JPS58223975A - Magnetic recorder and reproducer of video signal - Google Patents

Abstract

PURPOSE:To reduce the number of magnetic heads, by using partly magnetic heads for both speed in common to two kinds of tape speeds. CONSTITUTION:The magnetic heads 30, 31 are used in the 1st mode, i.e., fast mode, and magnetic heads 31, 46 are used in the 2nd mode, i.e., slow mode. The X value of the 1st mode is a track lengthwise direction 34 of respective gaps 32, 33 of the magnetic heads 30, 31, and the Y value is a distance 35 in a direction at a right angle to the track lengthwise direction of the magnetic heads 30, 31. The X and Y values of the 2nd mode are respectively distances 48 and 49. The magnetic head 31 is used in common for both the modes.

Description

[Detailed description of the invention] The present invention relates to a magnetic recording and reproducing device for video signals.

Video signal magnetic recording and reproducing devices (so-called VTRs) that use magnetic tape as a recording medium have been extensively researched.
Various methods have been proposed and put into practical use.

For example, in broadcasting VTRs that require high-quality playback images, the mainstream is the "direct color system" in which composite video signals are directly FM modulated and recorded, whereas in home VTRs that do not require high image quality, carrier color The mainstream is the "low frequency conversion method," which converts the signal to a lower frequency band.

Furthermore, various methods are employed depending on the purpose of use of the VTR and the required playback quality. An example of this is the "Y-C separation method" in which luminance signals and color signals are recorded on separate tracks.

Incidentally, the Y-C separation method is a method of recording luminance signals and color signals on separate tracks, but there are various methods depending on the method of processing color signals. For example, a method of FM modulating a carrier color signal subjected to quadrature two-phase modulation or a signal obtained by converting the carrier signal to a low frequency; two color signals (■ signal, Q signal, etc.) or two color difference signals (R- There is a method in which baseband signals (Y word, B-Y signal, etc.) are processed separately, FM-modulated separately, and then both are frequency-multiplexed. Since color information is transmitted in the form of quadrature two-phase modulation in the direct cuff type and low frequency conversion type, the hue information is degraded due to jitter generated in the VTR. However, in the above-described Y-C separation method in which color information is FM multiplexed in the baseband, such hue deterioration does not occur at all.

Therefore, FIG. 1 shows a block diagram of a conventional example of the above-mentioned Y-C9 type. Figure 1 Smell (・1,.)
fd*i (□Ika1, 36, Yu..Ika, (2) is the luminance signal processor, (6) is the color value processor" +11 unit, (3) and (7) are the modulators, +41+81+91Q31 110) and Q41 are demodulators, (Il+ is a luminance signal processor, (151 is a chrominance signal processor, θ2 is a luminance signal output terminal or chrominance signal output terminal, and 07) is a magnetic tape. Figure 1 shows four magnetic heads +4 to schematically illustrate the drawing.
), +81, 191, and 0 ( are shown in the figure, but in an actual helical scan VTR, the magnetic head for recording and the magnetic head for reproduction are usually shared, and the magnetic head is mounted on the cylinder. Ru.

The luminance signal is applied to a luminance signal processor (2) via a luminance signal input terminal (1). After being subjected to processing such as clamping and pre-emphasis by a luminance signal processor, it is guided to a modulator (3).As the modulator (3), an FM modulation method is generally used, and its stripping output signal is is magnetic head 1
4) is recorded on the magnetic tape θη. On the other hand, the color signal is subjected to clamping, pre-emphasis, etc. by the color signal processor (6) via the 1 color value input terminal (5), and is recorded on magnetic data 10η via the modulator (71). During reproduction, the signals recorded on the magnetic tape Oη are taken out via the magnetic heads (91 and (I3).

