JPS58220203A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To record and reproduce audio signals with high fidelity with the 1,5 head type omega wind helical scanning system, by recording the audio signal with compression at a part of the overlap part of the record/reproduction of an auxiliary head and that of a main head. CONSTITUTION:A tape 1 is driven toward an arroe A, and a magnetic head and an auxiliary head implanted to a rotary drum are turned toward an arrow B. The main and auxiliary heads form recording lock 2 and 3. The greater part of video signals is recorded and reproduced on the locus 2. The locus 3 is divided into three parts. Then the lacking part of video signals (signals in a vertical flyback period) is recorded in a region 4; while the signals obtained by giving the PCM conversion and time compression to the audio signals equivalent to a field are recorded in a region 5. A region 6 is defined as a guard band part. Desired angle and level differences are secured when the main and auxiliary heads are set to the rotary drum, and an erasing head is also provided in the same way. Thus it is possible to record and reproduce audio signals at a low speed and high fidelity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-fidelity recording and reproducing system for audio signals in a high-density recording type helical scan magnetic tape recording and reproducing apparatus.

Video signal recording and reproducing device using magnetic tape, so-called V
Various types of TR have been put into practical use, but
One of the methods is to wrap the magnetic tape (hereinafter simply referred to as tape) around the rotating head drum with the corners at 56°.
There is a so-called T5 head type omega (Ω)-wound helical type VTR that uses an auxiliary head to compensate for the vertical synchronization period (for example, 540 degrees), and is used in consumer home VTRs, etc. is also widely used.

By the way, not only such VTRs but also general VTI'Ls with a rotating head type helical scan system do not use a rotating head to record audio signals, but use a fixed head to record audio recording tracks along the length of the tape. It is designed to be recorded. Even with this type of sound-to-door signal recording and reproducing system using a fixed head, for example, broadcasting V
There is no particular problem when the tape running speed is sufficiently fast, such as with the TR type C format. In extremely strong equipment, the tape running speed is reduced as much as possible by increasing the recording density, and as a result, the recording and reproducing method of audio signals using the fixed head described above does not allow the tape to travel between the head and the tape. The relative velocity drops considerably from the desired value,
There is a problem in that it becomes impossible to record and reproduce audio signals with high fidelity.

In order to improve this, a VTR was proposed in which audio signals were also recorded and played back using a rotating head, but this required a rotating head drum to be equipped with a head for recording and playing back audio signals. A track for recording an audio signal is required in parallel with a track for recording a signal, which has the disadvantage of complicating the structure and likely increasing costs, as well as shortening the recording time.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, eliminate the need to attach an extra head to the rotating head drum, and enable recording and playback of audio signals with high fidelity even when the tape running speed is quite slow. We provide VTRs.
- In order to achieve this object, the present invention uses an auxiliary head in a 1.5-head omega-wound helical scan type VTR, and records an audio signal that has been time-compressed in advance on a part of the recording track by the auxiliary head. It is characterized by the following points.

Embodiments of the magnetic recording and reproducing apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a recording pattern on a tape according to an embodiment of the present invention, where 1 is the tape, 2 is the recording trajectory by the main head, and 3 is the recording trajectory by the auxiliary head.
indicates the running direction of the tape 1, and arrow B indicates the scanning direction by the main head and the auxiliary head. In this figure, only one recording locus 2 and 3 are shown, but this is for convenience of explanation; in reality, these recording loci are sequentially parallel to each other along the longitudinal direction of Qigu. It goes without saying that the trajectories 2 and 3 are arranged in such a way that guard nodes are provided between the trajectories 2 and 3.

The recording trajectory 3 by the auxiliary head is 3 along its longitudinal direction.
It is divided into two parts, of which 4 is a video signal recording part, 5 is an audio signal recording part, and 6 is a guard part between the video signal recording part 4 and the audio signal recording part 5.

