JPH0127639B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION When still images and moving images are selectively recorded on a disk-shaped recording medium as concentric or spiral recording trajectories, the present invention is capable of determining the purpose of still images and the purpose of moving images. This invention relates to a video and audio signal recording device that processes video and audio signals in order to realize it as a reasonably priced device.

Conventionally, as seen in the example of optical video discs, signals are recorded on a disc-shaped recording medium (hereinafter referred to as a disc) in the form of concentric circles or spiral recording trajectories, and are recorded at high density as binary signals such as irregularities or shading. A recording/reproducing device is being considered. In such an apparatus, a signal to be recorded is FM-modulated, converted into a binary signal, recorded as recording pits on a recording medium, and then reproduced.

Further, in the case of such a recording/reproducing apparatus, the recording pit is generally minute, about 1 .mu.m in diameter, and the recording track pitch is also about 2 to 3 .mu.m, so that a large capacity signal recording/reproducing apparatus can be obtained.

For example, in a device using such a disk,
When recording and playing still images concentrically and moving images spirally, generally one image is recorded and played back with one rotation of the disk for still images, so the audio signal is recorded at a length that can be used even if the band is compressed. However, in the case of a moving image, it is relatively easy to record and play back an audio signal during the period when the moving image is being recorded and played back. Further, although there are various purposes for recording and reproducing still images, in general, still images often have recorded contents that require high resolution, such as the inclusion of explanatory text to provide a certain explanation.

The present invention is capable of recording and reproducing a mixture of still images and moving images on the same disk, as described above, without adding a relatively complex circuit, and which requires high resolution still images. It is an object of the present invention to provide a video and audio signal recording device having a signal processing means for achieving the purpose of video recording and recording and reproducing audio at the same time.

First, FIG. 1 shows an example of an optical recording/reproducing apparatus. 1 generates a light beam l ₁ with a light source such as a He--Ne laser. Reference numeral 2 denotes an optical modulator, which optically modulates the light _l1 from the light source 1 using an FM-modulated video signal to generate light _l2 . The FM modulated video signal to be recorded is input to the terminal A, and in the case of a still image, it is input to the one-rotation recording gate circuit 21 (described later) via the switch 23, and the FM modulated video signal for one rotation (one frame) is inputted to the terminal A.
A modulation signal is applied to the optical modulator 2, and in the case of a moving image, it is input to the amplifier 22 via a switch 23, and a continuous FM modulation signal is applied to the optical modulator 2. 3 is a convex projection lens, 4 is a beam splitter, and 5 is a tracking mirror that rotates in the direction of the arrow around the rotation axis c to change the direction of the optical path. Reference numeral 6 denotes an objective lens, which is composed of an objective lens of a microscope, etc., and focuses the incident beam to about 1 μmφ and irradiates it onto the disk 15. Reference numeral 7 denotes a lens driving device composed of a voice coil and the like for driving the objective lens 6 in the vertical direction with respect to the disk 15. 15 is a disk, which is rotated by a motor 16. Further, the motor 16 and the disk 15 are the transport motor 1.
7 and the transfer shaft 18, a still image is transferred one pitch at a time, and a moving image is transferred continuously so that the recording trajectory becomes a spiral. FIG. 2 shows an example of an FM modulated signal recorded on the disk 15. T ₁ , T ₂ , and Tx are recorded information tracks, the track width W is about 1 μm, and the track interval p is about 2 μm. The length L of the recording pit is
It varies depending on the frequency of the recorded FM modulation signal,
These pits are recorded as unevenness or shading. Y
The portion is a still image portion recorded concentrically, and the X portion is a moving image portion recorded spirally. Reference numerals 8a and 8b in FIG. 1 are two-divided photoelectric detectors for receiving the transmitted light _I4 whose intensity is modulated at the pits transmitted through the disk 15 and recorded on the disk. The dividing line of this photoelectric detector is arranged parallel to the recording track. Reference numeral 9 denotes an adder which sums the output signals of the respective photoelectric detectors 8a and 8b and outputs the sum to terminal B as a reproduced signal. Further, 10 is a differential amplifier, which generates a signal representing the difference between the outputs of the respective photodetectors 8a and 8b. tracking control is performed so that the outputs of the two photodetectors 8a and 8b are equal.

