JP3161051B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head cylinder on which a magnetic head is mounted, which is driven by winding a magnetic tape around the magnetic head and slidingly contacting the magnetic head with the magnetic tape.
The present invention relates to a reduction in size and weight of a magnetic recording and reproducing device such as a video tape recorder that records and reproduces a video signal.

[0002]

2. Description of the Related Art A standard magnetic recording / reproducing apparatus (hereinafter referred to as a basic VT)
R) is configured as shown in FIG. Two rotary heads 101a and 101b having different azimuth angles are arranged so as to slightly protrude from the rotary head cylinder 102 at an interval of 180 degrees, and a recording tape 103 is obliquely wound around the rotary head cylinder 102. The rotating heads 101a and 101b are rotated at one frame period, whereby the rotating heads 101a and 101b alternately scan the recording tape for each field, thereby forming one track per field. Video signals (audio signals) are recorded. FIG.
As shown in (b), the rotation direction of the rotary head is rotating in the same direction as the tape traveling direction.

As a method of keeping the recording format (recording track pattern) of the basic VTR and making the diameter of the rotary head cylinder smaller than that of the basic VTR, a magnetic recording / reproducing apparatus such as a cassette type video tape recorder has recently been used. The diameter of the rotating head cylinder is set to 2/3 of the standard type, and the effective winding angle is 2
The type using a 70 ° four-head type small-diameter cylinder has become mainstream. FIG. 8 shows a situation in which recording is performed by switching the heads of a four-head type small-diameter cylinder. Rotating heads 104a to 104d are arranged at 90 ° on the circumferential surface of the cylinder and are divided on the recording tape so that the heads 104b, 104c, 1
Recording or reproduction is sequentially performed in the order of 04d and 104a.

[0004]

However, in the above-mentioned conventional construction, the diameter of the rotary head cylinder is 2/3 times that of the basic magnetic recording / reproducing apparatus, and the four-head type small-diameter cylinder system described in the conventional example is used to reduce the size of the apparatus. There are inevitably limits to the transformation.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and reduces the diameter of the rotary head cylinder to half or less of the rotary head cylinder of the basic VTR, thereby achieving the ultimate miniaturized V.
The purpose is to provide TR.

Further, Japanese Patent Publication No. Sho 62-56716 has already proposed that the diameter of a rotary head cylinder be reduced to half that of a basic VTR. Further, Japanese Patent Application Laid-Open No. Hei 4-132214 proposes a method of reducing the cylinder diameter without increasing the winding angle around the rotary head cylinder. However, when recording and reproducing one recording track by different heads, there is a problem in connection accuracy of video signals written by the respective heads. When a video is reproduced by these devices, the connection between the main head and the sub head is difficult. In this case, there is a problem that skew or color shift occurs.

[0007]

In order to achieve this object, a magnetic recording / reproducing apparatus according to the present invention comprises a head for rotating a head in substantially the same direction as a tape running direction to record and reproduce a video signal.
In the present magnetic recording and reproducing apparatus,
Video signal in the opposite direction from the back for each frame.
A signal reading means to be inspected, a video signal is recorded and reproduced on a tape by rotating at a speed v ₀ in the direction opposite to the tape running, the tape speed is set to V, and the track angle on the tape recorded by the basic magnetic recording and reproducing device is θ. when and _{was, a = v 0 * tanθ B} = V * tanθ Distant, lead angle of the rotating head cylinder at this time θ
₀ is cos (θ ₀ ) = (− 2 * A * B + √ (4 * A ² * B ² −)
_{^{4 * (A 2 + V 0}} 2) * (b 2 -V 0 2))) / (2 * (a 2
+ V ₀ ² )), a main head attached to the rotary head cylinder, which traces an upper recording track formed on an upper side in a longitudinal direction of the recording tape, and a track pitch of the recording track. p, the mounting height is different from the main head by d,
A lower recording track, which satisfies at least the equation of (d / p) = (even number) and is formed on the lower recording layer in the longitudinal direction of the recording tape, is continuous with the upper recording track traced by the main head. A sub head for tracing, a memory device for storing a sub video signal to be recorded by the sub head, and a reproducing unit for reading a main video signal recorded on the upper recording track by the sub head in a recording mode, A horizontal synchronization signal generator for synchronizing with the main video signal reproduced by the sub head, phase control means for adjusting the phase of the video signal, and a main video signal generated by the horizontal synchronization signal generator and phase control means. And a sub-video signal writing means for continuously recording the signal.

