JPH05130546A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To record and reproduce the still picture to a digital signal area (PCM area) without increasing the magnetic tape winding angle to a rotary cylinder in the magnetic recording and reproducing device capable of recording the still picture as well as the moving picture on the same magnetic tape. CONSTITUTION:The video signal of the moving picture is recorded on the area 7 of an inclined track on a magnetic tape 4. The PCM still picture signal is recorded on the extended area 8 of the inclined track. Accordingly, heads 2A and 2B for recording and reproducing still picture signal with the height and angle division (phase) properly set other than heads 1A and 1B for recording and reproducing video signals are provided on a rotary cylinder 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a video tape recorder capable of recording a still image together with a moving image.

[0002]

2. Description of the Related Art In recent years, in the field of magnetic recording, there is an increasing demand for high density recording, and even in a video tape recorder (VTR), it is possible to perform higher density recording by reducing the running speed of the magnetic tape. Is becoming. However, when the running speed of the tape decreases, for example, when an audio (voice) signal is recorded by using a fixed head, the relative speed cannot be set high, and thus the reproduction sound quality deteriorates. As one means for solving this, there is known a method in which the length of each track scanned by the rotary head is made longer than in the conventional case and a time-compressed audio signal is sequentially recorded in the extended portion.

Specifically, in an 8 mm VTR, which is one of the rotary two-head helical scan type VTRs, a magnetic tape was wound around 180 ° or more on a conventional rotary cylinder, whereas in this method the rotary cylinder is 1
The audio signal which is PCM-compressed and time-compressed is recorded on the portion of "θ" that is wound more than 80 + θ) degrees and is additionally wound.

FIG. 1 shows a tape traveling system of such a VTR, and FIG. 2 shows a recording track on a magnetic tape by the VTR shown in FIG. In FIG. 1, 4 is a magnetic tape, 3 is a rotary cylinder, 1A and 1B are recording / reproducing heads attached to the cylinder 3, and in FIG. 2, 12 is a video (image) of a track formed on the magnetic tape 4. The signal area portion, 13 is also a PCM audio signal area portion. The video signal area portion 12 is 18 of the rotary cylinder 3.
Traced by heads 1A and 1B at 0 degree, and again P
The CM audio signal area portion 13 is θ of the rotary cylinder 3.
Traced in minutes.

As an example of applying the method of recording a digital signal in another area while recording a video signal as described above, it has been proposed to record a still image in the PCM audio signal area 13 as a digital signal. If it is a still image, it is possible to record all the still image information on the magnetic tape 4 by scanning the PCM audio signal area 13 a plurality of times. According to this method, not only the still image can be shot using the same recording medium as the moving image shooting apparatus but also the conventional VTR, in which the tape running is stopped and the video signal of the same track is reproduced. It is possible to obtain still images with a much higher image quality than images.

[0006]

However, in the conventional example as described above, the wrap angle of the magnetic tape on the rotary cylinder becomes larger than the normal VTR by θ, as described above.
The running load on the magnetic tape increases correspondingly. Also,
There was a further problem to be solved, which was an obstacle to the reduction of the diameter of the cylinder.

In view of the above points, an object of the present invention is to record and reproduce a still image in a digital signal area (PCM audio signal area) without increasing the winding angle of the magnetic tape around the rotary cylinder. Another object is to provide a magnetic recording / reproducing apparatus.

[0008]

In order to achieve the above object, the present invention is directed to recording a video signal for a moving image on an inclined track on a magnetic tape and a digitized still image signal on the magnetic tape. In a magnetic recording / reproducing apparatus capable of recording in an extended area of the inclined track, a first head for recording / reproducing the video signal, a height of the first head, or a height of the first head. And a second head for recording and reproducing the still image signal whose angular phase is appropriately set to a predetermined value are arranged on a common rotary cylinder.

