JPS60163585A - Video tape recorder - Google Patents

Abstract

PURPOSE:To equalize a reproducing signal waveform of the 1st field to that of the 2nd one and to obtain reproduced videos at a multiplied speed by putting dimensions of each trunk width in order and equalizing the trunk width of the 1st magnetic head for a standard mode to that of the 2nd one and making the trunk width of a magnetic head for long-time mode equal. CONSTITUTION:Standard mode magnetic heads M1 and M2 having different azimuths are arranged on a rotational cylinder 1, and magnetic heads for long- hour mode S1 and S2 are installed. The relative height of a group of M1 and M2 and that of S1 and S2 are set so that their center of trunk width will be made equal. The heads M1 and M2 is arranged 180 deg. away from the heads M1 and M2. The distance between the heads M1 and M2 in the outer circumference of a rotational plane of a magnetic head and that of the heads S1 and S2 are multified by the n-fold distance between horizontal synchronizing signals recorded on a magnetic tape. Variance of an interval of a horizontal synchronizing signal caused by switching of a magnetic head output signal at the time of reproduction can be prevented, and reproduced videos are outputted at a multiplied speed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a helical scan type video tape recorder C (hereinafter abbreviated as VTR).

2. Conventional Structures and Their Problems In recent years, VTRs have been increasingly developed in the direction of longer recording times, increased functionality, smaller size, and cost reduction. Due to longer recording times, in recent years standard mode (2 hour mode) and long time mode (6 hour mode) have been introduced.
Most VTRs allow users to freely select and record either of the following methods according to their preference. However, when playing back recorded magnetic tapes, especially multi-speed playback, methyl, and slow-motion playback, it is possible to play back in long-time mode but not in standard mode, or in standard mode and long-time playback. Although time mode is possible, several noise bars appear during multi-speed playback, and image blur occurs during frame playback during still playback, making it unsatisfactory.

In addition, by providing two auxiliary magnetic heads (for long time mode) with different azimuth angles near the two main magnetic heads (for standard mode) with different azimuth angles, field still playback without image blur and standard There is a known method for realizing multi-speed playback without noise bars in the mode.

However, in order to realize long-time mode field still playback, the trunk width of the main magnetic node for standard mode is different. Therefore, when performing multi-speed playback in standard mode, the switching position of the main magnetic head and auxiliary magnetic head differs from field to field due to the difference in the output of the playback signal due to the difference in track width, resulting in partial vertical image blurring. This results in extremely poor image quality.

Hereinafter, with reference to the drawings, a case will be described in which long-time mode field still playback and noiseless multi-speed playback are performed using two conventional main magnetic heads and two auxiliary magnetic heads.

FIG. 1 is a diagram showing the arrangement of a conventional magnetic head and the configuration of a reproduction signal processing circuit. FIG. 2 is a diagram showing a recording track pattern in a long-time mode, a head trajectory when field still reproduction is performed, and a diagram showing reproduction signals of each magnetic head at that time. FIG. 3 is a diagram showing a recording trunk pattern in the standard mode, a head trajectory when triple speed reproduction is performed, and a diagram showing reproduction signals of each magnetic head at that time.

No. 118 is a diagram showing the arrangement of the magnetic heads, in which the rotary cylinder 1 has standard mode magnetic heads M1 and M2 with different azimuth angles and track widths, as well as magnetic heads M1 and M2 for the standard mode, which have different azimuth angles and track widths. , and both magnetic heads M1. Near M2, there is a magnetic head S for long time mode.
1 and S2 are arranged. And Figure 1 (B)
As shown, the azimuth angle of the magnetic head S1 placed near the magnetic head M1 is the same as that of the magnetic head M2, and the azimuth angle of the magnetic head S2 placed near the magnetic head M2 is the same as that of the magnetic head M1. is the same as

The magnetic head M1 for standard mode is the same as the track pitch for standard mode, and M2 is narrower than M1 because it is used for field still playback in long time mode. The track widths of the magnetic heads S1 and S2 for the long time mode are the same and are wider than the track pinch for the long time mode.

The track edges of each magnetic head are aligned to facilitate height adjustment. In addition, the distance between the magnetic head M1 and the magnetic head S1 and the distance between the magnetic head M2 and the magnetic head S2 on the outer periphery of the rotation plane of the magnetic head are the distance between the horizontal synchronization signals recorded on the magnetic tape. Let H be nH (n is a positive integer). In this embodiment, for example, n=2.

