JPH0648619Y2 - Information playback device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an information reproducing apparatus, and more particularly, to an information reproducing apparatus for reproducing digitized and recorded audio information.

BACKGROUND ART In an information reproducing apparatus such as a digital audio disc player, audio information digitized and recorded by a PCM (Palse Code Modulation) system is reproduced. FIG. 1 shows such a conventional information reproducing apparatus. In FIG. 1, for example, EFM (Eight to Fourteen) obtained from the recording disk 2 by the pickup 1 is shown.
Modulation) A modulated signal is supplied to the clock recovery circuit 3 and the demodulation circuit 4. A clock for demodulation is regenerated by the clock regenerating circuit 3 and supplied to the demodulating circuit 4. The demodulation circuit 4 demodulates the modulated signal according to the supplied clock to obtain PCM data, that is, digital data including time-division-multiplexed left and right channel audio information, and detects a frame sync signal to reproduce a sync signal. Is output. The reproduction synchronization signal output from the demodulation circuit 4 is supplied to the servo control device 5. The servo control device 5 drives the spindle motor 6 in accordance with the phase difference between the reference synchronization signal and the reproduction synchronization signal generated at a predetermined repetition frequency, and moves the information detection point in the circumferential direction of the recording disk 2 relatively. And the relative position of the pickup 1 in the radial direction of the recording disk 2.

On the other hand, the PCM data obtained by the demodulation circuit 4 is sequentially supplied to the error correction circuit 7 bit by bit. Error correction circuit 7
Is configured to cooperate with a RAM (Random Access Memory) 8 to detect and correct a code error by a parity bit or the like added to the PCM data in advance, and output an uncorrectable signal when uncorrectable. Has been done. The output of the error correction circuit 7 is supplied to the error correction circuit 9. The error correction circuit 9 corrects the error data in the output data of the error correction circuit 7 when an uncorrectable signal is generated by interpolation by an average value interpolation method or the like, or by digitally attenuating the error data and the data before and after the error data. Is configured. The PCM data corrected by the error correction circuit 9 is sequentially bit by bit D / A (digital / analog) conversion circuit 10
Is supplied to. The D / A conversion circuit 10 includes a demultiplexer that separates the time-division-multiplexed left and right channel audio information from each other and a low-pass filter that removes unnecessary components outside the audio signal band. The reproduced audio signals of the left and right channels are output from the D / A conversion circuit 10 and applied to the break contacts of the relay switches S ₁ and S ₂ . The make contacts of the relay switches S ₁ and S ₂ are grounded. The signals derived from the movable contacts of the relay switches S ₁ and S ₂ are transferred to the audio output terminals O ₁ and O ₂
Is supplied to each. A system control circuit 11 is provided in the relay coil L that drives the movable contacts of the relay switches S ₁ and S _2.
A muting control signal consisting of a higher level signal is supplied. The system control circuit 11 includes an operation unit (not shown)
In response to the command issued from
The servo control device 5 is controlled so that a search operation or the like is performed, and a muting control signal is generated during an operation other than the reproducing operation.

In the above configuration, when an operation other than a normal reproduction operation such as a pause operation is performed, a muting control signal is output from the system control circuit 11 and a drive current flows through the relay coil L, and the relay switches S ₁ , S ₂ Each of the movable contacts of the above contacts the make contact. Then, the audio output terminal
Muting is performed by grounding O ₁ and O ₂ . Therefore, when information other than audio information such as video information is recorded on the recording disk 2, muting is not performed when information other than audio information is reproduced by a normal reproduction operation, so that the audio output terminal O ₁ , O
_{In this case} , an abnormal signal is derived to cause an unpleasant sound, and in some cases, an audio device such as a speaker malfunctions. Also, since the conventional information reproducing apparatus cannot output digital data,
It was not possible to reproduce information other than audio information.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an information reproducing apparatus capable of reproducing information other than audio information while preventing generation of unpleasant sound.

An information reproducing apparatus according to the present invention comprises a digital data output means for deriving digital data before correction of a code error to a data output terminal, a detecting means for detecting an identification signal indicating the kind of recorded information, and a detected identification signal. The muting means for muting the signal derived to the audio output terminal in accordance with the above.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG.

