JPS6022706A - Signal recording and reproducing device - Google Patents

Abstract

PURPOSE:To perform the recording/reproducing with a video track having the same recording length as a two-head type VTR and at the same time to attain miniaturization of a rotor, by using >=3 heads of the same azimuth angle which are attached to the rotor with equal angular intervals. CONSTITUTION:Six heads H1-H6 are attached to a rotor 6 with equal angular intervals, and the same azimuth angle is given to each head. A magnetic tape 2 is wound around the rotor 1 at angles alpha and beta for overlap recording with 300 deg. effective winding angle. Both the rotor 1 and the heads are revolved by F(n- n)/n number of revolutions per second (n: number of heads) when a video signal of field frequency F is recorded. The video signal is supplied selectively to either one of those heads by a switch circuit. For instance, the video signal is supplied only to the head H1 when it reaches the place near a guide pole 3. This supply of video signal is continued until the head H1 is set near a guide pole 4. Then the video signal is supplied to the head H2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a signal recording and reproducing device, and in particular, it uses three or more heads attached to a rotating body at equal angular intervals to improve the current two-way
The present invention relates to a head type magnetic recording and reproducing apparatus (VTR) which records and reproduces video tapes having the same recording length on a magnetic tape.

Prior Art and Its Problems In a conventional two-head helical scan VTR using an azimuth recording/reproducing method, two heads are mounted opposite each other on a rotating body, and the azimuth angles of the two heads are made to differ in opposite directions with respect to the track width direction. It is well known that information signals such as video signals are recorded on a magnetic tape using two rotating heads.

However, in the above-mentioned VTR, the effective winding angle of the magnetic tape around the rotating body is 180 degrees, and even if a slight overlap recording is added, the rotation of the arbitrary head is only for about half a revolution of the rotating body. Since I was not using it for recording, I had no choice but to use a rotating body with a large diameter to obtain the required relative speed between the tape and the head.
In order to obtain a tape-head relative velocity of 5.80 rn/s, the diameter of the rotating body is 62 mm).

On the other hand, in a portable VTR, which is desired to be smaller and lighter, the large serrations of the rotating body have such a large effect that they affect the overall size of the device.

However, when standards such as tape patterns are established, the diameter of this rotating body becomes constant, and therefore even porta-pull type VTRs must be equipped with a rotating body of the above-mentioned large diameter.
This has placed restrictions on miniaturization and weight reduction of the device.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a signal recording/reproducing apparatus which solves the above problems by increasing the number of heads attached to a rotating body to three or more.

Means for Solving the Problems The present invention arranges n heads having the same azimuth angle (where n is a natural number of 3 or more) at equal angular intervals on a rotating body, and sets the field frequency F (H2). When recording and reproducing a video signal, the rotating body is rotated at a rotation speed of ((0-1)/n) ・F per second, and the rotating body is rotated 360° ・(n-1>/
The above-mentioned n heads are sequentially and cyclically switched at intervals of a period approximately equal to a valid ticket angle rotation period on a magnetic tape which satisfies the formula n and is being wound at an effective winding angle while traveling. Accordingly, during recording, signal recording tracks are sequentially formed with an i-rack pitch smaller than the track width, and during reproduction, the recorded green signal is scanned by scanning the recorded edge track, and the recorded green signal is reproduced. An example thereof will be described with reference to the drawings.

Embodiment FIG. 1 shows an embodiment of the head arrangement and tape winding relationship of the device of the present invention, and FIG. 2 shows the rotation of the head of the device of the present invention! 10 shows a perspective view of an embodiment in the vicinity of the structural part a. In both figures, the same components are designated by the same reference numerals.

In both figures, six heads f-1+, '! -12, t-h
.

H4, 1-1s and 1-16 are mounted and fixed at equal angular intervals of 60'. These heads 11-1-16
have the same azimuth angle gap, and their track widths TW are selected to be the same value.

The rotating body 1 is provided with guide poles 3 and 4 at an angle α0 for recording the valid ticket at an angle of 300° as shown in FIG. The magnetic tape 2 is spliced and wound over an angular range of a little more than 300°, including β°.

Also, the magnetic tape 2 is connected to the audio tape by the guide ball 4.
It passes in front of the controller 1 to the roll head 5 and is held between a capstan 6 and a pinch roller 7, and is moved in the direction of arrow X by the rotation of the capstan 6.

Further, the center of the rotating body 1 is connected to the motor 8 as shown in FIG.
is fixed to the tip of the rotating shaft 9, and furthermore, the disks 1Q, 1
1 and 12 are coaxially attached with their central portions penetrating and fixed to the rotating shaft 9.

On the disk 10 are magnets 1 to 138 magnetized to N poles.
and a magnet 13b magnetized to the S pole are mounted facing each other.

