JPS58220271A - Motor controller of digital disk player - Google Patents

Abstract

PURPOSE:To control accurately the revolving speed of a motor although it is impossible to extract the synchronizing signal of a digital data signal, by controlling the revolving speed of the motor on the basis of the comparison between the maximum or minimum inverting interval of the digital data signal and the standard value. CONSTITUTION:A recording signal processing circuit 13 extracts only the digital data signal component out of the signal read out of a disk 11. A maximum interting period detecting circuit 14 detects the maximum inverting period of the digital data signal supplied from the circuit 13 by means of the reference signal given from a reference signal genrating circuit 15 and then delivers the result of detection as a comparison signal. A motor control circuit 16 delivers the voltage signal corresponding to the comparison signal of the circuit 14 and applies it to a revolution driving motor 17 of a disk 12. Thus the winding driving current of the motor 17 is controlled, and the motor 17 is controlled so that its revolving speed is substantially constant for the maximum inverting period on the basis of the comparison output of the circuit 14.

Description

Detailed Description of the Invention [Technical Field of Invention □] 7- This invention relates to an improvement of a motor control device for a digital disc player.

[Technical Background of the Invention and Details thereof] Recently, digital audio discs DAD (hereinafter simply referred to as discs), in which audio signals are converted into digital PC'Ms as digital data signals and recorded on discs with uneven bit strings, and this disc are A nine-bit digital disc player has been developed that detects the bit string and plays back the original audio signal. Look forward to this, 'traditional analog'
It is now possible to reproduce high-fidelity audio signals, which was impossible with digital disc players.
.

By the way, such a disc has a bit length of c'
For example, when performing υ bit string tracking using an optical pickup, as the optical pickup moves from the inner periphery to the outer periphery, For this reason, conventional digital disc players generate a synchronization signal synchronized with each frame of the digital data signal from the frequency component of the digital data signal read from the disc. When the disk is removed, the rotational speed of the disk drive motor is controlled so that this synchronization signal has a substantially constant frequency. Also,
Such a digital display is capable of extracting a synchronizing signal by driving the motor to a predetermined rotational speed when a synchronizing signal cannot be obtained, for example when the motor starts rotating. Since then, the rotational speed of the motor has been controlled as described above.

However, in such digital disc players, there are cases where it is impossible to extract the synchronization signal due to the occurrence of disc dropout, and in this case, accurate control of the motor rotation speed becomes impossible. However, there was a problem in that it became impossible to maintain the correct rotational speed of the motor.

[Purpose of the invention]

This invention has been made in view of the above points, and it is possible to accurately control the rotational speed of a disk drive motor by extracting a synchronization signal of the digital data signal from the digital data signal x output from the disk. It is an object of the present invention to provide a motor control device for a digital disc player that is superior in quality.

[Summary of the invention]

That is, the present invention detects the maximum reversal interval or the minimum reversal interval of the read digital data signal in a digital disc player that reads out the digital data signal from the disc on which the digital data signal is recorded. a first means; a second means for comparing the maximum reversal interval or the minimum reversal interval determined by the first means with a predetermined reference value; and a third means for controlling the synchronous rotational speed of the motor for driving the rotation of the disk based on the comparison signal of the digital 1; It is characterized by allowing accurate control.

3- [Practice of the Invention, Same] First, an outline of a well-known digital disc player for playing a CD type (optical) digital audio disc DADp4 to which the present invention is applied will be explained.

That is, as shown in FIG. 1, a disc 113 mounted on a turntable 112 that is rotationally driven by a disc motor 111 is reproduced by an optical pickup 114. In this case, the optical pickup 114 directs the emitted light from the semiconductor laser 114a to the disk 11 through the beam splitter JJ4b and the objective lens 114c.
3 signal direction, and bits (reflectance of The reflected light from the different unevenness is passed through the objective lens 1140. 4-split photodetector 114 via beam splitter 114b
d, and the 4-split photodetector 4- is guided to the lid 114d, and the cough 4-split photodetector 114 (
1 is capable of outputting four reproduction signals photoelectrically replaced to the outside, and is linearly driven in the radial direction of the disk 113 by a pickup feed motor 115.

The four reproduced signals from the four-division photodetector 114d are then supplied to the matrix circuit 116 and subjected to predetermined matrix calculation processing, thereby generating a focus error signal F, a racking error signal and a high frequency signal R.
It is separated into F.

