JPS5843819B2 - Jiyou Broom Disk - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information recording disk reproducing apparatus configured to record video information concentrically or spirally and to reproduce it while rotating.

In recent years, video discs and recording/playback devices for them have been developed.

These types of devices can be broadly divided into those that scan the recording grooves of the disk with a needle, detect changes in the recording grooves as mechanical changes, and convert this into electrical signals, and those that are based on the recording grooves of the disk. There are two types: one that reads information optically.

FIG. 1 schematically shows the latter reproduction device,
A disk 1 on which information is recorded using grooves (pits) like an audio record is engaged with a shaft 3 of a motor 2, and the disk 1 is rotated at high speed.

An optical system for reading is arranged below the disk 1. First, a helium-neon laser 4 is provided as a light source, and a translucent prism 5 is installed in the straight direction of the laser beam emitted from the laser beam. It is arranged.

This prism 5 refracts the beam toward the disk 1 by about 90 degrees, but allows the returning beam reflected by the disk 1 to pass through without being refracted.

6 is a first mirror that reflects the reciprocating beam;
It is intended to change the course by about 900 degrees.

Reference numeral 1 denotes a second mirror, which reflects the outgoing beam in the direction of the disk 1 and reflects the returning beam in the direction of the first mirror 6.

Note that this second mirror 7 is pivotally supported, and its rotation can be electrically controlled as required.

8 is a beam focusing device for focusing the beam.

9 is a photodetector for detecting the returning beam reflected by the disk 1;

The above-mentioned prism 5, mirror 6, rotating mirror 7, beam concentrator 8, and photodetector 9 are integrated into an optical system device 10.
form.

This optical system device 10 is placed on a rail 11 and is movable in the radial direction of the disk 10.

In addition, 12 is a holding box, 13 is a support stand, 14 is a holding cylinder, 1
5 is the outbound beam, and 16 is the return beam.

Figures 2 and 3 show the recording state on the disc 1 and the relationship with the beam, and the signal shown in Figure 2A, which is an FM-modulated Eirin signal, passes through the limiter, and the signal shown in Figure 2 A signal like B is obtained, and corresponding grooves or pits 17 are formed as shown in FIG. 2C.

The width of this pit 170 is approximately 1μ, the distance between adjacent pits is approximately 1μ, the depth is approximately +λ (where λ is the wavelength of the laser beam), and is approximately 0.15μ, and the length of the pit is the same as the inner circumference of the disk. There is a difference depending on the outer circumference and also depending on the frequency of the F''M modulated wave, and is, for example, 1.5 to 6μ.

The pits 17 are formed in a spiral or concentric shape on the disk surface, and the tenth circumference forms the first field (odd field) of the rask scanning television receiver, and the remaining circumference forms the second field (odd field). Even number field) is formed, and 1 in one round.
It is designed to form a frame.

The outer circumferential diameter of the pits 17 is approximately 300 mmφ.
The inner circumferential diameter is approximately 70 to 80 m11Lφ, and the surface is plated with gold or aluminum.

In the apparatus configured as described above, if the disk 1 is rotated and the pit 17 is scanned with a laser beam, the pit 1
Information based on the array of 7 can be read out.

To explain this in more detail, helium, neon,
A laser beam 15 is sent out from the laser 4, refracted approximately 90 degrees to the right by the prism 5, further reflected toward the center of the disk by the first mirror 6, and then reflected toward the disk by the second mirror 7. The reflected light is focused by a focusing device 8.
, and irradiates the track where the pits 17 are arranged.

If S is irradiated onto an area where there are no pits, the beam will be reflected from the disk surface and return along the same trajectory.

However, when returning to the prism 5, the prism 5 is configured to allow the returning beam 16 to pass therethrough, so the photodetector 9 detects this beam.

On the other hand, if the beam is irradiated onto the pit 17, the beam spot is larger than the width of the pit 170, so the light reflected inside the pit 17 and the light reflected outside the pit interfere and cancel each other out. , and almost no output is generated.

In other words, the reflected beam 16 becomes weak and can be detected by the photodetector 9 in distinction from when the beam is irradiated onto areas other than pits.

By scanning the track with the beam in this way, it is possible to obtain video information for the (1) frame.

Frame changes are made by moving the optical system 10 radially along the rails 11.

