JPH03150765A - Reproducing device - Google Patents

Abstract

PURPOSE:To perform the continuous reproducing actions by providing a buffer memory which records data temporarily in a FIFO system and then reads them out at a constant speed and controlling the reading speed in response to the idle capacity of the buffer memory. CONSTITUTION:A pickup 2 serving as a data reading means reads the data out of the compact disk CD 1a and 1b and records them temporarily into a buffer memory 7 in a FIFO system. A read control means 10 sets a high reading speed when the idle capacity of the memory 6 exceeds the fixed value and then a normal reading speed equal to a level where the data are transferred from a data recording medium when the idle capacity of the memory 6 is less than the fixed value. Thus it is possible to continuously read the data out of the memory 6 and to carry on the reproducing action even though the data reading action is interrupted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for reproducing content stored on a data recording medium such as a compact disc. Compact disc (hereinafter referred to as C), which is a data recording medium
A compact disc player (hereinafter referred to as a CD player) that reads and plays the music data from a CD (hereinafter referred to as CD player) is equipped with an arbitrary player that has previously specified any song from among the songs recorded on multiple CDs. There are playback devices called CD changers, CD karaokes, etc. that have the ability to play back CDs in sequence.

Problems to be Solved by the Invention However, in the conventional playback device described above, the speed at which data is read from the CD by the data reading means is set to be approximately equal to the speed at which the playback signal is extracted to the outside of the device. While the reading of data by the pig reading means is transferred from one C to the pond CD or from another CD.
There is a problem in that the reproduction must be interrupted until the rotational speed of the CD reaches a rotational speed sufficient for reading data.

Continuous playback devices that can read and play data endlessly by connecting one magnetic tape in a loop are also widely used as playback devices that can avoid such interruptions in playback. However, even in the case of this continuous playback device, playback is still interrupted when the data reading means moves from the desired position on the magnetic tape to any other arbitrary position. Also.

In the case of this continuous playback device, the magnetic tape is used in a so-called special shingle suspension in order to run continuously along a certain meandering path, so if it is played back for a long time, it may cause serious trouble on the machine bridge. However, there are many problems, such as the reliability of the reproduced signal gradually being lost when the magnetic tape, which is a heavy recording medium, repeatedly comes into contact with the head, which is a signal detection section.

Therefore, an object of the present invention is to prevent the reproduction operation from being interrupted even if the data to be reproduced from the recording medium cannot be read by the reading means due to replacement of the recording medium from which the data is to be read. It is an object of the present invention to provide a reproduction device that can perform continuous reproduction.

Means for Solving the Problems The present invention provides a data reading means capable of reading data from a data recording medium by switching between a normal reading speed equal to the data transfer speed during recording and a high speed reading speed faster than this; a buffer memory for temporarily storing data read by the data reading means in a first-in, first-out manner and sequentially reading the data at a constant speed equal to the normal reading speed; Set the reading speed to fast reading speed,
and a reading speed control means for setting the reading speed of the data reading means to the normal reading speed when the free capacity of the buffer memory is less than a certain value, and even when reading of data by the data reading means is interrupted, The playback device is characterized in that data stored in a buffer memory is continuously read out and played back.

According to the present invention, even if the reading of data by the data reading means is interrupted due to replacement of the recording medium, the data stored in the buffer memory up to that time is continuously read and reproduced. Playback is not interrupted.

Embodiment FIG. 1 is a block diagram showing a schematic configuration of a reproducing apparatus which is an embodiment of the present invention. This playback device is a CD player that has a function of sequentially replacing and playing a plurality of CDs 1a, 1b, and the pickup 2 is
This is a data reading means for reading data recorded in the data storage area b. This pickup 2 can switch its data reading speed between a normal reading speed equal to the data transfer speed when data is recorded on the CDIa, lb, and a high speed reading speed faster than this.

The amplifier 3 is a circuit that amplifies the recorded signal, that is, the digital signal read out by the pickup 2, and the amplified digital signal is given to the demodulation circuit 4 at the next stage.

The digital signal demodulated by the demodulation circuit 4 is given to the buffer memory 6 via the buffer memory control section 5 at the next stage. This buffer memory 6 is a storage device for temporarily storing digital signals sent from the buffer memory control unit 5 in a first-in, first-out manner and sequentially reading them out again. This is a circuit for controlling the timing of writing digital signals and reading digital signals from the buffer memory 6.

Further, the buffer memory control unit 5 outputs a free space detection output C that indicates the free space of the buffer memory 6. The output C becomes a high level (hereinafter abbreviated as H level) when the free space exceeds a predetermined value, and becomes a low level (hereinafter abbreviated as L level) when the free capacity becomes less than a certain value.

The digital signal read from the buffer memory 6 is given to a digital-to-analog converter (hereinafter referred to as a D/A converter) 7 via the buffer memory control section 5. This D/A converter 7 is a conversion circuit that converts the sent digital signal into an analog signal and outputs it as a reproduced signal e.

