JPS6381651A - Disk player - Google Patents

Abstract

PURPOSE:To enable a stable and sure access motion at the time of accessing different kinds of track by identifying the kind of information track by the size of the amplitude of a reproducing signal read from a disk and performing the selection of an information reading track with the identification signal thereof. CONSTITUTION:Bits of information are read from plural kinds of information tracks (e.g. voice track and image track) on which the bits of information are recorded by a different basic space frequency with a reproducing means 1 and fed to a track identifying means 2. The means 2 transmits to a track selection means 3 an identification signal by identifying the kind of the information track from the size of the amplitude of the reproducing signals. The means 3 controls the reproducing means 1, performing the selection of the information reading track.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a disc player that reproduces information from a disc having a plurality of types of information tracks on which information is recorded at different fundamental spatial frequencies.

2. Description of the Related Art Compact disc players, video disc players, and the like are commercially available as players for reproducing signals from discs on which audio signals or video signals are recorded. Furthermore, recently, a standard has been proposed in which video tracks are mixed on a compact disc. In this type of disc, the focus length on the audio track where the audio signal is recorded is approximately 0.
．． While it is 9 to 3.3 μm, it is as small as about 0.6 μm on a video track where video signals and audio signals are recorded. In the following, an example will be explained in which a signal is reproduced from a disc in which audio tracks and video tracks coexist.

FIG. 5 shows a block diagram of an example of a conventional disc player, in which l is a playback means, 3 is a track selection means,
4 is a position detection means. The reproducing means 1 consists of a pink amplifier that reads signals from the disc, a control circuit necessary for reading, a position control means that controls the reading position, a motor that rotates the disc, and its control means, etc., and reproduces the signals recorded on the disc. is read and outputs a playback signal. The position detection means 4 is for detecting the read position on the disk by the pickup, for example, for extracting an address signal recorded on the disk,
There are some that detect the pickup position using a potentiometer. The track selection means 3 includes the position detection means 4
The reading position of the pink-up is controlled through the position control means in the reproduction means 1 based on the device signal composed of
°April 1986 issue P187).

Problems to be Solved by the Invention However, with the above configuration, when there are multiple types of information tracks on the same disk, for example, a video track and an audio track, in which information is recorded at different fundamental spatial frequencies, as described below, This may cause serious position detection difficulties. Generally, audio tracks and video tracks have different linear velocities during playback due to the difference in the amount of information per time. However, address information recorded on a disc can only be read when reproduced at an appropriate linear velocity, so this information is useless when accessing different types of tracks.

For example, when attempting to access a video track while an audio track is being played back, the pickup is moved in the direction of the video track, but once the reading position enters the video track, no address information can be obtained due to the difference in linear velocity.

Furthermore, even if the read position moves to a different track for some reason, the read position cannot be determined at all.

Also, position detection using a potentiometer is effective when the track position is known in advance, but since it does not directly detect the read position, accurate position information is difficult to obtain, and its application is limited due to cost. There are disadvantages such as being

Means for Solving the Problems In order to solve the above problems, the disc player of the present invention reads information from a disc having a plurality of types of information tracks on which information is recorded at different fundamental spatial frequencies and generates a reproduced signal. a reproduction means for outputting an information track; a track identification means for identifying the type of information track from the magnitude of the amplitude of the reproduction signal output from the reproduction means and outputting an identification signal corresponding to the type of the information track; The apparatus further includes track selection means for inputting an identification signal to control the reproduction means and select a track from which information is to be read.

Function: With the above-described configuration, the disc player of the present invention can accurately and easily determine the type of information track, so that different types of tracks can be stably accessed.

Embodiment An embodiment of the disc player of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a disc player according to an embodiment of the present invention. In FIG. 1, 1 is a reproduction means, 2 is a track identification means, and 3 is a track selection means. The structure and operation of the reproducing means 1 and the track selecting means 3 are the same as those explained in FIG. 5.

The track identification means 2 will be explained with reference to FIGS. 2 and 3. FIG. 2 is a circuit diagram of the track identification means in an embodiment of the present invention, and FIG. 3 is a signal waveform diagram for explaining FIG. 2. The waveforms at points A-D in FIG. ~ (denoted as d+. In Fig. 2, 10 is a transistor, 1) is an OP amplifier, 12 is a comparator,
R1-R7 are resistors, 01-C3 are capacitors, and R
1, R2, R3, CI.

Block 13 composed of C2 and 10 is an amplitude detection means, block 14 composed of R4, R5, C3, 1) is a pre-low-pass filter, and block 15 composed of R6 and R7゜12 is a discrimination means. It is.