In addition, in the case of this optical scanning, since mechanical tracking is not performed by the guide groove, in addition to the central readout beam 18, a tracking beam is simultaneously transmitted from the same optical system device 10, as shown in FIG. 2C. 19°20 beam 18
In FIG. 2C, beam 19 is located below the pit 17, beam 20 is located above the pit 17, and these two beams 19, 2
The light reflected by the 00 disk is read out by the photodetector 9 in the same way as the light reflected by the readout beam 18 from the disk.

In the photodetector 9, as shown in FIG.
The output T1 from the beam 20 and the output T2 from the beam 20 are detected separately, and after amplifying them respectively in the amplifiers 21 and 22, the difference between the two is determined in the difference circuit 23, and a second mirror is applied so that this difference becomes zero. The rotation device 24 of γ is controlled.

When a control signal is applied to the rotation device 24, the second Mirror 7 rotates.

The output T1. of beams 19 and 20. The signal based on T2 is
As described above, it is used to control the second mirror 7, and is also used to control the readout beam 18 to scan in a spiral pattern.

The circuit branching downward in FIG. 4 is for spiral scanning, and when the signals based on the outputs T□ and T2 pass through the low-pass filter 25, a large periodic displacement is detected, and this is detected by the amplifier. Motor 27 via 26
is applied to

As a result, the optical system device 10 sequentially moves in the radial direction as the disk 10 rotates.

As a result, the readout beam 18 accurately scans the spiral track in which the pits are arranged, and one frame of information is read out in one round of scanning.

The above-described disk device and devices similar thereto have features such as high information density, inexpensive recording media, simple playback device, and ability to freely play back any desired location.

However, this type of conventional video disc has the disadvantage that it cannot be played for a long time on a single disc.

In order to solve this type of drawback, it is possible to perform PCM time division multiplexing recording, but there are problems in that the cost of the device increases due to the provision of a PCM circuit, and when the amount of information is large, such as in a video signal. There was a problem in that it was difficult to record and reproduce PCM time division multiplexing in real time.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a disc playback device that can perform long-time playback with relative ease.

In order to achieve the above object, the present invention provides that a video signal period and a blank period not including a video signal are equal to one horizontal scanning time (IH).
The first standard television signals are arranged alternately, are formed based on the first standard television signal, and are formed in a form capable of restoring a signal that approximates the first standard television signal. a comb television signal;
The video signal period and the blank period not including the video signal are alternately arranged every horizontal scanning time (IH) and are formed based on a second standard television signal, and the second standard television signal a second comb-like television signal formed in a form capable of restoring a signal similar to a signal reading device for reading a signal from a disk on which a multiplexed television signal, which is multiplexed with the video signal period of a television signal inserted therein, recorded in real time using a frequency modulation method; and a signal reading device from the disk. and is configured to cause a relative scanning motion between the disk and the signal reading device to read signals in substantially real time by a first scan and a second scan subsequent to the first scan. a scan drive configured to perform scanning; and extracting the first comb television signal from a signal read in a first scanning movement by the scan drive;
interpolating the blank period of the first comb-shaped television signal based on a signal before the blank period to obtain a television signal that approximates the first standard television signal; extracting said second comb television signal from a signal read in a second scanning movement by the device; The present invention relates to a disc reproducing apparatus including a signal restoration device for obtaining a television signal approximate to the second standard television signal by performing interpolation based on the signal.

In addition, to show the correspondence between the present invention and the embodiments and modifications, the first comb-like television signal of the present invention is A in the embodiment.

A multiplexed signal of a horizontal butenyl signal and a vertical butenyl signal based on the first standard television signal such as I AH2A2 is intermittently broadcast, or A.

, A12 A2, etc. are simply broadcast intermittently, and the second standard television signal (
Similarly, for the serpentine television signal, a signal obtained by multiplexing a horizontal butenyl signal and a vertical butenyl signal based on a second standard television signal indicated by Bo, B1, 82, etc. is intermittently distributed. or B.

, B1, B2, etc., which are simply broadcast intermittently.

The signal reading device of the present invention is the reading scanning device 5 of the embodiment.
4, that is, a portion similar to the optical system device 10 in FIG.

The scanning drive device of the present invention includes the control device 571. The drive unit of the scanning device 54 (for example, the feed motor 27 in FIG. 4)
, the disk rotation motor 53, etc.