On the other hand, the reflected light _l3 from the disk 15 passes through the objective lens 6 and the tracking mirror 5, and is sent to the photodetectors 12a and 12b by the beam splitter 4.
reflected to. The photoelectric detectors 12a and 12b are composed of, for example, solar cells or the like. Reference numeral 13 denotes a differential amplifier, which extracts a signal representing the difference in the outputs of the photoelectric detectors 12a and 12b, applies it to a drive circuit 14 that drives the voice coil 7 in the vertical direction, and applies it to the drive circuit 14 that drives the voice coil 7 in the vertical direction.
Then, focus control is performed so that the height of the disk 15 is kept constant. 19 is a detector for detecting one rotation of the disk 15, which is composed of a phototransistor or the like, and detects a signal for each rotation of the motor 16. 20 is a waveform shaping circuit for shaping the signal from the detector 19; Waveform shaping circuit 20
The one-rotation signal a obtained from
Only one frame of the FM-modulated video signal applied from the optical modulator 2 is applied to the optical modulator 2.

An example of an optical recording and reproducing device has been described above, but when recording a color video signal on such an optical recording and reproducing device, the color signal and luminance signal are separated, and the separated color signal is converted into a low frequency signal. frequency and superimposes it on the FM modulated luminance signal. A so-called low-frequency conversion method is sometimes used.

FIG. 3 is an explanatory diagram of signal processing when a color video signal is recorded and reproduced using the low frequency conversion method in the optical video recording and reproducing apparatus as described above.

A color video signal as shown in 1 is separated into a luminance component and a color component as shown in 2, and as shown in 3, the luminance component is subjected to FM modulation and the color component is converted to a low frequency. The signals processed as in 3 are superimposed as in 4. The high frequency components in 4 are
It is the FM-modulated luminance component, and the color component converted to the low frequency range forms the envelope. The signal 5 is obtained by applying the limiter to the signal 4. The signal No. 5 contains an FM-modulated luminance component and a color component that is incorporated as a signal into the FM signal duty of the luminance signal. This 5 signal is recorded on the disk as a binary signal to be recorded. The above method is a method of low frequency conversion of a color signal using a binary signal, and is a method of recording a color video signal, and is generally a method of recording a color signal by pulse duty modulation. I'm calling.

When an apparatus for recording and reproducing a color video signal using the above signal processing method attempts to record and reproduce an audio signal at the same time, the following method has conventionally been adopted in which the audio signal component is treated as a frequency spectrum.

FIG. 4 shows the frequency spectrum of an audio signal in the case of the conventional color signal low frequency conversion method. In Figure 4, A and B are the audio signal components of two channels, C is the color signal component converted to low frequency, D is the FM-modulated luminance signal component, and E is the sideband of the luminance signal component. show. It is well known that the resolution of recorded and reproduced video is proportional to the width of the sideband region. If the signal processing shown in Figure 4 is performed and the audio signal components A and B are not recorded and played back in the case of still images, but are recorded and played back in the case of moving images, the purpose of recording and playing back audio in a moving image can be achieved. However, since the area E in FIG. 4 remains the same whether or not the audio signals A and B are input, the resolution of the video recorded and played back is the same. In other words, with the above conventional method, even when recording and reproducing still images that do not require audio, it is possible to obtain only the same resolution as when recording and reproducing moving images. I couldn't get it.

FIG. 5 shows an embodiment for improving the above-described drawbacks.

In Figure 5, the same numbers as in Figure 1 are
Show the same thing. F indicates a video signal input terminal, G indicates an audio signal input terminal, H indicates a video signal reproduction output terminal, and I indicates an audio signal reproduction output terminal. The video signal input from F is guided to a circuit 101 that separates the luminance component and color component, the luminance component is guided to the FM modulation circuit 102, and the FM modulated signal is divided into moving and still components. The screen is guided to the image mode changeover switch 103a. 104 is a filter circuit for moving image mode, and 105 is a filter circuit for still image mode.