It is installed at a position parallel to the axial direction of the rotary shaft 9 with respect to the installation position of the disk 1''4.
A magnet 14a magnetized to the north pole and magnets 1 to 14b magnetized to the south pole are placed on the top of the magnet 1, corresponding to the mounting position of the head +12.H5 facing toward each other. ing. Further, in a direction parallel to the axial direction of the rotating shaft 9, a magnet 15a magnetized to the north pole is fixedly attached to the disk 12 at a position corresponding to the mounting position of the head 1"3, and similarly, the magnet 15a is magnetized to the north pole. A magnet 1 (not shown) magnetized to the S pole is attached and fixed at a position on the disk 12 corresponding to the position.

When the rotary body 11 disks 10 to 12 and the heads 1-11 to H6 respectively record a video signal of field frequency F (to lz) on the magnetic tape 2, the motor 8 rotates the video signal every second ((
n-1)/n) ・They are rotated integrally at a rotational speed of F. Here, 1) is the number of heads. In this example, n is 6, and assuming that a video signal with a field frequency of 60 Hz is to be recorded, the rotation speed of the motor 8 is 50 rps from the above equation, and therefore, the rotation speed of the motor 8 is 50 rps.
The rotation speed of 0 to 12 etc. is also 50 rps. The rotating body 1 is rotated counterclockwise in FIG.

The above rotation creates a circle! l! Magnets 1-13 on 10
8.13b is provided at the same height as the circle aio as shown in FIG. As shown in (A), magnet 13a
When the magnet 1311 passes in front, it outputs a positive pulse, and when the magnet 1311 passes in front, it outputs a negative pulse.

Similarly, a rotational phase detection pulse (rotation detection pulse) as shown in FIG. A rotation detection pulse as shown in FIG. 3(C) is taken out from the rotation detection head 18 provided at the same height position.

The above rotation detection heads 16 to 18 are also heads H+ to
1 and 6 are set at such a position that they output a rotation detection pulse when the recording of the overlap recording angle α° on the guide ball 3 side shown in FIG. 1 is completed. Therefore, the rotation detection heads 16 to 18 are provided on the same line parallel to the axial direction of the rotating shaft 9 of the motor 8.

Next, the video signal recording operation by the heads 1-11 to 1''6 will be explained. For example, field frequency 601-1
After the video signal of Z (or 59,941-IZ) is converted into a signal format suitable for magnetic recording and reproduction, it is selectively sent to one of the heads H1 to H1-16 by a switch circuit. Supplied. Now, suppose that the head 11 starts to come into contact with the magnetic tape 2 near the guide ball 3, not shown in FIG.
The magnetic tape continues to be supplied until it comes near the guide ball 4 and is no longer in contact with the magnetic tape 2.

When the head l-1+ rotates 60 degrees after recording of one field of the recording video signal is started by the head 1''1, the head 1 installed at the trailing position with respect to the rotation direction
” 6 begins to contact the magnetic tape 2, and then the heads 1-11
When the head H5 rotates a total of 120 degrees, the head H5 begins to come into contact with the magnetic tape 2, and the head H5 further rotates a total of 180 degrees and
The head H4 starts to come into contact with the magnetic tape 2 from the time when a track portion of about 31b length is formed between the first and second wooden video tracks, and the head H4 rotates a total of 240 degrees to form a wooden video track. At the point when a track portion with a length of about 41b is formed, the head 1] 3 starts to come into contact with the magnetic tape 2, and the head 1] 1 rotates a total of 300 degrees to record one video rack. When all records are formed, head 1
”2 begins to come into contact with the magnetic tape 2.

Here, since the tape running speed is selected so that the magnetic tape 2 is made to run by one track pitch TP when the head H+ rotates 300', the head 1'1 forms one video I/rack recording. The above-mentioned heads Ha, H5, H4, H contact the magnetic tape 2 one after another.
3, the head 1-11 scans overlappingly a part of the video track recorded and formed. However, these heads l''6. Since recording video signals are not supplied to Hs, H4, and G13, no video track is recorded or formed by these heads. Head 1"1
When the head 1'' rotates about 300° and records are formed on almost the entire 1 wooden bidet 2+ 1- rack, the recording video signal of the next 1 field is supplied to the head 1'' 2 which starts to come into contact with the magnetic tape 2. Thereafter, the recording video signal continues to be supplied until the head H2 rotates about 300 degrees and comes out of contact with the magnetic tape 2. As a result, one video track on which a little more than one field worth of video signals is recorded by the head H2 is formed at a position adjacent to the video 1-rack recorded by the head 1-11. Here, head I + ~ 1''
6 has a track width TW of 11 to rack pitch y-T I
) J: Since it has been selected as Rira Elementary School, the recorded bidet, 1
A new video rack A1- is recorded without overwriting the +- rack.