The signal restoration device of the present invention includes the signal processing circuit 55 of the embodiment,
These are parts such as the gate circuit 58 and the display device 59.

According to the above invention, the following effects can be obtained.

(b) Since television signals are recorded and played back in real time, the configuration of the device is simplified.

(b) Rather than performing multiplex recording and reproduction using PCM or the like, a portion of the television signal is discarded and the resulting blank period is utilized for multiplex recording, which simplifies the configuration of the apparatus.

Even in real-time recording and playback, the first scan obtains an output corresponding to the first standard television signal, and the second
Since an output corresponding to the second standard television signal is obtained in the second scan, long-time playback is possible.

Next, embodiments of the present invention will be described based on the drawings.

FIG. 5 is an explanatory plan view showing a video disc according to the present invention.

The video disk 31 of this embodiment is a disk made of synthetic resin, on which information is recorded in pits so as to form a spiral track 32.
Information on the first field (odd field) of the television screen is recorded during 262.5 horizontal scanning periods from point 1 to point P2, and during the remaining half-cycle, for example, 26 from point 22 to point P3.
The information of the second field (even field) is recorded in 2.5 horizontal scanning periods.

Therefore, as shown by diagonal lines every half cycle, the vertical blanking period 33
is provided.

However, no video signal is simply recorded on this disk 31, and based on the composite video signal shown in FIG. The horizontal butenyl signal and the vertical butenyl signal are recorded every horizontal scanning period in a line time-division method, which will be explained in detail later.

The recording method is the same as the method shown in FIGS. 2 and 3, and is a frequency modulation recording method.

In FIG. 6, the rest except for the address signal 34 shown with diagonal lines are the same as a general television signal.

That is, period T is the vertical blanking period, and 3 in FIG.
3, and this vertical blanking period T is
In this example, an equivalent pulse period T1 of 3H (where H is one horizontal scanning time of 63.5 μs, for example), a vertical synchronization pulse period T2 of 3H, an equivalent pulse period T3 of 3H, and a horizontal synchronization pulse period of 12H. It consists of T4.

However, the color burst signal is omitted in this drawing.

In general television receivers, this vertical blanking period T
No display is made in , and a display based on the video signal 35 is performed after entering period T.

In this embodiment, the address signal 34 is applied, for example, to '0' during the vertical blanking period 33 at points A and B in FIG.
〃 corresponds to IKHz, and "1" corresponds to 2.5 KHz.
It is recorded using a frequency shift modulation method compatible with .

Next, recording of video signals using the line time division method will be described.

In the present invention, continuous video signals are not recorded on consecutive tracks, but are recorded intermittently.

That is, as illustrated in FIG. 5, for example, the same signal is not continuously recorded at 262.5H between the vertical blanking period at the 21st point and the vertical blanking period at the 22nd point. The first signal //6.1 and the second signal /f6.2 are recorded alternately for each IH.

Therefore, when looking at one signal train, it is an intermittent signal recording at the IH position, and a second signal is recorded in this intermittent portion.

A video signal train as shown in Fig. 6 is simply placed intermittently at every IH,
If the image is reproduced as is, the number of horizontal scanning lines will be halved, resulting in poor image quality.

Therefore, in this embodiment, instead of simply recording the video signal intermittently at every IH, a horizontal butenyl signal and a vertical butenyl signal are created, these are recorded at every IH, and the intermittent portion is recorded using this signal during playback. It is designed to be restored based on the

This type of signal transmission method does not require much resolution in the vertical direction for objects that are detailed in the horizontal direction, and it is said that if only the low frequency components have sufficient vertical resolution, there will be almost no loss in image quality. This is based on the property that the eye has a reduced ability to distinguish vertically detailed objects from horizontally detailed objects.

Figure 7 is a circuit diagram for creating a horizontal butenyl signal (sum signal) and a vertical butenyl signal (difference signal), and Figure 8 is a circuit diagram for creating a restored video signal based on the horizontal butenyl signal and vertical butenyl signal at the IH position. FIG.

In the circuit shown in FIG. 7, 36 is a standard television signal input terminal as shown in FIG. 6, 37 is a 1-line delay circuit,
38 is a mixing circuit that creates a sum signal, 39 is a mixing circuit that creates a difference signal, 40 is a low-pass filter, 41 is a band-pass filter, 42 is a horizontal butenyl signal output terminal, 43 is a vertical butenyl signal output terminal, 44 is a carrier color signal It is an output terminal.