[0008]

With this structure, the diameter of the rotary head cylinder can be reduced to one half or less of that of the basic magnetic recording / reproducing apparatus as compared with the conventional rotary head cylinder, and the connection between the upper recording track and the lower recording track can be performed with high precision. It can be realized.

[0009]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

First, a description will be given of an example in which the diameter of a rotating cylinder is halved when a general-purpose home VTR is a basic magnetic recording / reproducing apparatus (hereinafter referred to as a basic VTR).
FIG. 1 shows an example of the configuration of the rotary head cylinder in that case. In FIG. 1A, reference numeral 1 denotes a VT whose diameter is basic.
R is a rotary head cylinder of 1/2
Is the effective winding angle of the rotary head cylinder 1 of 30
It is wound diagonally at 2.4 °. Here, originally, it is necessary that the tape 2 be wound around the rotary head cylinder 1 over 360 °. However, since it is necessary to provide an appropriate space for each of the tape guide posts 3 and 4, the winding amount is set to be small. are doing. The rotary head cylinder 1 has a double azimuth head 5 as a main head having heads 5a and 5b having different azimuth angles, and a head 6 having a different azimuth angle from each other.
A double azimuth head 6 which is a sub head having a and 6b is provided at a position lower than the double azimuth head 5 by a height d. In addition, double azimuth heads 5 and 6
Is set to be shifted from the rotation center of the rotary head cylinder 1 by an angle α. Main heads 5a and 5b and sub heads 6a and 6b of double azimuth heads 5 to 6
Is a horizontal scanning section H (hereinafter, referred to as H).
Is set so as to avoid crosstalk between horizontal synchronization signals of adjacent tracks during recording and reproduction.

Here, the height d and the angle α are shown in FIG.
It is shown in FIG. 1- (b). The head mounting angle α and the height d will be described in more detail.

The following conditions are required in order for the recording tracks of the main head 5a and the sub head 6a to continuously obtain a tape pattern equivalent to the recording pattern of the basic VTR. 1) The azimuth angles of the heads in one recording track match. 2) Even and odd fields of a recording signal coincide in one recording track. 3) The order of the horizontal scanning period (the order of the horizontal scanning line number) on the tape pattern is continuous, and the horizontal scanning period (the length on the tape pattern of one horizontal scanning period) at the switching point of the main and sub heads. And the same as the horizontal scanning period of the portion other than the head switching point. 4) The height of the trucks must be the same.

The head mounting height d and the head mounting angle α satisfying the above conditions will be described with reference to FIG. Ra indicates the upper recording track range of the main heads 5a and 5b, and Rb indicates the lower recording track range of the sub heads 6a and 6b. The sum of the two recording ranges is the recording range for one field. When the main head 5a is located at the start point of the recording range Ra shown in FIG. 2B, the main head 5a is separated from the main head 5a by an angle α as shown in FIG. As shown, the sub head 6a mounted lower by the height d is located at the end of the recording range as shown in FIG. In FIG. 2, lα indicates a distance corresponding to the mounting angle α.
Assuming that the extension lines of the recording tracks scanned by the two heads 5a and 5b are the track A4 and the track A1, these tracks have the same recording magnetization direction, and the odd and even field relations of the video signal to be subsequently recorded. Must be the same. For this purpose, an odd number of recording tracks must be recorded between the tracks A4 and A1 (five in FIG. 2A). In other words, the distance d between the tracks A4 and A1 must be an even multiple of the track pitch p of the recording track.

Next, a method of dividing and recording one field of a video signal (FM audio signal) by the two double azimuth heads 5 and 6 will be described with reference to FIGS. It is impossible to write one track (one field) with one head because the diameter is half of the cylinder diameter of the basic VTR and the effective winding angle is 302.4 °. In FIG. 3, (1) shows the write timing of the main heads 5a and 5b, and (2)
Indicates the write timing of the sub heads 6a and 6b,
(3) shows the switching timing of the main head when reading the video signal from the CCD, and (4) shows the switching timing of the main head and the sub head. As described above, the A track (one field) is recorded by the main head 5a and the sub head 6ab, and the B track (1 field) is recorded by the main head 5b and the sub head 6b. In FIG. 2A, the recording tape 2 is moving in the direction of the arrow at a predetermined speed v, and the main head 5a and the sub head 6a are opposite to the traveling direction of the tape 2, that is, the basic VT.
The head is rotating in the direction opposite to the rotation direction of the R head. FIG.
5A, the main head 5a finishes recording the upper recording track A4-U of the track A4 and the sub head 6a
Is recording the lower recording track A1-L of the track A1. Here, in order for the sub head 6a to record the signal of the lower track A1-L, the main head 5a
, The lower recording track A1-L corresponds to the time required for the upper recording track A1-U recorded in FIG.
Must be stored.

