JPH06290401A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To provide a magnetic recording and reproducing device capable of improving a weak point of a usual helical scan VTR that is weak in random access, eliminating a loading mechanism and extremely being miniaturized. CONSTITUTION:A color video signal and an audio signal are converted in to the forms of an analog FM signal and a digital signal, etc., and the signals are recorded and reproduced on a magnetic tape 17 arranged in a planar shape, in a roughly semi-circular shape by magnetic heads 10, 11 rotating on a plane. Thus, the loading mechanism loading the magnetic tape on a rotary cylinder, etc., is eliminated, and a device size is remarkably reduced. Further, the searching time of the random access of program searching, etc., is remarkably reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video tape recorder (hereinafter referred to as VTR) for converting a color video signal and an audio signal of a color television signal into a digital signal or a frequency-modulated analog signal and recording / reproducing it on a magnetic tape or the like.
Abbreviated) and the like.

[0002]

2. Description of the Related Art Conventionally, VHSs of the VHS system and analog recording systems such as 8 mm video have been put to practical use and are widely used. Such a VTR
Is a so-called helical scan method in which a magnetic tape is wound around a rotating cylinder by approximately 180 degrees, and a signal is recorded by a magnetic head on the rotating cylinder.

[0003]

However, the conventional VHS system and VTR helical scan system such as 8 mm video require a mechanism for winding the magnetic tape around the rotary cylinder, that is, a loading mechanism. However, since the loading mechanism has a large volume, there is a limit to downsizing of the device, so that the device size becomes large and the device cannot be downsized. Moreover, the conventional helical scan type VTR has a drawback that it is weak in random access because it takes a long time to search for a cue.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a new head / tape scan type magnetic recording / reproducing apparatus which does not require this loading mechanism and can perform magnetic recording at high density.

[0005]

In order to solve the above-mentioned problems, the present invention uses a magnetic head that converts a color video signal and an audio signal into a form such as an FM signal or a digital signal, and rotates on a plane. Signals are recorded or reproduced on a magnetic tape arranged in a plane in a substantially semicircular or arc shape.

[0006]

With the above structure, the loading mechanism for the magnetic tape to the rotary cylinder is not necessary, and the size of the device can be dramatically reduced. Further, it is possible to solve the drawback of the magnetic tape, which is conventionally superior to the disk-shaped medium in that the recording capacity is large, but largely inferior in terms of random access.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a magnetic recording / reproducing apparatus according to the first embodiment of the present invention. In FIG. 1, 1 is an input terminal for a color video signal, and 2 and 3 are input terminals for a stereo audio signal. The respective signals are input to the recording side signal processing circuit 4 from the input terminals 1, 2 and 3.

FIG. 2 shows an example of the internal configuration of the recording side signal processing circuit 4. NTS input to the recording side signal processing circuit 4
The C color video signal is separated in the Y / C separation circuit 30 into a luminance signal Y and a color signal C. The separated Y signal is L
After being band-limited to 4.2 MHz in the PF 31, it is input to the FM modulation circuit 33 that is subjected to frequency modulation by being subjected to linear and non-linear emphasis in the emphasis circuit 32. Further, the separated C signal is low-frequency converted to a band of 100 kHz to 1 MHz by the frequency conversion circuit 34, and then band-limited in the BPF 35.

In FIG. 2, the stereo audio signal input to the recording side signal processing circuit 4 is band-limited to a band of 20 kHz by the LPFs 36 and 37, respectively, and then F
FM modulation is performed in the M modulation circuits 38 and 39. Here, the FM modulation frequency of the stereo audio signal is
Select a frequency between the FM luminance signal frequency and the low frequency conversion color signal frequency. The outputs of the three FM modulation circuits 33, 38 and 39 and the BPF 35 are added by the adder circuit 40, the recording signal level is adjusted by the recording amplifier 41, and output from the output terminal 5.

The signal output from the output terminal 5 is input to the input terminal 6 of the recording / reproducing changeover switcher 7. At the time of recording, the signal input to the recording / reproducing changeover switcher 7 is output from the two input / output terminals 8 and 9 to the two magnetic heads 10 and 11 which are arranged symmetrically with respect to the center of rotation on a fixed rotation surface. It Two magnetic heads 1
0 and 11 circularly move in the direction of arrow 16 on the plane,
A signal is recorded on the magnetic tape 17 with a track width of 6 microns during the period in which each head makes a half rotation. The two magnetic heads 10 and 11 may be mounted on, for example, a rotary cylinder (not shown) so that signals can be input and output via a rotary transformer (not shown).

