JPH02280542A - Connecting device for digital reproduction system - Google Patents

Abstract

PURPOSE:To surely send a reproduction data from other disk reproducing device by sending a digital data supplied externally via an optical cable to an optical cable automatically when a main power supply is interrupted. CONSTITUTION:When a main power supply circuit 37 is interrupted, since the output of a NAND circuit 29a is fixed to an H level regardless of a selection control signal SDIR in a selection circuit 30, a data SEXAUDA supplied externally via an optical cable 25 is switched forcedly so as to be led to an optical data transmission circuit 35. When the external data SEXAUDA is received through the optical cable 25, a voltage V+ at a noninverting input terminal + of a comparator 45 is a half of a backup voltage VBAK and higher than a reference voltage VR, then the output of the comparator 45 goes to an H level and a transistor(TR) Q1 is turned on. Thus, a driving current is supplied from the backup voltage VBAK to a light emitting diode 34 and the received data SEXAUDA is sent to an optical cable 36.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention relates to a digital playback system such as a compact disc player, and particularly relates to a digital playback system such as a compact disc player, etc. The present invention relates to an improvement in a connection device for optically transmitting reproduction data output from any one device to a common reproduction data processing device.

(Prior Art) As is well known, compact disc type digital audio discs have rapidly become popular and distributed in the market in recent years due to their characteristics such as small size, light weight, high speed random access, and high quality reproduction sound. This compact disc is turned into a library, and a jukebox-type disc playback device is used to play the disc.
Compact disc library playback systems have emerged to select and play any disc in a library.

FIG. 2 shows such a conventional compact disc library playback system. In other words, this system has multiple jukebox-shaped disc playback devices!
110, Ill, 112,...11
library stocker room 12 in which discs 110 and 111 are installed;

112, ..., a performance control room 14 in which a central control device 13 for controlling fins is installed, and a guest room 15
It is divided into.

Among these, each disc playback device 110, Ill.

112,..., lln each have 15
It is possible to accommodate 0 compact discs (not shown). In addition, these disc playback devices 110°11
1, 112, -----, lln have ID (Identifier) numbers k (-0, 1, 2
, -・-=, n) are attached. Furthermore, a disc playback device 110.

111, 112, ...... lln also has a disk number i (-
1,2°..., 150) are attached.

Here, the central control device 1f13 includes the operation keyboard 1
According to the input from 6, a disc playback device 110, 1 that accommodates a disc on which a target song is recorded.
11, 112, -11n, the disk number i and the song number on the command transfer line 1.
Send on 7. Then, the disc playback device 110 corresponding to the sent ID number k.

111, 112, . . . lln selects the disk with the specified disk number I and starts playing from the specified song number.

This designated disk playback device 110, 111.

112,..., l! The playback data output from 11 is sent to central control unit 13 via optical cable 1B.
optical transmission is carried out. The central control device 113 demodulates the received optical data, converts it into an analog audio signal and a subcode image signal, and outputs the signal to the speakers 19a to 1 in the guest room 15.
9d and television receivers 20a and 20b, where the desired music recorded on the designated disc is played back.

Then, the specified disk playback device 11G.

Ill, 112, . . . , lln is "
A status code indicating "normal execution" is sent onto the response transfer line 21. In this case, the unspecified disc playback devices G!110, 111, 112, -
-----, lln connects the optical cable 18 and the response transfer line 21 to the designated disk playback device 110 , 111 , 112 , which executes disk playback.
−=・, open for lIn.

Here, each disc playback device 110, ill,
112.

11n is a command transfer line 17. Optical cable 18
and a response transfer line 21, and are connected in a daisy chain. The central control device t13 includes a television camera 22. A laser video disc player 23, a video tape recorder 24, etc. are connected, and reproduction data output from these various reproduction devices can also be demodulated.

By the way, as shown in Figure 3, the digital audio data recorded on a compact disc includes subcode data, validity flag data, and audio channel number data (2 channels or 4 channels).
, Copy voting data.

Emphasis data (with or without pre-emphasis).

Parity information, preamble, etc. are attached and transmitted, and the transmission speed is approximately 3 Mb/sec.
It becomes.

For this reason, as shown in FIG. 2, there is a performance control room 14 in which the central control device 13 is installed, and a plurality of disc playback devices 11G, Ill, 112, = fi.
If the distance between the terminal and the terminal is approximately 100 to 200 meters, it is necessary to select and employ a cable with an extremely low probability of transmission errors.

Here, each of the disk playback devices 110, Ill
.

The daisy chain connecting portion between 112, . . . , lln is configured as shown in FIG.