The reason why this distance is set to be an integral multiple of H is to prevent the interval between horizontal synchronizing signals from being disturbed due to switching of the magnetic head output signal during reproduction.

Next, the configuration of the conventional example will be explained using ρ in FIG.

In FIG. 1 (q), the signals reproduced by the standard mode magnetic heads M1 and M2 and the long time mode magnetic heads S1 and S2 installed on the rotary cylinder 1 are transmitted to the rotary transformers R1, R2, R3 and The reproduced signals of Ml and M2 are sent to the head amplifier 2 via R4.
Sl and S2 are input to head amplifier 3. This is an input terminal for a bed switching signal synchronized with the rotation of the 10-digit rotary cylinder 1, and is input to the head amplifiers 2 and 3. This head switching signal selects reproduction signals for magnetic heads M1 and M2 and magnetic hands S1 and S2, respectively. The output signal of the head amplifier 2 is input to an envelope detection circuit 5 and a changeover switch 8. Similarly, the output signal of the head amplifier 3 is input to an envelope detection circuit 6 and a changeover switch 8. An envelope detection circuit 5 performs envelope detection of reproduction signals of the standard mode magnetic heads M1 and M2, and an envelope detection circuit 6 performs envelope detection of reproduction signals of the long time mode magnetic heads S1 and S2. The output signals of the envelope detection circuits 5 and 6 are input to the minus (←) and plus (→) terminals of the comparator 7, respectively. The output of the comparator 7 is Low level when the output signal of the envelope detection circuit 6 is larger than the output signal of the envelope detection circuit 6; When it is small, it becomes High level. The output of the comparator 7 is connected to a changeover switch 8, which switches the larger reproduction signal of the standard mode magnetic heads M1 and M2 and the long time mode magnetic heads S1 and S2 to be output to the reproduction signal output terminal 9. Switch 8 is switched.

11 is a mode control signal input terminal, and the mode control signal is input to the envelope detection circuits 6 and 6.

With this mode control signal, when envelope comparison is not required, such as during normal slow playback or still playback,
The outputs of the envelope detection circuits 5 and 6 are controlled so that, for example, during normal playback in standard mode, the output of the envelope detection circuit 6 is set to High level and the output of the envelope detection circuit 6 is set to Low level using a mode control signal. .

Further, during still reproduction, the envelope detection circuits 5 and 6 are alternately set to High level or Low level in units of fields. Therefore, during normal playback, the output of the comparator 7 becomes Low level, and the changeover switch 8 is changed to output the playback signals of the standard mode magnetic heads M1 and M2 to the playback signal output terminal 9. During still playback, the output of the comparator 7 becomes Low level. Output is H in field units
high and low, and the changeover switch 8 is switched to output the reproduced signals of the standard mode magnetic head M1 and the long-time mode magnetic head S2 of the same azimuth to the reproduced signal output terminal 9.

For standard playback in long-time mode, selector switch 8 is similarly set to output the playback signals of magnetic heads S1 and $2 for long-time mode to playback signal output terminal 9. For still playback in long-time mode, selector switch 8 is switched. By switching, the reproduction signals of the standard mode magnetic head M2 and the long-time mode magnetic head S1 having the same azimuth are outputted to the reproduction signal output terminal 9 for each field. □ Next, the operation when performing still playback in long-time mode and triple-speed playback in standard mode in the conventional example configured as shown in Fig. 1 will be explained using Figs. 2, 3, and 4. do.

In Figure 2, (,) indicates the long-time mode magnetic head S.
1 shows a state in which the recording track patterns recorded in steps 1 and S2 are repeatedly arranged, and one scale on the horizontal axis indicates the time of one field, and also indicates the timing of the hent switching signal. The vertical axis shows the amount of magnetic tape movement, part 1
The scale indicates the amount of track pitch that the magnetic tape travels during one field time during recording or normal reproduction. Since azimuth recording is used, tracks recorded by the magnetic head S1 cannot be reproduced by the magnetic head S2. Similarly, tracks recorded with the magnetic head S2 cannot be reproduced with one magnetic head S1.3, Fig. 2(a)
In the figure, the tracks recorded by the magnetic head S1 and the tracks recorded by the R1 magnetic head S2 are indicated by L. Further, the R track can be reproduced with M2 of the standard mode magnetic head, and the L track can be reproduced with M1. The thick lines in FIG. 2(a) represent the head trajectories of 81 and S2 of the long-time mode magnetic head when performing still playback.
The broken lines represent the head trajectories of the standard mode magnetic heads M1 and M2. FIG. 2(b) shows the head switching signal, and during the period when the head switching signal is High, reproduction signals are obtained from the magnetic heads M1 and Sl.
During the period when the head switching signal is Low, reproduction signals are obtained from the magnetic heads M2 and S2. Figure 2 (C)
6 is the reproduced envelope waveform reproduced by the standard mode magnetic head M1 and M2 when performing still reproduction.
D is the output signal of the Henodo amplifier 2 in FIG. 1(C).