FIG. 6 shows a diagram of a frequency spectrum when the signal processing of the present invention is performed. In FIG. 6, the same symbols as in FIG. 4 indicate the same things. F indicates the sideband of the luminance signal during a moving image, and G indicates the sideband of the luminance signal during a still image. In FIG. 5, a filter 104 is a high-pass filter that allows a region above the region F in FIG. 10
Reference numeral 6 indicates a circuit that performs low-frequency conversion processing on a color signal in a video signal. The audio signal input from G is 10
Passes through 7 amplifiers and 108 signal processing circuits.
Converted to frequencies A and B in Figure 6, 103
It passes through the switch b and is led to the mix circuit 109. With the above circuit configuration, switch 10
When 3 is in the still image mode, the filter output of 105 and the color signal of 106 are mixed in the mixing circuit of 109, and there are no A and B in Fig. 6, and the luminance sideband has a wide area of G. When the switch 103a is in the video mode, the filter output of 104, the color signal of 106, and the audio signal of 108 are mixed in a mixing circuit of 109, and the luminance sideband has a narrow region of . Enable recording of audio signals.

110 in FIG. 5 is an amplifier circuit, 111a, 11
1b is a switch for switching between still image mode and moving image mode, 112 is a high-pass filter with the same band as 104, and 113 is a high-pass filter with the same band as 105. 114 is a luminance signal demodulation circuit, and the demodulated luminance signal is guided to a mixer circuit 115. 116 is a low-pass filter for extracting the color signal component shown in FIG.
15 mix circuit, and is taken out from H as a reproduction signal. 118 is a band pass filter for extracting the audio signals A and B in FIG. 6; 119 is an audio signal demodulation circuit; the demodulated audio signal is output from I; In addition, switches 23, 103a, 103b, 111a, 11 for switching between still image mode and video mode
1b all move in conjunction with each other.

As explained above, according to the present invention, when recording and reproducing still images, video signals with high resolution are recorded and reproduced, and when recording and reproducing moving images, the resolution is determined by conventional circuit processing. The same result can be obtained, and audio signals can be recorded and reproduced in the conventional manner.

In other words, when recording and reproducing high-resolution explanatory texts and images as still images on a disk-shaped recording medium, high-resolution video signals can be recorded and reproduced, and when recording and reproducing moving images, the resolution must be slightly lowered. Although it is a sacrifice, it is possible to realize a device having a major feature of high commercial value as an optical recording and reproducing device, which is the ability to record and reproduce audio signals, with almost no increase in cost.

In addition, in the above explanation, an optical video signal recording and reproducing device has been explained as an example, but regardless of the optical device, it is possible to use a disk-shaped recording medium and use a low-frequency conversion method for color signal processing. It is clear that the invention can be applied to any device.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of a conventional optical recording and reproducing device, Fig. 2 is a diagram showing a recording pattern on a disk, and Fig. 3 is a diagram showing a recording pattern when a color video signal is recorded and played back using the low frequency conversion method. Explanatory diagram of signal processing,
Figure 4 is a diagram showing the frequency spectrum when a conventional color signal is low-frequency converted and an audio signal is also recorded.
FIG. 5 is a block diagram showing one embodiment of the present invention, and FIG. 6 is a spectrum diagram for explaining the frequency spectrum recorded and reproduced in one embodiment of the present invention. 1... Light source, 2... Light modulator, 8a, 8b...
Photodetector, 15...Disk, F...Video input terminal, G...Audio input terminal, 23, 103a, 1
03b, 111a, 111b...still image-video changeover switch, 102,114...brightness signal processing circuit, 106,116...color signal processing circuit, 1
08,119...Audio signal processing circuit, 104,1
05, 112, 113... Brightness signal filter,
116... Color signal filter, 118... Audio signal filter, H... Video signal output terminal, I
...Audio signal output terminal.

Claims (1)

[Claims] 1 Separate the color video signal to be recorded into a luminance component and a color component, perform FM modulation on the luminance component, convert the color component to low frequency and superimpose it on the FM luminance signal, and send the superimposed signal to a limiter circuit. In an optical recording and reproducing device that records on a disk-shaped optical recording medium that rotates at a constant rotation speed, when recording and reproducing moving images, the audio signal component is converted into the color signal component converted to the low frequency band and the FM luminance signal. The FM luminance component is converted into a frequency domain between the components and is superimposed on the composite signal of the FM luminance signal and color signal for recording and playback, and when recording and playing back still images, the FM luminance component is converted into the audio signal band for the video. Optical recording characterized by comprising means for recording and reproducing the band including the FM luminance component band and for color luminance components as the same band as for moving images, and means for switching between the still image and the moving image. playback device.