The amplitude detection means 13 performs envelope detection and extracts the upper envelope component of the reproduced signal input from point A.

FIG. 3 shows the situation when the big amplifier approaches the switching point between the audio track and the video track. Third
The point where the reciprocating signal amplitude of at (at) greatly attenuates in the middle indicates the switching point from the audio track to the video track.In the video track, at the same time as the linear velocity increases, compared to the audio track, the The spatial frequency in the linear velocity direction of the recorded signal is also increased.On the other hand, on the reproduction side, for example, since the MTF of the lens in an optical pick amplifier has a constant frequency characteristic, the difference in spatial frequency will not be reflected in the reproduction signal. This appears as a difference in signal amplitude.The amplitude detection means 13 captures this change in amplitude and outputs it to point B.This has a waveform as shown in FIG. 3(1)). After this signal has once passed through the pre-low-pass filter 14, it is compared with a predetermined value in the discrimination means 15 and outputted to point D as an identification signal. Figure 3 (C
The broken line at 1 indicates the threshold value of the discriminating means 15. Note that the pre-low-pass filter 14 is inserted to alleviate the influence of false detections due to disk defects, etc., but it can be omitted if such temporal false detections are not a problem. .

FIG. 4 is a signal waveform diagram showing the behavior when the pink amplifier approaches a switching point from an audio track to a video track while moving across an information track in the same embodiment. As the pink-up reading position crosses the track, the amplitude of the reproduced signal (al fluctuates greatly,
Since the fluctuation width of the audio track and the video track is different for the same reason as mentioned above, the identification signal fdl indicates the distinction between the video track and the audio track, as in the case of FIG. 3.

The embodiment is merely an example of the configuration of the present invention. Although the amplitude detection means 13 in FIG. 2 is an envelope detection circuit, there is no particular limitation as long as it detects amplitude.

Furthermore, the structure of the track identification means is not limited to the form shown in FIG. 2, but may be of any type as long as it generates an identification signal using reproduced signal amplitude information.

Furthermore, the position detection means described in the conventional example may be used in conjunction with the present invention. For example, if address information is used, more fine-grained access can be achieved within each track.

Effects of the Invention As is clear from the above description, the present invention provides a reproduction means for reading information from a disc having a plurality of types of information tracks in which information is recorded at different fundamental spatial frequencies and outputting a reproduction signal; track identification means for identifying the type of information track based on the amplitude of the reproduction signal output from the means and outputting an identification signal corresponding to the type of the information track; and inputting the identification signal output from the track identification means for the reproduction. Since the track selection means is provided to select a track for reading information by controlling the means, stable and reliable access operation can be performed even when accessing different types of tracks.

The track identification means includes an amplitude detection means for detecting the amplitude of the reproduced signal and outputting an amplitude signal, and a discrimination means for determining the type of the reproduced track by comparing the amplitude signal with a predetermined value and outputting an identification signal. and a pre-low-pass filter in front of the discriminating means,
A stable identification signal can be obtained even if the playback signal is temporarily disturbed due to a disk defect, making it possible to achieve more stable access operations9.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a disc player according to an embodiment of the present invention, FIG. 2 is a circuit diagram of the track identification means in FIG. 1, and FIGS. 3 and 4 are signal waveform diagrams at various parts of FIG. FIG. 5 is a block diagram of a conventional disc player. 1... Reproduction means, 2... Track identification means, 3... Track selection means. Name of agent: Patent attorney Toshio Nakao and one other person Figure 4

Claims (3)

[Claims] (1) A reproduction means for reading information from a disk having multiple types of information tracks on which information is recorded at different fundamental spatial frequencies and outputting a reproduction signal, and a reproduction means for outputting a reproduction signal from the magnitude of the amplitude of the reproduction signal output from the reproduction means. track identification means for identifying the type of information track and outputting an identification signal corresponding to the type of the information track; and a track for controlling the reproduction means by inputting the identification signal output from the track identification means to select an information reading track. A disc player comprising: selection means. (2) The track identification means includes amplitude detection means that detects the amplitude of the reproduced signal and outputs an amplitude signal, and compares the amplitude signal with a predetermined value to determine the type of the reproduced track and outputs an identification signal. A disc player according to claim 1, characterized in that the disc player comprises a determining means for determining whether or not the disc player is a disc player. (3) The disc player according to claim (2), wherein the track identifying means includes a pre-low-pass filter in front of the determining means.