JPS58141431A - Magnetic video recording and reproducing device - Google Patents

Abstract

PURPOSE:To obtain a high reproduced-tone quality even if a head height controlling mechanism due to a bimorph plate or the like is omitted and to simplify the device, by using a broad head and recording and reproducing a sound signal on a video track in a VTR of the pilot system. CONSTITUTION:The sound signal is converted to an FM modulation signal with video tracks 12-15 and is multiplexed to a video recording signal and is subjected to time base compression and is digitized and is recorded and reproduced on the extension of the video track. If video tracks 12-15 are used to record and reproduce the sound signal by a video head in this manner, the influence of wow and flutter is reduced considerably, and a broad head 16 where the track width is set to a value wider than the width of recording tracks which are left on a magnetic tape 1 at the recording time is used in the VTR adopting the pilot system. Since the influence of wow and flutter is reduced to a negligible level, the broad head 16 can be used even in the pilot system, and the complication of the device accompanied with the use of a DC high voltage is avoided because special devices for narrow track tracing and special reproducing are unnecessary. The probability of tracking errors is reduced whichever direction the momentary variance comes from.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an image recording system on a magnetic tape. Pi ay for track tracing of the video head on the signal recording track
Magnetic edge m reproducing device (hereinafter referred to as VT
(abbreviated as kL).

As is well known, the mainstream of general VTRKs is the two-head helical scan type, in which each video is recorded diagonally on a magnetic tape at high speed (644 or more). The audio signal is transmitted to the bottom of the magnetic tube using a fixed head at low speed (at the same speed as the tape is running). In addition, when the video head plays back the video track recorded in the diagonal direction,
E4RIK) The control signal for racing is
Again, data is recorded at the end of the magnetic tape with a fixed head, or multiplexed on the video guide track. The former is
CTL Banshiki, * is called Pi lot Banshiki.

Compared to the CTL Banshiki, the Pilot Banshiki has the advantage of having a polyurethane system for adjusting the center value of the track trace during playback, but it also has the advantage of being able to trace very narrow tracks and special playback (variable speed). , slow, still playback, etc.), there were five problems: expensive and large-scale devices were required. ^ is for the CTL method.

0 is of the Pjjos method. 1 is a magnetic tape 2 is an audio track, 5 is a control track, and 4 is a video track. 5 to 8 are also video tracks, but in order J
iidN number of pilot signals ip, to fp are recorded. (Therefore, if it is 0, there is no control track.) Also, 9 is a video head. To easily check the operation at the moment of production, compare the phase of the playback signal from the Condroldo 5y15 with the 90 rotation phase of the video head, and make this match the phase of the recording. For example, the video head 9 accurately traces the video track 4. The control signal is recorded and reproduced by an identification head different from the video head 9. Since the relative positions of both heads differ slightly from device to device, a tracking volume for the phase 841M is required when device compatibility is considered. −
In the case of the PNot system of 10,000, for example, when the video head 9 is on the video track 6, the Ill! li) Accurate tracing is achieved by controlling the rotational phase of the video head 9 so that the PNot signals of the peripheral signals fP and fp multiplexed on the racks 5 and 7 have approximately equal crosstalk. In this case, a tracking polycrystalline system like the above-mentioned CTL method is unnecessary.

It should be obvious.

In other words, the Pilot method has the advantage of not requiring a tracking polygon and no control track compared to CTL Manni, and will be useful in future VT systems.
It is thought that sI is often used in R.

Incidentally, in many of the current VTRs, the travel width of the video head is designed to be wider than the width of the video track actually left on the magnetic tape. This K will be explained using FIG.

The figure shows a single pattern on the magnetic tape mentioned in ■1 above.
indicates the state at the time of recording, and 0 indicates the state at the time of reproduction.

Also, arrows in the figure indicate the video head 1o and the magnetic head 11.
During recording, a video head (hereinafter also referred to as wide head) 10, which has a track width wider than the video track 11, runs over the video track 11, as shown in FIG. On the magnetic tape, a recorded pattern with the same width as the track width of the video head remains, but when the next track is recorded, part of it is erased, and an interposed track 11 with the width of the wind foot is erased. During playback, as shown in FIG. 0, one end of the video head 10 is moved to the same position as one end of the video track, that is, the same relative position as during recording, and the video head 10 is moved over the magnetic tape. Audio track 2 and control track 5 are W1110.
It may be the same as in the case of 00TL Manshiki.