The present invention also provides, as one form thereof, the above-mentioned first aspect.
The angular phase α and the height difference β of the second head with respect to the head of FIG. _{If P} ,

[0010]

[Formula 2] α = T · I · 360− (N−52.5) 360/525 β = (N + α / 180) T _P can be set.

[0011]

According to the present invention, since the still image signal recording / reproducing head whose position with respect to the video signal recording / reproducing head is set appropriately is newly provided separately from the video signal recording / reproducing head, the magnetic tape is wound around the rotating cylinder. It is possible to record / reproduce a still image in the digital signal area (PCM audio signal area) without increasing the angle and without increasing the ATF signal generator.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

For convenience of explanation, the NTSC system 8 m is used.
The mVTR will be described as an example.

FIG. 3 shows the angular relationship of the magnetic head in one embodiment of the present invention. FIG. 4 shows the height relationship and the angle relationship of the magnetic head of FIG. 3 and 4, 1A,
1B is a magnetic head for recording and reproducing a video (moving image) signal, 2
A and 2B are magnetic heads for recording and reproducing still image signals,
A and 2A and 1B and 2B have the same azimuth.
3 is a rotary cylinder equipped with magnetic heads 1A, 1B, 2A and 2B, and 4 is a magnetic tape. Further, α is the angle between the magnetic heads 1A and 2B and 1B and 2A, and β is the height difference (height difference) between the magnetic heads 1A and 2B and 1B and 2A.

FIG. 5 shows a circuit configuration of an essential part of an 8 mm VTR in one embodiment of the present invention having the magnetic head of FIG.
In FIG. 5, 21 is a video signal processing circuit for processing a video signal, 22 is a still image signal processing circuit for processing a still image signal, and 23 is a signal generator for generating four kinds of ATF signals f _{1 to} f _4. is there. 24 is a video signal and an ATF signal f
_{A first} summing amplifier for adding _{1 to} f ₄ and amplifying it, and a second summing amplifier 25 for adding and amplifying the still image signal and the ATF signals f _{1 to} f ₄ . 26 is the first summing amplifier 24
And a first switching circuit connected between the video signal recording / reproducing magnetic heads 1A and 1B, and a second switching circuit 27 connected between the second summing amplifier 25 and the still image signal recording / reproducing magnetic heads 2A and 2B. The switching of these switching circuits 26 and 27 is performed by the control of the system controller 28.

FIG. 6 shows the magnetic tape 4 having the above structure.
Shows a track pattern of a signal to be recorded or reproduced. In FIG. 6, 5A and 5B are track patterns recorded or reproduced by the video signal recording / reproducing magnetic heads 1A and 1B, respectively, and are synchronized in time with the still image signal recording / reproducing magnetic heads 2B and 2A. The track patterns to be recorded or reproduced are 6B and 6A. The track patterns 5A and 6B and 5B and 6A are N tracks.
There is a book gap, and the value of N is uniquely determined by the angle α ° and the height difference β that represent the positional relationship between the magnetic heads 1A and 2B and 1B and 2A described above. Note that 7 indicates a video signal area and 8 indicates a PCM signal area.

FIG. 7 shows the magnetic head 1 having the above-mentioned structure.
The timings of signals recorded or reproduced by A, 1B, 2A, and 2B are shown. In FIG. 7, the time difference between the magnetic heads 1A and 2B and 1B and 2A is represented by T.
The value of T is uniquely determined by α ° and β representing the positional relationship between the magnetic heads 1A and 2B and 1B and 2A described above.

