JPS601681B2 - Video and audio signal recording method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to provide a novel method for recording video and audio signals in a rotating head type magnetic green picture reproduction device (VTR).

Conventionally, simple VTRs have generally adopted the so-called helical scan method, in which the video signal is recorded as an oblique recording trajectory on a magnetic tape running by a rotating magnetic head, and the audio signal is recorded at the middle end of the magnetic tape. An audio track is formed in the running direction of the magnetic tape by a fixed magnetic head in contact with the magnetic tape, and recording or reproduction is performed using the running speed of the magnetic tape as the scanning speed. On the other hand, by increasing the recording density of video signals, the recording trajectory is narrowed and the running speed of the magnetic tape is reduced in order to reduce the amount of magnetic tape consumed and to make tape cassettes and devices smaller and lighter. However, it is difficult to ensure sufficient audio signal reproduction frequency characteristics based on the relative speed of the magnetic tape while reducing the running speed. Therefore, for example, a method may be considered in which the audio signal is recorded as a composite signal with the video signal using the same rotating magnetic head, but in this case, the audio signal may also be subjected to frequency modulation and Complex and expensive circuits such as demodulation are required, and after-recording of only audio signals is extremely difficult.Furthermore, when adjacent recording trajectories are played back at the same time, the field and frame correlations of the video signal are different from those of the audio signal. This would not be as expected and would result in direct crosstalk, making it extremely difficult to hear. If a guard is provided, high recording density of video signals cannot be expected. Furthermore, when frequency modulating an audio signal and sequentially switching a plurality of recording trajectories to obtain a reproduced audio signal, it is extremely difficult to remove switching noise during switching, resulting in a noisy reproduced sound. The present invention aims to solve these disadvantages, and will be explained below using examples.

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, FIG. 2 is a diagram showing a specific configuration example of the audio tape guide cylinder 5 in FIG. 1, and FIG. 1 shows an example of the arrangement (tape format) of recording trajectories on the magnetic tape 1 according to the embodiment shown in FIG. In FIG. 1, a magnetic tape 1 that is supplied from a supply reel (not shown) and driven by a driving means (not shown) such as a capstan pinch roller and runs at a predetermined speed vT in the direction of arrow 2 in the figure is a guide. The running position of the tape is guided by the posts 3 and 4, and the tape is wound spirally around the audio tape guide sill 5 at a predetermined angle, for example, 180 Q degrees (overlap angle Q'). They are built into the audio tape guide cylinder 5 and mutually set at a predetermined angle, for example, 180 degrees.
By supplying the audio signal to the vT vA magnetic heads 6 and 7, which are arranged at a relative angular position of 30° and rotate and scan at a relative scanning speed vA with respect to the magnetic tape, which is faster than the magnetic tape speed vT, the third As shown in the tape format example shown in the figure, the recording locus 28 of the audio signal is sequentially formed by a plurality of magnetic tapes, which are inclined backward by a predetermined angle ΦA with respect to the running direction of the magnetic tape. On the other hand, the magnetic tape 1 that has passed through the guide post 4 is wound around the video tape guide cylinder 8 over, for example, 180 degrees (overlap angle Q'), and then wrapped around the lead portion 9' of the lower fixed cylinder 9. The vehicle travels while being guided as to its driving position. The upper rotary cylinder is disposed coaxially with the lower fixed cylinder 9 and rotates at a frame period, for example. For example, if field skip recording is performed, the magnetic head is arranged at a relative angular position of 180 degrees. 11 and 12 (the other is used during playback). One field of video signals is supplied with a frame period, and the magnetic tape is scanned at a relative scanning speed with respect to the magnetic tape, which is faster than the running speed vT of the magnetic tape 1. While scanning the tape 1 at a scanning speed vv that is sufficiently faster than the relative scanning speed vA of the magnetic heads 6 and 7 with respect to the magnetic tape to which the audio signals are supplied, the magnetic heads 6 and 7 are scanned at a scanning speed vT > vA < vv as shown in FIG. As shown in FIG. 2, a recording locus 29 of video signals consisting of a plurality of lines oblique by a predetermined angle 8A with respect to the running direction 2 of the magnetic tape 1 is sequentially recorded.Note that the running speed vT of the magnetic tape 1, The relative scanning speed vA and scanning speed vv with respect to the magnetic tape are, for example, VT knee rib ISeC, VA knee 4 skin ISeC, VV 26 lse.
c.

