JPS606013B2 - Endless recording and playback method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endless recording/reproducing method, and more particularly to an endless recording/reproducing method for an optical recording disk in which recording is performed by exposing a photosensitive material on the disk using, for example, a laser light source.

・Conventionally, when endlessly reproducing signals from a disk as described above, the typical method was to provide two types of tracks on the same circle on the disk and record signals in opposite directions on each track. Even after one track has been reproduced, the disk is subsequently rotated in reverse to reproduce another track.

In this type of recording and playback method, ``After one track is finished recording, the other track is recorded, so it takes a long time to record, and since two tracks are provided, it is difficult to avoid errors when the wrong track is selected during playback.'' The disadvantage of this is that it cannot be corrected.The fact that the tracks are played back in an unplanned manner becomes a problem when attempting to record and play back at higher recording densities. The main object of the present invention is to provide an endless recording and reproducing apparatus that can perform endless reproduction and perform high-density recording and reproduction, while eliminating the above-mentioned drawbacks.

To summarize, this invention multiplex-records a time-series signal and an anti-time-series signal at the same time, reproduces the time-series signal in the same order as the recording order, and then continues ``recording the anti-time-series signal in the opposite order to the recording order''. The aim is to achieve endless recording and reproducing by reproducing in the order of .

The above objects and other objects and features of the invention will become more apparent from the following detailed description with reference to the drawings.

FIG. 1 is a functional block diagram showing the recording side of an embodiment of the present invention.

First, the structure and operation will be explained with reference to FIG. A disk W whose surface is coated with a photosensitive material,
It is rotated clockwise at a constant speed by a disc motor 5. A first housing 119 for recording is provided facing the disc 4, and inside the first housing 119 is an optical modulator 101 that optically modulates a laser beam 105 from an external laser light source 104. A lens turtle 03 and a mirror 102 are arranged to focus the laser beam 185 modulated by the optical modulator Qi onto the disk 4. Then, this first folding body 119 is sent from the outer circumference to the inner circumference of the opposing disk & by the feed motor 1201. On the other hand, even if the first audio signal recorded on the tape is reproduced in the first tape recorder 121, the first modulation circuit 12
given to 3.

The first modulation circuit 123 FM modulates the first audio signal and supplies it as one input to the addition circuit 126 . Also, the second
On the tape recorder 122, "a tape on which a second audio signal is recorded is played backwards", and the second audio signal is played back from this tape recorder 122 in the reverse order from when it was recorded. The second audio signal that is reproduced in the reverse order is an anti-time series signal, which is subjected to FM modulation in the second modulation circuit 124 and provided as one input to the adder circuit 126. The FM carrier frequency in the first modulation circuit 123 is fi, and the second
The FM carrier frequency in the modulation circuit 24 is assumed to be f2. The first audio signal and the second audio signal that have undergone this modulation are then added together in the adder circuit 26 and derived as a frequency-multiplexed signal.The spectrum of this frequency-multiplexed signal is As shown in Figure A, there are two FM waves centered on carrier waves Na1 and Shima2.
The frequency-multiplexed signal from the adder circuit 12 is voltage amplified by an optical modulator drive circuit 127 and added to the optical modulator 11. Therefore, the laser beam 105 emitted from the laser light source 184 is optically modulated by the predetermined M-wave signal in the optical modulator 01, and is then optically modulated by the mirror 102.
, the light is focused on the disk 4 through the condenser lens 103, and the photosensitive material on the disk 4 is exposed. Here, the first sparrow body 119 is moved in the radial direction of the disk 4 by the mahjong body feed motor 102, and at the same time, the disk 4' is rotated at a constant speed clockwise by the disk motor 5.
A spiral track on which signals are recorded is formed on the disk 4. In this way, when the recording to the innermost circumference of the disk 4 is completed, the reproduction of the two tape recorders 121 and 122 is stopped, and the first modulation circuit 12
3. Cut the input signal to the second modulation circuit 124 and stop the modulation. Therefore, the output from the first and second modulation circuits 123 and 124 will be only the carrier waves fl and f2. Furthermore, the termination signal oscillator 125 is activated and its output (which is a single frequency signal with frequency f4 shown in FIG. The suberatrum of the signal to be recorded is based on the two carrier waves fl, f
2 and this termination signal f4. This completes recording onto the disc 4. The reproduction of this recorded signal is performed by the second
This is accomplished by the playback side shown in the figure. FIG. 2 is a functional block diagram showing the reproduction side of an embodiment of the present invention.