In FIG. 8, 45 is an intermittent horizontal butenyl signal input terminal, 46 is an intermittent vertical butenyl signal input terminal, 47 is an intermittent carrier color signal input terminal, 48 and 49 are mixing circuits,
50 is a one-line delay circuit, 51 is a mixing circuit, and 52 is a restored television output terminal.

Next, signal separation, signal recording, and signal restoration using the circuits of FIGS. 7 and 8 will be explained with reference to FIGS. 9A to 91.

First, a video signal A for each IH as shown in FIG. 9A.

When 2A12A2, A32A4","-2An is applied to the standard television signal input terminal 36, the signal in that period and the signal delayed by the 1-line delay circuit 37 are added in the mixing circuit 38, and the The sum signal, ie, the horizontal butenyl signal A, as shown in Figure 9B.

10 A1 , AI + A22 A2 + A3 , A3 10 A4 , etc. are formed, and this is transmitted to the output terminal 42 .

On the other hand, in the mixing circuit 39, the signal during that period and the IH
The delayed signal is subtracted, and the difference signal, that is, the vertical butenyl signal AoA1)A□-A22 A2 is obtained as shown in FIG. 9C.
A32 A3 A4 etc. are formed.

The vertical butenyl signal passes through the low-pass filter 40 to obtain (Ao A1), t, , (AI A2)L
.

(A2 A3) L t (A3 A4) L
After that, it is sent to the output terminal 43.

Once the horizontal and vertical butenyl signals are formed as described above, after multiplexing them with a subcarrier, the horizontal and vertical butenyl signals are intermittently generated every IH by a switcher (not shown). horizontal and vertical butenyl signals are inserted into the intermittent portions.

That is, as illustrated in FIGS. 9D and 9E, the first signal is sent during each IH period from <11 to t2 and from t3 to t4, and the first signal is sent during each IH period from t2 to t3 and from t to t5.
The first signal is not sent during the H period.

9D and 9 in the signal intermittent portion of the first signal.
The horizontal tetenyl signal B of the second signal as shown by the dotted line in Figure E
o1B1. B2+B3 and vertical butenyl signal (Bo B
1)L, (B2 B3)L are inserted.

Therefore, the first signal and the second signal are multiplexed and recorded on the disk 31 in a line time division manner.

When obtaining a restored signal based on the horizontal butenyl signal and the vertical butenyl signal as shown in FIGS. 9D and 9E, first, the mixing circuit 48 generates the restored signal of the first line.

That is, the signal shown in FIG. 9D and the signal shown in FIG. 9E are combined.

For example, the broadband horizontal butenyl signal AO+AI = (
The 9th F is obtained by adding the vertical butenyl signal (Ao Ay,) t, and the vertical butenyl signal (Ao Ay)
As shown in the figure < (2Ao) L+(AO+AI)
An H signal is formed and this is used as the first line video signal.

Next, the mixing circuit 49 combines the signal shown in FIG. 9D and the signal shown in FIG. 9E in order to create a restored signal for the second line.

For example, horizontal butenyl signal A. 10A1= (Ao 10At
) L + (Ao + AI) H and the vertical butenyl signal (Ao - A1) t, are subtracted and the result is as shown in Fig. 9G.
A signal of (2A, ) L+(Ao+At)H is formed and delayed by the one-line delay circuit 50 to produce a signal as shown in FIG. 9H.

Thereafter, the mixing circuit 51 adds the first line signal shown in FIG. 9F and the second line signal shown in FIG. obtain.

The restored signal shown in FIG. 9(2) does not completely match the original signal shown in FIG. 9A.

However, since the first line and the second line have the same high frequency component, for example (Ao+AI)H, the difference is only to the extent that they are visually indistinguishable.

The system shown in FIGS. 1, 8, and 9A to 9I is known as a television two-channel multiplex transmission system that separates horizontal and vertical butenyl signals.

To summarize and explain again the state recorded on the video disk 31, the first type of signal, which is a multiplex of the horizontal butenyl signal, the vertical butenyl signal, and the carrier color signal of the first signal train, is intermittent for each IH. This is an intermittent signal train, which is FM modulated and recorded as pits.

Then, a signal based on the second signal is similarly recorded in the intermittent portion of the intermittent signal string related to the first signal.