The recording section 4 is the same as the recording section by the auxiliary head in a conventional 15-head type VTRIC, and the recording part 4 is the same as the recording part by the auxiliary head in a conventional 15-head type VTRIC. This is for supplementary purposes, and the signal of the portion of the video signal that includes the vertical synchronization signal is recorded.

The recording portion 5 is a portion where a time-compressed audio signal is recorded, and for example, a signal obtained by converting an audio signal of one field period into PCM and time-compressing is recorded.

This is the part where it is done.

As its name suggests, guard portion 6 is provided to guard between portions 4 and 5, to provide leeway for signal switching operation between these portions, and to ensure that recording is performed during erasing alone. Therefore, it may be a no-signal portion, or another signal, such as a serial number of a recording track, may be recorded.

Next, FIGS. 2(a) and 2(b) show an embodiment of the rotary head drum according to the present invention. In the figures, 7 represents the entire rotary head drum, 8 is the rotary drum, 9 is also a fixed drum, 10 is a main head (recording/reproducing method for recording trajectory 2 in FIG. 1; 11 is an auxiliary head (for recording/reproducing for recording trajectory 6 in FIG. 1); 12 is a main erasing head (erasing method for recording trajectory 2); 13 is an auxiliary erasing bed (erasing M for recording trajectory 3).

The main head 10 and the auxiliary head 11 are attached at positions separated by a distance X in the circumferential direction of the drum 8, and are configured to have a step y in the axial direction of the drum 8. Note that this also applies to the main erase head 12 and the auxiliary erase head 16.

Although the tape 1 is completely free of water in FIG. 2 (b), it runs in the direction of the arrow A while being wrapped around the drum 7 over an angle slightly less than 360 degrees, while the drum 8 runs in the direction of the arrow C.
As a result, the tape 1 is scanned by the main head 10 and the auxiliary head 11 in the direction of arrow B in FIG.
Recording and reproduction are performed according to the respective recording trajectories 2.3.

Note that this situation is the same as that of a well-known 15-head type VTR, but in this embodiment, the main head 10 and the auxiliary head 11 are
The height difference y between the main head 11 and the main head 11 is set so that even if the recording trajectory 3 is lengthened, it still overlaps with the recording trajectory 2 produced by the main head 11, and the audio signal is time-compressed in the recorded portion 5 obtained by this. I decided to record it.

Therefore, by using an audio signal recording processing circuit (not shown) and an audio signal reproduction processing circuit (not shown), the original audio signal is converted into PCM at the time of recording, and then time compressed for each field, gated with a switching signal, and supplied to the auxiliary head 11. An audio signal is recorded as a recording portion 5 on a recording locus 3 by the auxiliary head of the tape 1, and during playback, the signal reproduced by the auxiliary head 11iC is gated and extracted from the recording portion 5 of the tape 1, and time expansion and PCM demodulation are performed. If you do this, a continuous audio signal will be played.

To assist in this case, the relative speed between the gutter 11 and the tape 1 is sufficiently high regardless of the slow running speed of the tape 1. Therefore, according to this embodiment, For example, even if high-density recording is performed by slowing down the running speed of the tape 1, audio signals can be recorded and reproduced with high fidelity.

In addition, in such a 15-head VTR, the main head 10 and the auxiliary head 11 are switched, so that most of the video signal is recorded on the recording track 2 of the tape 1 by the main head 10, and during the vertical retrace period. IC T5 is set so that the auxiliary head 11 records on part 4 of the recording trajectory of the tape, so 7.

A switching pulse is created. Therefore, the above-mentioned gate switching signal can also be obtained from this switching signal.Next, the operation during post-recording will be explained.

As described above, if the switching signal is turned on and off, the timing at which the auxiliary head 11 traces the recorded portion 5 can be grasped, and the same is true for the auxiliary erasing head 13. Therefore, first, the auxiliary erasing head 15 erases only the recording portion 5, and then the auxiliary head 11 compresses the time of the audio signal to be dubbed and records it in the recording portion 5.

