JPH04337985A - Magnetic reproducing device - Google Patents

Abstract

PURPOSE:To further reduce the diameter of a tape guide cylinder in comparison with a standard video tape recorder, for which the diameter of the tape guide cylinder is decided at 40mm, and further to suppress the noise bars of a reproduced picture obtained on an image display device based on regenerative video signals in the case of selecting a variable speed reproducing operation mode in the reproducing video signals from a magnetic tape recorded by a compact video tape recorder not to increase the number of rotary magnetic heads. CONSTITUTION:On the conditions of setting a rotating angle mutually between two rotary magnetic heads 21A and 21B at alpha deg. and defining M as an even number in the case of selecting the variable speed reproducing operation mode such as a Cue reproducing operation mode or a Review reproducing operation mode, the traveling velocity of a magnetic tape 23 is made N-times as high as reference velocity for a capstan driving motor 24 by a capstan servo control circuit 27 and further, control is executed so as to obtain the state of satisfying relation expressed by M=N(1+alpha/360)-alpha/360.

Description

[Detailed description of the invention]

0001

FIELD OF INDUSTRIAL APPLICATION The present invention reads signals recorded on a magnetic tape with a large number of parallel recording tracks formed thereon by using a rotating magnetic head that scans the magnetic tape along the recording tracks formed thereon. The present invention relates to a magnetic reproducing device that obtains a reproducing signal based on a read output signal from a rotating magnetic head.

0002

2. Description of the Related Art A so-called video tape recorder, which is a device for recording a video signal on a magnetic tape or reproducing a video signal from a magnetic tape on which the video signal has been recorded, is
The tape guide cylinder includes a tape guide cylinder having an outer circumferential surface portion that serves as a running guide for the magnetic tape, and a rotating magnetic head disposed inside the tape guide cylinder. It is assumed that the magnetic tape runs on the outer circumferential surface of the tape guide cylinder, and in this case, the magnetic tape is wound around the outer circumferential surface of the tape guide cylinder at a preset wrapping angle. It is assumed to take on a state. The tape guide cylinder is, for example, divided in the direction of its central axis to form a fixed part and a rotating part, and the rotating part is rotated with respect to the fixed part at a preset rotation speed. The rotating magnetic head is, for example, attached to the rotating part of the tape guide cylinder and positioned between the fixed part and the rotating part of the tape guide cylinder, and rotates with the rotation of the rotating part of the tape guide cylinder. , with the magnetic gap forming portion facing the outer circumferential surface of the tape guide cylinder, the magnetic tape running on the outer circumferential surface of the tape guide cylinder during one rotation period is scanned obliquely to the traveling direction, and the magnetic Record signals on tape or read signals from magnetic tape.

Recording of video signals on a magnetic tape using such a tape guide cylinder and rotary magnetic head involves the recording of a large number of tapes, each extending at a predetermined angle of inclination with respect to the longitudinal direction of the magnetic tape. Recording tracks are arranged in parallel and one field period of a video signal is usually recorded on each recording track. Therefore, during a recording operation, a rotating magnetic head that scans a magnetic tape diagonally with respect to the traveling direction during one rotation period records one field period of video signals on the magnetic tape for each rotation. A recording track of a book is formed, and during a reading operation, the magnetic tape is scanned along the recording track formed on the magnetic tape every rotation to read one field period of the video signal.

[0004] Regarding such video tape recorders, many systems have been proposed with different specifications regarding the mechanism, specifications regarding signal recording and signal playback operations, specifications regarding operation control, etc., but one of them is As a standard video tape recorder that complies with The number of rotations of the rotating part in the tape guide cylinder (hereinafter referred to as cylinder rotation number), that is, the number of rotations of the rotating magnetic head is approximately 29.97 rps, and the number of rotations of the rotating magnetic head is approximately 29.97 rps.
There is one that is arranged as individual pieces with a rotation angle interval of 180 degrees. Such a standard video tape recorder belongs to a category in which the diameter of the tape guide cylinder is relatively small, and the tape guide cylinder and rotary magnetic head employed therein are different from the standard tape guide cylinder and the rotary magnetic head, respectively. It is considered a standard rotating magnetic head.

[0005] Furthermore, in order to further reduce the size and weight of the standard video tape recorder as described above, the diameter of the tape guide cylinder is made smaller than that of the standard tape guide cylinder. It has been proposed to construct a compact video tape recorder that is compatible with commercially available video tape recorders. Regarding such small video tape recorders, from the viewpoint of compatibility with standard video tape recorders regarding the recording format on the magnetic tape, (1) the length of the recording track formed on the magnetic tape is the same as that of the standard video tape recorder. (2) The period for one field period of the video signal recorded on the magnetic tape is equal to the length of the recording track formed on the magnetic tape by a standard video tape recorder. Therefore, it is required that the period be equal to the period of one field period of the video signal recorded on the magnetic tape.

Therefore, for a small video tape recorder, let the ratio of the diameter of the tape guide cylinder to that of a standard video tape recorder be a, the ratio of the tape winding angle be b, and the ratio of the cylinder rotation speed be c. (1) and (2)
In order to satisfy the following conditions, it is necessary that the relationship a·b=1, b/c=1 hold, and that the number of rotating magnetic heads be an even number of 4 or more. So, for example,
a = 2/3, b = c = 3/2, and the number of rotating magnetic heads is selected to be 4, so that
The diameter of the tape guide cylinder is 40mm・2/3 ≒26.
A compact video tape recorder having a tape length of 67 mm, a tape winding angle of 270 degrees, a cylinder rotation speed of 44.955 rps, and four rotating magnetic heads is constructed.

However, in a small video tape recorder constructed in this way, the number of rotating magnetic heads is
This is an increase compared to a standard video tape recorder, and it is necessary to provide four tape guide cylinders. Assembling four independent rotating magnetic heads involves considerable difficulty, and there is also a risk that the mounting accuracy of the four rotating magnetic heads may not be good. Furthermore, for example, fast forward playback (Cue playback), rewind playback (Re
It is considered extremely difficult to add a rotating magnetic head for variable speed playback, which is used for variable speed playback such as view playback and still image playback, and as a result, so-called noiseless variable speed playback is no longer possible. I end up.

Therefore, as mentioned above, for example, the diameter is set to 40
Compared to a standard video tape recorder having a standard tape guide cylinder with a diameter of approximately 26 mm and two standard rotating magnetic heads with a rotational speed of approximately 29.97 rps, the diameter of the tape guide cylinder is, for example, approximately 26 mm. .67 mm, yet still be compatible with standard video tape recorders in terms of recording format on magnetic tape, without increasing the number of rotating magnetic heads. A tape recorder has also been proposed by the applicant (Japanese Patent Application No. 3-90431). In such a small video tape recorder that does not involve an increase in the number of rotating magnetic heads, the diameter of the tape guide cylinder is, for example, the diameter of a standard tape guide cylinder (4
The tape winding angle is 2/3 times the tape winding angle (180 degrees) in a standard video tape recorder, that is, approximately 270 degrees. The rotation speed of the rotating magnetic head is twice that of the standard rotating magnetic head (approximately 29.97 rps),
That is, the rotational speed is approximately 59.94 rps, and the rotational angular interval between the two rotating magnetic heads is selected to be approximately 45 degrees, which is smaller than the rotational angular interval (180 degrees) between two standard rotary magnetic heads. It is assumed that the Under such circumstances, during recording operation, the video signal to be recorded is time-axis compressed at a predetermined time compression rate, and the recording video signal formed based on the time-axis compressed video signal is , recorded on a magnetic tape by two rotating magnetic heads, and during playback operation, recording video signals recorded on the magnetic tape are read alternately by two rotating magnetic heads, The recording video signal obtained during the output of the read signal from each head is time-axis expanded at a time expansion rate corresponding to the time compression rate during the recording operation, so that a reproduced video signal can be obtained.