The RF detection circuit 8 is a circuit for detecting the unprocessed digital signal output from the amplifier 3, that is, the RF signal a, and when the RF detection output from this circuit is output, it is output from the buffer memory control section 5. The free capacity detection output C is given as two outputs of the AND gate 9, and A
The output d of the ND gate 9 is given to the next stage reproduction speed control section 10 as a reading speed control output for switching and controlling the reading speed of the pickup 2. This reproduction speed control section 10 has the above-mentioned reading speed control output C.
The servo circuit 11 controls the drive circuit 12, and the drive circuit 12 performs rotational drive and replacement drive of the CDs 1a and lb. The CD exchange operation of the circuit 12 is performed based on a signal sent from the channel selection control section 13.

FIG. 2 is a timing chart showing the operation of the playback device when switching from the playback state of CD1a to the playback state of CD1b, of which FIG.
The data transfer lock ck when the pickup 2 reads data from b is detected by the RF detection circuit 8. FIG. 2 (2) shows the M product data amount Q of the buffer memory 6. The RF multiplied signal, FIG. 2 (4) shows the RF detection output S output from the RF detection circuit 8, and FIG. FIG. 6 shows the reading speed control output d output from the AND gate 9.

Next, the operation of the above playback apparatus will be explained with reference to the timing chart of FIG. Reading is done with a fast read speed. While the pickup 2 is reading, the RF detection output is at H level.

When time t1 is reached, the free capacity of the buffer memory 6 becomes less than a predetermined constant value, and the free capacity detection output C also changes from the H level to the L level. So RF
When the detection output is performed, the reading speed control output d, which is expressed as the logical product of the free capacity detection output C, changes from the previous H level to the L level.
As a result, data is read from the CD 1a by the pickup 2 at the normal reading speed. In this case, the normal reading speed is equal to the speed at which digital signals are read from the buffer memory 6, that is, the playback speed, so the free capacity of the buffer memory 6 does not change during this time.

When time t2 is reached, the CDs to be played are CD1a to C.
It is exchanged to D1b. Reading by the pickup 2 is not performed until time t4 when this exchange ends, but the reading is interrupted.
The data accumulated so far is successively read from the buffer memory 6, and the D/A converter 7 continuously outputs the reproduction signal e without interruption. During this time,
The accumulated data Q in the buffer memory 6 continues to decrease, and the free capacity becomes less than a certain value. As a result, the free capacity detection output C changes from L level to H level at time t3, but
Since the reading operation has already been interrupted, the RF detection output has changed from the H level to the L level, and as a result, the reading speed control output d is kept at the L level.

When time t4 is reached and the exchange from CD1a to CD1b is completed and the reading operation is restarted, the RF detection output changes from L level to H level, and as a result, the reading speed control output d changes from L level to H level. do. So 1 time t
After 4, data is read from the CD 1b by the pickup 2 at a high read speed, and as a result, the data IQ stored in the buffer memory 6 starts to increase again.

When the free space of the buffer memory 6 becomes less than a certain value at time t5, the free space detection output C changes from H level to L level, so that the reading speed $IJ 911 output d
changes from the H level to the L level, and thereafter data is read from the CD 1b by the pickup 2 at the normal reading speed.

In this way, even when the reading operation is interrupted when the CD1a is replaced with the CD1b, the playback signal e continues to be output without interruption.In the above embodiment, the case of a CD player is explained. However, this is not limited to this; for example, digital data can be recorded and reproduced using magnetic tape as a recording medium.
tal＾udi.

It can be similarly applied to tape-recorders and the like.

Furthermore, even if the data is not recorded on a recording medium as digital data, the analog signal read from the recording medium can be A/D-converted at a sampling rate corresponding to the reading speed. Reproduction equipment for disc players, compact cassette recorders, etc.! It is also applicable to

Further, in the above embodiment, the recorded data read by the pickup 2 is stored as is in the buffer memory 6, but depending on the quality of the data, data converted into a differential signal using ADPCM technology may be stored in the buffer memory 6.
It may also be applied in combination with a method of reducing memory capacity, such as by storing the data in a file and demodulating it during playback.

Effects of the Invention As described above, according to the playback device of the present invention, when the free space of the buffer memory is below a certain value, the data reading means reads data at high speed, while the free space of the buffer memory is at a certain value. In this case, the data reading means is configured to read data at a normal reading speed, and even if the reading of data by the data reading means is interrupted, the data stored in the buffer memory up to that point is continued to be read. Therefore, while the recording medium from which data is to be read is replaced or until the mechanical conditions between the recording medium and the data reading means are established,
Even if reading of data by the data reading means is interrupted, reproduction is not interrupted and continuous reproduction can be performed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a reproducing apparatus according to an embodiment of the present invention, and FIG. 2 is a timing chart showing the operation of the reproducing apparatus. la, lb...CD, 2...pickup, 5...
- Buffer memory control section, 6... Buffer memory, 8... RF detection circuit, 9... AND gate,
10... Playback speed control unit, 11... Servo circuit, 12... Drive circuit

Claims (1)

[Scope of Claims] Data reading means capable of reading data from a data recording medium by switching between a normal reading speed equal to the data transfer speed at the time of recording and a high speed reading speed faster than the normal reading speed; a buffer memory that temporarily stores the data read out in a first-in, first-out manner and sequentially reads the data at a constant speed equal to the normal reading speed; set to speed,
and a reading speed control means for setting the reading speed of the data reading means to the normal reading speed when the free capacity of the buffer memory is less than a certain value, and even when reading of data by the data reading means is interrupted, A playback device characterized in that data stored in a buffer memory is continuously read out and played back.