The reason for using the wide head as described above is as follows.

(1) Recent VT) I recording has become more dense, and the video track width has become extremely narrow (204 m or less).

If the track width of the video head is made to match this, if the position of the video head shifts due to slight mechanical fluctuations, the Niu output will be drastically reduced. Therefore, it is necessary to use a one-way wide head (one track spacing is, for example, 5 Q 4 m) to reduce the effects caused by the positional deviation.

tg+ %Special playback (aJ speed change, stay, slow, etc.°
) is because the magnetic tape runs at a different speed than when recorded.
Playback with the video head diagonally across the video track 1#I
An IK noise band appears. In order to reduce this, it is necessary to use a wide head.

The reason why the position of the video head 10 relative to the video track 11 is the same during recording and during playback as shown in FIG. 2 is as follows. Generally speaking, from the standpoint of track tracing, it is clear that the center of the video head and the center of the video track should be aligned during playback, that is, the relative positions of the video head and the video track may be different from those during recording. However, in this case, the playback signal from the audio track 2 has an increased wah-wah and undulation, resulting in a harsh and difficult-to-listen sound that is not practical.According to recent findings, this is because, for example, a rotating The influence of factors that cause wow, such as eccentricity of the cylinder (not shown) and vibration of the tape caused by the video head hitting the tape 1, can be affected by differences in the relative position of the video head during recording and during recording. The reason for this is that it differs depending on the time of birth.

By the way, as mentioned above, in the case of the Pilot universal VTI (in the case of the VTI), tracing is done so that the Pth (ii) from the direct track is approximately equal, so it is inevitable that the center of the video head and the intervening track are the same. It has no choice but to coincide with the center. Therefore, a wide head cannot be used for the above reason.

For this reason, it is necessary to use means other than a wide head for those that use an extremely narrow video track of 2 ppm or less, and for those that perform special playback. For example, if the video head is a bimorph board, etc. The height of the video head is controlled according to the crosstalk sag of the playback Pilot signal, and the video head always accurately traces a fixed video track in any case. (A well-known example is the Philips V-2000 model 1.) However, the bimorph board, including its control circuit, is quite expensive, so it is not suitable for use as a general-purpose VTR device. It is never [appropriate]. In addition, a power source of 100 V DC or more is required for its control, and it must not be connected to the rotating cylinder via a wire etc. There were problems such as the equipment becoming large-scale.

The present invention solves the above-mentioned problems, realizes special playback with narrow track traces or fewer noise bands without using a bimorph board, etc. in a VTR using the Pilot method, and also reduces wah 7 noise in the reproduced audio signal. We are trying to provide a method that can reduce F/ more than before.

That is, the same applies to Pilot type VTRs as well.

Using a wide head, the audio signal is.

By recording and playing back on the video track, good track traces can be obtained even when the head height control using a bimorph board or the like is eliminated.

It is also intended to contribute to achieving good reproduction performance, reducing the number of originals, and simplifying the device.

Next, examples of the present invention will be explained while also referring to their effects.

In the present invention, first, audio signals are recorded and reproduced using interposed tracks. There are several concrete practical methods for this, but for example, it may be used as Nhen-91 and multiplexed with the video recording signal (% public; 1972-9565).
), or as an extension of the video track, this can be digitalized in a time-based manner and recorded with a video head.

(Registered Publication; 1972-272<) In this case, the wow 7-) ivy of the reproduced audio signal is considerably less than when using the audio-only track 2 as shown in Figures 1 and 2. Become.

The salt mountains are as follows. The cause of wow 7yd is vibration in the running direction of the magnetic tape, so-called Mffx motion. This causes the reproduced audio signal to fluctuate over time m. When recording and reproducing using an audio-only track, that is, when recording and reproducing using a solid head, the influence of this longitudinal vibration appears as it is as wah 72 ivy.