Next, a description will be given of a means for continuously recording H between each other when a track of one field is divided into two parts and recording is performed by different heads. FIG. 4 shows a state in which a signal of the lower recording track A1-L is recorded. The rotary head cylinder 1 in the present embodiment rotates in a direction opposite to the basic VTR. The sub head 6a functions as a reproducing head while tracing on the upper recording track, and reads the phase of the horizontal synchronizing signal and the video signal of the track A1-U. When the sub head 6a starts writing the lower recording A1-L, it is set so that the signal is recorded in synchronization with the horizontal synchronization signal and the video signal of the upper recording track A1-U first. . Similarly, when writing the lower recording track B1-L of the azimuth reverse to the A1 track, the signal is recorded in the same procedure.

As described above, by reversing the rotation direction of the rotary head cylinder 1, the previously recorded track is traced and a signal is read, and the tracks A1-U are tracked with the same head based on the read signal. Track A
A 1-L connection can be made.

Next, the lead angle of the rotary head cylinder will be described. As is well known, the video track angle recorded on the recording tape is determined by the rotation speed of the rotary head cylinder and the tape speed. In this embodiment, in order to rotate the rotating head cylinder in the direction opposite to that of the basic VTR, it is necessary to set the lead angle of the basic VTR slightly larger than that of the basic VTR. When the lead angle is rotated at a speed v _{0 in} the direction opposite to the tape running direction and the video signal is recorded and reproduced on the tape, the tape speed is V, and the track angle of the basic VTR on the tape is θ, V ₀ * tan θ B = V * tan θ, and the lead angle θ ₀ of the rotary head cylinder at this time is cos (θ ₀ ) = (− 2 * A * B + √ (4 * A ² * B ² −)
4 * (A ² + v ₀ ² ) * (b ² −v ₀ ² ))) / (2 * (a ²
+ V ₀ ² )).

Next, a signal processing system of the VTR according to the present embodiment will be described. FIG. 5 shows an example of the signal processing system. CCD
The image captured in 7 is sample hold 8, AGC
A / D conversion is performed through 9. Here, the video signal read from the CCD 7 is read in the reverse direction from the back of one frame as shown in FIG. The read signal is temporarily stored in the memory 11, the upper-side recording signal is first sent out by the memory controller 12, and after D / A conversion, it is sequentially recorded by the main head 5a and the main head 5b. The sub-picture signals include the upper recording track A1-U and the lower recording track A1-L of the same frame, and the upper recording track B1-U and the lower recording track B1-
L, until the upper recording track A2-U and the lower recording track A2-L,... Can be connected and recorded as the same frame, that is, in the NTSC system, (the height d between the main head and the sub head) / ( Recording track pitch p) /
It is stored in memory for a time corresponding to 60. When the sub head 6a is scanning over the upper recording track A1-U, the signal of the upper recording track A1-U reproduced by the sub head 6a in FIG. And reads the phases of the horizontal synchronizing signal and the video signal. Thereafter, a horizontal synchronizing signal is generated in accordance with the phases of the read horizontal synchronizing signal and the video signal, and is fed back to the memory controller 12 having a built-in phase control means for adjusting the phase of the video signal. Thus, the timing of writing to the lower recording track A1-D of the sub head 6a is adjusted. When the sub head 6a moves away from the upper recording track A1-U at that timing, the changeover switch 15
The sub head 6a is switched from reproduction to recording. The recording of one track A1 is completed by the above procedure. Thereafter, signals are recorded in the same procedure.

As means for scanning the CCD 7 in the reverse direction from behind one frame, a basic V
The image entering the CCD 7 can be inverted with respect to the conventional basic VTR by minor changes such as adding a single lens to the lens system of the video camera adapted to the TR, and C
It can be easily realized without changing the scanning for reading the CD.

[0020]

As described above, in the magnetic recording / reproducing apparatus of the present invention, the upper recording track is formed on the upper side in the longitudinal direction of the recording tape by the main head. The head forms a lower recording track on the lower side in the longitudinal direction of the recording tape following the upper recording track. Here, the rotating head cylinder is rotating in a direction opposite to the rotating direction of the basic VTR. This allows the main head to trace the upper recording track, reproduce the signal of the upper recording track, and write the lower recording track just before the sub head records the lower recording track.

