JPS593749A - Digital audio disk player - Google Patents

Abstract

PURPOSE:To obtain speedily a prescribed speed, by dividing the frequency of a playback signal from a pickup and obtaining a sharp peak, performing F-V conversion and performing a rough adjustment of the speed of a motor, and controlling the playback signal precisely. CONSTITUTION:The playback signal A is frequency-divided by a frequency dividing circuit to obtain a signal B, which is converted by an F-V converting circuit 2 to obtain a signal C. The signal A has a sharp peak as compared with the signal A. The signal C is amplified by an amplifier 5, whose output is inputted as a signal D to an adder 10 through the 1st level adjusting circuit 6; and the spindle motor 12 is adjusted roughly and speedily through a motor driving circuit 11 within the 10% range of its prescribed speed. The signal A, on the other hand, is phase-locked by a bit clock generating circuit 7 to generate a bit clock signal E synchronizing with information bits, and the signal E is compared by a phase comparator 8 with a reference clock F; and a signal H is added by an adding circuit 10 through the 2nd level adjusting circuit 9 to drive the motor by the motor driving circuit 11, making performing the rough adjustment. Consequently, the motor attains to the target revolving speed speedily in starting and mode transition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital audio disc player, and more particularly to a rotation control circuit for a spindle motor provided to rotate a disc at a constant linear velocity.

Digital audio dinuku players play back digitized audio signals and synchronization signals that are optically arranged in high density at a constant linear velocity, and are excellent at providing high-fidelity playback signals. It has several features. In this case, the most important thing in performing high-fidelity playback is to control the rotation of the spindle motor according to the pink-up position so that the rotation of the disk during playback accurately maintains a constant linear velocity z5. It is.

Here, the rotation control of the Nubin 1 motor is performed by two systems: a coarse adjustment system and a fine adjustment system, and the coarse adjustment system is controlled using a signal obtained by F-V converting the Nuvector of the reproduced signal. This allows coarse adjustment to within ±10% of the reference rotation, and the fine adjustment system uses the phase comparison output between the bit clock generated in synchronization with the data included in the reproduced signal and the crystal-accurate reference clock. In terms of control, the machining standard rotation is finely adjusted to within ±1%. The control signals for the coarse adjustment system and the fine adjustment system thus generated are added together and then supplied to the motor drive circuit to control the spindle motor.

In this case, in a digital audio disc player, the difference in the rotational speed of the spindle motor when reproducing the inner circumference of the disc and when reproducing the outer circumference is more than double.

Along with this, the range of bacteriostatic control has become extremely wide.

However, in the spindle motor rotation control circuit having the above-described configuration, the bit clock generating circuit with the phase lock Clousot configuration that generates the bit clock can only be synchronized with respect to the paired signal during normal rotation. For this reason, when starting the motor, it is necessary to quickly adjust the rotation of the spindle motor to within ±10% of the specified value and accurately generate the bit clock used in the fine adjustment system. In this case, the control characteristics of the coarse adjustment system using a signal obtained by F-V conversion of the spectrum of the reproduced signal become loose, resulting in a response delay, and the system becomes extremely vulnerable to external disturbances. .

Therefore, an object of the present invention is to quickly control the rotation of the spindle motor to a range in which the pictoclock generation circuit used in the fine adjustment system is synchronously driven when starting the spindle motor, and to obtain stable operation even in the face of external disturbances. Our objective is to provide a complete digital fist audio disc player with rotation control circuit.

In order to achieve such an object, the digital audio disc player according to the present invention has a rotation control circuit composed of a coarse adjustment system and a fine adjustment system. By performing rotation control and Dragon I using signals, quick and stable rotation control is achieved by utilizing the specificity of the frequency spectrum of the reproduced signal □
□. The following describes the present invention using drawings.
A digital self-audio disc player will be explained in detail.