Figure 2 p) shows magnetic heads S1 and S2 for long-time mode.
This is the reproduced envelope waveform reproduced in , and is the output signal of the head amplifier 3 in FIG.

In order to perform still playback as field playback without image blurring, the changeover switch 8 is changed so that the playback signal of Sl is obtained during the period when the head switching signal is High, and the playback signal of M2 is obtained during the period when the head switching signal is Low. ) is obtained at the reproduced signal output terminal 9.

The shaded parts of the reproduced waveforms (C), (d), and (e) in Figure 2 indicate crosstalk components of adjacent tracks. generates crosstalk noise.

Therefore, the standard mode magnetic head M2 used for long-time mode still playback cannot be made as wide as M1 because of the large number of adjacent crosstalk components3.
, the limit of the crosstalk level is approximately -10 dB, and there is no problem in practical use as long as the crosstalk is at the level of the M2 reproduced signal shown in FIGS. 2(C) and 2(d).

Next, in such a head configuration, the standard mode 3
The case of double speed playback will be explained with reference to FIGS. 3 and 4.

In Fig. 3, (-) indicates that the recording track pattern recorded by long-time magnetic heads M1 and M2 is repeatedly arranged, and as in Fig. 2 (,), one scale on the horizontal axis corresponds to one field. It shows the time and also shows the timing of the head switching signal.

The vertical axis indicates the amount of movement of the magnetic tape, and one division thereof indicates the amount of track pitch that the magnetic tape travels during one field time during recording or normal reproduction.

Since azimuth recording is used, tracks recorded by the magnetic head M1 cannot be reproduced by the magnetic head M2.

Similarly, tracks recorded by the magnetic head M2 cannot be reproduced by the magnetic head M2. In FIG. 3(a), the track recorded by the magnetic head M1 and the track recorded by the L1 magnetic head M2 are indicated by R. Also,
R) The rack can be reproduced by long-time mode magnetic head S1, and the L track can be reproduced by S2. The thick lines in FIG. 3 (-) represent the head trajectories of the standard mode magnetic heads M1 and M2 during triple-speed reproduction, and the broken lines represent the head trajectories of the long-time mode magnetic heads S1 and S2. There is. ■) is a head switching signal.

((+) is the reproduction envelope waveform reproduced by the standard mode magnetic heads M1 and M2 during triple speed reproduction, and is the output signal of the head amplifier 2 in Fig. 1q) (d)
is the reproduced envelope waveform reproduced by the long-time mode magnetic heads S1 and S2, and is the output signal of the head amplifier 3 in FIG. 1(0). The reproduced envelope waveforms in FIGS. 3(C+) and (d) are passed through the envelope detection circuits 5 and 6, which are, for example, well-known diode detection circuits, in FIG. By switching, the reproduced signal shown in FIG. 3(e) is obtained at the reproduced signal output terminal 9. As a result, a good reproduced image without noise bars can be obtained during triple-speed reproduction in the standard mode. Note that the line spanning the reproduced envelope waveforms (C), (d), and (e) in FIG. 3 indicates a switching position based on envelope comparison.

As shown in FIG. 3, since the standard mode magnetic heads M1 and M2 have different track widths, the switching positions determined by envelope comparison are different between the period when the head switching signal is High and the period when it is Low.

For this reason, four switching lines appear on the playback screen, and between two of the lines, there is a partial vertical shift in the playback image, which significantly reduces the playback image quality.

, This situation will be explained using FIG. Figure 4(a)
shows the track pattern recorded by the standard mode magnetic heads M1 and M2, 5o and 52 are the tracks recorded by the magnetic head M1, and 51 is the track pattern recorded by the magnetic head M2. . Recording tracks 50, 51 and 52 are labeled with horizontal synchronization signal numbers. As is well known, in the case of standard mode recording, the horizontal synchronization signal is set with a horizontal synchronization signal difference of, for example, 1.5H.
The tracks are recorded so that the horizontal sync signals line up with the adjacent tracks.