Therefore, in this magnetic recording / reproducing apparatus, the diameter of the rotary head cylinder is set to 1/2 of the standard size.
Thus, the size of the apparatus can be reduced, and the connection between the upper recording track and the lower recording track can be accurately performed.

[Brief description of the drawings]

FIG. 1A is a plan view of a rotary head cylinder of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. FIG. 1B is a side view of a rotary head cylinder of a magnetic recording / reproducing apparatus according to an embodiment of the present invention. Detailed view of a double azimuth head of a magnetic recording / reproducing apparatus according to an embodiment of the present invention (d) Recording track pattern of a magnetic recording / reproducing apparatus according to an embodiment of the present invention

FIG. 2 (a) is a diagram showing a positional relationship between a recording track and an upper head and a lower head of a magnetic recording / reproducing apparatus according to an embodiment of the present invention; and (b) a magnetic recording / reproducing apparatus according to an embodiment of the present invention. Schematic diagram showing the positional relationship between the recording track of the upper stage head and the lower stage head

FIG. 3 is a timing chart showing operation switching timings of the upper head and the lower head of the magnetic recording / reproducing apparatus according to the embodiment of the present invention;

FIG. 4 is a diagram showing a situation where the lower head of the magnetic recording / reproducing apparatus traces the upper recording track in the embodiment of the present invention;

FIG. 5 is a diagram showing a signal processing system of a magnetic recording / reproducing apparatus according to an embodiment of the present invention.

6A is a diagram showing specifications for reading an image signal from a CCD of a basic VTR. FIG. 6B is a diagram showing a magnetic recording and reproducing apparatus according to an embodiment of the present invention.
Diagram showing reading specifications of image signal from CD

FIG. 7A is a diagram showing a four-head sequential switching head arrangement which is a rotary head cylinder of a conventional magnetic recording / reproducing apparatus. FIG. 7B is a diagram showing the rotational direction of the head in the conventional magnetic recording / reproducing apparatus. The figure shown

FIG. 8 is a diagram showing the relationship between a recording head of a four-head sequential switching system, which is a rotary head cylinder of a conventional magnetic recording and reproducing apparatus, and a recording track on a recording tape.

[Explanation of symbols]

 Reference Signs List 1 rotating head cylinder 2 recording tape 3 tape guide post 4 tape guide post 5 double azimuth head 6 double azimuth head 7 CCD 8 sample hold 9 AGC 10 A / D 11 memory 12 memory controller 16 playback device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-13214 (JP, A) JP-A-4-13215 (JP, A) JP-B-62-56715 (JP, B2) (58) Survey Field (Int.Cl. ⁷ , DB name) G11B 5/53

Claims (1)

(57) [Claims] A head is provided in substantially the same direction as the tape running direction.
Basic magnetic recording / reproducing device that rotates and records / reproduces video signals
The video signal with respect to the rotation direction of the head at
Signal reading means that scans backward from the back for every frame
When the video signal is recorded and reproduced on the tape by rotating at a speed v ₀ in the reverse direction to the tape running, the tape speed is V, and the track angle on the tape recorded by the basic magnetic recording and reproducing device is θ, _{= v 0 * tanθ B = V} * tanθ Distant, lead angle of the rotating head cylinder at this time θ
₀ is cos (θ ₀ ) = (− 2 * A * B + √ (4 * A ² * B ² −)
_{^{4 * (A 2 + V 0}} 2) * (b 2 -V 0 2))) / (2 * (a 2
+ V ₀ ² )), a main head attached to the rotary head cylinder, which traces an upper recording track formed on an upper side in a longitudinal direction of the recording tape, and a track pitch of the recording track. p, the mounting height is different from the main head by d,
A lower recording track, which satisfies at least the equation of (d / p) = (even number) and is formed on the lower recording layer in the longitudinal direction of the recording tape, is continuous with the upper recording track traced by the main head. A sub head for tracing, a memory device for storing a sub video signal to be recorded by the sub head, and a reproducing unit for reading a main video signal recorded on the upper recording track by the sub head in a recording mode, A horizontal synchronization signal generator for synchronizing with the main video signal reproduced by the sub head, phase control means for adjusting the phase of the video signal, and a main video signal generated by the horizontal synchronization signal generator and phase control means. A magnetic recording / reproducing apparatus comprising: a sub-video signal writing unit that continuously records a signal.