vv>>vA>vT. In addition to the above-mentioned field skip recording, methods for recording video signals at high density include, for example, aligning the direction in the gap between the magnetic heads 1 1 and 12 with the running direction 2 of the magnetic tape 1, and Scanning is performed so that recording loci 29 of smaller medium Tv are left in sequence, and
A method is used in which a phase-modulated video signal is applied to one of the magnetic heads 11 and 12, with the frequency of the carrier wave set so that the phase of the carrier wave substantially matches between adjacent recording tracks 29. During playback, the horizontal synchronization signal gap is set at 180B to ensure continuity during switching.
The information is sequentially reproduced by both magnetic heads 11 and 12 arranged at a distance from each other. Note that during playback, adjacent recording trajectories 29 are scanned at the same time, but since the phases of the carrier waves almost match, no beats occur, and the frame correlation of the video signals prevents unnaturalness in the playback screen. It is something that can be solved. As for the recording method of the audio signal, for example, a direct recording method using a well-known AC bias is performed, and by setting vv>>vA, the recording locus 29 of one video signal is transferred to the magnetic head 1.
From the time it takes for 1 or 12 to scan at the scanning speed vv,
It becomes possible to reduce the time required for the magnetic head 6 or 7 to scan the recording locus 28 of one audio signal at the relative scanning speed vA with respect to the magnetic tape.

That is, the audio signal recorded within one audio signal recording trajectory 28 is smaller than the pitch Pv of the video signal recording trajectory 29 compared to the video signal of two or more recording trajectories 29. The pitch PA of trajectory 28 is much larger, and PA>>Pv adjacent recording trajectory 2
A guard G is provided between 8 and 8, and recording or reproduction can be performed with sufficient TA>>Tv in the recording trajectory. This facilitates tracking and provides an audio signal without crosstalk and having good reproduction frequency characteristics. Furthermore, as shown in FIG. 3, when the recording trajectories 28 and 29 are not superimposed, it is possible to perform after-recording of the audio extremely easily. In addition, when switching between the magnetic heads 6 and 7, it is possible to employ the well-known fade-in and fade-out method, for example, by direct recording using an alternating current bias.
Switching noise can be substantially eliminated.

Here, a specific example of the configuration of the audio tape guide cylinder 5 will be explained using FIG. 2. Note that the video tape guide cylinder 8 may have a well-known configuration, so its description will be omitted.
Magnetic heads 6 and 7 arranged at relative angular positions of 180 degrees are supported by the upper fixed cylinder 14 via bearings 15 and 16, and are integrated into the lower rotating cylinder 13 with the rotating shaft 17 that rotates by press-fitting, gluing, etc. An audio signal is supplied via rotary transformers 18 and 19, and the spirally wound magnetic tape 1 is scanned and recorded.

Note that the transmission and reception of audio signals may be performed using a slip ring brush method. The upper fixed cylinder 14 is connected to a holding member 20 by screws 21, and by fixing the holding member 20 to a substrate 22 with screws 23, the position of the audio tape guide sill 5 in the running path of the magnetic tape 1 is determined. It is. Further, the rotating shaft 17 is supported in the thrust direction by a support member 26 fixed to the base plate 22 with screws 25 through a ball 24 at one end, and a belt 28 is used as a transmission means through an integrally coupled booley 27. Rotational force is transmitted to it, and it rotates at a predetermined rotational speed. The rotational drive source for the rotating shaft 17 may be a motor (not shown) that rotates at a low speed, or a motor (not shown) that rotates at a high speed the magnetic head 11 or 12 on which the video signal is transmitted. This is obtained via a deceleration transmission means (not shown). (Also, the direction of rotation is set to be the same as or opposite to the running direction of the magnetic tape.) Also, as a method of tracking the recording locus 28 of the audio signal when the magnetic heads 6 and 7 reproduce the audio signal, for example, In the vicinity of the longitudinal end of the recording locus 28, a control signal is recorded in a location corresponding to an overlap portion that is not substantially used during reproduction, and is reproduced by the magnetic heads 6 and 7 to perform tracking. By comparing the phase with a control signal related to the rotation of the drive source as a reference signal, an error signal is obtained and tracking servo becomes possible. In the schematic explanatory diagram of the embodiment shown in FIG. 1, the audio tape guide cylinder 5 is provided on the supply side of the magnetic tape 1 with respect to the video tape guide cylinder 8. It may be provided on the receiving side, or it may be integrated with the video tape guide 8. Furthermore, the method of forming the recording trajectory 28 of the audio signal is not limited to the method using the rotating magnetic heads 6 and 7 described above. constitutes a mechanism and a reciprocating mechanism,
A method may be adopted in which the magnetic tape is scanned with a predetermined phase difference in order to mutually compensate for scanning sections where the scanning speed is low. Next, another embodiment according to the idea of the present invention will be explained using FIG. 4. In FIG. 4, for example, the magnetic tape 1 is attached to the audio tape guide cylinder 5 shown in FIG. On the contrary, it is a tape format obtained by winding the tape in a spiral shape with the oblique direction.
In particular, the azimuth loss also occurs when the gap directions of the magnetic heads 11 and 12 built in the video tape guide cylinder 8 are mirror-inclined in different directions with respect to the scanning direction and the adjacent video recording tracks 30 are simultaneously scanned. This has the advantage of eliminating the occurrence of beats.