Further, during post-recording of a video signal, the auxiliary erasing head 11 is operated in response to a switching signal to erase only the recorded portion 4, and at the same time, the main erasing head 12 erases the recording locus 2. Subsequently, the main head 10 and the auxiliary head 11 are used to record the video signal to be post-recorded in the recording trajectory 2 and recording portion 4VC.

The operation at this time is shown in the timing chart.・8 The result will be as shown in Figure 5.

In Fig. 5, (a) is the vertical plank pulse of the video signal, (b) is the head switching pulse, and (C) is the vertical plank pulse of the video signal.
(d) is the recording/reproducing period by the main head 10; (d) is the recording/reproducing period by the auxiliary head 11; (e) is the erasing period by the auxiliary erasing head 15 during audio signal dubbing; (f) is the recording/reproducing period by the main head 10;
1 and 2 respectively represent erasing periods by the main erasing head 12 and the auxiliary erasing head 15 during video signal post-recording.

At this point, if the head track width of the main and auxiliary erasing heads 12 and 13 is made wider than the head track width of the main and auxiliary recording/playback heads 1G and it, erasure without any unerased areas can be achieved. Therefore, according to this embodiment, it is possible to arbitrarily perform post-recording of audio and video (・misalignment), and there is no possibility that the □fidelity of the audio signal will deteriorate (・.

By the way, in the above embodiment, the recording portion 5 of the audio signal in the recording trajectory 3 of the tape 1 by the auxiliary spatula 1 is
is placed temporally later than the recorded portion 4 of the video signal (
Alternatively, this may be placed temporally ahead of the recording portion 4 of the video signal. In other words, the auxiliary head 11 first records the time-compressed audio signal, and then records the vertical retrace portion of the video signal, and similar effects can be expected with this. Good (Same as l, scanning direction B of 1 head
The position of the recording locus 3 by the auxiliary head 11 can also be determined using various well-known methods. For example, the scanning direction B of the head may be the same as the running direction A of the tape, and the position of the recording locus 5 of the tape 1 may be changed. Needless to say, it may be moved to the upper end side.

By the way, in the embodiment of the present invention, the tracking method during playback is similar to the conventional helical scan VTR, in which a control signal is recorded along the longitudinal direction of the tape at the top or bottom end of the tape 1. You can use this to ensure tracking during playback.

However, in the present invention, the auxiliary head 11VC
It is also possible to record a pilot signal and use it to perform accurate tracking during playback, and the tape pattern in an embodiment of the present invention in which tracking is performed using the RC pilot signal. An example is shown in FIG.

In FIG. 4, reference numeral 14 denotes an extension of the recording trajectory 3 by the auxiliary head 11, which overlaps with the recording trajectory 2 on which the video signal is recorded by the main head 10. In this portion 14, pilot signals of different frequencies af and f2 are alternately recorded by the auxiliary head 11. Moreover, at this time, as shown in FIG. 4, pilot signals with frequencies f and f are alternately recorded in the recording section 14 by the auxiliary head 11, and then a pilot signal with frequencies f and 2 is recorded. A portion of the recorded portion 14 is overwritten and erased by the recording operation of the video signal by the main head 10, and furthermore, at this point, the main head 10
is made to scan exactly in the middle between the recorded portion 14 of the pilot signal of f and f2 which have already been recorded.

Then, as is clear from FIG. 4, the main head 10
A recording pattern is obtained in which pilot signals of frequencies fl and f are alternately provided in the guard band portion of the recording trajectory 2.

Therefore, during reproduction, when the main head 10 is scanning the recording trajectory 2, the reproduction level of the pilot signal that is reproduced as a crosstalk component from the adjacent guard band portion is checked, and the frequency f and If tracking control is performed so that the reproduction level of the pilot signal is maintained at the same level, accurate tracking can be easily and reliably obtained.

Note that, as a matter of course, these pilot signals are reproduced by the main head 10 as crosstalk components of the video signal, so the frequencies f, f, are in a band not used for the video signal. It is desirable that there be. For example, the frequency band 12 is on the lower side of the frequency band used for video signals recorded and reproduced by the main controller 10.