[0009] Constructed in this way, the diameter is approximately 26.6
A small video tape recorder equipped with a small tape guide cylinder with a diameter of 7 mm and two rotating magnetic heads with a rotation angle interval of approximately 45 degrees has a tape guide cylinder diameter that is equal to that of a standard video tape recorder. Although the diameter of the magnetic tape is smaller than that of the magnetic tape, the number of rotating magnetic heads is not increased, and the recording format on the magnetic tape is compatible with standard video tape recorders. It turns out.

FIG. 2 shows a small tape guide cylinder having a diameter of approximately 26.67 mm and a rotation angle interval of approximately 45 mm.
1 shows an outline of a recording system in a small-sized video tape recorder equipped with two rotary magnetic heads arranged in parallel. In such a recording system, a signal SV to be recorded containing a video signal and an audio signal, which are, for example, a color television signal based on the NTSC system, is introduced through the recording signal input terminal 11, and the recording signal SV is The signal SV from the input terminal 11 is supplied to the time axis compression recording signal forming section 12 . In the time axis compression recording signal forming section 12, the signal S
The luminance signal constituting the video signal in V is time-axis compressed in units of one field period, for example, at a time compression rate of 3/4, and frequency modulation (FM) processing is performed using the time-axis compressed luminance signal. The carrier color signal constituting the video signal in the time-base compressed FM luminance signal and signal SV obtained by this process is time-base compressed at a time compression rate of 3/4, for example, in units of one field period, and For example, the time axis compressed low frequency converted color signal obtained by frequency converting the axis compressed carrier color signal to the lower frequency side and the audio signal in the signal SV are time compressed in units of one field period. The time axis compressed FM audio signal obtained by time axis compression with a rate of 3/4 and FM processing using the time axis compressed audio signal is frequency multiplexed and synthesized.
A time axis compression recording signal Sm is formed.

Such a time axis compression recording signal Sm is shown in FIG.
As shown in A in FIG.
t・202.5/360 (where Ft represents a field period, for example, 1/60 second) is defined as T1, and T1 is the time point after which Ft represents a field period, for example, 1/60 second. From the start of the 2-field period, for example, the period Ft・247.5/360
The time-axis compressed FM luminance signal, the time-axis compressed low-frequency conversion color signal, and the time-axis compressed FM starting from time T1 and continuing for a period of Ft·3/4, assuming that the time after passing through is T2.
One field period Sm(n), Sm obtained by frequency multiplexing the first field period of each audio signal
(n+2),..., and period F starts from time T2.
One field obtained by frequency multiplexing the second field period of each of the time-domain compressed FM luminance signal, the time-domain compressed low-frequency conversion color signal, and the time-domain compressed FM audio signal, which last for t·3/4. period Sm(n-1), Sm(n+
1),... are arranged alternately, and switch 1
It is supplied to the movable contact 13a of No. 3.

The switch 13 operates its movable contact 13 in response to a switch control signal SW supplied from a control terminal 14.
The connection state between a and selection contacts 13b and 13c is controlled. As shown in B in FIG. 3, the switch control signal SW has a low level L during a period including each of one field period Sm(n), Sm(n+2), . . . in the time axis compression recording signal Sm. At the same time, one field period Sm(n
-1), Sm(n+1), .
3a to the selection contact 13b, and switch control signal SW
Selects the movable contact 13a when the contact 13 takes a high level H.
Connect to c. Thereby, selection contact 1 of switch 13
3b, the first recording signal component Sma, which is formed by intermittently connecting Sm(n), Sm(n+2), . . . for one field period, as shown in C in FIG. 3, is derived. , is supplied to the rotary magnetic head 21A through the recording amplification section 15A, and from the selection contact 13c of the switch 13, as shown in D in FIG.
Field period Sm(n-1), Sm(n+1),・
A second recording signal component Smb, which is formed by an intermittently continuous sequence of .

Each of the rotating magnetic heads 21A and 21B has a mutually different gap azimuth, and
It is attached to the rotating part of the tape guide cylinder 22, and is arranged between the rotating part and the fixed part of the tape guide cylinder 22, and rotates with the rotating part of the tape guide cylinder 22, so that the magnetic gap forming part is connected to the tape. The magnetic tape 23 is brought into contact with the magnetic tape 23 running on the outer circumferential surface of the guide cylinder 22, and the magnetic tape 23 is scanned in a direction forming a predetermined intersecting angle with respect to the running direction of the magnetic tape 23. The tape guide cylinders 22 of the rotating magnetic heads 21A and 21B
As shown in FIG. 2, the rotary magnetic head 21A and the rotary magnetic head 21B are attached to the rotating part in such a manner that the rotational angular interval between them is approximately 45 degrees.

The magnetic tape 23 is caused to run by a capstan 25 which is rotationally driven by a capstan drive motor 24 and a pinch roller 26 which is in contact with the capstan 25 with the magnetic tape 23 sandwiched therebetween. It is controlled by a stun servo control circuit 27 to cause the magnetic tape 23 to take a predetermined running speed. Further, the rotating portion of the tape guide cylinder 22 to which the rotating magnetic heads 21A and 21B are attached is rotationally driven by a cylinder drive motor 30, and the cylinder drive motor 30 is controlled by a cylinder servo control circuit 31 to rotating part,
Therefore, the rotating magnetic heads 21A and 21B are caused to have a predetermined rotation speed. Rotating magnetic head 21A
and 21B are rotated, for example, in the direction indicated by arrow XH in FIG.

The diameter of the tape guide cylinder 22, the tape wrapping angle for the tape guide cylinder 22, and the number of cylinder rotations, that is, the number of rotations of the rotating magnetic heads 21A and 21B, are as described above for a standard video tape recorder. The diameter of the tape guide cylinder 22 is set to approximately 26.67 mm, the tape winding angle of the tape guide cylinder 22 is set to approximately 270 degrees, and the two rotating magnetic heads 21A are set as a standard. The rotation speed of 21B and 21B is set to approximately 59.94 rps, and therefore,
The period of one rotation of the rotating magnetic heads 21A and 21B is approximately 1
/60 seconds, which approximately matches the field period Ft. The recording scanning state of the rotary magnetic heads 21A and 21B to form recording tracks on the respective magnetic tapes 23 is as shown in E in FIG. During each rotation, Sm(n), Sm( for one field period in the supplied first recording signal component Sma)
magnetic tape 2 during the period in which each of n+2), .
3, and the rotary magnetic head 21B scans the
As shown in F in FIG.
It is assumed that the magnetic tape 23 is scanned for recording during the period in which each of (n+1), . . . arrives. Thereby, each time each of the rotating magnetic heads 21A and 21B alternately records and scans the magnetic tape 23, one field period Sm(n), Sm(n+2), . . .
. . . and 1 in the second recording signal component Smb.
Field period Sm(n-1), Sm(n+1),・
... are alternately recorded on the magnetic tape 23 with recording tracks formed at a constant inclination angle with respect to the longitudinal direction of the magnetic tape 23.

