KR0133988B1 - Multi-speed audio signal reproducing disk player - Google Patents

Abstract

The present invention relates to a disc player for reproducing an audio signal at various speeds. The present invention comprises means for generating playback speed control information, a variable frequency generator for varying the frequency of the main clock and the frequency of the PLL according to the playback speed control information, and a DSP for processing the audio signal according to the variable frequency. .

Therefore, the present invention provides the effect of varying the playback speed of the audio signal.

Description

Disc player that plays audio signals at various speeds

1 is a block diagram showing a general audio signal reproducing apparatus.

2 is a block diagram showing a disc player for reproducing an audio signal at various speeds according to the present invention.

3 is a state diagram showing a display state of the display unit of FIG.

* Explanation of symbols for main parts of the drawings

11: key input unit 12: micom

13: D / A conversion unit 14: system clock generation circuit

15: PLL circuit 16: DSP

17 display unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc player for reproducing an audio signal, and more particularly to a disc player capable of controlling the length and length of a reproduction sound at various speeds.

In general, a compact disk (CD) employing a digital recording method divides an analog signal into a sampling frequency of 44.1 KHz, and then converts it into a digital signal combined with 1 and 0 by analog / digital conversion. A music signal is recorded on the disc in the shape of a projection called a pit.

At the time of reproduction, this digital signal is digitally / analog converted, and the clock component is removed and reduced to analog again to raise the amplification and the speaker. Such a CD-player is shown in FIG.

FIG. 1 is a block diagram showing a general audio signal reproducing apparatus. In reproduction, the pickup apparatus 3 shoots a laser beam in a corresponding region of the disc 1 to convert the beam reflected from the disc 1 into an electrical signal. The output signal of the pickup device 3 is input to the RF amplifier 4 in the form of a high frequency signal. The RF amplifier 4 amplifies the output signal of the pickup device 3 to a predetermined level, extracts an EFM (Eight to Fourteen Modulation) signal, and extracts the same to the DSP (Digital Signal Processor) 5. The DSP 5 includes an EFM demodulation circuit, a frame synchronization circuit, a CIRC decoder, and the like to perform overall system digital signal processing. The DSP (5) receiving the EFM signal from the RF amplifier (4) is the main clock (= 16.9344 MHz) generated by the system clock generation circuit (8) of the spindle motor (2) for rotating the data processing and disk (1). The drive unit 9 is controlled. The DSP 5 also matches the frequency phase of the EFM signal input from the RF amplifier 4 with the frequency phase of the main clock generated by the system clock generation circuit 8 according to the center frequency generated from the PLL circuit 7. Let's do it. That is, the DSP 5 PLL logs the EFM signal and the 1/4 division clock of the main clock, corrects the PLL circuit 7 with the error component, and controls the drive unit 9 of the spindle motor 2. The digital audio signal reconstructed by the DSP 5 is converted into an analog signal by the D / A converter 6, amplified to a predetermined size by the amplifier AMP, and then output to the line output terminal OUT.

In the case of performing the song practice function using such a CD-player, in the related art, the height of the reproduction sound can be adjusted according to the user's voice, but the beat is determined as a standard. However, in order to sing a song, the user may sing a little faster or slower, and thus, there is a need to variably adjust the length and length of the playback sound according to the user's preference. However, conventionally, there is a problem that does not have such a function does not respond to various needs of the user.

Accordingly, the present invention provides a device that can control the speed of the playback sound by varying the frequency of the main clock and the PLL, which are the basic clocks for the control and data processing of all servos, according to the data input from the microcomputer. In providing.

Disc player for reproducing an audio signal at various speeds of the present invention for achieving the above object is a disc player for reproducing audio data from an audio data recording disc, the motor for rotating the disc and the speed of the playback sound A key input unit for inputting a selection command, a control unit for varying the frequency of the system clock generation circuit and the PLL circuit according to the playback sound fast selection command of the key input unit, and a frequency of the main clock and the PLL that are varied by the control unit. A system clock generation circuit and a PLL circuit for supplying to the DSP, and a DSP for processing audio data read out from the disk according to the variable frequency, and for controlling the rotation speed of the motor.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram showing a disc player for reproducing an audio signal at various speeds according to the present invention. As shown, the disc player of the present invention includes a spindle motor 2 for rotating the disc 1 at a predetermined speed, and a pickup device 3 for detecting data recorded on the disc 1. Equipped with. An output terminal of the pickup device 3 is connected with an RF amplifier 4 which amplifies the output signal to an appropriate level. An output terminal of the RF amplifier is connected with a DSP 16 for signal processing and restoring the EFM signal. The output terminal of the DSP 16 is connected with a D / A converter 6 for converting the restored digital audio signal into an analog signal. An output terminal of the D / A converter 6 is connected to an amplifier AMP for amplifying the analog audio signal to a predetermined level and outputting the same to the line output terminal OUT.