For ease of explanation, the recording section and the reproducing section are shown separately in FIGS. 1 and 2, but in reality, the recording section and the reproducing section are in the same device. Of course. The structure and operation thereof will be explained below with reference to FIG.
The weight is moved in the radial direction of the disk 4 by the weight sending motor 20 . Inside this second weight body 19, a reproduction light source topime splitter 2, a lens 3, and a photodetector 6 are housed and held. The light beam emitted from the light source 1 has its optical path bent at a right angle by a beam splitter 2,
The light is collected by the lens 3 and focused on the surface of the disk 4.

Two signals shown in FIG. 3a are frequency-multiplexed and recorded on the disk 4. The two signals, one modulated with a carrier frequency fIMHz and one with a carrier frequency fPaz, have the same band width and are spaced apart from each other.

This frequency-multiplexed signal is recorded in a spiral shape on the surface of the disk 4 as a physical deformation of unevenness. Therefore, the light focused on the surface of the disk undergoes a change in reflectance and diffraction due to the unevenness, passes through the lens 3 and the beam splitter 2, and is converted into an electrical signal by the photodetector 6, which is made of, for example, a photodiode. converted. This photodetector 6
The electrical signal is amplified by a preamplifier 7 and then applied to a filter 8. As mentioned above, when reproducing using the light beam from the light source 1, in order to read signals from a disc with extremely high-density recording, the reproducing beam must be placed on top of the spiral track. Although an automatic control (optical tracking) mechanism is required to properly focus the light beam onto the track, for ease of illustration or explanation, the is omitted from illustration.The filter 8 is shown in FIG. 3b.
It has a passband characteristic as shown in FIG.

Now, assuming that the local oscillator 11 is oscillating at a frequency 〆a (=P1 - 〆3), the light source modulation circuit 10 is excited at this frequency 〆a, and the light source 1 is driven by this light source modulation circuit 10.'' Therefore, the light intensity of the light source 1 changes with the frequency P a. When such light is focused on the surface of the disk 4 and a signal is read out, the light incident on the photodetector 6 is caused by the local oscillator. 11 oscillation frequency fa and carrier frequency fl
, f2 and the sum and difference frequency components. In other words, na ten〆a=2 na na 3 ““River…(1}
Na・1〆a=Na3……(2}〆2±
It is glue.

Therefore, the output of the filter 8, which has a pass band width as shown in FIG. becomes. Therefore, in the demodulation circuit 9 receiving the filter B output, the first audio signal from the first tape recorder 121 recorded by the carrier wave 1 is reproduced. In reality, the signal read from the disk 4 is subject to time axis fluctuations due to the irregular rotation of the disk drive motor 5 and the eccentricity of the disk 4.

Therefore, the low frequency converted signal selected by the filter 8 is guided to the amplitude detection circuit 13, which detects the signal. The fluctuations are canceled out when the reproduction light beam from the light source 1 and the reflected light from the disk 4 are mixed. Therefore, the output of the demodulation circuit 9 is demodulated as a stable signal with no time axis fluctuations. Output.
As described above, the signal is reproduced from the outer circumference to the inner circumference of the disk 4, and when it reaches the innermost circumference, the output from the optical multiplexer 6 and therefore the preamplifier 7 contains the aforementioned self-termination signal 〆4. is obtained, and the termination detection circuit 14 detects the termination information 4 accordingly.

When this termination detection circuit turtle 4 detects this termination signal,
Disc motor rotation direction control circuit 17, second armor feed motor gutter conversion circuit 15, and bias voltage generation circuit 2
give a control signal to the In response, the disk motor rotation control circuit 17 reverses its state and the disk motor 5, and therefore the disk 4, begins to rotate in the opposite direction. Furthermore, since the second cliff body feed motor polarity conversion circuit 15 reverses its state and the motor 20 starts rotating in the opposite direction, the second coating body 19 for reproduction is moved from the innermost circumference to the outer circumference of the disk 4. At the same time, the voltage obtained from the bias voltage generation circuit 12 changes, and the oscillation frequency of the local oscillator 11 controlled thereby is changed from the above-mentioned Naa to 〆b (=〆2-Na3). Therefore, the light intensity of the light source changes at the frequency 〆b of the light source, and the light incident on the photodetector 6 includes the sum and difference frequency components of the oscillation frequency ``nab'' and the carrier frequencies 〆1 and 〆2. I'm here. In other words, “Na1±pb=Na1
±(p2-p3)……・”'4}〆20nab;2na2-
Na 2 ...... (5) Na 2 - Na b = Na 3
......{6).

Therefore, the output of the filter 8 having the pass band shown in FIG. . In this way, contrary to the case described above, the signals are read out from the inner circumference to the outer circumference, so that the second audio signal from the second tape recorder turtle 22, which was recorded as an anti-time series signal, is As described above, according to this embodiment, normal time-series signals and anti-time-series signals are recorded by frequency multiplexing from the outer circumference to the inner circumference. This time series signal is transmitted towards the innermost circle, and when the reproduction reaches the innermost circle, the anti-time series signal is transmitted from the inner circle to the outer circle to make a normal time series signal.
The recording time is shortened, and there is no need to form two types of tracks during endless playback, so there is no need to worry about tracks.

