JPH073496Y2 - Compact disk player - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a compact disc player capable of reproducing an audio signal as music information and a data signal of a computer, and in particular, an audio signal and a data signal are recorded in a mixed manner. The present invention relates to a compact disc player suitable for playing a compact disc.

(B) Conventional Technology A compact disc player (CD player) is known which reproduces a compact disc (CD) in which an information signal is recorded as a digital signal by projections called pits by using an optical pickup device. As the CD, there is known a disc on which an audio signal which becomes music information is recorded as an information signal. For example, JP-A-61-294
As disclosed in Japanese Patent Laid-Open No. 58-58, it is considered that a data signal such as a program of a host computer (for example, a personal computer) is recorded on the CD and the CD is used as a read-only storage element (ROM) for the data signal. Has been. The standard also allows the CD to record the audio signal and the data signal in a mixed manner.
Therefore, the currently marketed CD players are dedicated to audio signals that can play only CDs with audio signals recorded, but eventually a signal processing circuit for data signals is added to the current CD players, Recorded CD (CD
It is expected that there will be CD players on the market that can also play ROMs.

(C) Problems to be solved by the device However, when the data signal is reproduced by the CD player capable of reproducing the above-mentioned CD-ROM, the power source of the acoustic amplifier is turned on, and the acoustic amplifier is operated by the function switch. If the reproduction signal from the CD player is input as the input signal, the reproduction signal of the data signal is emitted as noise from the speaker through the acoustic amplifier. Therefore, when the CD-ROM is played back by the CD player, the sound amplifier is turned off, or
Alternatively, it is necessary to switch the function switch to something other than a CD player, but in the case of a CD in which audio signals and data signals are mixed, it is impossible to prevent the generation of the noise by operating the acoustic amplifier as described above. is there.

On the contrary, when the audio signal is reproduced by the above-mentioned CD player, the reproduced signal of the audio signal may adversely affect the host computer via the signal processing circuit for the data signal.

The present invention provides a CD player made in view of the above points.

(D) Means for Solving Problems The present invention detects and reproduces a Q channel signal of a subcoded signal which is recorded on a disc and includes information indicating whether or not it is a data signal. A discriminating means for discriminating that the inner track is a data trag in which a data signal is recorded, and a data signal reproduced from the disc when the disc track is discriminated by the discriminating means for digital processing corresponding to a computer. Data signal signal processing means for converting into a signal, and prohibiting means for prohibiting the data signal reproduced from the disc when the data track is identified by the identifying means from being output as an analog signal via the audio output means. And is provided.

(E) Operation The present invention utilizes the Q channel signal of the sub-coding signal recorded on the disc to output the reproduction signal of the data signal by activating the prohibiting means when the track being reproduced is the data track. It is forbidden to do so and puts the signal processing means for data signals into an operating state.

(F) Embodiment FIG. 1 is a block diagram showing an embodiment of the present invention.
Is a compact disc (CD) on which audio signals and data signals are recorded together, (2) is a spindle motor for rotating the CD (1), (3) projects a light beam,
An optical pickup device having an optical sensor for receiving a light beam reflected from the CD (1), (4) a preamplifier for amplifying and shaping the waveform of a signal generated from the optical sensor of the optical pickup device (3) , (5) are focusing control for converging the light beam of the optical pickup device (3) to a signal surface on the CD (1) by the output signal generated from the preamplifier (4) and the light beam. A pickup control circuit for performing tracking control to follow a surface track, (6) reproduces a clock for digital processing of the output signal (serial digital signal) generated from the preamplifier (4). Together with the digital processing based on the clock, the output signal from the information signal, synchronization signal, sub-coding signal and error A main signal processing circuit that demodulates a signal for correction / detection and then corrects an error in the signal,
(7) is supplied with the sub-coding signal detected by the main signal processing circuit (6), and disc position information (music number, index number, elapsed time of each song, etc.) contained in the sub-coding signal The display means (8) is displayed by and the input means (9) consisting of a key switch
A microcomputer for performing various kinds of operation control according to the operation of the spindle motor (10) for phase comparison between a synchronization signal extracted by the main signal processing circuit (6) and a reference signal obtained from a crystal oscillator. A motor rotation control circuit for controlling the rotation of 2), (11) is the preamplifier (4)
RAM for absorbing the rearrangement of the data of the output signal from CD and the rotation irregularity of the CD (1) and outputting the digital signals processed by the main signal processing circuit (6) at equal intervals, (1
2) is a D / A converter for converting a digital signal output from the main signal processing circuit (6) into an analog signal,
(13) is an analog circuit composed of a filter circuit that cuts unnecessary signals from the analog signal generated from the D / A converter (12) and extracts an audio signal, and an amplifier circuit that amplifies the audio signal, (14) is a gate circuit for inhibiting the audio signal from the analog circuit (13) from being supplied to the audio output terminal (15) by a control signal from the microcomputer (7),
(16) is a host computer connected to a data output terminal (17) by further digitally processing the data signal digitally processed by the main signal processing circuit (6) when the data track on which the data signal is recorded is reproduced. (18)
It is a signal processing circuit for a data signal which is converted into a digital signal compatible with (for example, a personal computer).

Here, a method for identifying the data track on the CD will be described in detail.