In this way, as shown in FIG.
On the magnetic tape 23, a recording track Ta is formed every other rotation of the rotating magnetic head 21A, and a recording track Tb is formed every other rotation of the rotating magnetic head 21B. The recording track Tb is arranged between each set of two adjacent recording tracks Ta, and the recording track Ta by the rotary magnetic head 21A and the recording track Tb by the rotary magnetic head 21B are arranged.
and are alternately arranged in parallel. In this case, since the rotational angular interval between the rotating magnetic head 21A and the rotating magnetic head 21B is approximately 45 degrees, as shown in FIG.
The magnetic tape 23 (
In the scanning of the object (traveling in the direction indicated by the arrow XT), first, scanning by the rotating magnetic head 21A is started, and then, after a delay of a time corresponding to a rotation angle interval of approximately 45 degrees, scanning by the rotating magnetic head 21B is started. is carried out under the conditions in which it is started. Therefore, if the rotating magnetic head 21A and the rotating magnetic head 21B are
Assuming that they are arranged in a straight line in the scanning direction with respect to 3 without any difference in position (step) in the direction perpendicular to the scanning direction, the recording track Ta is
After the recording track Tb is formed by the recording scan by the rotary magnetic head 21B, the rotary magnetic head 21B takes a position 21B' shown by the dashed line in FIG.
is not arranged at the center between two adjacent rotary magnetic heads 21A, and recording tracks Ta and Tb are not formed at equal intervals on the magnetic tape 23.

Therefore, in reality, as shown in FIG.
The rotating magnetic head 21B rotates the magnetic tape 23 relative to the rotating magnetic head 21A within a time period corresponding to a rotation angle interval of approximately 45 degrees in a direction orthogonal to the scanning direction for the magnetic tape 23. 21
A step ST corresponding to the moving distance in the direction perpendicular to the scanning direction by B is provided. Such a step S
By providing T, after the recording track Ta is formed by recording scanning by the rotary magnetic head 21A,
When the recording track Tb is formed by the recording scan by the rotating magnetic head 21B, the rotating magnetic head 21B
is located closer to the rotary magnetic head 21A by a step ST than the position 21B', which is indicated by a solid line in FIG. Recording tracks Ta and Tb are formed at equal intervals on the magnetic tape 23.

[0018]

[Problems to be Solved by the Invention] Generally, when a playback operation is performed in a video tape recorder, the running speed of the magnetic tape is set as a reference speed, which is the running speed of the magnetic tape during the recording operation, and a rotating magnetic head is used to perform a playback operation. In addition to the normal playback mode in which signals are read from the magnetic tape, there is also a fast-forward playback mode in which the rotating magnetic head reads signals from the magnetic tape when the magnetic tape travels at a different speed from the reference speed. mode (cue playback operation mode), rewind playback operation mode (R
(view playback operation mode), still image playback operation mode (
A variable speed regeneration operation mode such as a still regeneration operation mode) is selectively taken. Among these variable-speed playback operation modes, when the cue playback operation mode or the review playback operation mode is adopted, signal discontinuity occurs with respect to the playback screen obtained on the image display device based on the playback video signal output at that time. It is desirable to suppress the noticeable noise bars that appear due to.

In order to suppress such noticeable noise bars that appear on the playback screen, playback video signals are sequentially formed based on read output signals obtained alternately from each of the two rotating magnetic heads. For this purpose, Cue playback operation mode or Rev
Under the ew reproduction operation mode, for each rotation of the two rotating magnetic heads having mutually different gap azimuths, one and the other of the two rotating magnetic heads
Alternately, the start position of scanning the magnetic tape is placed on a recording track formed by a rotating magnetic head having a gap azimuth corresponding to the gap azimuth of one of the two rotating magnetic heads. In addition, it is required as a noise bar suppression condition that reproduction output signals from one and the other of the two rotating magnetic heads are taken out alternately for each rotation of the two rotating magnetic heads. And two rotating magnetic heads are 1
In a standard video tape recorder arranged with rotational angle intervals of 80 degrees, in the cue playback operation mode or the review playback operation mode, the running speed of the magnetic tape is selected to be an even multiple of the reference speed. The two rotating magnetic heads will alternately place the scanning start position on the magnetic tape on every odd numbered recording track every half rotation. The above-mentioned noise bar suppression condition is satisfied by alternately extracting the read output signals from the two rotating magnetic heads every half rotation of each of the rotating magnetic heads.

However, as mentioned above, for example, a small video tape recorder equipped with a small tape guide cylinder having a diameter of approximately 26.67 mm and two rotating magnetic heads having a rotation angle interval of approximately 45 degrees When the cue playback operation mode or the review playback operation mode is used to obtain a playback video signal from the magnetic tape on which the video signal has been recorded, the rotational angular interval between the two rotating magnetic heads is Because the angle is not 180 degrees, the two rotating magnetic heads are 1
A similar approach to standard video tape recorders arranged with 80 degree rotational angular spacing would fail to satisfy the noise bar suppression conditions described above.

[0021] In view of these points, the present invention provides, for example, a tape guide cylinder with a diameter of 40 mm and a tape winding angle of 1
Compared to a standard video tape recorder, which has an angle of 80 degrees, two rotating magnetic heads, and a rotating speed of about 29.97 rps, the diameter of the tape guide cylinder is smaller, Images can be produced from magnetic tape on which video signals have been recorded using a compact video tape recorder that is designed to be compatible with standard video tape recorders regarding the recording format of the magnetic tape without increasing the number of magnetic heads. In reproducing video signals from a magnetic tape on which video signals have been recorded by such a small video tape recorder, for example, variable speed playback such as Cue playback operation mode, Review playback operation mode, etc. An object of the present invention is to provide a magnetic reproducing device capable of suppressing noise bars in a reproducing screen obtained on an image display device based on a reproduced video signal outputted at that time when an operation mode is selected. .