However, when recording and reproducing using a video track, that is, when recording and reproducing using a rotating head, the influence of this longitudinal vibration is approximately the same as the speed of the rotating head (several VI) and the speed of the magnetic tape (1 to 5 crry). degree). In the case of a fixed head type, the sound playback signal of current general-purpose VTRs often reaches iiO,51, but if it is a one-rotation head type, it will be more accurate than reconnaissance @ (about 01-). It is possible to make it smaller. [If it were a fixed head type, it would be very impractical.]
Even if the roughness increases, recording and reproducing using a rotary head system can ensure sufficient sound quality for practical use.

As described in 5 above, by recording and reproducing audio signals with the video head using a special track, the effects of wah and 72 ivy can be significantly reduced. Use the wide head.

Earlier, it was mentioned that in case (1) using the Piot method, the center position of the video head and the center position of the video track inevitably coincide during playback. It was also stated that in this case, if a wide head is used, there is a problem in that the wow and vines in the audio reproduction signal of the identification head type increase. However, in the present invention, since the audio signal is recorded and reproduced on the video track, this increase in wah 72 is not a problem at all, and sufficient performance for practical use can be ensured.

Figure 5 shows the recording pattern of the magnetic tape 1 when the present invention is implemented. video head.

Since this is a Riot-type VTR, please refer to Figure #11 (2) first.
) There is no control track 5, and since audio signals are recorded and reproduced on video tracks 12 to 1.5, there is no audio track 2. In addition, recorded and reproduced for other purposes1
! It is okay to record the number in the corresponding position. For example, a key signal may be placed at the location where the control track or audio track used to be.

The operation at the time of recording shown in FIG. however.

Video tracks 12 to 15 K each have a different number of rotations.
The i lot signal as well as the audio signal are recorded. Figure 5a
During the reproduction shown in K, as explained earlier, the center position of the video head 16 is made to coincide with the center position of the interposed track to be scanned.

Even if such track tracing is performed, wow-black does not pose a problem in the reproduced audio signal. Also, unlike the conventional example shown in Figure 2 @, the video heads are 11111 on both the left and right sides! ) Since the track is traced across the rack K, the possibility of tracking loss is reduced even if instantaneous fluctuations are applied in any direction.

In addition, since a wide head can be used, even when tracing extremely selective video tracks or performing special playback, you can place the video head on a special electric device such as Bimorph+R for even more control! 14r: There is no need to do it, and it will not cause an increase in the price of the device or a decline in the number of manufacturers.

Furthermore, as shown in FIGS. 5(f) and (c), in the present invention, the control track and the audio track are not imaged separately, and the fixed head for recording and reproducing these signals can be removed. Therefore, tape running f#! There is also the fact that it makes designing an ellipse easier.

That’s all! ! As explained above, the present invention uses Pi in a VTR.
The idea is to record and playback audio signals in DD using a video head using a lot type control, and to use a so-called 1-wide head for the video head.

To list the effects one after the other, it is possible to reduce the effects of wah and 7 easy caused by the video head tracing different positions during recording and playback to a non-problematic level using the above-mentioned audio signal method. can. For this reason pi
Even if you use a 1-wide head, it is possible to use a special denomination for tracing tracks or cursive writing. It is possible to avoid changing the equipment to AM due to multi-voltage transportation.

Furthermore, the tendency for temporary fluctuations to cause tracking errors from any direction is reduced. A fixed head for externally recording the f voice and control qt signal can be omitted, and the design of the device becomes easier. and these matters,
It has the advantage that the advantage of the Pilot method, which is %II of the original US, in that the tracking policy is small, can be utilized as is.

[Brief explanation of the drawing]

1 and 2 are recording pattern diagrams on a magnetic tape in a conventional VTR, and FIG. 5 is a turn diagram of recording on a magnetic tape in a VTR according to the present invention. 1...Magnetic tapes 12 to 15 ...Video track 10...Wide video head agent Benfunshi Usui 1) $d Kei 1g1J Sai 2 Showa 3 (A) (B) 1

Claims (1)

[Claims] The P-th O1 signal for the video head to accurately trace the first recorded track during playback, and the video head, for example, an FM modulation signal, a time threshold pressure signal, and a digitized audio signal. What is claimed is: 1. A magnetic recording and reproducing apparatus comprising: a video head having means for recording and reproducing information on a magnetic tape;