Next, the magnetic tape 17 has a total width of 30 mm.
The above is wound around the two supply-side reels 19 and the take-up-side reels 20 having a diameter of 10 mm or less, and the supply-side reel motor 21 and the take-up-side reel motor 22 are used to
By rotating one reel, the magnetic tape 17 can be moved from one reel to the other reel of the two reels.
7 runs in the direction of arrow 18. Two reel motors 2
The rotation control of 1 and 22 is performed by the reel drive circuit 23, and the tape can be fed in the direction indicated by the arrow 18 and the opposite direction thereof at a speed several thousand times or more faster than the normal running.

Here, the track length corresponding to half the circumference of the head is about 9
Since it is 7 mm, the recording area of one track is about 0.4 square mm when the track pitch is 4 μm. 10 per second
Since the M-bit signal is recorded in 2 square mm, the number of tracks per second is 2 / 0.4 = 50. Therefore, 1
The tape feed rate per second is 50 times 4 microns, only 0.2 mm. Therefore, even if it is 1000 times 0.2 mm,
Since it is 2 m, that is, 20 cm, the conventional fast-forward reel servo can be used sufficiently. It should be noted that there is no problem even if the number of tracks per second is set to 50 for PAL signals broadcast in Europe, 59.94 for NTSC signals, and 60 for HDTV. ,
Rather, the input video signal and the recording track pattern can be easily matched.

FIG. 3 shows an example of a track pattern when the number of tracks per second is adapted to the NTSC system.
In FIG. 3, T (n), T (n-1), T (n-
2), T (n-3) ... Are each one track, and the track next to the track T (n-1) is T.
(N) is recorded, and adjacent tracks have a reverse azimuth relationship with each other. The width of each recording track is 4 microns (μm).

Generally, any portion may be used, but as an example, in FIG. 3, a linear track for a fixed head exists at the center of the track and is used as a time reference. For example, a control signal used in the VHS-VTR and a linear audio signal that can be used as a cue audio signal are recorded by the fixed head 13 shown in FIGS. 2 and 3 and reproduced by the reproducing head 15 shown in FIG.
The linear tracks may be formed not only on a part of the magnetic tape 17 but also on the whole.

At the time of reproduction, contrary to the case of recording, the signals reproduced from the two magnetic heads 10 and 11 are input from the output terminal 24 of the recording / reproduction changeover switcher 7 to the input terminal 2 thereof.
5 is input to the reproduction side signal processing circuit 26, and the output terminals 27, 28 and 2 are processed through a process reverse to that at the time of recording shown in FIG.
It is output from 9. In FIG. 4, the input signal is amplified by the reproducing head amplifier 30, and then four BPFs 31 and 3 are provided.
4, 37 and 40. The output signal of the BPF 31 is FM-demodulated by the FM demodulation circuit 32, de-emphasized by the de-emphasis circuit 33 and input to the addition circuit 36. Further, the output signal of the BPF 34 is converted into a carrier color signal of the original NTSC signal standard in the frequency conversion circuit 35 and is also input to the adder 36, and the NTSC color video signal is output from the adder 36. The stereo audio outputs of the BPF 37 and the BPF 40 are FM, respectively.
After being input to the demodulation circuits 38 and 41 and FM demodulated,
Unnecessary high frequency components are cut by the LPFs 39 and 42, respectively, and then output from the output terminals 28 and 29.

Here, the width Wt of the magnetic tape is, for example,
By setting it to 2.5 inches (about 63.25 mm), the search time for random access such as cueing can be dramatically shortened by 10 times or more compared to the conventional case.
For example, the recording signal has a transmission rate of 10 Mbps (1
With a digital signal of 10 Mbits per second), if the area of the magnetic tape required to record a 1-bit signal is 2 microns square, the tape area required to record for 3 hours is 0.216 square meters. Becomes Recent high performance vapor deposition tape (Co-Ni tape, Co-Cr tape,
Co-O tape) and metal particle tape (M
If the shortest recording wavelength is 0.5 μm and the track pitch is 4 μm using P tape and BaFe tape), a recording density of 2 μm per bit can be sufficiently realized.