[0022]

[Means for Solving the Problems] In order to achieve the above-mentioned object, a magnetic reproducing apparatus according to the present invention is designed to reproduce a magnetic tape on which recording signals are recorded by forming a plurality of recording tracks arranged in parallel. a magnetic tape drive unit that runs at a predetermined running speed; a tape running speed control unit that controls the operation of the magnetic tape drive unit; and a tape drive unit that rotates the magnetic tape that is run by the magnetic tape drive unit for contact scanning; In a normal playback mode in which the running speed of the magnetic tape is used as a reference speed, each rotation alternately moves the magnetic tape to a plurality of parallel recording tracks formed thereon. Two rotating magnetic heads scan each recording track with an appropriate tracking state and read the recording signals recorded on each of the recording tracks, and two A read output signal extraction unit that alternately extracts read output signals from each of the rotating magnetic heads, and a signal reproduction processing unit that obtains a reproduction signal based on the read output signal extracted by the read output signal extraction unit, When a specific variable speed playback operation mode is adopted in which the running speed of the magnetic tape is different from the reference speed, the rotation angle interval set for the two rotating magnetic heads is α degrees, and M is an even number. When this happens, the tape running speed control section causes the magnetic tape drive section to
The running speed of the magnetic tape is set to be N times the reference speed, and the control is performed so that the relationship expressed by the formula: M=N(1+α/360)−α/360 is satisfied. , configured.

In the magnetic reproducing device according to the present invention, 2
Cue playback operation mode, Re
When a specific variable speed playback operation mode, such as a view playback operation mode, in which the running speed of the magnetic tape is different from the reference speed, the running speed of the magnetic tape is set to N times the reference speed, and , formula: M=N(1+α/360
)−α/360・・・・・・・・・(
A state is established in which the relationship expressed by a) is satisfied. Then, video signals are recorded by the recording system in the compact video tape recorder as shown in FIG. 2, and from the magnetic tape on which recording tracks are arranged in parallel as shown in FIG. 4, the Cue playback operation mode is started. Alternatively, when the video signal is reproduced in the Review reproduction operation mode, the equation (a ) is multiplied by Tt・Vt, formula: Tt・Vt・M=Tt・Vt・N(1+α/360
)-Tt・Vt・α/360
=Tt・Vt・N + Tt・V
t・N・α/360
-Tt・Vt・α/360
...The relationship expressed by (b) holds true.

The first term on the right side of equation (b): T
t・Vt・N represents the distance that the magnetic tape moves during one rotation of each of the two rotating magnetic heads, and the second term: Tt・Vt・N・α/360 represents the distance that the magnetic tape moves during one rotation of each of the two rotating magnetic heads. The third term: Tt・Vt・α/360 represents the distance that the magnetic tape moves while each of the heads rotates through an angular range corresponding to the rotational angular interval between them. Between two rotating magnetic heads, each rotating magnetic head is provided to alternately scan the magnetic tape with a proper tracking state for each of the recording tracks formed at equal intervals on the magnetic tape. It represents the distance along the running direction of the magnetic tape (corresponding to the distance LS in FIG. 4) corresponding to the step in the direction perpendicular to the scanning direction of the magnetic tape (corresponding to the step ST in FIG. 4). Therefore, the right-hand side of equation (b), which subtracts the third term from the sum of the first and second terms, is the rotation direction of the two rotating magnetic heads whose mutual rotation angle interval is α. From the time when the leading one starts scanning the magnetic tape to the time when the other one following one starts scanning the magnetic tape after each of the two rotating magnetic heads has rotated once, the magnetic tape represents the distance traveled.

On the other hand, Tt·Vt is the pitch (
The distance along the running direction of the magnetic tape (corresponding to LP in FIG. 4) corresponding to the distance (corresponding to PT in FIG. 4)
Furthermore, since it represents the distance along the running direction of the magnetic tape corresponding to the pitch of scanning the magnetic tape by each of the two rotating magnetic heads during normal reproduction operation, the left side of equation (b): Tt. Vt·M represents a distance that is an even number multiple of the distance along the running direction of the magnetic tape, which corresponds to the pitch of recording tracks formed at equal intervals on the magnetic tape. Since the left side is connected to the right side by an equal sign, the leading one in the rotational direction of the two rotating magnetic heads whose mutual rotation angle interval is α starts scanning the magnetic tape. After each of the two rotating magnetic heads makes one revolution, the distance that the magnetic tape moves from the time when the other one starts scanning the magnetic tape after each of the two rotating magnetic heads rotates is equal to The pitch is an even number multiple of the distance along the running direction of the magnetic tape corresponding to the pitch of the recording track formed by the pitch.

Therefore, when the cue playback operation mode or the review playback operation mode is adopted, one of the two rotary magnetic heads scans the magnetic tape during one rotation period of the two rotary magnetic heads. After starting from a certain recording track, during the next rotation period of the two rotating magnetic heads, the other of the two rotating magnetic heads scans the magnetic tape from a certain recording track to an odd number of recording tracks. The recording starts from the other recording track that was placed.

[0027] Then, the read output signal extracting section alternately extracts the read output signals from each of the two rotary magnetic heads for each rotation of the two rotary magnetic heads, and a reproduction signal is formed based on the read output signals. Therefore, when the Cue playback operation mode or the Review playback operation mode is adopted, the noise bar suppression condition described above is satisfied, and the playback screen obtained on the image display device based on the playback video signal output at that time is set to the noise bar. is said to have been suppressed.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of a magnetic reproducing apparatus according to the present invention. In this example, a time axis compression recording signal Sm is recorded by the recording system in a small video tape recorder shown in FIG. As shown in FIG. 4, a luminance signal, a carrier color signal, and an audio signal forming a color television signal are reproduced from a magnetic tape 23 on which recording tracks Ta and Tb are arranged in parallel. In this example, as a rotating magnetic head for reading,
Two rotating magnetic heads 2 in the recording system shown in FIG.
1A and 21B are provided, and the tape guide cylinder is also provided with a tape guide cylinder similar to the tape guide cylinder 22 in the recording system shown in FIG. 2. In FIG. , a tape guide cylinder, and other devices, circuit sections, etc. corresponding to the devices, circuit sections, etc. in the recording system shown in FIG. 2 are shown with the same reference numerals as in FIG. 2.

In the example of the magnetic reproducing apparatus shown in FIG. 1, the diameter of the tape guide cylinder 22 is 2/3 times the diameter (40 mm) of a standard tape guide cylinder, that is, approximately 26 mm.
．． 67 mm, and the tape winding angle is 3/2 times the tape winding angle (180 degrees) in a standard video tape recorder, that is, approximately 270 degrees. Further, the two rotating magnetic heads 21A and 21B have mutually different gap azimuths, and the rotational angular interval between them is the same as the rotational angular interval between the two standard rotating magnetic heads (180 degrees). The tape guide cylinder 22 is attached to the rotating portion of the tape guide cylinder 22, with a step ST between the tape guide cylinders 22 and 45 degrees, which is smaller than that of the tape guide cylinder 22, as shown in FIG. Rotating magnetic head 2
Tape guide cylinder 2 with 1A and 21B attached
The rotating part in the tape guide cylinder 22 is rotationally driven by a cylinder drive motor 30, and the cylinder drive motor 30 is controlled by a cylinder servo control circuit 31 to drive the rotating part in the tape guide cylinder 22, and thus the rotating magnetic head 21A.
and 21B, and the rotation speed is the rotation speed of a standard rotating magnetic head (
approximately 29.97rps), that is, approximately 59.94r
ps, and rotate in the direction shown by arrow XH. Therefore, one of the rotating magnetic heads 21A and 21B
The period of rotation is approximately 1/60 second, and is the original field period F of the video signal compressed in the time axis and recorded to form the signal Sm for time axis compression recording on the magnetic tape 23.
It approximately matches t.