As shown in FIG. 2, a pickup 1 for reading a modulation signal from a recording disk 2, a clock recovery circuit 3, a demodulation circuit 4,
Servo control device 5, spindle motor 6, error correction circuit 7, RAM 8, error correction circuit 9, D / A conversion circuit 10, system control circuit 11, relay switches S ₁ , S ₂ and relay coil L
Are connected in the same way as the device of FIG. However, in this example, the digital data and the uncorrectable signal output from the error correction circuit 7 are supplied to the data output terminal O ₃ and the uncorrectable output terminal O ₄ via the buffer gate 12, respectively. The muting control signal output from the system control circuit 11 is supplied to one input terminal of the OR gate 13. A pull-down resistor R is connected between the other input terminal of the OR gate 13 and the ground. The other input terminal of the OR gate 13 is connected to the external mute input terminal I.

In the above configuration, when the external mute input terminal I is in the open state, the potential of the other input terminal of the OR gate 13 is almost equal to the ground potential by the pull-down resistor R and when the signal of logic "0" is applied. Will be similar to. Therefore, at this time, the output of the OR gate 13 becomes high level only by the muting control signal output from the system control circuit 11, and the drive current flows through the relay coil L. Therefore, normal reproduction of audio information is performed in the same manner as the conventional device.

Here, when, for example, video information other than audio information is recorded on the recording disk 2, the digital data including this video information is derived to the data output terminal O ₃ . By supplying the data derived at the data output terminal O ₃ to, for example, a computer having a CRT display, the video information can be reproduced. If information indicating the recording position of information other than audio information is recorded as a non-audio information identification signal at a predetermined position on the recording disk 2, digital data including information other than audio information will be D / A conversion circuit. By being supplied to 10, the generation time of the abnormal signal derived to the audio output terminals O ₁ .O ₂ can be detected by the computer. Then, if the sensed occurrence time to provide a high-level signal from the computer to the external mute input terminal I, the audio output terminal O ₁ .O drive current flows in the relay coil L
_The abnormal signal derived in ₂ can be muted, and the generation of unpleasant sound can be prevented.

In the above embodiment, the digital data is transferred by serial data transfer in which each bit is sequentially transferred, but the digital data may be transferred by parallel data transfer in which all bits are simultaneously transferred. Further, when the digital data output from the error correction circuit 7 is interleaved, a deinterleave circuit may be provided before the buffer gate 12. Further, at this time, a delay circuit for delaying the uncorrectable signal may be provided. Further, in the above embodiment, the control of the muting means is performed by the positive logic,
The control of the muting means may be performed by negative logic. Further, in the above embodiment, the muting means was formed by the mechanical relay,
The muting means may be formed by an electronic switch.

Effect As described above in detail, the information reproducing apparatus according to the present invention is obtained by deriving the digital data before the correction of the code error to the data output terminal and detecting the identification signal indicating the kind of the recorded information. Since the signal derived to the audio output terminal can be muted according to the identification signal, information other than audio information can be reproduced and uncomfortable sound at the time of reproduction other than audio information. It is possible to eliminate the occurrence of the noise and the failure of the audio equipment caused thereby. Also,
Even if an uncorrectable code error occurs, digital data before correction of the code error, that is, digital data including information other than audio information, is meaninglessly modified for correction. Is output, it is possible to minimize the influence of a code error on a device that processes digital data including information other than the audio information. Further, by further adding an error correction code to digital data including information other than audio information, it becomes possible to improve the error detection and correction capability as compared with the case of the recording format of the current digital audio system.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional information reproducing apparatus, and FIG.
FIG. 1 is a circuit block diagram showing an embodiment of the present invention. Explanation of code of main part 7 …… Error correction circuit, 10 …… D / A conversion circuit 11 …… System control circuit, 12 …… Buffer gate 13 …… OR gate S ₁ , S ₂ …… Relay switch, L ...... Relay coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Kashiwazaki, 4,2610 Hanazono, Tokorozawa, Saitama Prefecture, Tokorozawa Plant, Pioneer Co., Ltd. (72) Takataka Kunimaru 4-2610, Hanazono, Tokorozawa, Saitama Pioneer Tokorozawa Factory Co., Ltd. (56) Reference JP-A-58-164383 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. A reproduced audio signal is generated by reading digital data including audio information and an identification signal associated with the digital data from a recording medium to correct and correct a code error and then supplying the digital / analog converting means. A digital data output means for deriving the digital data before correction of the code error to a data output terminal, and the identification signal is a non-audio information identification signal. An information reproducing apparatus, comprising: a detection unit that detects that a signal is output, and a muting unit that mutes a signal derived to the audio output terminal according to a detection result of the detection unit.