FIG. 1 is a circuit diagram showing an embodiment of a digital audio disc player according to the present invention, and in particular an embodiment of a rotation control circuit. In the figure, reference numeral 1 denotes a frequency dividing circuit that divides the frequency of the reproduced signal A, and in this embodiment, a frequency dividing circuit that divides the frequency of the input signal by three is used. This is a frequency/voltage conversion circuit that generates an output obtained by converting the spectrum of data self-injected to the signal B supplied from the 3-digit frequency divider circuit 1, and is triggered by the input signal and has a negative polarity of, for example, 0.25 μs. /J'Lunu ThR's monomaru Senno Ibrator circuit 3 and monomulti/? A low-panel filter 4 removes ripples from the negative output of the ibrator circuit 3 and converts it into direct current. 5 An amplifier circuit that amplifies the output signal 0 of the frequency/voltage conversion circuit 2, 6 a first adjustment circuit that adjusts the level of the output signal of the amplifier circuit 5 and generates a coarse adjustment signal, and 7 a reproduction signal. A phase lock loop (PLL) that uses a human input as input and generates a bit clock E synchronized with the data included in this reproduced signal.
) A pit clock generation circuit 8 is a reproduced signal generated from the pit clock generation circuit 7. The phase of a bit clock signal E synchronized with human data is compared with a reference clock F supplied from a crystal oscillation circuit (not shown). The phase comparator circuit generates four output signals G corresponding to the phase difference. Output signal G of 9-digit phase comparison circuit 8
e A second level adjustment circuit that adjusts the level in relation to the level of the output signal generated from the second level adjustment circuit 6; Addition circuit for adding output signal H, 11
This is a motor drive circuit that rotates the spindle motor 12 at a speed corresponding to the output signal I of the adder circuit 10.

In the motor rotation control circuit configured as described above, when a reproduction signal A is supplied from a pickup (not shown), the reproduction signal A is frequency-divided by three in a frequency dividing circuit 1 and outputted as an output signal B. be done. Then, in the frequency/voltage conversion circuit 2, the spectrum of the data contained in this frequency-divided output signal B is subjected to F-Vi conversion to produce an output signal 0.
is generated as. In this case, the reproduced signal is a signal expressed by the non-zero return method (NR, Z-I), and this signal includes, for example, an information signal expressed within the range of 3 to 11 bits and an 11-bit @0''. Since it is a signal with a specificity consisting of a series of synchronization signals, the spectrum of this reproduced signal A has a peak at about 480 kHz, as shown in Figure 2 (, 1), and is relatively It has a gentle characteristic.On the other hand, the reproduced signal A'fc2
The frequency-divided signal has a peak when measured as a ctrum, and this peak portion has a characteristic that is slightly emphasized. Furthermore, when we measure the spectrum of the signal obtained by dividing the input signal A by 4, we find that it is about 12Q as shown in Figure 2 (c).
It has a steep characteristic with a peak in the KHz region. In this way, it has been found that as the division ratio for the input signal A increases, the peak portion of the spectrum characteristics becomes steeper. In the V-line part of this spectrum characteristic, even if the content of the reproduced signal changes, only a slight variation within 5X occurs, and tX can be considered to be constant. Therefore, in the above embodiment, since the frequency divider circuit 1 has a frequency divider configuration of 4, the output signal B is K 1 as described above.
This means that it has a spectrum characteristic with a steep peak around 20 KHz. The frequency-divided output signal B having such spectral characteristics is processed by the frequency/voltage conversion circuit 2 into F-
Vf conversion is performed. In this case, since the F-V conversion characteristic of the frequency/voltage conversion circuit 2 has the characteristic shown in FIG. The output has a figure-8 characteristic with a peak when the frequency-divided signal B is supplied. In other words, the mono multivibrator circuit 3 is triggered by the output signal B of the two frequency/voltage converter circuits and the frequency divider circuit 1, and the monomultivibrator circuit 3 is triggered by, for example, 0.
A negative ξ run of 25 μS is generated. And this mono multivibrator circuit 3. By removing ripples from the output signal O in the rotor ξ filter 4, a DC 4 output signal O having figure-8 characteristics with respect to the rotation of the disk is generated. Therefore, this output signal 0 is sent out as an output signal via the amplifier circuit 5 and the second level adjustment circuit 6, and this output signal Dk is output from the adder circuit 1.
0 to the motor drive circuit 11, an automatic frequency control circuit is configured and the rotation of the spindle motor 12 is controlled so that the peak of the spectrum of the reproduced signal A becomes a predetermined DC voltage. Therefore, by adjusting the first rubel adjustment circuit 6 to obtain normal rotation, the condition of constant linear velocity can be greatly improved (even if it deviates) when starting the spindle motor 12 or during fast forwarding during pink-up. ,
Corresponding to the output signal of the frequency/voltage conversion circuit 2, it is possible to quickly and roughly adjust the rotational speed within a range of 10% of the specified rotational speed. Then, by frequency-dividing the reproduced signal Alt, it is converted into a signal having a steep peak spectrum characteristic, and the frequency
Since the output signal is supplied to the voltage conversion circuit 2, the 8-curve characteristic of the output signal is steep, and rough adjustment of the lattice spindle motor 12 can be performed more quickly, and it is stable against disturbances.