The magnetic tape 23 is made to run by a capstan 25 which is rotationally driven by a capstan drive motor 24 and a pinch roller 26 which is in contact with the capstan 25 with the magnetic tape 23 sandwiched therebetween. It is controlled by a stun servo control circuit 27 to cause the magnetic tape 23 to take a predetermined running speed.

When the normal playback operation mode is adopted, the operation mode setting control signal CS supplied to the capstan servo control circuit 27 through the terminal 42 and to the switch 56 through the terminal 57 is set to the normal playback mode. It represents the operation mode, for example, is assumed to be a low level. As a result, the capstan servo control circuit 2
7 controls the capstan drive motor 24 to cause the magnetic tape 23 to run at a reference speed, which is the running speed during the recording operation when recording tracks Ta and Tb are formed on the magnetic tape 23, and controls the running of the magnetic tape 23. The speed is set to the reference speed, and the switch 56 connects the movable contacts 56c connected to enable terminals of the field memories 76, 80, 81, and 84 to the selector connected directly to the enable signal forming section 55. It is connected to the contact 56b, and as a result, the enable signal forming section 55
An enable signal SE from the field memories 76, 80, 81 and 84 is always supplied to the enable terminals of the field memories 76, 80, 81 and 84 through the switch 56.
Each of 80, 81 and 84 is kept in a writable state at all times.

Under these conditions, the magnetic tape 23 is made to run at a reference speed, and two rotating magnetic heads having different gap azimuths are arranged with a rotation angle interval of about 45 degrees between them. 21A and 21
At the rotation speed where B is approximately 59.94 rps, arrow
Rotated in the direction indicated by H, the rotating magnetic heads 21A and 21B are in a state of scanning the magnetic tape 23 along the recording tracks Ta and Tb formed thereon. At this time, since the two rotating magnetic heads 21A and 21B are arranged with a step ST between them, the recording tracks Ta and Tb, which are alternately arranged parallel to each other at equal pitches on the magnetic tape 23, The two rotating magnetic heads 2
For each rotation of 1A and 21B, the rotating magnetic head 2
1A is the first recording signal component Sma recorded on the recording track Ta by scanning the magnetic tape 23 along the recording track Ta corresponding to the gap azimuth during recording.
Sm(n) for one field period compressed on the time axis,
The state of reading each of Sm(n+2),..., and
The rotating magnetic head 21B moves the magnetic tape 23 along the recording track Tb corresponding to the gap azimuth during recording.
to read each of the time-axis compressed one field period Sm(n-1), Sm(n+1), . . . in the second recording signal component Smb recorded on the recording track Tb. The states are alternated.

As a result, the rotating magnetic head 21A scans the magnetic tape 23 during each rotation period indicated by diagonal lines in A of FIG.
During each tape scanning period during rotation, in the manner shown in C in FIG.
m(n+2), . The second recording signal component S is scanned, and the second recording signal component S is generated in a manner as shown in D in FIG.
Sm(n
-1), Sm(n+1), . . . are respectively sent out as read output signals.

The first magnetic head sent out from the rotating magnetic head 21A
1 field period Sm(n), Sm(n+2), . . . of the recording signal component Sma compressed in time axis
The time axis of the second recording signal component Smb sent out from the rotating magnetic head 21B is compressed for one field period Sm
(n-1), Sm(n+1), . switch 43
is supplied from the control terminal 44 and alternately takes a low level L and a high level H for each period including each tape scanning period of the rotary magnetic heads 21A and 21B, as shown by E in FIG. and a low level L is applied to the selection contact 43b during a period including each of the time-axis compressed one field period Sm(n), Sm(n+2), . . . of the first recording signal component Sma, and The second contact point 43c
The switch control signal SW takes a high level H in a period including one field period Sm(n-1), Sm(n+1), . . . which is time-base compressed of the recording signal component Smb.
The switch control signal SW is at low level L.
When the switch control signal SW is at high level H, the movable contact 43a is connected to the selection contact 43b, and when the switch control signal SW is at high level H, the movable contact 43a is connected to the selection contact 43c. As a result, the first recording signal component Sma obtained alternately from the reproduction amplification units 41A and 41B is time-base compressed for one field period, and the second recording signal component Smb is time-base compressed for one field period. Each field period is derived from the movable contact 43a of the switch 43, forming a series of time-domain compressed recording signals Sm as shown in F in FIG.

The time-domain compressed recording signal Sm obtained from the movable contact 43a of the switch 43 includes a time-domain compressed FM luminance signal Yf' and a time-domain compressed low frequency conversion color signal C.
c' and the time-axis compressed FM audio signal Af', respectively, are supplied to a high-pass filter (HPF) 71, a band-pass filter (BPF) 72, and a BPF 73, respectively. Then, the time axis compressed FM luminance signal Yf' in the time axis compressed recording signal Sm is obtained from the HPF 71 and is supplied to the luminance signal reproduction processing section 74. In the luminance signal reproduction processing section 74, various processes including demodulation processing are performed on the time-axis compressed FM luminance signal Yf'. The luminance signal Y' is obtained and the analog/digital converter (A/
(D converter) 75. In the A/D converter 75, the time-domain compressed luminance signal Y' is digitized to obtain a digital time-domain compressed luminance signal DY', which is supplied to the field memory 76.

Further, a time-base compressed low-frequency converted color signal Cc' in the time-base compressed recording signal Sm is obtained from the BPF 72 and is supplied to the color signal reproduction processing section 77. In the color signal reproduction processing section 77, various processes including frequency conversion processing are performed on the time axis compressed low frequency converted color signal Cc'.
A time-domain compressed carrier color signal C' based on the A/D
The signal is supplied to the converter 78. In the A/D converter 78, the time-base compressed carrier color signal C' is digitized to obtain a digital time-base compressed carrier color signal DC', which is supplied to the decoder 79. In the decoder 79, a digital time axis compressed red color difference signal DR' which is formed by intermittently connecting digital time axis compressed color difference signals from the digital time axis compressed carrier color signal DC' and a digital time axis compressed red color difference signal DR' which is made up of an intermittent series of digital time axis compressed color difference signals and a digital time axis compressed color difference signal DR' which is made up of an intermittent series of digital time axis compressed color difference signals The series of digital time-base compressed blue color difference signals DB' are individually taken out, and a digital time-base compressed red color difference signal DR' and a digital time-base compressed blue color difference signal D are obtained from the decoder 79.
B' is supplied to field memory 80 and field memory 81, respectively.

Furthermore, the time axis compressed FM audio signal Af' in the time axis compressed recording signal Sm is obtained from the BPF 73 and is supplied to the audio signal reproduction processing section 82. The audio signal reproduction processing section 82 performs various processes including demodulation processing on the time-axis compressed FM audio signal Af', and the audio signal reproduction processing section 82 performs time-axis compression based on the time-axis compressed FM audio signal Af'. The audio signal AU' is obtained and supplied to the A/D converter 83. In the A/D converter 83, the time-domain compressed audio signal AU' is digitized to obtain a digital time-domain compressed audio signal DA', which is supplied to the field memory 84.