In the CD (1), a signal including reproduction control information and disc position information called a sub-coding signal in which one block is completed in a cycle of 1/75 second by the main signal processing circuit (6) is music or data of a host computer. It is recorded together with the information signal. The sub-coding signal is composed of 8 channels P to W,
Since the Q channel among them contains the control signal which becomes the reproduction control information for notifying whether or not it is the data signal, the track currently being reproduced is the data signal by identifying the control signal of the Q channel. It can be identified whether or not. In that case, the control signal can be identified from "0100" or "0110" in the data track. In the case of the apparatus of FIG. 1, the control signal is identified by a program written in the microcomputer (7) as shown in the flowchart of FIG. The program first detects the Q channel from the sub-coding signal demodulated by the main signal processing circuit (6), extracts the control signal of the Q channel (step), and the control signal is "0100" or "0110". Or not (step,). If the control signal is "0100" or "0110", a prohibition signal is generated from the microcomputer (7) to turn off the gate circuit (14) and the output end of the analog circuit (13) and the audio output terminal ( 15) is separated from the signal processing circuit, and the microcomputer (7) activates the data signal signal processing circuit (16) (step). Then, this program ends. On the other hand, if the control signal is neither "0100" nor "0110", the program ends without doing anything.

Now, it is assumed that an optical track in which an audio signal is recorded as an information signal of the CD (1) is traced by the light beam generated from the optical pickup device (3). The signal recorded on the track traced by the light beam is read by the optical pickup device (3), then amplified and waveform-shaped by the preamplifier (4) and supplied to the main signal processing circuit (6). Therefore, the signal recorded on the audio track is
The main signal processing circuit (6) demodulates and extracts various signals, performs error correction processing, and rearranges them regularly as audio signals. Then, when the sub-coding signal is extracted by the main signal processing circuit (6), the microcomputer (7) operates according to the reproduction control information included in the sub-coding signal and is included in the sub-coding signal. The display (8) is displayed according to the disc position information. Here, since the track currently being reproduced is an audio track, the control signal of the Q channel, which is one of the reproduction control information, is neither "0100" nor "0110" indicating the data track. (7) does not generate an inhibit signal to the gate circuit (14), nor does it generate a signal to activate the data signal signal processing circuit (16). Therefore, the data signal signal processing circuit (16) is in a non-operating state and is in a state of not transmitting the digital audio signal output from the main signal processing circuit (6). It is not supplied to the host computer (18), but only to the D / A converter (12). Audio signal (parallel digital signal) supplied to the D / A converter (12)
Is converted into an analog signal, unnecessary signals are cut and amplified by the analog circuit (13), and the gate circuit (14)
To the audio output terminal (15). Therefore, the sound corresponding to the audio signal recorded on the CD (1) is emitted from the speaker (not shown) via the acoustic amplifier (not shown) connected to the audio output terminal (15). .

On the other hand, when the data track of the CD (1) is being traced by the light beam generated from the optical pickup device (3), the Q channel control of the sub-coding signal extracted by the main signal processing circuit (6) is performed. Since the signal is "0100" or "0110", the microcomputer (7) generates an inhibition signal to turn off the gate circuit (14) and turn on the data signal signal processing circuit (16). . Therefore, the data signal which has been subjected to error correction processing by the main signal processing circuit (6) and rearranged regularly is sent to the host computer (18) as data via the data signal signal processing circuit (16). It is transmitted and not supplied to the audio output terminal (15). Therefore, when the host computer (18) is operated by using the data signal recorded on the CD (1), no signal is supplied to the acoustic amplifier, so that the data signal is generated by being converted into an analog signal. Noise is not emitted from the speaker.

In the device of FIG. 1, a gate circuit (1) is provided in order to prohibit the reproduction signal reproduced from the CD (1) from being supplied to the audio output terminal (15) when reproducing the data track.
4) was used, but when an audio track is reproduced by providing a switch circuit at the output end of the main signal processing circuit (6), the output signal of the main signal processing circuit (6) is the D / A converter (12). The output signal of the main signal processing circuit (6) may be supplied to the data signal signal processing circuit (16) when the data track is reproduced.

In addition, the signal supplied to the D / A converter (12) inside the main signal processing circuit (6) and the signal processing circuit for data signal (1
A signal supplied to the D / A converter (12) at the time of reproducing a data track means that the audio signal is silent in the main signal processing circuit (16) if the signal is diverted from the signal supplied to 6). It is also possible to prohibit audio output by converting all 16-bit signals to "0".

(G) Effect of the Invention As described above, according to the present invention, the reproduction signal reproduced from the disc when the data track is identified is prohibited from being output as an analog signal through the audio output means. Therefore, the noise generated by the data signal being converted into an analog signal can be prevented, and the operation of the data signal signal processing means is stopped when it is identified that the data track is not a data track. It is possible to prevent the signal from adversely affecting the host computer via the data signal signal processing means.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a flow chart for explaining the present invention. Explanation of main drawing numbers (6) …… Main signal processing circuit, (7) …… Microcomputer, (12) …… D / A converter, (13) …… Analog circuit, (14) …… Gate circuit, (16) …… Signal processing circuit for data signals.

Claims (1)

[Scope of utility model registration request] 1. A compact disc player for reproducing a compact disc recorded with a digital signal, an audio signal as music information, a data signal as control information for a computer, a reproduction control information and a sub-coding signal as disc position information. Audio output means for outputting an audio signal reproduced from the disc as an analog audio signal, and the subcoding signal is detected, and the track being reproduced by the subcoding signal is a data track on which the data signal is recorded. Identification means for identifying the existence of the data track, signal processing of the data signal reproduced from the disc when the data track is identified by the identification means, and conversion into a digital signal compatible with the computer, Data signal signal processing means for stopping the signal processing operation when it is discriminated that it is not a track, and a data signal reproduced from the disc when the data track is discriminated by the discriminating means through the audio output means. And a prohibition unit that prohibits the output as an analog signal.