This is an example in which a so-called azimuthal high-density recording method is adopted. In the same machine as described above, the running speed of the magnetic tape 1 is set to VT, and the audio magnetic head 32 (more than one is required, but one
Only these are schematically shown on the recording trajectory 31 of the audio signal.

) with respect to the magnetic tape is vA, and the scanning speed of the imaging magnetic heads 33 and 34 having an azimuth angle of 20 is vv, then each speed is set so that the relationship vv>>vA>>vT holds. It is set. In particular, the recording locus 30 of the video signal and the recording locus 31 of the audio signal are recorded so as to have at least an overlapping portion, and the recording position of the audio signal corresponding to the video signal in the tape running path is Similar to the embodiment shown in FIG. 1, it is provided on the supply side with respect to the recording position of the video signal, and once the recording trajectory 31 of the audio signal is formed, the recording trajectory 30 of the video signal is recorded in a superimposed manner. be. Then, the angle y formed by the equiangular bisector of the azimuth angle 20 between the video magnetic heads 33 and 34 and the direction in the air gap of the audio magnetic head 32 is approximately a right angle (y≠90o). magnetic head 3
This is to set the directions in the gaps 3, 34, and 32. That is, the magnetization direction on the recording trajectory 30 of the video signal and the magnetization direction on the recording trajectory 31 of the audio signal are approximately perpendicular to each other,
This provides the advantage that substantially no interference noise is reproduced even if other recording loci 30 or 31 are scanned during reproduction. In addition, since the recording position of the audio signal precedes the video signal, for example, if a direct recording method using AC bias is adopted, the recording wavelength of the audio signal is extremely large compared to the video signal, so the magnetic powder coating of the magnetic tape It is possible to record deep layers, and even if an extremely short wavelength video signal is superimposed and recorded thereafter, only the surface layer is recorded, and the deterioration of the reproduced audio signal is substantially tolerable. Next, regarding an embodiment in which an audio tape guide cylinder 5 and a video tape guide cylinder 5 as shown in the embodiment of FIG. 1 are integrated based on the idea of the present invention, a specific configuration example of the tape guide cylinder is shown in FIG. 5. An example of the tape format based on this is shown in FIG. 6 and will be explained. Fifth
The figure shows a magnetic tape 1 running in the direction of arrow 2 at a running speed vT in an audio and video tape guide cylinder 35 in a spiral shape of 180 Q degrees (Q is the overlap angle, and magnetic heads 36, 37, 38, 39 is wound around the magnetic tape 1 at an angle such that it contacts almost the entire length of the magnetic tape 1, and is arranged so that it slightly protrudes from the outer circumferential surface, and the audio signal is recorded on the magnetic tape 1 before the video signal. The audio magnetic heads 36 and 37 scan at a relative scanning speed vA and are at a relative angular position of 180 degrees to each other, and the audio magnetic heads 36 and 37 scan at a scanning speed vv and are positioned at a relative angle of 180±8 degrees to each other (as an example, similar to the explanation in FIG. 1). In the case of field skip recording, 8 degrees is an angular deviation determined to obtain continuity of the horizontal synchronizing signal during switching during reproduction.

