JPH07201128A - Optical disc player - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] We propose an optical disk reproducing device that reduces the financial burden on the user and has a simple configuration. [Structure] An external digital audio signal is a signal processing circuit 22.
When supplied to A, the operation of the servo control circuit is stopped, and the first and second clocks are generated by the signal processing circuit 22A based on the supplied external digital audio signal to the phase comparison circuit 23. A selection means for supplying the external digital audio signal is provided to the signal processing circuit 22.
When it is supplied to A, the operation of the servo control circuit is stopped by the selecting means, and the voltage control type crystal oscillation circuit 25 is voltage controlled based on the output from the phase comparison circuit 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reproducing apparatus for an optical disc on which a digital audio signal is recorded.

[0002]

2. Description of the Related Art Currently, commercially available optical video discs (hereinafter referred to as LV discs) basically have the structure shown in FIG.
The FM video signal S _V as shown in FIG. 2 is recorded in the high frequency range, and the FM of the two channels is below the FM video signal S _V.
The audio signals S _A and S _B are recorded. In the case of a long-time LV disc that is rotated at a constant linear velocity, the above-mentioned 3
In addition to the signals S _V , S _A and S _B , as shown in FIG.
The digital audio signal S is provided in the low range further below the M audio signal S _A.
D is recorded.

This digital audio signal S _D is an optical digital audio disk (hereinafter LA
It is recorded according to the same format as that of a disc) and its reproduction requires an LV disc player compatible with digital audio signals and a dedicated adapter as shown in FIG.

In FIG. 4, reference numeral 10 denotes an LV disc player, in which a reproduction signal from the optical pickup 11 is
It is commonly supplied to the video demodulator 13 and the low-pass filter 14 via the high-frequency amplifier 12. The FM video signal S _V is demodulated by the video demodulator 13 to obtain a video signal, and the digital audio signal S _D is acquired by the low-pass filter 14.
Are separated.

Reference numeral 20 is an adapter for the digital audio signal S _D , and the digital audio signal S _D separated in the LV disc player 10 is input from an input terminal 21 to an EFM demodulation / signal processing circuit (hereinafter simply referred to as a signal processing circuit). ) 22
Is supplied to. The output terminal 22r of the signal processing circuit 22
And 22w lead frame clock (RF
CK) and the write frame clock (WFCK) are supplied to the phase comparison circuit 23, and the output of the phase comparison circuit 23 is passed through the low pass filter 24 to the voltage controlled crystal oscillation circuit (VC).
XO) 25 variable capacitance diode (not shown). The output of the VCXO 25 has a frequency of 8.46.
72 MHz, which is supplied to the signal processing circuit 22 as a master clock and is phase locked loop (PLL).
Is configured. A 16-bit digital audio signal is derived from the signal processing circuit 22 to the output terminal 26 and converted into an analog audio signal by a DA converter (not shown).

The signal processing circuit 22 and the phase comparison circuit 23 of the adapter 20 are mounted on the same large scale integrated circuit (LSI), and the inverting amplifier (not shown) constituting the VCXO 25 is also mounted on the same LSI. .

The above-mentioned WFCK is a synchronizing signal for constant linear velocity control, and is a reproduction signal (Eight to Fourteen Modul) supplied to the signal processing circuit 22.
ation signal) and its frequency is 7.35 kHz. Also, RFCK is VCXO25
Is obtained by dividing the output of the signal processing circuit 22 to 7.35 kHz in the signal processing circuit 22. As described above, the VCXO 25 is a component of the PLL, and the LV disc player 10
From the reproduction EFM signal supplied to the signal processing circuit 22 from the slave.

[0008]

As described above, since the digital audio signal S _V of the LV disc is recorded in the same format as the LA disc, most of the LSI for reproducing the LA disc is included in the reproducing adapter. Used as is.

However, since this LSI is quite expensive, the LV disc digital audio adapter is also expensive. In addition, when a user purchases an LA disc player, a substantial double investment is forced, which increases the economic burden on the user.

In order to solve the above problems, it may be considered to add a digital audio signal reproducing function of an LV disc to the LA disc player.

An example of the structure of such an LA disc player is shown in FIG. In FIG. 5, parts corresponding to those in FIG. 4 are designated by the same reference numerals, and redundant description will be omitted.

In the LA disc player for LV digital audio shown in FIG. 5, an input signal changeover switch 27 is inserted between the input terminal 21 and the signal processing circuit 22, and VC
A switch 28 is provided on the input side of the XO 25. The reproduction output of the optical pickup 31 of the LA disc player is supplied to the high frequency amplifier 32 at one fixed contact 27a of the switch 27.
Via the input terminal 2
Connected to 1. One fixed contact 28a of the switch 28
Is grounded, the other fixed contact 28v is unconnected, the movable contact 28c is directly connected to the input side of the VCXO 25, and the output of the low-pass filter 24 or the ground potential is switched and supplied. The output of the second phase comparison circuit 33, to which RFCK and WFCK are supplied in common with the phase comparison circuit 23, passes through the low-pass filter 34 and the drive amplifier 35, and the spindle motor 3
6 is supplied. When reproducing the digital audio signal of the LV disc, the switches 27 and 28 are set to the connection state shown in the figure, and operate exactly as in the case of the conventional adapter described above. In this case, the spindle motor 36 does not need to rotate.