A magnetic head (9) traces the track recorded by the magnetic head (4), and its output is demodulated by a demodulator (110) and guided to a luminance signal processor (11). The luminance signal processor (11) performs operations such as de-emphasis,
The +4 generated luminance signal is sent to the luminance signal output terminal 02. Similarly, on the color signal side, the output of the magnetic head 031 is demodulated by a demodulator (14), subjected to operations such as de-emphasis by a color signal processor (151), and reproduced via a color signal output terminal θd. Sent as a color signal.

Next, FIG. 2 shows a recording pattern on the magnetic chip 10η in the conventional example of FIG. 1. In Figure 2, (2η is a magnetic tape, (18) and (20) are luminance signal tofutsukaku (
19) and H are the tracks for color signals, (22 is the horizontal synchronizing signal position, (4) is the magnetic head gap, and Q
The value is the track pitch between Y and 0, the arrow (2B is the magnetic tape running direction, and f29! is the magnetic head scanning direction. The scanning of the magnetic head is the magnetic head (4
) and (8) are (231 and +2) respectively.
Starting from position 41, scanning is performed in the four directions indicated by the arrows. Scanning of track (20+ and H is track (+sl and 0!)
This is done immediately after the scan.

By the way, the playback function of a VTR is not only normal playback, but also "continuous feed υ", 2m rewind, and "stay" playback are often required.While watching the desired scene on the monitor TV screen, When searching (so-called "picture search") or editing, the above-mentioned playback function with irregular tape advance is required (hereinafter, playback with such irregular tape advance will be referred to as "special playback").

During special playback, the tape feed speed is different from that during recording, so the magnetic head scans across the recorded track. At this time, Ik crosses multiple adjacent tracks, so if the horizontal synchronization signal positions on the magnetic tape are not lined up in a straight line perpendicular to the track longitudinal direction, a time axis discontinuity point will occur every time it crosses a track. Existence causes skew. Another major problem during special playback is that noise bands occur on the monitor TV screen when the track is crossed. However, depending on the relationship between the torque width and guard band width for the luminance signal and chrominance signal, a noise band may occur in the luminance signal [! Between 8 and 8, it is possible to extract an almost normal luminance signal using the color signal filter. When this method is employed, it is further necessary to arrange the horizontal synchronization signal position on the luminance signal track and the horizontal synchronization signal position on the color signal track in a straight line perpendicular to the longitudinal direction of the track. Therefore, it is necessary to align the gaps between the magnetic heads (4) and (81) in Fig. 1. However, as a practical matter, it is difficult to mount the two magnetic heads close to each other due to the shape of the magnetic heads. is impossible,
This is also a problem from the aspect of cross-resistance between both magnetic heads. Due to these conditions, the magnetic head for the luminance signal and the magnetic head for the chrominance signal are installed offset in both the track longitudinal direction and the direction perpendicular to the longitudinal direction. By doing this, the recording pattern on the magnetic tape is as shown in FIG. 6. The amount of deviation (2) in the track longitudinal direction of both heads on the magnetic arc η is NQ.
This aα is often normalized by the distance corresponding to one horizontal scanning period on the magnetic tape (b). Therefore, from the similar explanation, the Q value must be an integer.

Next, FIG. 3 shows the head arrangement IR for forming the magnetic tape pattern as shown in FIG. 2. Figure 3 (is a diagram when looking at the cylinder from the outside, - is a magnetic head for brightness signal, @l
) is a magnetic head for color signals, (three parts and two parts are magnetic heads (9) and body (1), respectively) head gaps, (341i
dX value, S average is Y value, and (goods) is cylinder rotation direction. Of course, the X value is 041, the Y value (3Q is the 21st 1st Q) and the track pitch between Y and 0 (
It is legalized by the trowel. To put it strictly in 7j4, the X value (goods) and the Q value (or
The value (200) is slightly different, and the track pitch between Y-Shinshu and Y-0 is also slightly different (this is because the magnetic tape Q1 is not stationary but is running, but a detailed explanation will be omitted).

As explained above, in the Y-○ separation method, when mounting both magnetic heads, the relative positional relationship must be set strictly to a predetermined value. The above-mentioned X value (goods) and Y value f31'9 are determined by the size of the magnetic tape, the diameter of the cylinder, the number of horizontal scans in one field, etc., so if these conditions are different, A different magnetic head arrangement is required.

On the other hand, in a video signal magnetic recording and reproducing device, tape consumption, tape performance, and playback image quality are related to each other, and the higher the amount of tape erased, the higher the quality of the image, and the higher the quality. If image quality is not required, tape consumption can be reduced. In this way, there is a need for a function that can vary the consumption rate of magnetic tape (proportional to the feeding speed of the magnetic tape) in accordance with the required reproduction image quality and the magnetic tape used.

Therefore, for example, in order to switch the feeding speed of the magnetic tape during recording and use hJ performance in two modes, the number of magnetic heads is doubled as shown in FIG. FIG. 4 is a top view of a cylinder of a Y-C type signal magnetic recording/reproducing apparatus which can be used by switching between two magnetic tape speeds.

In Fig. 4.

07) ~ 0 (sub) are magnetic heads for recording and reproducing at the first tape speed, '(, 111 ~ (44J are magnetic heads for self-recording and reproducing at the second depth bead, It is.

Magnetic head (371-kl is set to the X value and Y value for the first tape speed, magnetic head @1) ~ 0
Shu is set to the X value and Y value in the case of the second tape speed.

As is clear from Figure 4, in the conventional method, in order to enable recording at two tape speeds, the number of heads mounted on a cylinder must be exactly twice that of the case when only one tape speed is used. Put it away.

For example, in the case of FIG. 4, the number of magnetic heads is eight, and if flying erase is also considered, as many as 12 heads are required. With this many heads, it becomes extremely difficult to create multiple channels of slip rings and rotary transformers, and the large number of heads increases costs.Also, unused magnetic heads come into contact with the tape. This causes various problems.

Therefore, the present invention can record and play back at two different tape speeds, and special playback is possible no matter which tape speed is recorded, and the number of magnetic heads is only 3/2 times that of a single speed. It is an object of the present invention to provide a video signal magnetic recording and reproducing apparatus using a method that does not require the following methods.

That is, as mentioned above, it is originally necessary to install a dedicated magnetic head for each of the two types of tape speeds, but in order to achieve the above object, the present invention partially incorporates magnetic heads for both speeds. The number of magnetic heads can be reduced by sharing the magnetic heads.One embodiment of the present invention will be described below with reference to the drawings. First, the first embodiment of the present invention is shown in Figs. 5 and 6. Fig. 5 is a view of the cylinder seen from the outside, similar to Fig. 3. is the head gap, (C) is the X value, ←9) is the Y value, and ■~(Company) are the same as G30j~+3[1 in FIG. 3, so the explanation will be omitted.

Now, the mode in which the magnetic tape speed during recording is fast is defined as the "first mode", and the slow mode is defined as the "second mode". In the first mode, the magnetic head and (31) are used.
In the second mode, magnetic heads (31) and (a) are used. That is, the magnetic head (31) is used in both modes. The X value in the first mode is the respective gap O4 and f131% of the magnetic head and button), and the rack longitudinal distance (
The Y value in the first mode is the distance (31
It is. Similarly, the X and Y values of the second mode are distance - and (49), respectively. With such a magnetic head arrangement, the cylinder rotates in the direction.

Next, FIG. 6 shows the recording pattern on the magnetic tape in the second mode. Figure 6 shows the recording pattern when the magnetic tape feeding speed is approximately half that of Figure 2.
The pattern in FIG. 2 is the first mode, and the pattern in FIG. 6 is the second mode. In Figure 6, (+8)' to (19
)' correspond to (18) to (29) in FIG. 2, so their individual explanations will be omitted. However, the track width of each track α (211') in Figure 6 is the track width of the track (211') in Figure 2.
18) - (21), and the angle between the longitudinal direction of the magnetic tape and the longitudinal direction of each track (18)' - (21)' is also a smaller angle than in Figure 2 because the tape speed is different. is getting smaller. To further simplify the diagram,
The spacing of the horizontal scanning positions (5)' is different.

Of course, Qg(25)' is an integer, and the horizontal synchronizing signal positions of both the luminance signal track and the chrominance signal track are aligned in a straight line in a direction perpendicular to the longitudinal direction of the track.

Next, FIG. 7 shows how the magnetic head is mounted on the cylinder. FIG. 7 is a view of the cylinder looking down from above, where (56) is the cylinder and (50) to (55) are magnetic heads, respectively. Magnetic head (50) (51) (52
) and l541 are for the first mode, magnetic head (50) (
51) (52) and +51 are the second mo.

- This is a magnetic head for hard disks. The magnetic head (O) and (to) in Fig. 5 correspond to the magnetic head (30) in Fig. 5, the magnetic head (O) and (to) correspond to the magnetic head (30) in Fig. 5, the magnetic head @2 and the ball (to) correspond to the magnetic head ( 4 (f) respectively.

Furthermore, a second embodiment of the present invention is shown in FIGS. 9 and 10. FIGS. 9 and 10 show embodiments that take into account the improvement of stagger loss, but before going into explanation of these figures, stagger loss and its improvement method will be explained in conjunction with FIG. 8. 8th
The figure is a slightly simplified version of the magnetic tape pattern shown in Figure 6, where 581 and 11 are the centers of the magnetic tape, η and 11 are the center lines of the luminance signal tracks, and 581 and 11 are the centers of the chrominance signal tracks. Lines @1) to 1641 are magnetic heads, (yellow to η are stagalos, respectively. In the first embodiment shown in FIGS. 5 and 6, the magnetic head button) and decoys are magnetic heads, respectively. It was implemented in such a way that heads @0, 12, and 131 were in relationship. By the way, as already mentioned, due to various constraints, the magnetic heads are mounted in a staggered manner with predetermined X and Y values, respectively. Therefore, in most cases, the positions of each magnetic head on the magnetic tape at the start of scanning are not aligned in a straight line in the longitudinal direction of the magnetic tape. Therefore, in the first mode, the magnetic head I21 protrudes by a distance F, and no information is recorded in this area by the magnetic head Ill, and only magnetic head fighting is used. This kind of area is called Stagaros.

This distance - (However, strictly speaking, since the tape speed is fast in the first mode, this (l+T) is a slightly different value)
becomes Stagaros. Furthermore, since the magnetic head 4 and the gate are used in the second mode, the stagger loss due to the magnetic head increases to a distance tsIli.

Therefore, in the second embodiment of the present invention, the magnetic head f63
) in a direction perpendicular to the longitudinal direction of the track and
Place the magnetic head at the position 141 where the truck has been retracted, and mount the magnetic heads 621 and (61 on the cylinder. By doing this, the stagger loss is reduced to a distance of 6η,
The magnetic tape usage efficiency is improved compared to the first embodiment shown in FIG. 5.

Needless to say, even when using magnetic heads, the horizontal synchronization timings of each track on the magnetic tape are aligned on a straight line perpendicular to the longitudinal direction of the track.

For the above reasons, in the second embodiment of the present invention, the magnetic head is arranged as shown in FIG. In Figure 9, (30
) to (The trowels are the same as the same numbers in Fig. 5, so detailed explanations are omitted. (69) is the magnetic head, V (
2) is the Herad gap, inner) is the X value, and qUro is the Y value. In the end, in Fig. 5, (6)
This means that it has moved to position 9). In the diagram shown in FIG. 8, magnetic heads 16Il (621 and (2) correspond to magnetic heads (30), (31) and (61), respectively.

Further, FIG. 10 shows how the head scans the magnetic tape in the second embodiment shown in FIG. 9.