), the video magnetic heads 38 and 39 at relative angular positions are used to record audio and video signals tilted by predetermined angles OA and OV with respect to the running direction 2 shown in FIG. FIG. 3 shows an example audio and video tape guide cylinder configured to form trajectories (66 and 65). Note that the running speed vT and the relative scanning speed vA and vv with respect to the magnetic tape are vv>
>vA>vT. In other words, the audio and video tapes are prophecies, and the lower parts of the heads 38 and 39 are 40 shillings.
A rotary disk 43 is integrated with a hollow rotary shaft 42 rotatably held via a bearing 41 and a rotary disk 43 by press-fit adhesive or the like.
The rotary driving force is applied to the hollow rotating shaft 42 through the piston 4.
The transmission is transmitted to a motor shaft 48 which rotates in the direction of an arrow 46 to a pulley 45 fixed at a lower miller 4 through a belt 49 stretched between the main part of the pulley 48 and a motor shaft 48 which rotates in the direction of an arrow 46.
Video signals are transmitted and received by a rotary transformer 52 which is bonded to and opposed to a pedestal 51 and a rotary disk 43, respectively, which are fixed to each other by means of screws. On the other hand, the scanning speed vv of the video magnetic heads 38 and 39
The audio magnetic heads 36 and 37, which scan at a relative scanning speed vA with respect to the magnetic tape, which is much slower than the magnetic tape, are rotatably supported by an upper cylinder 53 on one side and a hollow rotating rat 42 on the other via a bearing 54, and rotate. It is attached to a rotating disk 56 that is integrated with the rotating shaft 55 by press-fitting adhesive, etc., and the rotational driving force is transmitted between the large diameter pulley 58 fixed to the rotating shaft 55 with a pin 57 and the nose and diameter of the pulley 48. The audio signal is transmitted via a belt 59 mounted on the upper cylinder 53 and the rotary transformer 60 mounted opposite the rotary disk 56, respectively.

The rotating shaft 55 is held in the illustrated direction by a pulley 58.
and a holding member 62 fixed to the rotating shaft 55 with screws 61.
The upper, middle, and lower cylinders 53
, 63, 4 screws 63 to fix the relative position coaxially
It is attached to the continuous section 64 by. By adopting such a configuration, audio signals are formed on the magnetic tape 1 as recording trajectories 65 and 66, respectively, in advance of video signals, as shown in FIG. 6, while maintaining the relationship vv>>vA>vT. , as a high-density recording method for video signals,
For example, in addition to the above-described field skip recording, the direction in the gap of the video magnetic heads 38 and 39 is made to coincide with the tape running direction 2, and the recording trajectory 6 of the medium Tv is smaller than that during scanning of the gap.
Scanning is performed so that 6 remains sequentially, and the adjacent recording locus 65
A phase modulation recording method is used in which the frequency of the carrier wave is set so that the phase of the carrier wave almost matches between the two. Regarding the audio signal, the angle y between the direction of the air gap between the audio magnetic heads 36 and 37 and the air gap direction of the video magnetic heads 38 and 39 is set to be almost perpendicular (y≠900). The above-mentioned direct recording method using an AC bias that enables deep recording is adopted, and a recording trajectory 66 of an audio signal having a TA in the trajectory is formed via a G in the guard.
In this case, as explained in FIG. 4, interference between video and audio signals does not substantially pose any problem during playback. Also, as mentioned above, vv>>vA (>vT)
By doing so, the pitch P of the recording trajectory 65 of the video signal is
It becomes possible to set the pitch PA of the recording trajectory 66 of the audio signal to PA>>Pv, which is much larger than v, and by being able to take G during guard, it is possible to easily obtain an audio signal without crosstalk.

Next, a seventh embodiment of another tape format obtained with substantially the same configuration as the concrete configuration example of the audio and video tape guide cylinder 35 shown in FIG. 5 according to the idea of the present invention will be described.
This will be explained using FIG. 8 and FIG.

Note that items common to Figures 5 and 6 are shown in Figure 7.
The same reference numerals are used in the figures and FIG. 8 as well. That is, in the embodiment shown in FIG. 5, the winding angle and oblique angle of the magnetic tape 1 around the audio and video tape guide cylinder 35 are controlled by both the audio magnetic heads 36, 37 and the video magnetic heads 38, 39. The structure is set so that it extends from one end of the magnetic tape 1 in the middle direction to the other end, but in the embodiment shown in FIG. 7, magnetic heads for audio and video (36, 37 and 38 , 39 are arranged so that recording trajectories 66 and 65 of the audio and video signals are recorded in a portion that does not extend from one end of the magnetic tape 1 in the substantially middle direction to the other end as shown in FIG. This is an embodiment in which the winding angle and oblique angle of the magnetic tape 1 around the video tape guide cylinder 35 are set.

In the examples shown in FIGS. 7 and 8, the recording trajectories of the audio and video signals (66 and 65, respectively) are mutually located on the magnetic tape 1.
This is an example in which the inside is roughly divided into two, but for example, although not shown, it is possible to increase the number of audio magnetic heads and reduce the effective winding angle of the audio magnetic heads around the rotating surface to change the recording trajectory of the video signal. The proportion may be increased. In this way, the recording trajectories of audio and video signals (66 and 65, respectively)
) are recorded without being superimposed, the audio and video magnetic heads 36 and 37 shown in the example of FIG.
There is no need to set the directions in the gap between (38, 39) in a special relationship, and after-recording of audio signals is also easily possible.