Therefore, a signal recording/reproducing device capable of endless reproduction and extremely high density can be obtained. In addition, in the above-mentioned embodiment, an audio signal was described as a signal to be recorded, but "this may be another signal.

For example, if it is some kind of measurement data, a tape recorder or the like may be used instead of the tape recorders 21 and 122. Furthermore, although a method has been described in which the disc moves from the outer periphery to the inner periphery and then back to the outer periphery, it may be reversed from the inner periphery to the outer periphery and then back to the inner periphery.

In order to detect the innermost or outermost circumference, that is, the end, we recorded the end signal during recording and detected it during playback. The signal to be recorded may be detected by optical detection, etc.Furthermore, although the signal to be recorded is FM, it may be possible to use a well-known modulation method such as AM or PM. Let be an unmodulated wave,
Of course, it is also possible to multiplex record the other signal as a modulated wave.

Of course, the recording medium may be a disc-shaped outer sheet. As described above, according to the present invention, since time-series signals and anti-time-series signals are multiplexed onto a single track, high-density recording can be performed in a short time, and endless playback is possible. This provides an endless recording and reproducing system.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. i is a functional block diagram showing the recording side of an embodiment of the present invention.

FIG. 2 is a functional block diagram showing the reproduction side of an embodiment of the present invention. FIG. 3a is an illustrative diagram showing the frequency spectrum of the recording signal, and FIG. 3b is an illustration showing the passband of the filter. In the figures, the same reference numerals indicate the same or equivalent parts, 1 is a reproduction light source, 2 is a beam splitter, 4 is a disk, 5 is a disk motor, 6 is a photodetector, 8 is a filter, and 9 is a demodulation circuit. 10 is a light source modulation circuit, 11 is a local oscillator, 12 is a bias voltage generation circuit, 14 is an end detection circuit; 15 is a second spindle feed motor gutter conversion circuit;
17 is a rotation direction control circuit, 2 rivers and a second cliff body feed motor;
101 is a light modulation adjuster, 104 is a laser light source, 121' is a first tape recorder, 122 is a second tape recorder, 123 is a first modulation circuit, 124 is a second modulation circuit,
125 is a termination signal generation circuit, and 126 is an adder circuit.
Hair 'Figure Hair 3 Figure Takashi 2 Figure

Claims (1)

[Scope of Claims] 1. means for generating a recording light beam; means for providing first information to be recorded; means for providing second information to be recorded; means for modulating light according to the first and second information to be transmitted, and the recording light beam modulated by the light modulation means is irradiated, and the recording light beam modulates the first and second information. A first step that changes the relative position between a recording medium on which is recorded and a recording light beam irradiated onto the recording medium and the recording medium.
means for generating a reproduction light beam; means for modulating the reproduction light beam at a certain frequency; means for irradiating the modulated reproduction light beam onto the recording medium; means for converting the reproduction light beam irradiated onto the recording medium into an electrical signal; and second displacement means for changing the relative position of the reproduction light beam irradiated onto the recording medium and the recording medium. A recording/reproducing apparatus comprising: upon recording, the first information is generated as a normal time-series signal, the second information is generated as a counter-time-series signal, and the recording light beam is directed to the recording medium. The time-series signal of the first information and the anti-time-series signal of the second information are recorded in a frequency multiplexed manner from one end to the other end, and upon reproduction, first the reproduction light beam is The first information is read out from one end of the recording medium toward the other end, and the modulation frequency of the reproduction light beam is set to a first readout frequency, and the first information is read out so that the reproduction light beam and the recording medium detecting that the position has reached the other end of the recording medium; in response to the detection, the reproducing light beam is directed from the other end to the one end of the recording medium; An endless recording/reproduction method in which the second information is read by using a modulation frequency as a second readout frequency. 2. In order to detect that the reproducing light beam has reached the other end of the recording medium, a termination signal is recorded at the other end during recording, and upon reading out the termination signal during reproduction, the reproducing light beam 2. The endless recording/reproducing method according to claim 1, wherein the endless recording/reproducing system detects that the light beam reaches the other end. 3. In order to detect that the reproduction light beam has reached the other end of the recording medium, the relative position change by the second displacement means is mechanically or optically detected. An endless recording/reproducing method according to claim 1. 4. In order to detect that the reproduction light beam has reached the other end of the recording medium, a lack of reproduction information from the recording medium is detected. Endless recording and playback method described. 5. Claim 1, characterized in that the first reading frequency and the second reading frequency are further controlled by the output of the electrical signal converting means.
The endless recording and reproducing method according to any one of Items 1 to 4.