In the case of LA disc reproduction, both switches 27
And 28 are connected in the opposite state to that shown in the drawing, and VCXO2
The ground potential is supplied to 5, the output thereof, that is, the master clock is fixed, and the second phase comparison circuit 33 uses RFCK as a reference to perform the phase servo control of the spindle motor 36.

In the LA disc player for LV digital audio shown in FIG. 5, the signal processing circuit 22 outputs RFCK and W.
There are two phase comparison circuits 23 and 33 supplied with FCK. However, in the current LA disk reproducing LSI, only one such phase comparison circuit is mounted for servo control of the spindle motor 36, so a separate phase comparison circuit must be provided, and the circuit configuration is The problem of complexity arises.

In view of the above point, the present invention reduces the economical burden on the user in an optical disc reproducing apparatus capable of reproducing both a digital voice signal obtained from an optical disc by an optical pickup and an external digital voice signal. , Is to propose a simple configuration.

[0016]

According to the present invention, a first clock generated by a signal processing circuit 22A based on a digital audio signal reproduced by an optical pickup from an optical disk and a voltage controlled crystal oscillation circuit 25 are used. A phase comparison circuit 23 to which a second clock formed by dividing the output master clock by the signal processing circuit 22A is supplied, and a motor 36 that drives an optical disk based on the output of the phase comparison circuit 23. In the optical disc reproducing apparatus including a servo control circuit for servo-controlling the servo control circuit, when the external digital audio signal is supplied to the signal processing circuit 22A, the operation of the servo control circuit is stopped and The signal processing circuit 22A generates the first and second clocks based on the digital audio signal, and outputs the first and second clocks. A selecting means for supplying to the comparison circuit 23 is provided, and when the external digital audio signal is supplied to the signal processing circuit 22A, the selecting means stops the operation of the servo control circuit, and a voltage is output based on the output from the phase comparison circuit 23. This is an optical disk reproducing device configured to control the voltage of the control type crystal oscillating circuit 25.

[0017]

According to this structure, it is not necessary to provide a phase comparison circuit when reproducing the external digital audio signal, and the circuit structure is simplified.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the optical disc reproducing apparatus according to the present invention will be described below with reference to FIGS.

The structure of one embodiment of the present invention is shown in FIG. In FIG. 1, parts corresponding to those in FIGS. 4 and 5 are designated by the same reference numerals, and redundant description will be omitted. In FIG. 1, 4
0 is the system controller of the LA disc player,
It includes a microcomputer, is connected to an operation key K, and is connected to an interface 42 mounted on an LSI 41 for LA disc reproduction together with a signal processing circuit 22A and a phase comparison circuit 23, and its output is a constant linear velocity control circuit. 43. Signal processing circuit 22A to EF
The frame synchronization detection signal of the M signal is supplied to the system controller 40 via the interface 41.

The output of the phase comparison circuit 23 passes through one output terminal 43p of the constant linear velocity control circuit 43 and a changeover switch 44.
Of the reference voltage E _REF from the other output terminal 43r is supplied to the common contact 45c of the changeover switch 45. Each fixed contact 4 of switch 44
4v and 44a are connected to the input sides of the active low-pass filters 24A and 34A, respectively, and the fixed contacts 45v and 45a of the switch 45 are connected to both the active low-pass filters 24A.
And 34A on the control input side, respectively. Both switches 44 and 45 are controlled by system controller 40 along with switches 27 and 28. The specific configuration of both active low-pass filters 24A and 34A is shown in FIGS. 2A and 2B.

The operation of this embodiment is as follows. LA
When playing a disc, when the user operates the key K, the switches 27, 28, 44 and 45 are controlled by the system controller 40 to be switched to the connection state opposite to that shown in the drawing. The high frequency signal from the optical pickup 31 is supplied to the signal processing circuit 22A, and a fixed master clock is supplied from the VCXO 25 to which the ground potential is input. One output terminal 43 of the constant linear velocity control circuit 43
The output of the phase control circuit 23 is supplied from p to the active low-pass filter 34A via the switch 44, and the reference voltage E _REF is supplied from the other output terminal 43r to the active low-pass filter 34A.
It is supplied to A as a gate voltage, and the phase servo control of the spindle motor 36 is performed as described above.