Field memories 76, 80, 81 and 8
4 is supplied with an enable signal SE through a switch 56 to its enable terminal to enable writing, and a write clock pulse QW and a read clock are sent from the timing pulse generator 85. A pulse QR is provided. A synchronizing pulse Pv synchronized with the level change part of the switch control signal SW is supplied to the timing pulse generating section 85 through a terminal 85A, and the timing pulse generating section 85 generates a write clock pulse QW.
Frequency 4・ft/3 (ft is, for example, 10~15MH
Based on the timing of the synchronization pulse Pv, each field period of the digital time-base compressed luminance signal DY' sent from the A/D converter 75 is stored in the field memory 76. The reading clock pulse QR having a frequency ft is sent out intermittently every period when the clock pulse QR is supplied.

Thereby, in the field memory 76, the digital time-base compressed luminance signal DY' is divided and written for each field period according to the write clock pulse QW, and the digital time-base compressed luminance signal DY' that has been written is Each field period of signal DY' is
It is read out according to the read clock pulse QR. At this time, since the frequency ft of the read clock pulse QR is set to 3/4 times the frequency 4·ft/3 of the write clock pulse QW, the field memory 76 outputs the written digital time axis compressed luminance. The time axis of each field period of the signal DY' is expanded at an expansion rate of 4/3 and is sequentially and continuously sent out, forming a digital luminance signal DY as a whole. A conversion section) 86 is supplied.

In the D/A converter 86, the digital luminance signal DY is converted into an analog signal to obtain a luminance signal Y.
It is reproduced as the luminance signal Y at the video signal output terminal 8.
7.

Furthermore, in the field memory 80,
According to the write clock pulse QW, each field period of the digital time-base compressed red color difference signal DR' is sequentially written, and each field period of the written digital time-base compressed red color difference signal DR' is written as the read clock pulse. At the same time, each field period of the digital time-base compressed blue color difference signal DB' is sequentially read in the field memory 81 according to the write clock pulse QW, and the written digital time-base compressed blue color difference signal DB' is sequentially read out according to the QR. Blue color difference signal D
Each field period of B' is the read clock pulse QR.
are read out sequentially according to In such a case, the frequency ft of the read clock pulse QR is equal to the write clock pulse Q.
Since it is said to be 3/4 times the frequency of W, 4·ft/3,
From the field memory 80, the time axis of each field period of the written digital time-base compressed red color difference signal DR' is expanded at an expansion rate of 4/3 and is continuously sent out. DR is obtained, and each field period of the written digital time-axis compressed blue color difference signal DB' is continuously transmitted from the field memory 81 with its time axis expanded at an expansion rate of 4/3. A digital blue color difference signal DB is obtained. Both the digital red color difference signal DR and the digital blue color difference signal DB are supplied to the encoder 88, and in the encoder 88,
Both the digital red color difference signal DR and the digital blue color difference signal DB are combined to form a digital carrier color signal DC, and the digital carrier color signal DC obtained from the encoder 88 is supplied to the D/A converter 89.

In the D/A converter 89, the digital carrier color signal DC is converted into an analog carrier color signal to obtain a carrier color signal C, which is outputted to the video signal output terminal 90 as a reproduced carrier color signal C.

Further, in the field memory 84, the digital time-base compressed audio signal DA' is divided and written for each one field period according to the write clock pulse QW, and the written digital time-base compressed audio signal DA' is written in accordance with the write clock pulse QW. Each of the signal DA' for one field period is read out in accordance with the read clock pulse QR. In such a case, the frequency f of the reading clock pulse QR
Since t is 3/4 times the frequency 4·ft/3 of the writing clock pulse QW, the written digital time-base compressed audio signal DA' is output from the field memory 84.
The time axis of each field period for one field period is expanded at an expansion rate of 4/3 and is sent out continuously, and these as a whole form a digital audio signal DA.
/A converter 91.

Then, in the D/A converter 91, the digital audio signal DA is converted into an analog audio signal AU.
is obtained and output to the audio signal output terminal 92 as a reproduced audio signal AU.

In this way, the magnetic reproducing apparatus shown in FIG. 1 reproduces the luminance signal Y, the carrier color signal C, and the audio signal AU forming the video signal from the magnetic tape 23 under the normal reproduction operation mode. Although the example uses a tape guide cylinder 22 having a smaller diameter than a standard tape guide cylinder, it is sufficient to have only two rotating magnetic heads 21A and 21B. .

On the other hand, in the example of the magnetic reproducing device shown in FIG.
7 and to the switch 56 through the terminal 57, the operating mode setting control signal CS represents the variable speed reproduction operating mode, for example, assumes a high level. As a result, switch 56 causes field memory 76 to
, 80, 81, and 84 are connected to the selection contact 56a connected to the enable signal forming section 55 via the switch 54.

Further, the capstan servo control circuit 27 which receives the operation mode setting control signal CS which takes a high level,
The running speed of the magnetic tape 23 of the capstan drive motor 24 is set to N times the reference speed, and in this case, α is the rotation angle interval (approximately 45 degrees) between the rotating magnetic head 21A and the rotating magnetic head 21B. and M is an even number, M=N(1+α/360)−α/360
Control is performed so that the relationship expressed by is satisfied.

It is assumed that the magnetic tape 23 runs at a running speed that is N times the reference speed, and M=N(
1+α/360)−α/360 If the relationship expressed by
The rotation period of each of A and 21B is Tt (≒ 1/59.
94) and the reference speed for the magnetic tape 23 is V
As t, the formula: Tt・Vt・M=Tt・Vt・N(1+
α/360) - Tt・Vt・α/360
=Tt・Vt・N +
Tt・Vt・N・α/360
-Tt・Vt・α/36
The relationship represented by 0 holds true. In this formula, Tt·Vt·N represents the distance that the magnetic tape 23 moves during one rotation of each of the rotating magnetic heads 21A and 21B, and Tt·Vt·N·α/360 is
It represents the distance that the magnetic tape 23 moves while each of the rotating magnetic heads 21A and 21B rotates in an angular range corresponding to the rotation angle interval between them, and is expressed as Tt・Vt・α/36
0 represents the distance LS (see FIG. 4) along the running direction of the magnetic tape 23 corresponding to the step ST between the rotating magnetic heads 21A and 21B. Therefore, the right side of the above equation indicates that while the rotating magnetic heads 21A and 21B are ahead in the rotational direction indicated by the arrow After each of the heads 21A and 21B makes one revolution, until the time when the rotating magnetic head 21B, which follows the rotating magnetic head 21A in the rotational direction, starts scanning the magnetic tape 23,
This represents the distance that the magnetic tape 23 moves.