Of these, the focus error signal F is used together with the focus search signal from the focus search circuit 110 to drive the focus servo system FB of the optical pickup 114.

Further, the tracking error signal T is used together with a search control signal given via a system controller 117 (described later) to drive the tracking servo thread T8 of the optical pickup 114 and to drive the pickup feed motor 115 (linear tracking)? 1+IIf41
It is offered to

The remaining high frequency signal RF is then supplied to the reproduction signal processing system U as the main reproduction signal component.

That is, the reproduced signal processing system U first guides the reproduced signal to a waveform shaping circuit 120 controlled by a slice level (eye pattern) detector 119 to separate unnecessary analog components and necessary data components. The synchronous clock regeneration circuit 121 and the first
The signal is supplied to the edge detector 1f12eL of the signal processing system 122.

Here, the synchronous clock from the synchronous clock regeneration circuit 121 is guided to the synchronous signal separation clock generation circuit 122b in the first signal processing system 122 for data demodulation, and is used to generate a synchronous signal separation clock. .

On the other hand, the reproduced signal that has passed through the edge detector 122a is guided to the synchronization signal detector 122C, where the p synchronization signal is separated by the synchronization signal separation p-block, and the demodulation circuit 1
B, FM@tuned stone led by 22d.

Among these, the synchronization signal company synchronization signal keeping circuit 12jlet-
The input/output control circuit Z, ? of the input data processing timing signal generation circuit 113, together with the synchronization signal separation clock, is protected from malfunctions caused by the input data processing. ! I&
At the same time, the control signal and display signal components, which are subcodes, are guided to the control display processing circuit 112h and the subcode processing circuit 1221.

Then, the subcode data IDV Sdem controller interface 7/8 circuit 122 .subcode data is subjected to necessary error detection and correction in the subcode processing circuit 1221 . The data is supplied to the system controller 111 via.

7- Here, the system controller 111 includes a microcomputer, an interface circuit, a driver circuit, etc. 9, and controls the CAD playback device to a desired state by a command signal from the control switch 124, and also controls the above-mentioned The subcode (for example, index information of the song to be played) is displayed on the display 125.

Note that the input data processing timing signal generation circuit 1
The timing signal from 112f is sent to data select circuit 1.
The above data bus input/output control circuit '@ 12 via 22J
2g, as well as frequency detector 122 and phase detection H122L and PWMfA.
Iill 122m via 22m sc motor xrr
It is provided to automatic frequency control AiO and automatic phase control PC for driving with constant linear velocity CLv method.

In this case, the phase detector 1221 includes the crystal oscillator 1.
A system clock is supplied from a system clock generation circuit 122p which operates based on an oscillation signal from j2n.

Then, the input/output control 4 of the second postcard processing time wr111B
11 circuit 123a is passed through a V-drome detector JJJk) for error detection and correction or correction;
Error pointer control circuit 1i13a.

The correction circuit 123 (1) and the data output surface Wrl 13e are blanked and subjected to necessary error correction, date leave, error correction, etc., and digital-to-analog D/A conversion is performed.
The formula is derived in 26.

In this case, the external memory control circuit wt11131 cooperates with the data selection circuit 122J to select the data necessary for correction 11Fl! By controlling the built-in external memory 121, data necessary for correction is taken in through the input/output control circuit 123a.

In addition, the tie thinking control circuit 111361 front V
System clock generation circuit I Based on the system clock □ from B11p, error correction and correction and D/
It is designed to supply a tie-setting control signal necessary for A f conversion.

The muting (detection) control circuit 123h also controls the output from the error pointer control circuit 423C or the control signal given via the system controller 117 to perform error correction and start operation of the DAD Niu device. It is used to carry out predetermined muting control necessary for special termination, etc.

First, the D/A transformer 126 determines the analog signal δ.
The received audio signal is supplied to a speaker 130 via a low-pass filter 128 and an amplifier 129.

As is well known, the gFM modulation wheel described above is designed to convert equal bit data into 14 bit data.
f! j/i+, the maximum inversion interval is 11 bits, and the minimum inversion interval is 3 bits.

An embodiment of the present invention will be described in detail with reference to page 1 below.

FIG. 2 shows the configuration of a motor control device for a digital disc player according to the present invention.

That is, the optical pickup 11 is for generating signals recorded on the disk 12, and its output end is connected to the input end of the recording signal processing circuit Is. This recording signal processing circuit 13 is a reproduction processing system JJ8J shown in FIG.
/C, and extracts only the digital data signal component from the signal continuously output from the disk 11, and its output terminal is connected to the detection input terminal of the large rut reversal period detection circuit 14.