However, FIG. 4 shows a daisy-chain connection part for digital audio data of the disc playback device 111, and other disc playback devices 110, 112
, . . . The daisy-chain connection portion of lln has the same configuration, so the explanation thereof will be omitted.

That is, the second disc reproducing device after the disc reproducing device 111. ......, the digital audio data obtained from lln is transmitted to the disc playback device 112.
is taken into the disc playback device 111 via the optical cable 25, and the photodiode 2B and the amplifier circuit 27
The optical data receiving circuit 28 is converted into electrical digital audio data SEXAUDA. This digital audio data SP, XAυDA is supplied to one input terminal of a selection circuit 30 consisting of NAND circuits 29a to 29d.

In addition, the other input terminal of this selection circuit 30 is connected to a PC obtained by playing the disc by the disc playback device 111 itself.
Digital audio data S AUDA obtained by passing M data S CDDA through a digital audio interface encoder 31 is supplied. The selection circuit 30 selectively outputs either the digital audio data S_EXAtlDA or the digital audio data S_AUDA in response to the selection control signal S_DIR.

This selection control signal S DIR becomes "H" level when the disk playback device 111 is designated by the central control unit 13, and at this time the selection circuit 30 selects the self-played digital audio data S At1DA from the first data transmission circuit. 35. In addition, the selection control signal S DIR is transmitted to the subsequent disk playback devices 112゜..., fi after the disk playback device WUt.
When n is specified, the level becomes °L", and at this time the selection circuit 30 selects the subsequent disc playback device 112...
.

Then, the digital audio data 9 S EXAIIDA * S AUDA outputted from the selection circuit 30 is
I; E, amplification circuit 32° resistor 33 and light emitting diode 3
The optical data is converted into optical data by the optical data transmission circuit 35 consisting of 4, and transmitted to the disc playback device 110 via the optical cable 3B.
supplied to

Here, power is supplied to the optical data receiving circuit 281 selection circuit 30 and the optical data transmitting circuit 35 from a main power supply circuit 37, respectively. Note that this main power supply circuit 37 also supplies power to other circuits (not shown) within the disc playback device 111. In this main power supply diagram IF137, external power supplied to the outlet 39 is turned on and off by the power relay 3B.

That is, the opening and closing of this power supply relay 38 is controlled by a power supply 0N10FF circuit 41 that is supplied with power from a backup auxiliary power supply circuit 40 that is always supplied with external power from an outlet 39, and the external power supply to the main power supply circuit 37 is controlled. The on/off is controlled. This power supply 0N1
The 0FF circuit 41 controls the power supply relay 38 using a signal S 0N10FF generated based on a command output from the central control unit 13 via the command transfer line 17.

Further, the digital audio data S ALIDA is generated by adding subcode data 5SuB and validity flag data s to 2-channel CM data S CDDA of 16 bits/channel obtained by playing the disc, by the digital audio interface encoder 31.
vp, emphasis data S EXPH, copy prohibited data 5 cpy, number of channels data SC)! It is generated by performing multiple breaks on the preamble data and the preamble data.

However, with the connection means of the conventional disc playback device as described above, it is not possible to, for example, cut off the main power of the disc playback device with ID number k (k<n) and replace the disc stored inside. When maintenance work is performed, the disk playback device 11 with ID numbers from +1 to n will have +
1. Even if the main power is turned on to the lln and one of them is playing a disc and sending digital audio data over the optical cable,
Since the optical data relay operation cannot be performed by the disk reproducing device fflllk at the D number, a problem arises in that digital audio data cannot be transmitted to the central control unit 13.

For this reason, conventionally, when performing maintenance work by cutting off the main power of any disc playback device, the optical data receiving circuit 281 selection circuit 30 and the optical data transmitting circuit 35 shown in FIG. A relay adapter with a similar configuration is prepared separately, and the disk playback device that is undergoing maintenance work is diverted to the relay adapter to transmit digital audio data, which is inconvenient to handle. There is also.

(Problem to be Solved by the Invention) As described above, in the conventional connection means for disc playback devices, if the main power of one of the plurality of disc playback devices connected in a daisy chain is cut off, the connection after that is interrupted. Since the output data from the disc playback device cannot be transmitted, there is a problem in that a separate relay adapter must be prepared when the main power supply is cut off, which is inconvenient to handle.

Therefore, this invention was made in consideration of the above circumstances, and it is possible to cut off the main power of any one of the multiple disc playback devices connected in a daisy chain without using a separate relay adapter or the like. An object of the present invention is to provide an extremely good connection device for a disc playback system that can reliably transmit playback data from another disc playback device.