During the period when this head 12 is recording and forming one video 1-rack, the heads l-1+, H6, and H5°1-14 each scan a part of the track overlappingly. Since recording video signals are not supplied to these heads, a bidet Δ[·rack is not formed by these heads. Immediately before the head H2 finishes recording on the first bidet head, the head L-
1a begins to come into contact with the magnetic tape 2, and at this point the next field of video signal begins to be supplied to the head 13.

As a result, a video track is recorded and formed by the head H3 at a position adjacent to the video track recorded and formed by the head H2 via a guard band having a value obtained by subtracting the track width TW from the track pitch TP.

Thereafter, the same operation as above is repeated.

In this way, heads H+, H2, 13°114,
For Hs and 1''6, Figure 3 (D), (E).

(F), (G), (+-1) and (I) are indicated by diagonal lines.The period is one field plus the overlap recording period.
By switching and inputting the video signal based on the rotation detection pulse shown in (A) to (C) of the same figure, the head
-l I→1"2→H3→1"4→H5→H6→1"1
→...Video tracks are sequentially formed in which video signals corresponding to one field plus an overlap recording period are recorded in the following order.

Note that in FIG. 1, the video signals of the fields before and after that one field are recorded in an overlapping manner during the α° rotation period before the start of signal recording of one field period and the β° rotation period after the end of recording. are shown in Figure 3 (D) to (1
) is also clear. As is well known, this makes it possible to prevent the reproduced signal from being cut off even if the head switching point 1- during reproduction changes somewhat.

Also circle 110.11.12 and rotation detection head 16.17
．． 18 is, for example, only the disc 10 and the rotation detection head 16, and the rotation detection head 17. The other rotation detection pulses obtained in '18 may be electrically generated by a delay circuit and used as head switching signals.

FIG. 4 shows tape patterns recorded and formed by heads H1 to H6, etc., and shows video tracks t1, t2, . ts,
t4. ts, je,... are heads H+.

H2, H3, H4, Hs, He, . . . indicate recorded video tracks. In addition, the vertical synchronization signal in the recorded video signal is frequency-divided by 1/2, etc. in Fig. 3 (J
) are recorded on the control track 19 shown in FIG. 4 by the control roller in the head 5 shown in FIG.

Video track j+, j2. j3. ta, js.

t6. As shown in FIG. 3(K), the first field F1 and the second field F1 of the recording video signal are
2nd, 3rd field F3, 4th field top 4
, fifth field F5, sixth field F6 .
... are recorded sequentially.

Furthermore, a guard band having a value equal to the difference between the track pitch TP and the track width TW is formed between adjacent video tracks of each of the video tracks t1 to [6 with the track width TW.

In other words, one tape pattern (J1) shown in FIG. -1+ to H6, it is possible to record and form a tape pattern that is completely tape compatible with the above two-head VTR.

Here, the tape pattern shown in FIG. 4 is recorded and formed.
(The relationship between the diameter of the rotated body and the diameter d of the head-attached rotary body for 2 heads V T f<) is as follows: n-1>) (1).In this embodiment, the number n of heads is 6, so the rotating body 1
The diameter of
3/5 (8 roar.

Therefore, according to this embodiment, the fourth
It is possible to form a tape pattern that is completely compatible with a two-head VTR as shown in the figure.

FIG. 5 shows the relationship between the diameter and the number of heads, 11.

As is clear from the figure and equation (1), the number of heads n
(n is a natural number of 3 or more) becomes a dog, 2-head VT
The diameter approaches half of the diameter d of the rotating body to which the head is attached.

In addition, as mentioned above, the field frequency of the video signal is F
(Hz), and the number of heads is n, then the rotation speed N(r
ps) is expressed by the formula N=F(n-1)/n (rps) (2), so as shown in Figure 6, the number of rotations N approaches F as the number of heads increases. .

Here, since the flywheel effect of a rotating body with a diameter is proportional to the square of the number of rotations N, the second-order moment of loss of the rotating body 1 is required to achieve the same flywheel effect as a 2-head VTR]. In this embodiment, the rotation speed is 2-head VTR.
1.67 (9, so it becomes 0.36. This leads to the reduction of the superimposition of the rotating body 1, and the head of the 2-head VTR is attached to the rotating body 1). When using a rotating body, the flywheel effect is 2
As a result of being a dog more than a companion, jitter induced by uneven rotation of the rotating body 1 is reduced.

Next, the motion 1'1 yo during reproduction will be explained. During playback, the transmission path from each rotary transformer connected to each of the video heads H1 to H6 to the preamplifier is provided with a switch circuit, and this switch circuit is shown in Fig. 3(A). The rotation detection pulses of the heads H2 and H4 shown in FIG.
, 1-16 rotation detection pulses.