FIG. 10 is a block diagram showing an apparatus for reproducing a video disc constructed as described above.

This playback device includes a motor 53 for rotating the disk 31, a readout scanning device 54, a signal processing device 55, a signal detection device 56, a control device 57, a gate circuit 58, and a display device 59.

To explain these in detail, the motor 53 is connected to the disk 3
1 is rotated at a high speed, for example, once at a speed of 10 seconds.

The readout scanning device 54 reads the pits on the S track by moving it in the radial direction of the disk 310 in a spiral manner, and in the case of this embodiment, it is explained in FIGS. 1 to 4. It is configured so that it can be read out using the same method as the previous method.

The signal processing device 55 demodulates the signal read out by the readout scanning device 54.

The signal detection device 56 separates and detects the address signal 34 from the read signal, and controls the control device 57 and the gate circuit 58 based on this.

The control device 57 controls the beam emitted from the readout scanning device 54 to scan over the tracks of the disk, and also receives a control signal based on the address signal from the signal detection device 56 to move the beam from point A to B on the disk. After scanning to the point, control is performed so that the scanning returns to point A and scans from point A to point B.

The gate circuit 58 opens the gate for each IH based on the horizontal synchronization signal given from the display device 59, and allows only one of the first signal and the second signal to pass through.

For example, as shown in FIG. 9D, A is indicated by a solid line.

10 A1 and Bo + B t shown by dotted lines are alternately mixed in each IH, and one is removed to create a state as shown in FIG. 9F, for example.

The display device 59 includes a restoration circuit as shown in FIG. 8, and has the same configuration as a normal television receiver.

With the disc and playback device configured as described above,
When reproducing the display, first set the gate circuit 58 so that the first signal passes through it.

For example, from tl to t2 and t3 in FIGS.
The gate is set to open between t4 and t4.

After setting in this manner, the disk 31 is rotated at a constant speed by the motor 36, and scanning is started from point A on the outer circumference of the disk toward point B on the inner circumference.

As a result, the information pits arranged on the track are read out by the laser beam as explained in FIGS. 1 to 4, and processed by the signal processing device 55.

In the state processed by the signal processing device 55, the first signal and the second signal are in a mixed state, so this is sent to the gate circuit 58 and only one of them is separated and selected.

This separation is achieved by opening a gate for each IH based on the horizontal synchronization signal.

The intermittent signal formed by passing through the gate circuit is converted into a restored television signal as shown in FIG. 9I by a restoration circuit as shown in FIG. will be done.

As the scanning on the disk 31 progresses and reaches point B, the detection device 56 detects the address signal inserted in this vertical blanking period.

This address signal is then given to the control device 57,
Based on this, the scanning device 54 quickly returns to point A, and
Scanning is started again from point B toward point B.

At the same time, based on the address signal of point B, the gate circuit 5
8 will be controlled, and the gate will turn on and off more gradually than before.

That is, in FIGS. 9A to 9, the gate opens during the period from t2 to t3 and from t4 to t.

Therefore, the first signal is cut and only the second signal is transmitted.

Then, the intermittent signal based on the second signal is processed by the restoration circuit shown in FIG. 8, resulting in a television signal with the intermittent portion compensated for, which is displayed on the cathode ray tube.

Therefore, it is possible to play back twice as much as conventional discs.

FIG. 11 shows another embodiment, in which the disk is scanned from point A on the outer circumference to point B on the inner circumference, and then scanned from point 8 toward point A. .

Therefore, as shown in FIG.
If there is a continuous signal train from 100 to 100, 1.2.3, . . ., pa.
50 is recorded, and 5 is recorded every IH from point B to point A.
Numbers from 1 to 100 are recorded.

In the reproducing apparatus shown in FIG. 11, the signal detection device 56 shown in FIG. 10 is built into the display device 59.

In the apparatus configured in this way, if scanning starts from point A, as shown in FIG.
The first signal and the second signal are detected in a mixed state as shown in FIG.

However, since the gate circuit 58 opens only at the IH position, only the first signal consisting of the information 1.2.3, etc. passes through and is not included in the display device 59. The intermittent signal is converted into a continuous signal as shown in FIG. 91 by a signal restoration circuit, and this is displayed.

When the scanning reaches point B on the disk, an address signal is detected in this process and is applied to the control device 57, so that the scanning device 54 starts scanning in the opposite direction.