The disc player of the present invention also includes a key input unit 11 for inputting a long and short selection command of the playback sound, and a microcomputer 12 for generating control data in accordance with the long and short selection command of the key input unit 11. The control data of the microcomputer 12 is input to the D / A converter 13 to generate a corresponding operating power source. A system clock generation circuit between the D / A converter 13 and the DSP 16 for supplying variable mayclock and PLL frequency to the DSP 16 according to the operating power input to the D / A converter 13 ( 14 and the PLL circuit 15 are connected respectively. Between the DSP 16 and the spindle motor 2, the drive unit 9 for varying the rotational speed of the spindle motor 2 is connected as the main clock is variable. The microcomputer 12 is configured to be connected to a display unit 17 for displaying the short and short state of the current playback sound.

The operation of the disc player for reproducing the audio signal at various speeds of the present invention configured as described above will be described in more detail.

First, when a user inputs a long and short selection command of the playback sound through the key input unit 11, the playback sound length and short selection command is applied to the microcomputer 12. The microcomputer 12 outputs control data for variably adjusting the main clock frequency and the PLL center frequency in response to the input playback sound field short selection command. The control data is inputted to the D / A converter 13 so that the main clock and PLL increasing frequency generated by the system clock generation circuit 14 and the PLL circuit 15 are generated corresponding to the fastness selected by the user. To supply. Therefore, the system clock generation circuit 14 and the PLL circuit 15 vary the oscillation frequency by the operating power supply and supply them to the DSP 16. In the embodiment of the present invention, the main clock oscillation frequency is about 3 MHz with 16.9344 MHz as the center frequency, and the short and long periods of the reproduction sound are slow and four steps, and the frequency variable range is 750 KHz. Also, the PLL center frequency is adjusted to 1/4 of the main clock. The DSP 16 receives the main clock from the system clock generation circuit 14 to generate a read frame clock (RFCK) and a write frame clock (WFCK), respectively. The period of the read clock RFCK and the write clock WFCK is compared with the main clock to generate an MDP signal and an MDS signal for controlling the driving speed and phase of the spindle motor 2, respectively. This MDP signal is output to the drive unit 9 of the spindle motor 2 and performs phase control in the disk constant speed (CLV) method. The MDS signal is also output to the drive unit 9 of the spindle motor 2 to control the speed. The DSP 16 matches the period T of the frame read clock RFCK and the write clock WFCK through the PLL circuit 15 with the frequency divided by 1/4 of the main clock. In addition, the frame read clock (RFCK) is generally composed of six samples of one frame, so the standardized frequency (= 44.1 KHz) is divided into six equal to 7.35 KHz. The frame write clock (WFCK) is also 7.35KHz with PLL lock.

The MDP signal and the MDS signal are determined by the frame read clock RFCK or the write clock WFCK. Thus, if the DSP 16 is adjusted in a state where only the main clock and the PLL center frequency are set, all clock frequencies are changed. Thus, the disk rotational speed of the spindle motor 2 can be varied, and the length and length of the reproduction sound can be variably adjusted.

The pickup device 3 has a variable time for reading data to be picked up as the disk rotation speed is varied. The output signal of the pickup device 3 is amplified to the RF amplifier 4 at a constant level, and the detected EFM signal is input to the DSP 16. The DSP 16 uses the variable main clock to process the EFM signal input from the RF amplifier 4 and restore the original signal. The recovered signal is converted into an analog audio signal by the D / A converter 6, and then amplified to a predetermined level by the amplifier AMP and output through the line output terminal OUT. In addition, the microcomputer displays the short and long term of the currently reproduced audio signal on the display unit 17 as shown in FIG.

As described above, the present invention relates to a disc player for reproducing an audio signal at various speeds, and has an effect of allowing a user to select various lengths of playback sounds.

Claims (3)

A disc player for reproducing audio data from an audio data recording disc, the disc player comprising: a motor for rotating the disc and a key input unit for inputting a command for selecting a speed of reproduction sound; A controller for varying a frequency of a system clock generation circuit and a PLL circuit according to a playback sound speed selection command of the key input section; A system clock generation circuit and a PLL circuit for supplying a frequency of the main clock and the PLL variable by the controller to the DSP; And a DSP for processing audio data read out from the disc according to the variable frequency and controlling the rotational speed of the motor. The disc player of claim 1, further comprising a display unit connected to the control unit and indicating a speed state of a reproduction sound. The audio signal according to claim 1 or 2, wherein the DSP controls the PLL circuit such that the main clock supplied from the system clock generation circuit and the PLL center frequency supplied from the PLL circuit coincide with each other. Disc player to play.