On the other hand, in the above equation, Tt·Vt is
Pitch PT for recording tracks Ta and Tb formed at equal pitches on the magnetic tape 23 (see FIG. 4)
The distance LP along the running direction of the magnetic tape 23 corresponding to
(See FIG. 4), and furthermore, the magnetic tape 2 by each of the rotating magnetic heads 21A and 21B during normal playback operation.
3 represents the distance along the running direction of the magnetic tape 23 corresponding to the pitch for scanning, so the left side of the above equation: Tt・Vt・M is the recording track Ta and Tb.
represents a distance that is an even multiple of the distance LP along the running direction of the magnetic tape 23 corresponding to the pitch PT. Since the left side and the right side of the above equation are connected by an equal sign, from the time when the rotating magnetic head 21A starts scanning the magnetic tape 23, after each of the rotating magnetic heads 21A and 21B has made one revolution, The distance that the magnetic tape 23 moves until the rotating magnetic head 21B starts scanning the magnetic tape 23 is the recording track Ta.
and magnetic tape 2 corresponding to the pitch PT for Tb.
The distance LP along the traveling direction of No. 3 is an even number multiple.

Therefore, under such circumstances, as shown in FIG. 7, one of the rotating magnetic heads 21A and 21B
During the rotation period, the rotating magnetic head 21A rotates the magnetic tape 2.
After starting the scanning for 3 from above the recording track Ta,
In the next one rotation period of each of the rotary magnetic heads 21A and 21B, the rotary magnetic head 21B scans the magnetic tape 23, and the rotary magnetic head 21A starts scanning the magnetic tape 23 from the recording track Ta to an odd number of recording tracks Ta. and a recording track T separated by Tb.
The state is set to start from above a. Therefore, from the rotary magnetic heads 21A and 21B that scan the magnetic tape 23 in this way, the first recording signal component Sma and , a second recording signal component S obtained intermittently by being read intermittently from a plurality of recording tracks Tb.
mb are alternately and sequentially derived with constant repetition timing.

In the capstan servo control circuit 27, the specific value of N selected to satisfy the relationship expressed by M=N(1+α/360)−α/360 is determined by the relationship between the rotating magnetic heads 21A and 21B. Since the rotation angle interval is approximately 45 degrees, when α=45 and the cue playback operation mode is taken, for example,
It is set to "9", and when the Review playback operation mode is selected, it is set to, for example, "-7". Under such conditions, in the cue playback operation mode, N=9 and M=10, and 9x fast forward playback is performed in which the magnetic tape 23 is run at 9 times the reference speed. Also, in the Review playback operation mode,
By setting N=-7, M=-8, and 7x speed rewind playback is performed in which the magnetic tape 23 is run in the rewinding direction at 7 times the reference speed.

Under such a variable speed reproduction operation mode, the first recording signal component Sma and the plurality of recording signals are intermittently read from a plurality of recording tracks Ta obtained intermittently from the rotary magnetic heads 21A and 21B, respectively. The second recording signal component Smb read intermittently from the recording track Tb is also transmitted to the switch control signal SW through the reproduction amplification sections 41A and 41B in the same manner as in the normal reproduction operation mode.
The signals are taken out alternately through a switch 43 controlled by a switch 43, and are used as an intermittent time-base compression recording signal Sm. Then, the intermittent time axis compression recording signal Sm from the switch 43 is supplied to each of the HPF 71, BPF 72, and BPF 73, and in the same manner as in the normal playback operation mode,
Intermittent time axis compression recording signal S from the A/D converter 75
A digital time-base compressed luminance signal DY' based on m is sent out and supplied to the field memory 76, and also
A digital time-domain compressed carrier color signal DC' based on the intermittent time-domain compressed recording signal Sm is obtained from the converter 78,
Furthermore, a digital time-axis compressed red color difference signal DR based on the intermittent time-axis compressed recording signal Sm is output from the decoder 79.
' and digital time-base compressed blue color difference signal DB' are individually taken out and supplied to field memories 80 and 81, respectively. The time-base compressed audio signal DA' is sent out and supplied to the field memory 84.

The intermittent time-base compression recording signal Sm from the switch 43 is also supplied to the envelope detecting section 51, and the intermittent time-base compression recording signal Sm is supplied from the envelope detecting section 51 to the envelope detecting section 51. A detection output signal SA having the same level is obtained and supplied to the level comparator 52. In the level comparison section 52, the level of the detection output signal SA from the envelope detection section 51 is compared with a predetermined constant level of the reference voltage VR obtained from the reference voltage source 53, and the level comparison section 52 outputs the detection output signal SA. A level comparison output signal SQ is obtained which takes a high level when the level of the reference voltage VR is higher than the level of the reference voltage VR, and takes a low level otherwise. The switch 54 is turned on when the level comparison output signal SQ takes a high level, and the enable signal SE from the enable signal forming section 55 is applied to the switch 5.
4 and field memories 76, 8 through switch 56.
0, 81, and 84, and is in an off state when the level comparison output signal SQ takes a low level, so that the enable signal SE from the enable signal forming section 55 is Supply to the enable terminals of each of field memories 76, 80, 81 and 84 is blocked. Such level comparison section 5
Switch 54 according to the level comparison output signal SQ from 2
As a result of the operation, each of the field memories 76, 80, 81 and 84 is stored in the field memories 76, 80, 81 and 84 when the intermittent time axis compression recording signal Sm from the switch 43 has a level higher than a predetermined level, that is, when the intermittent time Only when the axial compression recording signal Sm has been properly read by the rotary magnetic heads 21A and 21B, a write-enabled state is established.

Therefore, in the field memory 76, the digital time axis compressed luminance signal DY' based on the time axis compressed recording signal Sm properly read by the rotary magnetic heads 21A and 21B is transmitted to the timing pulse generator 8.
The digital time axis compressed luminance signal DY' is written according to the write clock pulse QW from the timing pulse generator 85, and is read out from the field memory 76 according to the read clock pulse QR from the timing pulse generator 85. The written digital time-base compressed luminance signal DY' is sent out after its time-base is expanded at an expansion rate of 4/3, and is supplied to the D/A converter 86 to form the digital luminance signal DY. In the D/A converter 86, the digital luminance signal DY is converted into an analog signal to obtain a luminance signal Y, which is output to the video signal output terminal 87 as a luminance signal Y reproduced under the variable speed reproduction operation mode. Ru.

Furthermore, in the field memory 80,
The digital time axis compressed red color difference signal DR' based on the time axis compressed recording signal Sm properly read by the rotating magnetic heads 21A and 21B is the writing clock pulse QW.
At the same time, the written digital time-base compressed red color difference signal DR' is sequentially read out according to the reading clock pulse QR, and at the same time, in the field memory 81, the rotary magnetic heads 21A and 2
Time axis compression recording signal S properly read out by 1B
The digital time-base compressed blue color difference signal DB' based on m is written in accordance with the writing clock pulse QW, and the written digital time-base compressed blue color difference signal D
B' is read out according to the reading clock pulse QR. Then, the written digital time axis compressed red color difference signal DR' is sent out from the field memory 80 with its time axis expanded at an expansion rate of 4/3, thereby obtaining the digital red color difference signal DR.
The written digital time axis compressed blue color difference signal DB' is continuously sent out from the field memory 81 with its time axis expanded at an expansion rate of 4/3, thereby obtaining a digital blue color difference signal DB. Then, a digital red color difference signal DR and a digital blue color difference signal D
Both of B are supplied to the encoder 88, and the encoder 88
, both the digital red color difference signal DR and the digital blue color difference signal DB are combined to form a digital carrier color signal DC, and the digital carrier color signal DC obtained from the encoder 88 is supplied to the D/A converter 89. . In the D/A converter 89, the digital carrier color signal DC is converted into an analog carrier color signal C to obtain a carrier color signal C, which is reproduced in the variable speed reproduction operation mode.
The signal is output to the video signal output terminal 90 as a signal.