Also, since one field of signals is recorded on one track and one frame of signals is recorded on two tracks, the first track records 1H to 262.5H, and the second track records 262.5H to 525H. However, since almost the same information is recorded in the 1H and 263H, the same numbers are given for convenience of explanation. The head switching signal for triple speed playback in Figure 3 is Hi.
The initial position at which the standard mode magnetic head M1 is switched to the long mode magnetic head S1 during the period gh is shown in FIG.
), for example, when the 8th H of the recording track 60 has finished being reproduced. Standard mode magnetic head M1
The distance between the magnetic head S1 and the magnetic head cap of the long-time mode magnetic head S1 is nH as described above, and in this embodiment, it is 2
Suppose that the magnetic head S1 is rotating in advance of the magnetic head M1. Therefore, in Fig. 4(a), A
When the magnetic head M1 is switched to the magnetic head S1 at the position shown in FIG.
) as shown in 53.

Next, during the period when the head switching signal is Low, the standard mode magnetic head M2 is switched to the long time mode magnetic head S.
The first position to switch to 2 is position B in Fig. 4(a),
For example, assume that the 4th H of the recording track 51 has been reproduced. Similarly, it is assumed that the magnetic head S2 is rotating in advance of the magnetic head M2. Therefore, at this time, the horizontal synchronization signal number of the reproduced signal is 64 in FIG. 4(b).
It becomes as shown in .

In FIG. 4(b), 53 is a reproduction signal of the first field, and 54 is a reproduction signal of the second field, and these two constitute one frame of reproduction image. The most problematic part of the reproduced signals 53 and 54 is the period between switching positions A and B, and the horizontal synchronization signal numbers of the reproduced signal 53 are 5.6, 7.
．． 8, the horizontal synchronizing signal numbers of the reproduced signal 54 of the next field are 9.10 and 11.12, which are shifted by 4H, and during this period, the information in the first field and the second field are significantly different. , there was vertical jitter on the playback screen, making it very unwatchable.

Note that Fig. 4 is only for explaining the problem in principle, and in the triple speed playback shown in Fig. 3, the difference between the switching positions of the first field and the second field is approximately 1.3 m5.
ec and a period corresponding to about 20'H causes vertical jitter on the playback screen.

As explained above, in the past, the standard mode magnetic head and the long-time mode magnetic head were installed close to each other, and in order to realize long-time mode field still playback, the track width of one side of the standard mode magnetic head was In a video tape recorder configured to narrow the area, when multi-speed playback is performed in standard mode, no noise bar appears on the playback screen, but there is some vertical jitter in some areas, resulting in a good multi-speed playback image. The problem was that it could not be done.

Similar problems occur even at speeds n times higher than speeds other than triple speeds. For example, at 9x speed, the width of the vertical jitter is about 7H of Z at 3x speed, but it occurs in three places on the playback screen, and the total is about 20H, as in the case of 3x speed.

OBJECTS OF THE INVENTION An object of the present invention is to provide a video tape recorder that can obtain good reproduced images during multi-speed reproduction.

Composition of the Invention The video tape recorder of the present invention allows a magnetic tape to travel at a constant speed at a predetermined first or second speed (where the first speed is greater than the second speed) during recording, and is azimuthal to each other. First and second magnetic heads having different angles are provided at a position of 18oO on the rotating substrate, and a third magnetic head having an azimuth angle different from the first magnetic head and the same as the second magnetic head; 9 fourth magnetic nodules, which are the same as the first magnetic head and whose angles are different from those of the second magnetic head, are provided at positions 1800 on the rotary head substrate near the first and second magnetic heads, respectively; , and when recording at the first speed, the first and second magnetic heads are used, and when recording at the second speed, the third and fourth magnetic heads are used. A helical scan type video tape recorder, wherein the first and second magnetic heads have the same track width, the third and fourth magnetic heads have the same track width, and the first and second magnetic heads have the same track width. The track width TW of the magnetic head of
1 is the track width TW2 of the third and fourth magnetic heads.
TP and the track pitch of the second speed is wider than TP
2, and the trunk pitch of the first speed TP1=3XTP
2, 2XTP2≦TW1≦3XTP2 TP2≦TW2≦2XTP2, and the first and second magnetic heads and the third
and the fourth magnetic head are arranged so that their track width centers are aligned, and as a result,
Second, it is possible to eliminate partial vertical fluctuations in the playback screen during multi-speed playback due to differences in switching positions for each field.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 5 is a diagram showing the arrangement of magnetic nodes in one embodiment of the present invention. Note that the same components as in FIG. 1 are given the same reference numerals. In FIG. 5, (5) is a diagram showing the arrangement of magnetic nodes, and the rotary cylinder 1 has magnetic heads M1 and M for standard mode with different azimuth angles.
In addition to No. 2, long-time mode magnetic heads S1 and S2 are arranged similarly to No. 114.

