JPH1021650A - Digital output circuit for reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the adverse influence of the digital output of a digital output circuit on the other component or external equipment when the output circuit outputs reproduced signals in the form of analog signals by interrupting the digital output by an interrupting means. SOLUTION: A microcomputer 2 of a CD unit 1 controls a switch circuit 7 so that the circuit 7 can be turned on when a CD reproducing mechanism 3 which can reproduce a plurality of disks outputs reproduced signals in the form of digital signals through a digital output terminal 8 and optical cable 14. When the mechanism 3 outputs reproduced signals in the form of analog signals through an analog output terminal 9, the microcomputer 2 controls the switch circuit 7 so that the circuit 7 can be turned off. Therefore, the digital output of the mechanism 3 is interrupted by means of the switch circuit 7 and the adverse influence of the digital output on a tuner section 4 or external television receiver can be reduced. In addition, the unnecessary interference to an analog output line can also be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a digital output circuit in a disc player.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 2, there is a vehicle-mounted system in which a CD unit 1 and a navigation unit 10 are combined. The CD unit 1 includes a microcomputer 2 for controlling the entire operation, a CD disk on which an audio signal is recorded, and a CD-RO on which map data is recorded.
CD playback mechanism 3 capable of playing M disks and the like;
A tuner unit 4 such as M or FM, and a digital reproduction output from a CD reproduction mechanism 3 which converts the digital reproduction output into an analog signal.
/ A converter 5 and amplifier 6 for amplifying analog signals
A digital output terminal 8 for supplying a digital reproduction output from the CD reproduction mechanism 3 to the outside, and an analog output terminal 9 for supplying an analog signal amplified by the amplifier 6 to the speaker 11.

The navigation unit 10 is connected to a digital output terminal 8 of the CD unit 1 by, for example, an optical cable 14, and a built-in CPU is connected to a system control line 12 of the microcomputer 2 of the CD unit 1. CD with map data recorded in
-When a ROM disk is reproduced, map data is input through the digital output terminal 8, and the map data and the current position data obtained by detecting the current position of the vehicle can be displayed to guide the vehicle.

[0004]

By the way, in the above-mentioned in-vehicle system, even when a CD disk (for example, a music CD) on which an audio signal is recorded by the CD reproducing mechanism 3 is reproduced, the digital signal is output to the digital output terminal 8. Is normally output, and an interference radio wave is generated from the wiring 13 extending to the CD playback mechanism 3 and the digital output terminal 8, thereby causing the television receiver 4 installed in the tuner section 4 or the vicinity to be closed. However, there is a problem that an adverse effect, which may lead to deterioration of reception, may be given to a device.

[0005] It is an object of the present invention to provide a digital output circuit in a playback device that solves the above-mentioned problems.

[0006]

A digital output circuit in a reproducing apparatus according to the present invention has a first output terminal for outputting a reproduced signal in an analog signal format, and a second output terminal for outputting a reproduced signal in a digital format. And a shut-off means for shutting off the supply of the digital output signal to the second output terminal when the first output terminal is used.

Further, in the digital output circuit in the reproducing apparatus according to the present invention, the reproducing apparatus is a disk player having a reproducing mechanism capable of reproducing a plurality of disks having different recorded contents, and the shut-off means is provided for the plurality of disks. During reproduction of the specific disc, supply of the digital output signal to the second output terminal is interrupted.

In the digital output circuit of the reproducing apparatus according to the present invention, the reproducing apparatus is a CD player, and the plurality of disks are a CD disk on which audio signals are recorded and a CD-ROM disk on which map data is recorded. The specific disc is the CD disc.

[0009]

In a reproducing apparatus having a first output terminal for outputting a reproduced signal in an analog signal format and a second output terminal for outputting a reproduced signal in a digital format, when the first output terminal is used, the shut-off means is used. To cut off the supply of the digital output signal to the second output terminal. Therefore, it does not adversely affect other components or external devices in the vicinity.

