1 and data is alternately output to 2 channels (L and R channels), and a speed detection signal for motor 2 is obtained from the frequency fluctuation of the synchronization signal reproduced from disk 1. , furthermore, a digital signal processing circuit consisting of a timing circuit for performing these operations, 7 an oscillator that generates a reference clock for the digital signal processing circuit 6, and 8 a digital signal processing circuit that processes time information recorded on the disk 2. The circuit 6 separates and inputs the signals, and detects the presence or absence of track skipping based on the continuity of the signal, and supplies a jump control signal to the servo circuit 5 to return the pickup 3 to its original position. A track jump detection circuit outputs a gate signal until the pickup 3 returns to its original position, 9 is an AND circuit, and 10 is a write address counter that synchronizes with the data output from the digital signal processing circuit 6. A counting operation is performed using pulses gated by an AND circuit 9. 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 counter 10.
This is a switch that changes the output of the counter 10.11, and is controlled by the digital signal processing circuit 6. When reading, select the output of counter 11,
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, and 15 is a sample and hold circuit that samples and holds the output of the DA converter 14 to obtain two channels of audio signals.

The operation shown in FIG. 1 will be explained with reference to an operation timing diagram of the track jump detection circuit 8 and a memory map showing the stored contents of the memory 13 shown in FIG.

A signal detected by the pickup 3 from the 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 uses the clock oscillated by the oscillator 7 as a reference, and performs two clocks.
Channel binary encoded 16-bit audio data is alternately stored in memory 1 at a sampling frequency of 44 degrees and 1 kHz.
3, and also supplies a clock synchronized therewith to the AND circuit 9 and the read address counter 11.

Here, the operation of the track jump circuit 8 will be explained with reference to the timing diagram of FIG. The time information from the digital signal processing circuit 6 consists of minutes and 2 seconds and frames, as shown in FIG. 2 88, and a frame is in units of 1775 seconds. When pickup 3 is accurately tracing the tracks of disk 1, the minute/second frames change continuously, but
When track jump occurs, discontinuity occurs. If this discontinuity causes the pickup 3 to jump to the next track, it is determined that the time is discontinuous in an increasing direction, and a jump pulse is generated in the servo circuit 5 to return the trace position of the pickup 3. Add signal 8B.

As a result of this operation, the position of the pickup 3 traces the track before the occurrence of track skipping, and the time information changes as shown in FIG. 2 88. As a result, the output 8G of the track jump detection circuit 8 is as follows.

The pulse shown in FIG. 2 8G is generated from the time when the track jump occurs until the pickup 3 returns to its original position.

Due to the operation of the track jump detection circuit 8, the memory 1
The data written to 3 is controlled.

Next, the operation of this memory 13 will be explained with reference to the memory map shown in FIG.

The output data from the digital signal processing circuit 6 is binary encoded 16-bit data, and two channels are output alternately. When the pickup 3 is tracing correctly on the track, the time column order is L n y
It is output as Rnt Ln + 11Rn, 1--1. Here, if a track jump occurs after Ln, Rn, or 3, the primary data becomes discontinuous, and the digital signal processing circuit 6 outputs Lm, RIl, LIl.
Start outputting data at the track jump destination in the order of l+xt R11+ 1--1. Track jump detection circuit 8
While the pick-up position is returned to its original position by the operation of , the data in this section is discontinuous data. Since the write address counter 10 is stopped in this discontinuous data section by the AND circuit 9, in FIG.
is written to addresses 6 and 7, and then the digital signal processing circuit 6 outputs data Ll, Ryo+Lllya, , R11+, but since the write operation has stopped, these data are not stored in the memory. 3, and the writing operation is restarted when the pickup 3 returns to its original position.

As a result, addresses 8 and 9 on memory 3 contain Lllll.
+4t RI++41 Ln+st Rn+G --
One consecutive piece of data is written.