In the present invention, while the video signal recording / reproducing magnetic heads 1A and 1B are tracing the video signal area 7 on the magnetic tape 4 as described above, they are located on the extension of the track N lines before. Paying attention to the fact that the still image signal recording / reproducing magnetic heads 2B and 2A trace the existing PCM signal region 8 by a time T, and when recording or reproducing a still image signal in the PCM signal region 8 described above, Since the video signal and the still image signal do not have the time restriction as in the case of the video signal and the audio signal, the interval between the video signal track and the still image signal track recorded or reproduced within one rotation of the rotary cylinder 3 is Paying attention to the fact that there is no problem even if N shifts, a dedicated magnetic head for recording and reproducing still image signals 2
If a still image is recorded or reproduced using A and 2B, even if the amount of the magnetic tape 4 wound around the rotating cylinder 3 is the same as that of a normal VTR, as will be described later, the still image is recorded or recorded in the PCM area 8. It is said that reproduction can be made possible.

The 8 mm VTR generally employs the ATF method (automatic tracking feedback method) as the tracking method. The arrangement on the tape pattern of the ATF system, as shown in FIG. 8, taking a 4-track completion method for continuously and repeatedly arranged four kinds of signals f ₁ ~f _4. That is, in the video signal area 7, f ₁ · f
₃ and f ₂ · f ₄ have the same azimuth, f ₁ → f ₂ → f
If the ATF signal in the video signal area is f ₁ in the PCM signal area 8 in the order of ₃ → f ₄ , then f
_2, if f ₂ f _3, f if ₃ f _4, if f ₄ f ₁ is disposed.

Here, as described above with reference to FIG. 5, when the signal processing circuit of the embodiment of the present invention is constructed, the magnetic heads 1A and 2 are formed.
Since the recording timings of B, 1B, and 2A overlap as shown in FIG. 7, the ATF frequencies must be the same. That is, as shown in FIG.
The track interval N of each track recorded in A and 2B and 1B and 2A is an interval N = 4n-1 (n = integer) obtained by subtracting 1 from a multiple of 4.

Next, the magnetic heads 1A and 2B and 1B and 2
The α ° and β, which are the positional relationships of A, will be described in more detail. Since the relationship between the magnetic heads 1A and 2B is the same as the relationship between the magnetic heads 1B and 2A, the following description will be given with the relationship between the magnetic heads 1A and 2B as a representative.

First, as shown in FIG. 10, the magnetic head 1
Consider a case where the angular division between A and 2B is 0 (α ° = 0 °) and the height is β ′. FIG. 11 shows the positions of the magnetic heads 1A and 2B on the tape 4 at this time. 11
9 is a vector representing the movement (rotation) of the magnetic head 1A for the video signal, and 10 is the magnetic tape 4
Is a vector representing the movement of (reverse to the actual direction). Reference numeral 11 is a vector representing a track pattern formed on the magnetic tape 4 by combining the two vectors 9 and 10. Further, θ ₀ is a track angle when the magnetic tape 4 is stopped, and θ ₀ = 4 ° 53′6 ″. θ ₁ is a track angle when the magnetic tape 4 is running, and the above θ ₀ and the tape speed V _T (= 14.34)
5 mm / s), the rotating cylinder diameter D (= 40 mm), and the cylinder rotation speed I (= 29.97 rps) are calculated by the following equation (1). It should be noted that all of the above specific numerical values are determined by the 8 mm VTR tape format.

[0023]

[Equation 3]

The video track width T _P is

[0025]

[Equation 4]

[0026]

In FIG. 11, assuming that the video signal magnetic head 1A is located at the video area start point P, the still image signal magnetic head 2B whose height is lowered by β'is It is located at point Q. Ie

[0028]

[Equation 5]

[0029] If the projection point of the point Q on the extension line of the track pattern vector 11 starting from the point P is P ′,

[0030]

[Equation 6] ∠ PQP ′ = θ ₁ −θ ₀ , therefore,

[0031]

[Equation 7]

It becomes

This track interval

[0034]

[Outer 1]

If N is N and N = 4n-1 (n is an integer), the magnetic head 2B for the still image signal is located on the extension of the locus of the magnetic head 1A for the video signal and the ATF recording is performed. Satisfy the format. That is,

[0036]

## EQU8 ## β '/ COS (θ ₁ −θ ₀ ) = NT _P , N = 4n−1 (n is an integer) (4) Further, on the position point Q of the magnetic head 2B for the video signal and its extension line. If the video signal start point of a certain track is point R and the projection point of point Q on the line segment PR is Q ',

[0037]

[Formula 9] ∠ PQQ ′ ＝ θ ₀ , ∠ QRQ ′ ＝ θ ₁

[0038]

[Equation 10]

Is

[0040]

Mathematical Expression 11 γ = β ′ · COS (θ ₀ ) / SIN (θ ₁ ).