Further, when the tape width is 2.5 inches, the effective tape width is about 62 mm, so the required tape length is about 3.48 m. Converting this value per hour is only 1.16 m. For example, VHS-VTR
Is the tape length per hour in the standard mode of 12
It is 1/100 or less when compared with 0 m. Therefore, even by using the tape fast-forward / rewind technology currently put to practical use in the VTR, random access such as head start can be realized in less than 1/100 time. That is, an arbitrary signal can be retrieved from a huge recording signal of 3 hours in an extremely short time of several seconds.

As described above, according to the present embodiment, the drawback of the magnetic tape, which is conventionally superior to the disk-shaped medium in that it has a large recording capacity but is greatly inferior in terms of random access, is solved. it can. In addition, the device size can be dramatically reduced.

A second embodiment of the present invention will be described below with reference to the drawings. The second embodiment differs from the first embodiment in the configuration of the recording side signal processing circuit 4.
FIG. 5 shows an example of the internal configuration of the recording-side signal processing circuit 4.
In FIG. 5, the NTSC color video signal input to the input terminal 1 of the recording side signal processing circuit 4 is separated into vertical and horizontal sync signals by the sync signal separation circuit 43, and the
A master clock (abbreviated as MCK) is generated by the L circuit (phased lock loop circuit) 44. The MCK output of the PLL circuit 44 is input to the frequency dividing circuit 45 and produces a reference clock for the three A / D converters 46, 47 and 48 and the digital signal processing circuit 49.

The A / D converter 46 converts the color video signal into an 8-bit digital signal at a sampling frequency of 13.5 MHz and inputs the digital signal processing circuit 49. Further, the A / D converters 47 and 48 convert the stereo audio signal into a 16-bit digital signal at a sampling frequency of 2.64 MHz and input the digital signal processing circuit 49. These signals are subjected to signal processing such as band compression, interleaving and addition of error correction code in the digital signal processing circuit 49, and then output from the output terminal 5 and input to the recording / reproducing changeover switcher 7 in FIG. It The subsequent signal processing is the same as the first
Is the same as the embodiment described above. The reproducing process is the reverse of that at the time of recording. First, after reproducing data is decoded into a digital signal, error correction processing is performed, de-interleaving is performed, and then the original signal is restored.

In the present embodiment, there is no problem if the recording track pattern has a circular shape smaller than a semicircle. Further, for example, if the length of the magnetic tape is set to 116 m, recording / reproducing for a long time of 100 hours becomes possible. Furthermore, by making the tape width smaller, by making a semicircular track pattern of 180 degrees into an arcuate track pattern of 90 degrees, 60 degrees, etc., it is possible to configure a more compact mechanism, and to reduce the size of the device. Can be realized. As magnetic tape cases, cassette halves with supply and take-up side reels such as the current VHS-VTR, and reels with only one side of supply side or take-up side such as computer data cartridges. It is possible to use a cassette half that has only this.

Further, as shown in FIG. 6, the reels on the supply side and the take-up side are close to each other and are very small at the time of storage, and at the time of operation, the magnetic tape is pulled out by one or a plurality of post pins. Half can be used. In this case, the cassette half has a very compact shape and is easy to handle.
6 (a) is a schematic view of the cassette half during storage, FIG. 6 (b) is a schematic view of the cassette half during use, with the lid open, and FIG. 6 (c) is during storage. 6D is a schematic view of the shape of the tape in the cassette half, and FIG. 6D is a schematic view of the shape of the magnetic tape during use.

[0023]

As described above, according to the present invention, a color video signal and an audio signal are converted into a form such as a digital signal,
For example, a loading mechanism for loading and unloading a magnetic tape onto a rotating cylinder by recording and reproducing a signal in a semicircular shape on a magnetic tape arranged in a plane by a magnetic head rotating on a plane is not available. It becomes necessary and the size of the device can be dramatically reduced.