[Structure J of the Invention (Means for Solving the Problems) A connecting device for a disc playback system according to the present invention includes a receiving means for receiving digital data transmitted via an optical cable and converting it into an electrical signal, and a receiving means for receiving digital data transmitted via an optical cable and converting the digital data into an electrical signal. A reproduction means for reproducing a recorded recording medium, a selection means for selectively deriving digital data obtained from the reproduction means and the reception means, and a selection means for converting the digital data derived by the selection means into optical data and connecting an optical cable. A plurality of digital playback devices each having a transmitting means for transmitting data through the digital playback device, a main power supply that can control main power to be supplied and cut off to the playback means, and an auxiliary power supply that can constantly supply auxiliary power for backup. , is intended for daisy chain connections.

and a selection control means for causing the selection means to select the digital data obtained from the reception means based on the output of the first detection means; means.

The selection means, the transmission means, the first detection means, and the selection control means are configured to be supplied with power by an auxiliary power source.

(Function) According to the above configuration, the auxiliary power supply supplies power to the receiver means 1 selection means, the transmission means, the detection means 1a1, and the selection control means, and when the main power supply is cut off, Since the selection means is automatically switched so that the digital data supplied from the outside is sent via the optical cable, daisy chain connection can be made without using a separate relay adapter etc. Even if the main power supply of one of the multiple disc playback devices is cut off due to maintenance work, etc., playback data from other disc playback devices can be reliably transmitted, making handling convenient. .

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings. In FIG. 1, the same parts as in FIG. 4 are designated by the same reference numerals. That is, the digital audio data SEX output from the optical data receiving circuit 28
^vDA is supplied to a buffer circuit 43 consisting of a capacitor CI, resistors R1 to R3, and an inverter 42, and is converted into digital data whose zero-peak is set to the backup voltage V BAK level output from the auxiliary power supply circuit 40.

The digital data output from the buffer circuit 43 is converted into a DC voltage by a low-pass filter 44 made up of a resistor R4 and a capacitor C2, and then supplied to a non-inverting input terminal of a comparator circuit 45. In addition, this comparison circuit 45
A main power supply cutoff signal S POVER indicating whether or not the main power supply circuit 37 is cut off is supplied to the non-inverting input terminal of the main power supply circuit 37 via a diode Di.

Furthermore, the backup voltage V BAK output from the auxiliary power supply circuit 40 is connected to the inverting input terminal of the comparison circuit 45.
A reference voltage VR generated by dividing the voltage by resistors R5 and Re is applied. This reference voltage VR is VR-R5-VBAK/(R5+R8)-(1/3), assuming that the resistance value of resistor RB is twice the resistance value of resistor R5.
) -VBAK.

The output SCNTP of the comparison circuit 45 is NP
Nm is supplied to the base of a transistor Ql. The emitter of this transistor Q1 is connected to the optical data transmitting circuit 3.
The light emitting diode 34 is connected to the light emitting diode 34 through a resistor 33 that constitutes the light emitting diode 5. Further, the backup voltage VBA is applied to the collector of this transistor Ql.

On the other hand, the selection circuit 30 includes NAND circuits 29a to 29d.
In addition to the inverter 46. A diode D2 and a pull-down resistor R7 are attached. And Nando Enclosure 29
A selection control signal SDIR is supplied to one input terminal of the NAND circuit 29a, and a main power cutoff signal SDIR is supplied to the other input terminal of the NAND circuit 29a via a diode D2 and a pull-down resistor R7.
POMIl'R is supplied.

The operation of the above configuration will be described below. First, when the main power circuit 37 is not cut off,
The main power cutoff signal S POVER is at the "H" level, and the selection circuit 30 plays back the disc internally and the data S EXAUDA supplied from the outside via the optical cable 25 based on the selection control signal S D4R. The optical data transmission image W135 operates to selectively derive either one of the data SAUDA obtained by the optical data transmission image W135.

At this time, the main power cutoff signal SPOvI'R of 1H''a level, which is approximately equal to the backup voltage VBA, is forcibly supplied to the non-inverting input terminal of the comparator circuit 45 through the diode DI. The voltage V+ at the input terminal is set higher than the reference voltage VR at the inverting input terminal.

Therefore, the output of the comparator circuit 45 is at the "H° level" and turns on the transistor Ql.
Optical data can now be transmitted from the optical data transmitting circuit 35.

On the other hand, when the main power supply circuit 37 is cut off, the main power supply cutoff signal SPOVER is at the 'L' level, and the selection circuit 30 causes the output of the NAND circuit 29a to be at the 'H' level regardless of the selection control signal SDIH. Because it is fixed, data SEX supplied from the outside via the optical cable 25
AUDA is forcibly switched to be guided to the optical data transmission circuit 35.