Here, according to the above equation (2),

[0042]

[Equation 12]

Substituting in the above equation

[0044]

[Equation 13]

Further, according to the equation (4),

[0046]

(14) γ = N · COS (θ ₀ ) · COS (θ ₁ −θ ₀ ) · V _T / 2I (5)

By the way, in the 8 mm VTR format, H (horizontal) of the scanning line and + 1H (horizontal synchronizing signal interval) are determined as shown in FIG. 12, and this 1H is expressed by the length.

[0048]

[Equation 15]

It becomes

Therefore, when the equation (5) is expressed by using H,

[0051]

[Equation 16]

It becomes

Here, in the 8 mm VTR format, the PCM area 8 starts about 36 ° before the video area 7 as shown in FIG. In addition, if the horizontal synchronization signal interval H described above is expressed by an angle, from one frame the number of search lines = the number of H = 360 °

[0054]

[Equation 17] Since 1H = 360 ÷ 525 ° (8), the start angle of the PCM area 8 is set to H
In terms of (horizontal sync signal interval)

[0055]

[Expression 18] 36 ° ÷ 1H = 36 ÷ (360 ÷ 525) = 52.5H (9)

Now, consider the case where the time T in FIG. 7 is zero. That is, if γ in the above equation (7) is equal to 52.5H, the time when the magnetic head 1A for the video signal enters the video area 7 and the time when the magnetic head 2B for the still image signal enters the PCM area 8 are exactly the same. Therefore, the time T in FIG. 7 becomes zero. Therefore, the above equation (7) is

[0057]

[Formula 19]

Thus, it is inconsistent with 4n-1 (n = integer) in the above equation (4). Therefore, the angle division amount of the magnetic heads 1A and 2B is set to a predetermined angle instead of zero. The setting method and the range of N will be described below together.

First, from the above equation (4), N = 4n-1 (n =
If the magnetic head 1A for the video signal reaches the video area 7, the magnetic head 2B for the still image signal is already in the PCM area 8 when the video signal magnetic head 1A reaches the video area 7. Since it causes inconvenience, N is 55 or more (n
Is 14 or more). Further, in FIG. 11, line segment PQ
Since the point R where the extension line of the above intersects the lower end of the magnetic tape 4 is the boundary point between the fixed cylinder and the rotating cylinder, the magnetic head 2B for still image signals cannot exist below this point R. Therefore, from FIG.

[0060]

[Equation 20]

[0061]

[Outside 2]

Substituting equations (4) and (11) above into

[0063]

[Formula 21] COS (θ ₁ −θ ₀ ) ・ N ・ T _P <1.7855 / COS (θ ₀ ) ∴N <1.7855 ÷ T _P ÷ COS (θ ₁ −θ ₀ ) ÷ COS (θ ₀ ) ≈87.6 ( 12) That is, N is 87 or less (n is 22 or less).