Furthermore, in the field memory 84, the digital time axis compressed audio signal DA' based on the time axis compressed recording signal Sm properly read out by the rotating magnetic heads 21A and 21B is transmitted to the timing pulse generator 8.
The digital time-base compressed audio signal DA' is written in accordance with the write clock pulse QW from the timing pulse generator 85, and is read out from the field memory 84 in accordance with the read clock pulse QR from the timing pulse generator 85. The written digital time-base compressed audio signal DA' is sent out after its time-base is expanded at an expansion rate of 4/3, and is supplied to the D/A converter 91 to form the digital audio signal DA. In the D/A converter 91, the digital audio signal DA is converted into an analog signal to obtain the audio signal AU, which is output to the audio signal output terminal 92 as the audio signal AU reproduced under the variable speed reproduction operation mode. Ru.

The luminance signal Y, the carrier color signal C, and the audio signal AU reproduced in the variable speed reproduction operation mode obtained in this way are transferred to the magnetic tape 23 in the variable speed reproduction operation mode. is assumed to travel at a traveling speed that is N times the reference speed, and M=N(1+α/3
60) - α/360 is satisfied, and the rotational magnetic heads 21A and 21B scanning the magnetic tape 23 are to be alternately and sequentially derived at a constant repetition timing.
A first recording signal component Sma is intermittently obtained by being read intermittently from a plurality of recording tracks Ta, and a second recording signal component Sma is intermittently obtained by being intermittently read from a plurality of recording tracks Tb. Since it is assumed that the signal component Smb is reproduced based on the signal component Smb, the reproduced screen obtained on the image display device when these signals are supplied to the image display device is one in which noticeable noise bars are suppressed.

In the example shown in FIG. 1, the two rotating magnetic heads 21A and 21B are arranged such that the rotation angle interval between them is 45 degrees. The arrangement of the heads 21A and 21B is not limited to this example, but the rotation angle interval between them is 45.
It can be made smaller or larger than the degree. In this case, M=N(1+α/360)−α/360 is satisfied when variable speed playback modes such as Cue playback operation mode and Review playback operation mode are taken.
The specific value of N that establishes the relationship expressed by is
Although the rotation angle interval between the rotating magnetic heads 21A and 21B is changed, for example, the rotating magnetic head 21
When the rotation angle interval (α) between A and 21B is approximately 60 degrees, when the cue playback operation mode is taken, for example, N=7 and M=8 accordingly. , and 7x fast forward playback is performed, and when the Review playback operation mode is set, for example, N=-5 and M=-6 accordingly, 5 Double speed rewind playback is performed.

[0059]

As is clear from the above description, the magnetic reproducing device according to the present invention has, for example, a tape guide cylinder with a diameter of 40 mm, a tape winding angle of 180 degrees, and a number of rotating magnetic heads of 2. Compared to a standard video tape recorder in which the rotational speed of the rotating magnetic head is approximately 29.97 rps, the diameter of the tape guide cylinder is made smaller, without increasing the number of rotating magnetic heads. ,
When reproducing video signals from a magnetic tape on which video signals have been recorded using a compact video tape recorder that is compatible with standard video tape recorders regarding the recording format of the magnetic tape,
When a specific variable speed playback operation mode such as a cue playback operation mode or a review playback operation mode is used, the magnetic tape
The traveling speed of the pump is set to be N times the reference speed, and the formula:
By assuming that the relationship expressed by M=N(1+α/360)−α/360 is satisfied, this can be obtained under specific variable speed playback operation modes such as Cue playback operation mode and Review playback operation mode. The reproduced video signal is supplied to an image display device so that a reproduced screen obtained on the image display device can have noticeable noise bars suppressed.

[Brief explanation of the drawing]

FIG. 1 is a block connection diagram showing an example of a magnetic reproducing device according to the present invention.

FIG. 2 is a block connection diagram schematically showing an example of a recording system of a compact video tape recorder that records video signals on a magnetic tape to be reproduced according to the example shown in FIG. 1;

FIG. 3 is a time chart used to explain the operation of the recording system of the small-sized video tape recorder shown in FIG. 2;

4 is a conceptual diagram for explaining the operation of the recording system of the small-sized video tape recorder shown in FIG. 2 and the operation of the example shown in FIG. 1; FIG.

5 is a conceptual diagram illustrating the recording system of the compact video tape recorder shown in FIG. 2 and the arrangement of rotating magnetic heads in each of the examples shown in FIG. 1;

FIG. 6 is a time chart used to explain the operation of the example shown in FIG. 1;

FIG. 7 is a conceptual diagram used to explain the operation of the example shown in FIG. 1;

[Explanation of symbols]

21A Rotating magnetic head 21B Rotating magnetic head 22 Tape guide cylinder 23 Magnetic tape 24 Capstan drive motor 25 Capstan 26 Pinch roller 27 Capstan servo control circuit 30
Cylinder drive motor 31 Cylinder servo control circuit 43 Switch 51 Envelope detection section 52 Level comparison section 54 Switch 55 Enable signal formation section 56 Switch 71 HPF 72 BPF 73 BPF 74 Luminance signal reproduction processing section 76 Field memory 77 Color signal reproduction processing section 80 Field Memory 81 Field memory 82 Audio signal reproduction processing section 84 Field memory

Claims (1)

[Claims] 1. A magnetic tape drive section for running a magnetic tape on which recording signals are recorded forming a plurality of parallelly arranged recording tracks at a predetermined running speed, and operation control for the magnetic tape drive section. A normal playback operation mode is adopted in which the magnetic tape running by the magnetic tape drive unit is rotated for contact scanning, and the running speed of the magnetic tape is set as a reference speed. In this case, each rotates the magnetic tape alternately.
The magnetic tape is scanned over each of a plurality of recording tracks arranged in parallel formed on the magnetic tape in an appropriate tracking state, and the recording signals recorded on each of the recording tracks are read. a read output signal extraction unit that alternately extracts read output signals from each of the two rotating magnetic heads for each rotation of the two rotating magnetic heads; and a read output signal extraction unit and a signal reproduction processing section that obtains a reproduction signal based on the read output signal extracted by the above-mentioned. Under the assumption that the rotation angle interval set for the two rotating magnetic heads is α degrees and M is an even number, the tape running speed control unit causes the magnetic tape drive unit to control the running of the magnetic tape. The speed is set to N times the reference speed, and the formula: M=N(1+α/360
) - α/360 A magnetic reproducing apparatus is characterized in that it is controlled to satisfy the relationship expressed by: