JPS6359633B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses two rotating magnetic heads having different azimuth angles to record one field of video signal as one recording trajectory inclined with respect to the longitudinal direction of the magnetic tape. This invention relates to a helical scan type magnetic recording and reproducing apparatus (hereinafter referred to as a VTR) that sequentially records television signals.

This type of VTR, for example, uses the VHS system.
There is a VCR.

This VHS system VTR is generally configured to be able to select between a standard recording mode (2 hour recording mode, track pitch 58 .mu.m) and a long recording mode (6 hour recording mode, track pitch 19 .mu.m) by changing the tape speed. The present invention thus provides a system that can switch between standard recording mode and long-time recording mode.
In each recording mode, the VTR is configured so that a static reproduction image, which is reproduced by stopping the tape during reproduction, and a slow-motion reproduction image, which is reproduced by intermittently moving the tape, can be obtained satisfactorily. One embodiment will be described below with reference to the drawings, taking the VHS system as an example.

Figure 1 schematically shows the arrangement of magnetic heads on a rotating head cylinder, where R and L are a pair of magnetic heads for the 6-hour mode, R',
L' is a pair of magnetic heads for 2-hour mode, and the width of each head is 30 μm for R, L, and R', and L' is 30 μm.
It is 45 μm. Furthermore, the magnetic heads of each pair of magnetic heads have an index angle of approximately 180 degrees from each other.

The magnetic heads R and R', L and L' each have the same azimuth angle, and the magnetic heads R, L' and L have the same azimuth angle.
The interval R' is set on the same plane of the rotary head cylinder so as to correspond to the recording locus length (370 μm) of one horizontal scanning period on the magnetic tape.

In other words, when recording and playing in 2-hour mode,
During recording and reproducing in the 6-hour mode, the R' and L' magnetic head pairs are used to perform recording and reproducing.

Recording trajectories on the magnetic tape in both recording modes are schematically shown in FIGS. 2a and 2b, respectively. FIG. 2a is a schematic diagram showing the recording trajectory on the magnetic tape in the 2-hour mode, and FIG. 2b is a schematic diagram showing the recording trajectory on the magnetic tape in the 6-hour mode.

Ra, Ra', La, and La' in Fig. 2 a and b are the recording trajectories of the heads R, R', L, and L', respectively, and Rb,
Rb′, Lb, Lb′ are the heads R, R′,
These are the scanning trajectories of L and L'. When playing back still images in 2-hour mode recording, use a wide head.
Using magnetic heads L and L' having the same azimuth angle including L', a field still image is obtained by repeatedly reproducing one field of video signal. In this case, compared to the case where heads R and R' having the same azimuth angle are used, the level of the reproduced signal when reproduced by head L' becomes higher because the head width is wider. Also, 6
When reproducing still images recorded in time mode, magnetic heads R and R' are used.

Next, we will explain so-called fine slow playback, in which the same recording trajectory is repeatedly reproduced multiple times, and then the magnetic tape is intermittently run to the next recording trajectory of the same azimuth, and the same azimuth recording trajectory is repeatedly reproduced. .

First, fine slow playback of 2-hour mode recording will be explained.

For fine-slow reproduction of this two-hour mode recording, three heads, heads L, L' and R', are selectively used. Figure 3a shows the playback state when the tape is stopped, and similarly to the still image playback described above, heads L and L' are used to record the recording trajectory by head L'.
Play La′ repeatedly. When the magnetic tape is repeatedly reproduced a predetermined number of times, the magnetic tape is moved to the next recording locus La' during the next three field periods.

The playback trajectory for each field period of these three field periods is shown in FIGS. 3b, c, and d.

FIG. 3e shows the reproduction state at the next tape stop.

That is, as shown in FIG. 3a, the last scan when stopped is performed by the head L, and the recorded trajectory La' by the head L' is reproduced, and the first field period of the three field periods during movement is as shown in FIG. As shown in Fig. 3b, head L' reproduces the recording trajectory La' by head L', and in the second field period, as shown in Fig. 3c, head R' reproduces the recording trajectory La' by head R'.
After playing Ra′, the next 3rd field period is shown in Figure 3d.
As shown in FIG. 3, the recording locus La' recorded by the head L' is reproduced by the head L'.