When reproducing the digital audio signal of the LV disc, when the user operates the key K, each switch 2
7, 28, 44 and 45 are controlled by the system controller 40 to be switched to the connection state shown. A high frequency signal from the optical pickup 11 of the LV disc player 10 is supplied to the signal processing circuit 22A. From one output terminal 43p of the constant linear velocity control circuit 43 to the phase control circuit 23
Is supplied to the active low-pass filter 24A via the switch 44, and the reference voltage E _REF is supplied from the other output terminal 43r to the active low-pass filter 24A as a gate voltage. As described above, the PLL including the VCXO 25 is supplied. And the output of the VCXO25, that is, the master clock is L
Slave synchronization with the WFCK of the reproduction EFM signal of the V disc.

In this case, the active low-pass filter 34A
Is not supplied with the reference voltage as the gate voltage,
Inactive state. Therefore, the drive signal is not supplied to the amplifier 35, and the spindle motor 36 is stopped.

When a standard type LV disc in which an audio signal is analog recorded is reproduced, the EFM signal is not reproduced and the lack of the EFM signal is detected by the system controller 40.
Is detected, the muting signal Sm is output, and the audio signal transmission system (not shown) is cut off.

As described above, in this embodiment, the phase comparison circuit for spindle servo mounted on the LA disk reproducing LSI is used for the VCXO phase servo when reproducing the digital audio signal of the LV disk. Therefore, there is no need to provide a phase comparison circuit outside, and the circuit configuration becomes simple.

It should be noted that the two active low-pass filters 24A and 34A may be combined into one to have a simpler configuration in the drawing. However, as can be easily understood from FIG. 2, since various characteristics such as a time constant required for each active filter are considerably different, one active filter is used at the time of reproducing the LA disk and at the time of reproducing the digital audio signal of the LV disk. If the low-pass filters are switched and used, the configuration actually becomes rather complicated.

[0027]

As described above in detail, according to the present invention, in the optical disc reproducing apparatus capable of reproducing both the digital audio signal obtained from the optical disk by the optical pickup and the external digital audio signal, The phase comparison circuit for servo control of the motor that drives the disk is controlled to control the voltage of the voltage-controlled crystal oscillation circuit that transmits the master clock when an external digital audio signal is supplied to the signal processing circuit. Since it is also used to generate a signal, there is no need to provide a dedicated phase comparator circuit for generating the control signal externally, reducing the financial burden on the user and obtaining a simple configuration. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of an optical disc reproducing apparatus according to the present invention.

FIG. 2 is a connection diagram showing a specific configuration of a waist of the embodiment shown in FIG.

FIG. 3 is a spectrum diagram for explaining the present invention.

FIG. 4 is a block diagram showing a configuration example of a conventional digital audio signal adapter of an optical video disc.

FIG. 5 is a block diagram showing an example of the configuration of an optical disc reproducing apparatus used for explaining the present invention.

[Explanation of symbols]

 22A EFM demodulation / signal processing circuit 23 Phase comparison circuit 24A, 34A Active low-pass filter 25 Crystal oscillation circuit 31 Optical pickup 36 Spindle motor

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[Procedure amendment]

[Submission date] November 21, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

[0016]

SUMMARY OF THE INVENTION The present invention is directed to a signal based on a digital audio signal reproduced by an optical pickup from an optical disk and a crystal oscillation circuit for generating a master clock.
The phase comparison circuit 23 to which the frequency-divided output of the path 25 is supplied, and the servo control circuit for servo-controlling the motor 36 for driving the optical disk by the output of the phase comparison circuit 23 are provided.
In the optical disc reproducing device, the phase comparison circuit 23
, The servo control circuit and the crystal oscillator circuit
25, a switching circuit 44 for selectively switching the output supply
When a signal based on an external digital audio signal is supplied to the phase comparison circuit 23, the phase comparison circuit 23
The output of is supplied to the crystal oscillation circuit 25 by the switching circuit 44.
Then, the optical disk reproducing apparatus is characterized in that the crystal oscillator circuit 25 is voltage-controlled based on this output .

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

[0017]

According to the present invention, an external digital voice signal is transmitted.
When a signal based on the signal is supplied to the phase comparison circuit 23
Outputs the output from the phase comparison circuit 23 to the switching circuit 44.
Supply to the crystal oscillator circuit 25, and based on this output, the crystal
The voltage of the oscillator circuit 25 is controlled.

Claims (1)

[Claims] 1. A first clock generated by a signal processing circuit based on a digital audio signal reproduced from an optical disk by an optical pickup, and a master clock output from a voltage control type crystal oscillating circuit. And a servo control circuit for servo-controlling the motor for driving the optical disk based on the output of the phase comparison circuit. In the optical disc reproducing apparatus, when an external digital audio signal is supplied to the signal processing circuit, the operation of the servo control circuit is stopped, and the signal processing circuit is based on the supplied external digital audio signal. Selection means for generating the first and second clocks and supplying them to the phase comparison circuit When the external digital audio signal is being supplied to the signal processing circuit, the operation of the servo control circuit is stopped by the selecting means, and the voltage control type crystal oscillation circuit is operated based on the output from the phase comparison circuit. An optical disk reproducing device that is controlled by voltage.