[0010]

FIG. 1 is a block diagram showing one embodiment of a digital output circuit in a reproducing apparatus according to the present invention, and shows a case where the digital output circuit is used in a vehicle-mounted system shown in FIG.
1, the same components as those in FIG. 2 are denoted by the same reference numerals. 1, a switch circuit 7 is inserted between the CD playback mechanism 3 and the digital output terminal 8 in addition to the configuration of the block diagram of FIG.
The turning off is controlled by the microcomputer 2.

First, the CD-RO mechanism 3
When reproducing an M disk, the microcomputer 2
Controls the switch circuit 7 to be turned on, and transmits map data to the navigation unit 10 via the digital output terminal 8 and the optical cable 14. The navigation unit 10 checks the content of the input data by the built-in CPU to determine whether or not the data is a ROM. Since the data is a ROM, the navigation unit 10 continuously obtains data from the digital output terminal 8 and displays a map or the like. (Since the CD-ROM can be identified by the CD reproducing mechanism 3 of the CD unit 1 and the microcomputer 2, even if this identification information is transmitted to the built-in CPU of the navigation unit 10 via the system control line 12, good.)

Next, when a CD disk is reproduced by the CD reproducing mechanism 3, the switch circuit 7 is maintained in the ON state, and a reproduced digital signal, for example, TOC information, is transmitted via the digital output terminal 8 and the optical cable 14. It is transmitted to the navigation unit 10. As a result of checking the content of the input data by the built-in CPU, the navigation unit 10 determines that the disk is not a ROM, and transmits data to the microcomputer 2 of the CD unit 1 via the system control line 12 indicating that the disk is not used for navigation. Tell The microcomputer 2 of the CD unit 1 controls the switch circuit 7 to be turned off based on the above information, and starts sound reproduction. The reproduced audio signal is supplied to the speaker 11 via the analog output terminal 9.

Therefore, the digital output from the CD reproducing mechanism 3 is cut off by the switch circuit 7, and the adverse effect on the tuner unit 4 and the external television receiver, which has been a problem in the conventional system, is reduced. Leads to improvement. Also, unnecessary interference with the analog output line is reduced.

[0014]

As described above, as an embodiment of the present invention, it is assumed that the reproducing apparatus is a CD.
Although the case of a player has been described, the present invention is not limited to this. For example, the present invention may be applied to a case where the playback device plays a DAT (digital audio tape), an MD (mini disc), a DVD (digital versatile disc), or the like. It is feasible.

[0015]

According to the digital output circuit of the reproducing apparatus according to the present invention, by shutting off the digital output, it is possible to reduce adverse effects on other components and nearby external devices.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a digital output circuit in a playback device according to the present invention.

FIG. 2 is a block diagram illustrating an example of a digital output circuit in a conventional playback device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CD unit 2 Microcomputer 3 CD reproduction mechanism 4 Tuner part 5 D / A converter 6 Amplifier 7 Switch circuit 8 Digital output terminal 9 Analog output terminal 10 Navigation unit 11 Speaker 12 System control line 13 Wiring 14 Optical cable

Claims (3)

[Claims] 1. A reproducing apparatus comprising: a first output terminal for outputting a reproduction signal in an analog signal format; and a second output terminal for outputting a reproduction signal in a digital format.
A digital output circuit in a playback device, comprising: a cutoff unit that cuts off supply of a digital output signal to the second output terminal when the output terminal is used. 2. The circuit according to claim 1, wherein the playback device is a disc player having a playback mechanism capable of playing back a plurality of discs having different recorded contents, and the blocking means is a specific disc among the plurality of discs. A digital output circuit in a reproducing apparatus, wherein the supply of a digital output signal to the second output terminal is interrupted during reproduction of the digital output signal. 3. The circuit according to claim 2, wherein the reproduction device is a CD player, and the plurality of disks are a CD disk on which an audio signal is recorded and a CD on which map data is recorded.
A digital output circuit in a playback device that is a ROM disk and the specific disk is the CD disk.