As shown in ) in Figure 1, the magnetic head M for standard mode
1 and M2 and long-time mode magnetic heads S1 and S
Set the relative heights of the two heads so that the centers of the track widths are aligned, and the track width is set so that the trunk pitch of the long-time mode is TP2.The track width of the magnetic head for the standard mode is 2XTP2, and the track width of the magnetic head for the long-time mode is set as TP2. The track width is set to 1.5XTP2. The block diagram of the reproduced signal processing system is the same as that in FIG. 1q.

Magnetic heads M1 and M2 are 180° apart from each other.

The magnetic heads S1 and 82 are also separated from each other by 18QO.

Also, the distance between the magnetic head M1 and the magnetic head S2 on the outer periphery of the rotation plane of the magnetic head, and the magnetic head M2
The distance between the magnetic head and the magnetic head S2 is nH (n is a positive integer), where H is the distance between the horizontal synchronizing signals recorded on the magnetic tape. The reason why this distance is set to be an integral multiple of H is to prevent the interval between horizontal synchronizing signals from being disturbed due to switching of the magnetic head output signal during reproduction.

Next, the operation when triple speed playback in the standard mode is performed in this embodiment will be explained with reference to FIG. In FIG. 6, (a) shows a state where the recording track pattern recorded by the standard mode magnetic heads M1 and M2 is repeatedly arranged, one scale on the horizontal axis indicates the time of one field, and at the same time the timing of the head switching signal. It also shows. The vertical axis indicates the amount of movement of the magnetic tape, and one division thereof indicates the amount of track pitch that the magnetic tape travels during one field time during recording or normal reproduction.

Since this is azimuth recording, the trunk recorded with magnetic head M1 cannot be reproduced with magnetic head M2.
Similarly, the trunk recorded by the magnetic head M2 cannot be reproduced by the magnetic head M1. Figure 6(a)
In the figure, the trunk recorded by the magnetic head M1 is indicated by L, and the track recorded by the magnetic head M2 is indicated by R. Further, the R track can be reproduced by the long-time mode magnetic head S1, and the L track can be reproduced by 82. The thick lines in FIG. 6(a) represent the head trajectories of the standard mode magnetic heads M1 and M2 during triple-speed reproduction, and the broken lines represent
The head trajectories of the long-time mode magnetic heads S1 and S2 are shown. ■) is a head switching signal. (C) is the reproduction envelope waveform reproduced by the standard mode magnetic heads M1 and M2 during triple speed reproduction, and is the output signal of the head amplifier 2 in FIG. 1 (q).
d) is the reproduced envelope waveform reproduced by the long-time mode magnetic heads S1 and S2, and the head amplifier 3 shown by ◎ in Fig. 1
is the output signal of

The reproduced envelope waveforms shown in FIGS. 6(C) and 6(d) are passed through envelope detection circuits 5 and 6, which are, for example, well-known diode detection circuits shown in FIG. 10, and subjected to envelope comparison by a comparator 7. By switching the selector switch 8, the reproduced signal shown in FIG. 6(e) is obtained at the reproduced signal output terminal 9. As a result, in this embodiment as well, a good reproduced image without noise bars is obtained during triple speed reproduction in the standard mode. Note that the playback envelope waveform in Figure 6 (
The line spanning C), (d) and (e) indicates the switching position by envelope comparison.

As shown in FIG. 6, since the trunk widths of the standard mode magnetic heads M1 and M2 are the same, the reproduced signal waveforms reproduced during the high and low periods of the head switching signal are the same, and the envelope comparison shows that the reproduced signal waveforms are the same. The switching position is also approximately the same.

Since the switching positions of the first field and the second field are the same, there is no vertical shift in the reproduced image due to the difference in switching positions, and the four switching lines become two visually, resulting in a significant improvement in image quality. It can be measured.