Next, 55≤N≤87 (14≤n≤22)
In the case of, the magnetic head 1A for the video signal is moved to the video area 7
The position of the magnetic head 2B for still image signal at the time of reaching

[0065]

[Equation 22]

It is in front of the minute. That is, the magnetic head 2A for the still image signal may be shifted counterclockwise from the magnetic head 1A for the video signal by this amount. The above formula (1
In 3),

[0067]

[Equation 23]

Let us say. Substituting equation (8) into equation (13),

[0069]

[Equation 24]

To obtain

At this time, the height correction β ″ for the phase of α ′ is

[0072]

[Equation 25]

Therefore, the total height β ″ ″ becomes β ″ ″ = β ′ + β ″, and the above equations (4) and (1)
By 5)

[0074]

[Equation 26]

It becomes here

[0076]

[Equation 27]

In addition,

[0078]

[Equation 28]

To obtain

Up to now, the deviation T of the signal start time of the magnetic heads 1A and 2B has been described as 0, but it may not be T = 0 separately, and the correction of the track deviation due to the time deviation may be corrected by the above-mentioned α'and β '. All you have to do is "". As a result, the total α and β are as follows.

[0081]

[Equation 29]

In the above embodiment of the present invention,
As an example of a magnetic recording / reproducing apparatus, an NTSC system 8 mm
I mentioned VTR, but other recording / playback VTR
Of course, the present invention can also be applied.

[0083]

As described above, according to the present invention,
In addition to the video signal recording / reproducing magnetic head, a still image signal recording / reproducing head whose position is appropriately set with respect to the video signal recording / reproducing magnetic head is newly arranged. Without increasing the angle of angle and increasing the number of ATF signal generators,
The effect that the still image can be recorded / reproduced in the PCM area of the magnetic tape can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing a tape traveling system of a conventional VTR.

FIG. 2 is an explanatory diagram showing recording tracks on the magnetic tape of FIG.

FIG. 3 is a schematic plan view showing a tape running system according to an embodiment of the present invention.

FIG. 4 is a development view showing an angle and a positional relationship of the magnetic head of FIG.

5 is a block diagram showing a circuit configuration of an 8 mm VTR signal processing system according to an embodiment of the present invention having the magnetic head of FIG.

FIG. 6 is an explanatory diagram showing a recording track (track pattern) on a magnetic tape according to an embodiment of the present invention.

FIG. 7 is a timing chart showing the timing of recording / reproducing signals of the magnetic head of FIG.

FIG. 8 is a signal arrangement diagram showing an arrangement of an 8 mm VTR format ATF signal on a tape pattern according to an embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a relationship between a recording track on a magnetic tape and an arrangement of ATF signals according to an embodiment of the present invention.

10 is a diagram showing an example of a positional relationship of the magnetic head of FIG.

11 is an explanatory diagram showing in detail a recording locus on a magnetic tape by the magnetic head having the arrangement shown in FIG.

FIG. 12 is an explanatory diagram showing an H arrangement in an 8 mm VTR format.

[Explanation of symbols]

1A, 1B Video signal magnetic head 2A, 2B Still image signal magnetic head 3 Rotating cylinder 4 Magnetic tape 5A, 5B Video signal track 6A, 6B Still image signal track 7 Video signal area 8 PCM signal area 9 Magnetic head movement Shown vector 10 Vector showing magnetic tape movement 11 Vector showing relative movement of magnetic head and magnetic tape 21 Video signal processing circuit 22 Still image signal processing circuit 23 Signal generator 24, 25 Summing amplifier 26, 27 Switching circuit 28 System controller

Claims (2)

[Claims] 1. A video signal for a moving image is recorded on an inclined track on a magnetic tape, and a digitized still image signal is recorded on an extended area of the inclined track on the magnetic tape. In a possible magnetic recording / reproducing apparatus, a first head for recording / reproducing the video signal, and a height of the first head, or the still image whose height and angle phase are set to predetermined values as appropriate. A magnetic recording / reproducing apparatus, wherein a second head for recording / reproducing a signal is disposed on a common rotary cylinder. 2. An angular phase α and a height difference β of the second head with respect to the first head, a time shift is T, a track number corresponding to a track gap is N, and a rotation speed of the rotary cylinder. Where I is the video track width and T _P is the video track width, α = T · I · 360− (N−52.5) 360/525 β = (N + α / 180) T _P The magnetic recording / reproducing apparatus according to claim 1.