Further, the width of the magnetic tape is, for example, 2.
By setting it to 5 inches (about 63.25 mm),
Random access search time such as cueing is 1 compared to the conventional
It can be dramatically shortened by 0 times or more. If the effective tape width is set to about 62 mm, the tape length required for recording for 3 hours is only about 3.48 m. Therefore,
Even with the tape fast-forward / rewind technology currently used in the VTR, random access can be realized in less than 1/100 of the current time. That is, an arbitrary signal can be called up within an extremely short time of several seconds.

As described above, it is possible to solve the drawbacks of the magnetic tape, which is conventionally excellent in that it has a large recording capacity as compared with the disk-shaped medium but is largely inferior in terms of random access. Further, since the cassette half itself can be made extremely small, a system of a magnetic recording / reproducing device which is very small and easy to handle can be constructed.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of a recording side signal processing circuit in the first embodiment of the present invention.

FIG. 3 shows a recording track according to the first embodiment of the present invention.
Diagram showing an example of a pattern

FIG. 4 is a schematic diagram showing an example of a reproduction side signal processing circuit in the first embodiment of the present invention.

FIG. 5 is a diagram showing an example of a recording side signal processing circuit according to a second embodiment of the present invention.

FIG. 6 is a schematic view showing an example of a cassette half and a magnetic tape used in the present invention.

[Explanation of symbols]

 1 Color video signal input terminal 2 Stereo audio signal input terminal 3 Stereo audio signal input terminal 4 Recording side signal processing circuit 5 Recording signal output terminal 6 Recording signal input terminal 7 Recording / playback switcher 8 Output terminal 9 Input terminal 10 Magnetic head 11 Magnetic Head 12 Output terminal 13 Recording fixed head 14 Input terminal 15 Fixed playback head 16 Magnetic head rotation direction 17 Magnetic tape 18 Magnetic tape advancing direction during normal recording / playback 19 Supply reel 20 Takeup reel 21 Supply side Reel motor 22 Take-up side reel motor 23 Reel drive circuit 24 Reproduction signal output terminal 25 Reproduction signal input terminal 26 Reproduction side signal processing circuit 27 Color video signal output terminal 28 Stereo audio signal output terminal 29 Stereo audio signal output terminal 4 9 Recording side digital signal processing circuit

Claims (10)

[Claims] 1. An apparatus for converting a color video signal and an audio signal into an analog signal form, and recording and reproducing the digital signal on a magnetic recording medium by a magnetic head,
A magnetic recording / reproducing apparatus comprising: a magnetic head rotating on a fixed surface, wherein the analog signal is recorded or reproduced on the magnetic recording medium in a substantially semicircular shape. 2. An apparatus for converting a color video signal and an audio signal into a form of a digital signal, and recording and reproducing the digital signal on a magnetic recording medium by a magnetic head,
A magnetic recording / reproducing apparatus comprising: a magnetic head rotating on a fixed surface, wherein the digital signal is recorded or reproduced on the magnetic recording medium in a substantially semicircular shape. 3. The magnetic recording according to claim 1, further comprising a fixed head, wherein the fixed head records and reproduces a time reference signal or an audio signal on a part or the whole of the magnetic recording medium. Playback device. 4. The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic heads are two magnetic heads that are arranged symmetrically with respect to a rotation center on a fixed rotation surface. 5. The magnetic head is arranged on a rotary cylinder with respect to its center of rotation (360 /
3. The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic recording / reproducing apparatus comprises N magnetic heads arranged in N) degrees symmetrically. 6. The magnetic recording / reproducing apparatus according to claim 1, wherein the magnetic recording medium is a magnetic tape. 7. The magnetic tape is wound around two supply-side reels and a take-up-side reel each having a total width of 30 mm or more and a diameter of 10 mm or less, and the reel drive motor drives the two reels. 7. The magnetic tape is moved from one reel of the two reels to the other reel by rotating the reel.
The magnetic recording / reproducing apparatus described. 8. The magnetic recording / reproducing apparatus according to claim 7, wherein the magnetic tape is taken out of a cassette case accommodating the magnetic tape by a fixed post. 9. The magnetic tape taken out of the cassette case accommodating the magnetic tape by the fixed post is such that only an arc portion scanned by the rotary magnetic head is on a constant surface. Magnetic recording and reproducing device. 10. The magnetic recording / reproducing apparatus according to claim 1, wherein the azimuth angles of the recording tracks recorded on the magnetic recording medium are opposite to each other and the azimuth angles of the adjacent tracks.