As a result, head 11 ~ 1'' 6 becomes 1''
1 → 1" 2 → (-13→ 1" 6I →
1-15 → H6 → H+-) ... is switched cyclically every 300° rotation period of the rotating body 1 (that is, one field bright interval), and the reproduction signal of the - head is output from the switch circuit. taken out.

The heads H1 to H1-16 start contacting the magnetic tape 2 every one field period in the same way as during recording.
→1"2→H3→1"4→1"s→1"6→1-11→
. . . Since the heads H1 to H6 start contacting each other in this order, the heads H1 to H6 sequentially contact each other in the same order as during recording.
6. . . . scans above and reproduces those green signals. In addition, the recorded edge control pulses of the roll track 19 to the controller 1 are picked up and reproduced by the control head in the fixed head 5, and are used as sampling pulses for tape running control and for the rotation of the rotating body 1. The output rotation detection pulses of the rotation detection heads 16 to 18 are also used as sampling pulses for the phase control of the head servo circuit. Ru.

The reproduced signal taken out from the switch circuit has a predetermined II
j The raw signal processing circuit converts the signal into a reproduced single-image signal in the original signal form and outputs it to a monitor display device.

Application Examples Note that the present invention is not limited to the above embodiments, and if the number of heads n is a natural number of 3 or more, the diameter of the rotating body is determined from equation (1) as the diameter of the rotating body of a 2-head VTR. (For example, at 0-3, the diameter of the rotating body is 3/4 times the diameter d from equation (1))
, 3 or more, the device of the present invention can be applied. However, the number of rotations N of the rotating body for attaching the head and the effective tape winding angle will depend on the number of heads (11) under the condition that one field of video signal to one track is recorded and reproduced as shown in Fig. 4. In that case, the number of rotations N is expressed by the above equation Q, and the angle J is expressed by the equation ((n-1)/n)·360°. Note that, as a matter of course, the running speed of the tape is the same as that of a two-head VTR, regardless of the number of heads (11).

Effects As described above, according to the present invention, n heads (where n is a natural number of 3 or more) with the same azimuth angle are attached at equal angular intervals and the rotating body is rotated every second ((n-1 ＞/n)・
F (where F is the field frequency of the recorded video signal) and rotates at a rotation speed of 360' x (n-1).
Since the above 11 heads are sequentially switched to record and reproduce signals on a magnetic tape mounted at an effective winding angle of /n, two heads with the same azimuth angle are now separated by 180 degrees. f1 is taken up by the rotating body at 2
The deep pattern and the tape pattern recorded and formed by the two-head VTR can be recorded and formed by the rotary body for the head number f of this two-head VTR, which has a small diameter J. In addition, the rotating body can be made smaller in diameter, allowing for smaller equipment.
The weight can be reduced, and if a rotating body with the same moment of inertia as the head mounting rotating body of a 2-head VTR is used, the flywheel effect will be more than double, so jitter caused by uneven rotation can be reduced. It has the advantage of being able to reduce the amount of energy used.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the relationship between the head arrangement and tape winding 1 of the apparatus of the present invention, and FIG. 2 is a perspective view showing an embodiment of the head rotation mechanism of the apparatus of the present invention; Figure 3 (A) ~
(I〈) is the operation β1 light time chart 1-1 of the apparatus of the present invention. Figure 4 is a diagram that does not show the tape pattern recorded and formed by the apparatus of the present invention, and Figure 5 is a diagram showing the diameter of the rotating body and the number of heads. FIG. 6 is a diagram showing the relationship between the rotation speed of the rotating body and the number of heads. DESCRIPTION OF SYMBOLS 1...Rotating body, 2...Magnetic tape, 5...Audio control head, 6...Capstan, 7
...Pinch roller, 8...Motor, 9...Rotating shaft, 10-12...Disc, 16-18...Rotation detection head, H1-H6...Head. Figure 2 Figure 3

Claims (1)

[Claims] Eleven heads (for LC, n is a natural number of 3 or more) with the same azimuth angle are arranged at equal angular intervals on a rotating body, and when recording and reproducing video signals of field frequency F (Hz), the rotating body is Rotate at a rotation speed of ((n-1)/n)・F per second, and give the rotating body 360′・(n-1)/n
The n heads, which are sequentially and cyclically switched at intervals approximately equal to the effective winding angle rotation period, are placed on a magnetic tape that is wound and run while being wound at an effective winding angle that satisfies the following formula: A signal recording and reproducing apparatus characterized in that during recording, signal recording tracks are sequentially formed at a pitch of 1 to 100, which is larger than the track width, and during reproducing, the recorded edge tracks are scanned to reproduce the recorded green signal.