As described above, the concept of the present invention has the following features and many advantages associated with it.The first feature is that a magnetic tape running at a prescribed tape speed can be The first magnetic head to be scanned records the video signal at a relative speed faster than the predetermined tape speed, and records the video signal on the magnetic tape at a relative scanning speed to the magnetic tape that is slower than the scanning speed of the first magnetic head. scan.

The audio signal is transmitted by a second magnetic head group consisting of a plurality of heads.
The purpose of this method is to scan and form recording trajectories of video signals and audio signals, each consisting of a plurality of tapes that are tilted at a predetermined angle with respect to the running direction of the magnetic tape. Recording of audio signals that achieves high-density recording, reduces magnetic tape consumption, makes cassettes and devices smaller, lighter, and less expensive, and has good frequency characteristics and can virtually eliminate switching noise. is possible. Further, if the recording trajectory of the video and audio signals is formed so that it does not distort, after-recording becomes possible. The second feature is that one of the plurality of second magnetic heads records one audio signal in a time longer than the time it takes for the first magnetic head to scan and form the recording locus of the video signal. The goal is to scan and form trajectories, thereby achieving high recording density for video signals, while setting the pitch between recording trajectories sufficiently wide and providing a guard band for audio signals where frame correlation cannot be expected. Therefore, it is possible to provide a recording method that makes it possible to obtain a good reproduced audio signal without crosstalk.

Furthermore, the recording trajectory of the video signal and the recording trajectory of the audio signal are scanned and formed by overlapping at least a portion thereof, and the magnetization direction on the recording trajectory of the video signal and the magnetization direction on the recording trajectory of the audio signal are mutually By setting the directions in the air gap of the first magnetic head and the plurality of second magnetic heads so as to form a substantially right angle, in addition to the advantage of the first feature, the area occupied by the recording trajectory of the audio signal on the magnetic tape is reduced. This increases the crosstalk prevention effect due to the enlargement during guarding, makes it possible to relax the tracking accuracy and widen the trajectory, and increase the reproduction output. Also, the fifth
As shown in the embodiment shown in the figure, by coaxially disposing a video magnetic head and an audio magnetic head in the same head cylinder, the audio and video recording and playback positions are always in a constant relationship, and the audio and video recording “Differences” between video and audio occur when changing tapes due to playback positions differing between devices.
It never happens.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing one embodiment of the present invention, FIG. 2 is a cross-sectional view of the same essential part, FIGS. 3 and 4 are views showing examples of recording patterns on the magnetic tape of the present invention, and FIG. 6 is a sectional view of a main part showing another embodiment of the present invention, FIG. 6 is a diagram showing a recording pattern on a magnetic tape by the same device, FIG. 7 is a side view showing still another embodiment, and FIG. 8 is a diagram showing a recording pattern on a magnetic tape by the same device. DESCRIPTION OF SYMBOLS 1... Magnetic tape, 5... Audio tape guide cylinder, 6, 7... Audio magnetic head, 10... Rotating cylinder, 11, 12 ...
...Video magnetic head. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Claims (1)

[Scope of Claims] 1. A first magnetic head scanning a magnetic tape running at a predetermined tape speed records a video signal at a relative scanning speed with respect to the magnetic tape faster than the predetermined tape speed; An audio signal is recorded by a plurality of second magnetic heads that scan the magnetic tape at a relative scanning speed with respect to the magnetic tape, which is slower than the scanning speed of the first magnetic head, and the video signal and the audio signal are respectively recorded on the magnetic tape. A video and audio signal recording method characterized in that recording is performed as a plurality of recording trajectories that are inclined at mutually different predetermined angles with respect to the running direction of a magnetic tape. 2. One of the plurality of second magnetic heads scans and forms one audio recording trajectory in a time longer than the time it takes for the first magnetic head to scan and form one video signal recording trajectory. A video and audio signal recording system according to claim 1, characterized in that: 3 Scanning is performed by overlapping at least a portion of the recording trajectory of the video signal and the recording trajectory of the audio signal, and the magnetization direction on the recording trajectory of the video signal and the magnetization direction on the recording trajectory of the audio signal are The video and audio signal recording system according to claim 1, characterized in that the gap directions of the first magnetic head and the plurality of second magnetic heads are set to be substantially perpendicular to each other. . 4. The first magnetic head and the second magnetic head have the same rotation center axis and are configured to be rotated at different positions in the axial direction, and the magnetic tape also has the same central rotation axis. 2. The video and audio signal recording system according to claim 1, wherein the magnetic head is wound spirally at a predetermined angle and runs along the rotation locus of a magnetic head.