Recently, digital discs have been widely used in many fields. For example, a CD (abbreviation of Compact Disc) is used for digital audio records. A CD-ROM (ROM; abbreviation of Read Only Memory) is used for data memories. An LV (abbreviation of Laser Vision) disc is used for video records. In those digital discs, recorded data or information are reproduced at a speed specified to each kind of the digital discs. Thus, reproduction apparatus of digital discs are designed to reproduce the digital discs at the sole reproduction speed, i.e., a standard speed specified to each of the digital discs.
Referring now to FIG. 1, an example is shown of the conventional reproduction system for digital discs, e.g., a CD dubbing system. The CD reproduction system is provided for carrying out a dubbing from CD players to analog tape recorders.
In FIG. 1, the CD reproduction system comprises a CD player 10 and an analog tape recorder, e.g., a cassette tape recorder 11. The CD player 10 includes a CD reproducing mechanism section 12, a clock generator 13 and a signal processor 14.
The CD reproducing mechanism section 12 comprises a disc drive motor 15, a disc turntable 16 and a pickup device 17. The clock generator 13 generates a clock pulse Pck with a prescribed frequency Fck. The clock pulse Pck is applied to the signal processor 14.
The signal processor 14 comprises a servo control section 14a and an information signal reproducing section 14b. The servo control section 14a is coupled to the disc drive motor 15 and the pickup device 17 for supplying servo control signals thereto, as described later in brief. The information signal reproducing section 14b is coupled to the pickup device 17 for receiving an RF signal (RF; abbreviation of Radio Frequency) Srf read from a CD 18 and sent to the CD reproducing mechanism section 14.
The disc drive motor 15 drives the disc turntable 16 under the servo control of the servo control section 14a. The pickup device 17 shifts in the radial direction of the CD 18 under the servo control of the servo control section 14a. Thus, the pickup device 17 traces a record track on the CD 18 in a CLV (Constant Linear Velocity) speed. The pickup device 17 reads the CD 18 during the tracing of the record track of the CD 18 so that an RF signal Srf corresponding to the digital data recorded on the CD 18 is output from the pickup device 17.
The pickup device 17 outputs the RF signal Srf corresponding to the digital data, as described above. The RF signal Srf is applied to the information signal reproducing section 14b of the signal processor 14. A data slice circuit (not shown) in the information signal reproducing section 14b slices the RF signal Srf at a prescribed threshold level so that the RF signal Srf is shaped to the original digital data.
The servo control section 14a of the signal processor 14 generates two servo control data SCm and SCp and a bit synchronizing signal BS from the reproduced digital data. A motor servo control data SCm is applied to the disc drive motor 15, as described before. A pickup servo control data SCp is applied to the pickup device 17, as described before. The servo controls for both the disc drive motor 15 and the pickup device 17 are carried out in using the digital data obtained from the output of the pickup device 17, i.e., the RF signal Srf, and also the clock pulse Pck applied from the clock generator 13.
The information signal reproducing section 14b of the signal processor 14 demodulates an analog data AD from the reproduced digital data under the control of the clock pulse Pck. The analog data AD is applied to the cassette tape recorder 11. The cassette tape recorder 11 then records the analog data AD.
The conventional reproduction apparatus of digital discs, however, have a drawback that a reproduction of the digital discs takes a relatively long time the same as a standard record time provided for each of the digital discs.