At this time, the disk 31 is rotated in the opposite direction to start scanning from point B to point A.

As a result, in FIG. 12, it is scanned from right to left, and 5
It is read as 1.49.52.48,...ioo.

However, since the gate circuit 58 only opens every other IH, the second signal passes through in the order of 51, 52, 53, . . . , -100, and becomes an intermittent signal.

This intermittent signal is restored in the same way as the first signal and displayed on the display device.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above-described embodiments, and can be further modified.

For example, in the embodiment, two types of signals were recorded alternately on the same channel, but as shown in FIG.
Channel 1 ch and second channel 2 ah may be recorded alternately at every other IH.

At this time, only the first channel is reproduced in the first scan, and the second channel is reproduced in the second scan.

Moreover, it is also applicable to disks other than those shown in FIGS. 1 to 4.

Furthermore, intermittent signal transmission and restoration are shown in FIGS. 7 to 9A.
■The method is not limited to the one shown in the figure, and another method may be used.

For example, the signal of the previous line may be used as is as the signal of the secondary line, although the resolution will be lowered.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view for explaining a video-disc playback device, Fig. 2 is an explanatory diagram for explaining recording on the disc, Fig. 3 is a sectional view of the pit portion of the disc, and Fig. 2 is a circuit diagram of a tracking section in the device shown in FIG. 1. FIG. 5 to 10 show embodiments of the present invention, in which FIG. 5 is a schematic plan view showing the recording state of a video disc, and FIG. 6 is a composite video signal including an address signal to be recorded. 7 is a circuit diagram of the part that forms horizontal butenyl signals and vertical butenyl signals, FIG. 8 is a circuit diagram of the signal restoration section, and FIGS. 9A to 9■ are signal separation, recording, Fig. 9A is a waveform diagram of the original signal, Fig. 9B is a waveform diagram of the horizontal butenyl signal, Fig. 9C is a waveform diagram of the vertical butenyl signal, and Fig. 9D is a waveform diagram for recording. Figure 9E is a waveform diagram of an intermittent horizontal butenyl signal, Figure 9F is a waveform diagram of an intermittent vertical butenyl signal for recording, and Figure 9F is a waveform diagram of an intermittent vertical butenyl signal for recording.
Figure 9G is a waveform diagram of the restored signal for the second line, Figure 9H is a waveform diagram of the restored signal of the second line, and Figure 9I is the waveform of the restored television signal. 10 are block diagrams showing the playback device. 11 and 12 show another embodiment, in which FIG. 11 is a block diagram of a reproducing apparatus, and FIG. 12 is an explanatory diagram for explaining the recording state on a disc. FIG. 13 is a frequency band diagram for explaining a modified example of recording on a disk. 31... Disc, 32... Track, 33... Vertical blanking period, 34...
・Address signal, 35...Video signal, 53...
...Motor, 54...Scanning device, 55...
... Signal processing device, 56 ... Signal detection device, 51 ... Control device, 58 ... Gate circuit, 59 ... Display device.

Claims (1)

[Claims] 1. A video signal period and a blank period not including a video signal are 1.
Alternately arranged for each horizontal scanning time (IH), formed based on a first standard television signal, and formed in a form capable of restoring a signal that approximates the first standard television signal. based on a first comb-like television signal, which is arranged alternately every horizontal scanning time (IH), such as a video signal period and a blank period not including a video signal, and a second standard television signal. and a second comb-like television signal formed in a form capable of restoring a signal similar to the second standard television signal; reading a signal from a disk on which a multiplexed television signal, which is multiplexed such that the video signal period of the second comb-shaped television signal is inserted into the blank period of the television signal, is recorded in real time using a frequency modulation method; a signal reader configured to cause a relative scanning motion between the disk and the signal reader to read signals from the disk by the signal reader in substantially real time; a scan drive device configured to perform a second scan subsequent to the first scan; and a scan drive device configured to perform a second scan after the first scan; extracting a standard television signal, and interpolating the blank period of the first standard television signal based on a signal before the blank period to produce a television signal that approximates the first standard television signal. obtaining the second comb television signal and extracting the second comb television signal from the signal read in a second scanning movement by the scan drive; A disc reproduction device comprising: a credibility restoration device for obtaining a television signal approximate to the second standard television signal by interpolating a period based on a signal before the blank period.