In this way, during the movement period, a good slow reproduction image can be obtained by using heads R' having different azimuth angles.

FIG. 4 is a schematic diagram for obtaining a fine-throw reproduced image of 6-hour mode recording, in which heads R, R', and L are used.

4a and 4e show the state when the tape is stopped, as in FIG. 2b, and the recording locus Ra is repeatedly reproduced using heads R and R'. b, c, and d are during movement, and heads R, L, and R are used, respectively.

That is, as shown in FIG. 4a, the last scan at the time of stop is performed by head R', and the recorded trajectory Ra by head R is reproduced, and the first field period among the three field periods during movement is as shown in FIG. 4b. As shown in FIG. 4, head R reproduces the recording trajectory Ra by head R. Then, in the second field period, head L reproduces the recording trajectory La by head L, as shown in FIG. The field period is the 4th
As shown in FIG. d, the head R reproduces the recorded trajectory Ra by the head R.

As described above, according to the present invention, four heads including one wide head are provided, and by selectively switching two head pairs or each head according to each recording/reproducing mode, the standard recording mode and normal recording and playback in long-time recording mode, still image playback,
A good slow playback image can be obtained.

In addition, the width of the other head of one wide head is:
It is clear that heads may be constructed with slightly different head widths.

[Brief explanation of drawings]

FIG. 1 is a plan view schematically showing the arrangement of heads on a head cylinder according to an embodiment of the present invention, FIG.
Fig. 3 is a pattern diagram schematically showing recording trajectories in standard recording mode and long-time recording mode; Figures 4a, b, c, d, and e are pattern diagrams showing the relationship between the recording trajectory and the reproduction head trajectory during slow reproduction image reproduction in the long-time recording mode. R, R', L, L'...magnetic head, Ra, Ra',
La, La′...Head trajectory during recording, Rb, Rb′,
Lb, Lb'...Head trajectory during playback.

Claims (1)

[Scope of Claims] 1. A first magnetic head pair consisting of first and second magnetic heads having different azimuth angles, a third magnetic head having the same azimuth angle as the first magnetic head, and the third magnetic head having the same azimuth angle as the first magnetic head. a second magnetic head pair consisting of a fourth magnetic head having the same azimuth angle as the second magnetic head and having a width wider than the first, second, and third magnetic heads; A rotary head cylinder having an index angle of 180° and having magnetic heads between different pairs of magnetic heads arranged on the same plane so that magnetic heads having different azimuth angles are close to each other, and rotation of each magnetic head. a control means capable of winding a magnetic tape along a trajectory and selectively switching the magnetic tape between a standard recording mode speed and a long-time recording mode speed slower than the standard time recording mode speed; 1. A magnetic recording and reproducing apparatus comprising a selection means for scanning a magnetic tape by selectively switching between two magnetic heads arranged approximately 180 degrees apart. 2. The selection means selectively uses the magnetic heads of the second pair of magnetic heads when recording and reproducing at the standard time recording mode speed, and uses the magnetic heads of the first pair of magnetic heads when recording and reproducing at the long time recording mode speed. 2. A magnetic recording and reproducing apparatus according to claim 1, characterized in that the magnetic recording and reproducing apparatus is switched. 3. The selection means uses the second magnetic head and the fourth magnetic head when reproducing a still image by stopping the running of the magnetic tape during reproduction of a magnetic tape recorded at the standard time recording mode speed. 2. The magnetic recording and reproducing apparatus according to claim 1, wherein the magnetic recording and reproducing apparatus is selectively switched. 4. When playing back a still image by stopping the running of the magnetic tape during playback of a magnetic tape recorded at the long time recording mode speed, the selection means selects the first mode.
2. The magnetic recording and reproducing apparatus according to claim 1, wherein the magnetic recording and reproducing apparatus is selectively switched to use the second magnetic head and the third magnetic head. 5 When the magnetic tape is intermittently driven during playback to obtain a slow playback image, if the recorded magnetic tape is recorded at standard time recording mode speed, the selection means selects the second, third and fourth magnetic tapes. When the head is selectively used and recording is performed at a long time recording mode speed, the selection means is the first,
2. A magnetic recording and reproducing apparatus according to claim 1, wherein the second and third magnetic heads are selectively used.