The maximum inversion period detection circuit 14 includes, for example, the first processing system 122.0 edge detector 122a, the synchronization signal detector zxxc, and the tie-building signal generation circuit 1xxt in FIG.
, the frequency detector 121 has various components such as a phase filter and an output device 1B21. This maximum inversion period detection (8) path 14 generates a reference signal 1g1'N! at the reference signal input terminal. The output end of r15 is connected. This one
1- The reference signal generation circuit 15 includes, for example, the crystal oscillator IJ2n and the system clock generation circuit 127 shown in FIG.
? It is composed of p, etc.

That is, the maximum inversion period detection circuit 14 detects the maximum inversion period of the digital gator signal provided from the recording signal processing circuit 13 using the reference signal provided from the reference signal generation circuit 15. The detected maximum inversion period is compared with a predetermined maximum inversion interval serving as a target value. The maximum inversion period detection circuit 14 outputs the detected polished rice as, for example, a digital comparison signal from an output section.

Note that the operation of detecting the maximum inversion period of the maximum inversion period detection (b) circuit 14 is performed for a predetermined period of time (the period between the rising edge and the falling edge of the output signal of the recording signal processing circuit 13). Based on the above, the count value of the counter is counted by a counter using a hand signal.Then, if the count value of this counter is larger than the value of the register for storing the maximum reversal period, the value of the register for storing the maximum reversal period is counted. 12- is stored in the register, which allows for the detection of the maximum inversion period.

Further, the maximum reversal period detected within a predetermined period can be made possible by, for example, setting the complement of the maximum reversal period, which is a target value, as an offset value in advance. In this case, the value stored in the maximum inversion period storage register directly serves as a comparison signal for the maximum inversion period detection circuit 14.

By the way, the output section of the maximum inversion period detection circuit 14 is as follows:
It is connected to the input section of the motor control circuit 16. This motor control circuit 16 includes, for example, the pwu transformer II in the m1 diagram.
1m and low-pass filters (r, PF), etc., and outputs a voltage signal corresponding to the comparison signal of the minimum reversal period detection circuit 14, and is used for (2) transfer movement of the disk 12. An output end is connected to a rotation control input end of the motor 110. Accordingly, the winding drive current of the motor 17 is controlled so that the rotational speed is controlled such that the maximum reversal period is approximately constant based on the comparison output of the maximum reversal period detection circuit 14. Become.

In other words, as above, VC4! The i4-based device controls the rotational speed of the motor 170 based on the maximum inversion period of the digital data signal read from the disk and given to it. Even if the synchronization signal is not excellent, the rotational speed of the motor 17 can be controlled more accurately than in the past.

Although the maximum inversion period of the digital data signal is detected in the above-mentioned method, it is clear that the motor can be controlled by detecting the minimum inversion period. In addition, if the synchronization signal of the digital data signal cannot be detected, the motor rotation speed is controlled by the device shown in Figure 2, and if the synchronization signal is detected and ignored, the motor rotation speed is switched to be controlled by the conventional method. It is also possible to configure a light motor control device.

In addition, various modifications and applications are not limited to the above embodiments, and are possible without departing from the gist of the present invention.

〔Effect of the invention〕

As detailed above, according to the present invention, it is possible to accurately control the rotational speed of the disk drive motor even if it is not possible to extract the synchronization signal of the digital data signal from the digital data signal that is successively output from the disk. A good motor control device for a digital disc player can be provided.

[Brief explanation of drawings]

FIG. 1 is a diagram schematically showing a digital disc player to which the present invention is applied, and FIG. 2 is a diagram showing the outline of a digital disc player to which the present invention is applied. ... Maximum inversion period detection circuit, 15...
・Reference signal generation AT path, 16...Motor control circuit, 1
7...Motor. Applicant's agent Patent attorney Takehiko Suzue 4

Claims (1)

[Claims] In a digital disc player for generating a digital data signal from a disc on which a digital data signal is recorded, a first means for detecting a maximum reversal interval or a minimum reversal interval of the read digital data signal; A second method for comparing the maximum reversal interval or the minimum reversal interval evaluated by the first means with a predetermined reference value.
and third means for controlling the rotational speed of the motor for rotating the disc based on the comparison signal obtained by the second means. Control device.