As described above, according to this embodiment, the standard mode magnetic heads M1 and M2 have the same track width, and the long mode magnetic heads S1 and S2 have the same track width, so that during multi-speed reproduction. Set the playback signal switching position to the first
By making the field and the second field the same, it is possible to eliminate partial vertical wobble in the playback screen and to visually reduce the number of switching lines to half that of the conventional system, thereby obtaining a good playback image. In this embodiment, the trunk width of the standard mode magnet, heads M1 and M2 is twice the long time mode track pitch TP2, but by aligning the centers of the respective track widths, the standard mode magnet Even if the head M1 is not wider than M2, it is possible to obtain a good reproduced image without generating noise bars at the switching point of the reproduction signal during multi-speed reproduction in the standard mode. In addition,
The track widths of the standard mode magnetic heads M1 and M2 are determined by the crosstalk noise level of adjacent tracks when used for still playback in the long mode, so they cannot be made very wide, but the center of each track width can be By aligning the magnetic heads, it is possible to make the magnetic head much wider than the standard mode magnetic head used for long-time mode still playback in the conventional configuration. Therefore, it is possible to obtain a field still reproduction image that is comparable to the conventional one and a multi-speed reproduction image that is significantly improved than the conventional one.

Effects of the Invention As is clear from the above description, the present invention is a helical scan type video tape recorder in which a standard mode magnetic head and a long time mode magnetic head are installed, in which the centers of the respective track widths are aligned. By making the track widths of the standard mode magnetic heads M1 and M2 the same and the track widths of the long time mode magnetic heads the same, the reproduced signal waveforms of the first field and the second field are made to be the same. By eliminating the partial vertical play that occurs during multi-speed playback and by halving the number of playback signal switching lines, it is possible to obtain a good multi-speed playback image. Furthermore, by correcting the difference in the horizontal synchronization signal when switching the reproduction signal using a delay line, a high-quality multi-speed reproduction image without noise or skew can be obtained.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the arrangement of the head structure and playback signal processing system of a conventional video tape recorder;
The figure is a diagram for explaining still playback in long-time mode in the conventional example shown in Figure 1, Figure 3 is a diagram for explaining triple-speed playback in standard mode in the conventional example shown in Figure 1, and Figure 4 is a diagram for explaining 3x playback in standard mode in the conventional example shown in Figure 1. FIG. 1 is a diagram for explaining the occurrence of partial vertical play during multi-speed playback in the conventional example; FIG. 6 is a diagram showing an example of the arrangement of the head structure in the video tape recorder of the present invention; FIG. is the standard time mode 3 in the embodiment of the present invention.
FIG. 3 is a diagram for explaining double speed playback. Ml, M2...Standard mode magnetic head, Sl. S2...-Magnetic head for long time mode, 1...
Rotating cylinder, 2, 3...Head amplifier, 6,
6... Envelope detection circuit, 7... Comparator, 8... Changeover switch. Name of agent: Patent attorney Toshio Nakao and one other person ()
c＞ ”- ふ Σ E 目 4 Figure 2 Figure 3 Figure 5 (C) (B) Mouth m [] [I] N1 βt N2 βdo Figure 6

Claims (1)

[Claims] The magnetic tape can be run at a constant speed at a predetermined first or second speed (where the first speed is greater than the second speed) during recording, and the first and second tapes have different azimuth angles. a second magnetic head is provided at a position of 180° on the rotating substrate, and a third magnetic head whose azimuth angle is different from the first magnetic head and the same as the second magnetic head; A fourth magnetic head, which is the same as the first magnetic head, is installed near the first and second magnetic heads, respectively, at 180 mm of the rotary head substrate.
0 position and when recording at the first speed, the first and second magnetic heads are used; when recording at the second speed, the third and fourth magnetic heads are used. A helical scan video tape recorder configured to use a helical scan type video tape recorder, wherein the first and second magnetic heads have the same trunk width, and the third and fourth magnetic heads have the same track width, The track width TW1 of the first and second magnetic heads is wider than the track width TW2 of the third and fourth magnetic heads, and the track pitch of the first speed is TPl, and the track width of the second speed is TPl. The pitch is TP2, and the track pitch TP at the first speed is
1=sxTP2, 2XTP2≦TW1≦3XTP2 TP2≦TW2≦2XTP2, and the first and second magnetic heads and the third
and a video tape recorder, characterized in that the fourth magnetic head is installed so that the track width and center of the fourth magnetic head are aligned.