In FIG. 10, (b) to (low+9) represent the (e)th track to (%+9)th track, respectively, at IV to 4V.
indicate the first buoy V-do to the fourth buoy 7-read, respectively, and the thick solid line indicates the state where the magnetic head is tracing. To explain this in relation to No. 6 and 1, tracks Q8)-(2+1' in FIG. 6 are (to) to (6+3), respectively, and the first boolean
At the time when IV) starts, the magnetic head is groaning and (1) td.
-3) Tracks, namely Track Ken' and Track @I
It is located at the starting point of Y and takes exactly one field period to complete the scan. Immediately after that, the second fee /1/
V (2v) starts, the magnetic head starts (w2) and (w5)
It is located at the starting point of the track, which is two tracks ahead of the track @1Y, and exactly one field Jt.
It takes 1J to complete the scan. Similar operations will be repeated thereafter.

By the way, in the explanation of the present invention, only the Y-C separation method has been described, but the present invention is not limited to the case where the luminance signal and the color signal are separated, and the present invention can achieve the same effect in any separation method. It is clear that it will work. It goes without saying that the present invention can be applied to both analog recording and digital μ recording.

Furthermore, in FIGS. 5 and 9, which are embodiments of the present invention, two other magnetic heads are arranged before and after the magnetic head C which is shared by both tape speeds. Of course, it is possible to place the shared magnetic head at the end, but the X value and Y value need to be set as small as possible from the viewpoint of time axis fluctuation between both heads, tracking accuracy, etc. The magnetic head arrangement shown in FIGS. 5 and 9 is most appropriate in terms of crosstalk between magnetic heads.

In addition, in the second embodiment of the present invention shown in FIG. 9, the magnetic head (as shown in FIG.
641, there is a track @碍 and track F39). However, it is not necessary to limit the shape to such a shape, and the shape may be separated by two more tracks depending on the characteristics of the magnetic recording/reproducing apparatus used. In short, the positional relationship between the magnetic heads 4 and Ca1l may be set so that the number of tracks recorded by each magnetic head is N (N is a positive integer N=1.2, . . . ).

Furthermore, for signals recorded via a head that is shared by two tape speeds, it is usually better to use the same side of the two signals for both tape speeds from the standpoint of head amplifier design during playback. is convenient.

From the above explanation, it can be concluded that the present invention is a video signal magnetic recording and reproducing device that divides and records into two channels, and is capable of recording and reproducing at two types of magnetic tape speeds with a small number of heads. .

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional example of a Y-C separation type video signal magnetic recording/reproducing device, FIG. 2 is a recording pattern diagram on a magnetic tape in the conventional example of FIG. 1, and FIG. The pupil diagram on the cylinder of the magnetic head, Fig. 4 is a diagram showing the arrangement of the magnetic head on the cylinder of the conventional example (concentrated acid), and Fig. FIG. 6 is a diagram of the recording pattern on the magnetic tape when recording in the second mode.
FIG. 7 is a diagram showing the arrangement of magnetic heads on a cylinder showing an embodiment of the present invention, FIG. 1st
The θ diagram is a diagram for explaining W and Figure 9. (b))l(4(2) or 4...Two magnetic heads, (31)...Shared magnetic head agent Yoshihiro MorimotoFigure 1Figure 2q Figure 3Figure 4 5 Figure 7J? Figure 7 Figure 7 Figure 7 Figure 1 Figure 1θ

Claims (1)

[Scope of Claims] 1. In a video signal magnetic recording and reproducing device that records a video signal by dividing it into two channels and is capable of recording at two types of tape speeds, one of the two channels has the same IVIrL head. E'2 [Video signal magnetic recording and reproducing device configured with 3 heads for use at both tape speeds of category i. 2. Out of the three heads, two heads used at both tape speeds are configured to be placed between two heads used exclusively at each of the above two tape speeds. A video signal magnetic recording and reproducing device according to claim 1. a At least one of the two heads is used at both tape speeds between a track recorded by that head and a track recorded by a head used at both tape speeds. The video signal according to claim 1, characterized in that the video signal is implemented so that there are N tracks recorded by the head and N tracks recorded by at least one of the heads (N is a positive integer). Magnetic recording and reproducing device.