In the example shown in FIG. 3, the read address counter 11 is designed to read data with a delay of 16 addresses from the value of the write address counter 1o.

This difference corresponds to the allowable stop time of the write address counter 10. Therefore, this difference amount is determined by taking into consideration the time required for the pickup 3 to return to its original position, and by increasing the capacity of the memory 3.

This difference amount can also be increased, and the allowable value of the stop time of the counter 10 can be increased.

In this way, the stored contents of the memory 3 can be continuous data, and by sequentially reading out these data and applying them to the DA converter 14, continuous sound can be reproduced even when a track jump occurs. .

FIG. 4 shows another embodiment of the present invention in which the number of track jumps is not limited in the embodiment shown in FIG. In the embodiment shown in FIG. 1, the allowable stop time of the write address counter 10 is limited by the capacity of the memory 3. As a result, if track skipping occurs several times, the stop time of the write address counter 10 may exceed this allowable value. Therefore, in the embodiment of FIG. 4, the write address counter 10 and the read address counter 11 are
An address monitoring circuit is installed to monitor the difference between disk 1 and
Switching control is now possible to increase the transmission speed of playback data from the

In FIG. 4, L6 is an address monitoring circuit, 7A.

7B is an oscillator, 7B is a reference clock frequency for normal playback speed, 7A is a reference clock for high playback speed, and 1
7 is a switch for selecting the oscillators 7A and 7B, and is controlled by the address monitoring circuit 16. Other symbols are the same as those in FIG. 1 and have the same functions.

The operation in FIG. 4 is almost the same as in FIG. 1, but when the difference between the write address counter 10 and the read address counter 11 becomes less than a certain value, the address monitoring circuit 16 changes these values. Subtraction, the output is obtained by a decoder that detects that it is below a certain value, and the switch 17
controls to select one oscillator 7A. As a result, the reference clock frequency of the digital signal processing circuit 6 increases, and since the speed detection signal of the motor 2 is also proportional to this, the rotational speed of the disk 1 increases. This increases the transmission speed of data reproduced from the disc 1, and the data writing speed of the memory 13 becomes faster than the reading speed. Now write address counter 1
The difference between 0 and the read address counter 11 increases.

Because of this operation, even if the write address counter 10 stops due to track skipping and the difference with the read address counter 11 decreases, the address monitoring circuit 16
And since the data reproduction speed is increased by the oscillator 7A,
Write address counter 1o and read address counter 1
It is possible to always keep the difference from 1 above a certain amount. Therefore, no matter how many times track skipping occurs, the data read from the memory 13 will be continuous, and continuous sound can be reproduced.

〔Effect of the invention〕

According to the present invention, writing playback data using a memory,
In addition, the time from when track skipping occurs until the pickup returns to its original position is detected based on the continuity of time information recorded on the disc, and the playback data for this section is
By controlling it from being written to memory,
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.
A timing diagram showing the operation of the track jump detection circuit 8,
FIG. 3 is a memory map diagram showing the contents of the memory 13 shown in FIG. 1, and FIG. 4 is a configuration diagram showing another embodiment of the present invention. 8... Track jump detection circuit, 10... Write address counter, 11... Read address counter,
13...Memory. Figure 1 Figure Z Figure 8 &

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; Track jump detection means is provided for detecting discontinuity in the time code obtained by the information reading means to detect the occurrence of track jump, and the track jump detection means detects the read position on the disk before the discontinuity of the time code occurs. The information reading means is moved from the occurrence of discontinuity in the time code to the reading position on the disk before the occurrence of discontinuity. Writing to the storage means is stopped, and the information data is stored in the storage means for a certain period of time. A disc playback device characterized by reading data at intervals. 2. In the disc playback device according to claim 1, a certain amount of data is stored in the storage means for storing information data at the start of disc playback and when a track jump is detected by the track jump detection means. What is claimed is: 1. A disc reproducing apparatus comprising a rotating means for rotating the disc and a control means for increasing the operating speed of the information reading means.