In this way, when the rough adjustment of the spindle motor 12 is quickly performed and its rotation is set within the specified 10% range, the phase locked loop (PLL) of the bit clock generation circuit 7 that inputs the reproduced signal AI is locked. do,
A bit clock signal E synchronized with the information bits included in the reproduced signal A is generated. Then, the phase difference between this pit clock signal E and the crystal level reference signal F supplied from the oscillation circuit (not shown) is determined in the phase comparator circuit 8, and a level output corresponding to this phase difference is obtained. A signal G is generated. This output signal G is level-adjusted in relation to the coarse adjustment signal gK generated from the second and fourth level adjustment circuit 6 in the second level adjustment circuit 9, and is output as a fine adjustment signal H. Ru. The fine adjustment signal H is added to the coarse adjustment signal in the adder circuit 10 and then supplied to the motor drive circuit 11, whereby the rotation of the spindle motor 12 is matched to a specified value and the linear velocity is always constant. is rotated accurately as

In the above embodiment, the case where the frequency dividing value of the frequency dividing circuit 1 was set to 3 was explained, but this frequency dividing ratio is not limited in any way, and as the frequency dividing value increases, the spectrum changes. The peak of the characteristic becomes steeper, and faster and more stable rotation control can be performed.

As explained above, the digital audio disc player according to the present invention converts the frequency and voltage of the spectrum of the playback signal supplied from the pickup to obtain the rough adjustment signal for the spindle motor, and divides the playback signal to convert the frequency. By supplying the voltage to the church voltage conversion circuit, the peak of the spectrum is made steeper.

Therefore, when the linear velocity deviates significantly from the specified value, such as when starting up the spindle motor or during rapid feed of the pickup, the rotation of the spindle motor can be quickly and coarsely adjusted to bring it into the sideways range of the fine adjustment system. It can be adjusted.

In addition, since the reproduced signal is frequency-divided to make the peak of the spectrum characteristic steeper and then supplied to the frequency/voltage conversion circuit to obtain the coarse adjustment signal for the spindle motor, the coarse V4 adjustment signal for linear velocity deviation is It has various excellent effects such as rapid changes and greatly improved stability against disturbances.

[Brief Description of the Drawings] Fig. 1 is a circuit diagram showing an embodiment of a rotation control circuit of a spindle motor used in a digital audio disc player according to the present invention, and Fig. 2 (a) to (C) show playback signals. Fig. 3 is a diagram showing the spectrum characteristics of the signal frequency-divided by changing the frequency division ratio of 1&:, and Fig. 3 is an F-■ characteristic diagram of the frequency/voltage conversion circuit shown in Fig. 1. 1... Frequency dividing circuit, 2... Frequency/voltage conversion circuit, 3
・・・Monomulti-no-ibrator circuit, 4...tlf
f −/ξ filter, 5... amplifier circuit, 6, 9.
...1st and second rail adjustment circuits, 7.. Bit clock generation circuits, 8.. Phase comparison circuits, 10.. Addition circuits, 11.. Motor control circuits, 12.. Spindle motors. Figure 2■ 319- Figure 3■ (Hz to FOO

Claims (1)

[Claims] A voltage signal corresponding to the frequency of the reproduction signal supplied from the pickup is generated, and based on this voltage signal, output as a coarse adjustment signal for coarsely adjusting the rotation of a spindle motor for rotating the disk. frequency/voltage conversion circuit,
In a digital audio disc player equipped with a circuit that controls the rotation of the Touki spindle motor using the coarse adjustment signal, the rotation is controlled by increasing the change in the coarse adjustment signal in response to a change in the level of the playback signal. In order to quickly and coarsely adjust the rotational deviation of the spindle motor, a circuit divides the frequency of the reproduced signal so that the frequency spectrum characteristic of the reproduced signal has a steep peak, and supplies the frequency-divided signal to the frequency/voltage conversion circuit. A digital-audio disc player 1 characterized by being provided with a circuit.