Here, the digital audio data is digitally modulated by a pi-phase method in which the DC component is zero, and when data S EXAUDA is received from the outside via the optical cable 25, the voltage at the non-inverting input terminal of the comparison circuit 45 is V
+ is 1/2 of the backup voltage V BAR and is higher than the reference voltage VR, so the output of the comparator circuit 45 becomes "H° level" and the transistor Ql is turned on. Therefore, the light emitting diode 34 , a drive current is supplied from the backup voltage V BAK, and the received data S EXAUDA is sent to the optical cable 36 .

In addition, data S BX is transmitted from the outside via the optical cable 25.
When JklJDA is not received, the optical data receiving circuit 29 outputs °H level. When the output of the optical data receiving circuit 29 continues to be fixed at the "H" level, the input level of the inverter 42 is biased above its threshold level by the resistors R2 and R3, so that the output of the buffer circuit 43 becomes "H". It's L level. In this case, the output of the comparison circuit 45 also becomes "L° level,"
Since the transistor Ql is turned off, the drive current to the light emitting diode 34 is cut off, and data is no longer sent to the optical cable 3B.

Therefore, according to the configuration of the above embodiment, the optical data receiving circuit 281 selection circuit 3. O2 optical data transmission circuit 3
5. The buffer circuit 43, comparison circuit 45, etc. are driven by the backup voltage VBAK output from the auxiliary power supply circuit 40, and when the main power supply is cut off, data S supplied from the outside via the optical cable 25 is automatically driven. E
Since the selection circuit 30 is switched so that the XAllDA is guided to the optical cable 3B, the main power supply of one of the multiple disc playback devices connected in the daisy chain can be switched, for example, without using a separate relay adapter or the like. Even if the system is shut down for maintenance work or the like, playback data from other disk playback devices can be reliably transmitted, making handling convenient.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As detailed above, according to the present invention, the main power of any one of a plurality of disc playback devices connected in a daisy chain can be shut off without using a separate relay adapter or the like. Also, it is possible to provide an extremely good connection device for a disc playback system that can reliably transmit playback data from other disc playback devices.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of a connection device for a disc playback system according to the present invention, FIG. 2 is a block diagram showing a compact disc library playback system, and FIG. 3 is a digital audio data format. FIG. 4 is a block circuit configuration diagram showing a conventional connection means. 110-lln...Disc playback device, 12...Library stocker room, 13...Central control unit,
14... Performance control room, 15... Guest room, 16... Operation keyboard, 17... Command transfer line, 1
8... Optical cable, 19a - 19d = speaker,
20a, 20b--television receiver, 21
...Response transfer line, 22... Television camera, 23... Laser video disk player,
24... Video tape recorder, 25... Optical cable, 2B... Photodiode, 27... Amplifying circuit, 28... Optical data receiving circuit, 29a to 29d...
NAND circuit, 30...Selection circuit, 3...Digital audio interface encoder, 32...Amplification circuit, 33...Resistor, 34...Light emitting diode, 3
5... Optical data transmission circuit, 3B... Optical cable, 3
7... Main power circuit, 38... Power relay, 39...
Outlet, 40... Auxiliary power circuit, 41... Power supply 0N10FF circuit, 42... Inverter, 43...
Buffer circuit, 44...Low pass filter, 45...
・Comparison circuit, 4-inverter.

Claims (2)

[Claims] (1) A receiving means for receiving digital data transmitted via an optical cable and converting it into an electrical signal, a reproducing means for reproducing a recording medium on which digital data is recorded, and a digital signal obtained from the reproducing means and the receiving means. A selection means for selectively deriving data, a transmission means for converting the digital data derived by the selection means into optical data and transmitting it via an optical cable, and supplying and shutting off main power to the reproduction means. In a connecting device for a digital playback system in which a plurality of digital playback devices each having a controllable main power source and an auxiliary power source capable of constantly supplying auxiliary power for backup are connected in a daisy chain, the main power source is cut off. comprising a first detection means for detecting, and a selection control means for causing the selection means to select digital data obtained from the reception means based on the output of the first detection means, the reception means, the selection means, A connecting device for a digital playback system, characterized in that the auxiliary power supply supplies power to the transmitting means, the first detecting means, and the selection control means. (2) a second detection means for detecting the presence or absence of digital data received by the reception means when the main power supply is cut off;
2. The connecting device for a digital playback system according to claim 1, further comprising a cutoff means for cutting off the supply of said auxiliary power to said transmitting means based on the output of said second detection means.