Alternatively, the video signal to be recorded is divided into a luminance signal and a color signal by a low-frequency conversion FM recording method, and the luminance signal is 1M modulated and the color signal is on the lower side of the FM luminance signal band. In the case where the frequency is converted and arranged, the setting may be made to be in the middle of these bands.

Note that at this point, the frequency f of the pilot signal.

f! This allows you to select the appropriate one, and not just the video signal (
If it is possible to prevent it from affecting the time-compressed audio signal, the pilot signal can be recorded in the entire area of the recording/playback portion by the auxiliary head 11, that is, including the recording portion 4°5.6. Good too.

By the way, as is clear from FIG. 4, the pilot signal for tracking cannot be taken out over the entire scanning period by the main head 10, but the period during which the pilot signal is missing is very small. Therefore, there is almost no possibility that the tracking accuracy will decrease due to this, and tracking can be performed with sufficient accuracy for practical use.

Furthermore, in the embodiment of FIG. 4, the frequencies of the pilot signals are alternated between adjacent recording trajectories. That is, in the recording trajectory formed, the frequency is f in the guard band portion on the left side and f in the guard band portion on the right side, but in the next recording trajectory, the left side is f1 and the right side is fl.

Therefore, during tracking, it is necessary to alternately invert the frequency of the tracking error signal for each recording locus, but in the above embodiment, by detecting the pilot signal with the auxiliary head 11VI-, this inversion control can be easily performed. It can be done reliably. In other words, since the height difference y between the auxiliary head 11 and the main head 10 is constant and known, if you check the frequency of the pilot signal reproduced from the auxiliary head 11, then the main head 1
This is because it can be immediately determined which of the pilot signals on the left and right sides of the recording trajectory 2 being scanned by 0 is f8 and the other is φif. In particular, auxiliary head 1
In the case of the embodiment in which the pilot signal is recorded over the entire recording trajectory according to No. 1, there is no need to provide an extra reproduction period, and accurate detection is always possible.

In the above description, detailed explanations of PCM conversion, time compression, and time expansion of audio signals have been omitted, but well-known ones may be used in a general state.

As explained above, according to the present invention, even when the tape running speed cannot be obtained sufficiently fast, it is possible to install an extra head on the rotating head drum or increase the tape winding angle. (Since it is possible to record and play back audio signals with high fidelity, high-performance helical scan method VT eliminates the drawbacks of conventional technology and does not degrade sound or image quality due to dubbing etc.) i'L'l Low cost can be provided with.

[Brief explanation of the drawing]

FIG. 1 shows 15 recording patterns on a magnetic tape in an embodiment of the magnetic recording/reproducing apparatus according to the present invention. FIG. 2 is an explanatory diagram showing an embodiment of the rotary head drum according to the present invention, in which (a) is a front view thereof, (b) is a side view thereof, and FIG. ~(f) are timing charts showing the operation of the present invention. FIG. 4 is an explanatory diagram showing an example of a recording pattern on a magnetic tape in another embodiment of the present invention. 1... Magnetic tape 2... Recording trajectory by the main head 3... Recording trajectory by the auxiliary head 4... Recording portion of the vertical retrace period of the video signal 5... Recording portion of the time-compressed audio signal 6...Gart band part 7...Rotating head drum 8...Rotating drum 9...Fixed drum 10...
Main head 11...Auxiliary head 12...Main erase head 13...Auxiliary erase head 14...Pilot signal recording portion 16. ? 1 Figure / Sai 3 Figure Sai 42 A, -1111

Claims (1)

[Claims] (1) In a T55 head type omega helical scan type magnetic recording/reproducing device equipped with a main head and an auxiliary head, there is a period in which a signal recording/reproducing period by the auxiliary head overlaps with a signal recording/reproducing period by the main head. 1. A magnetic recording and reproducing device, characterized in that a part thereof is configured to record and reproduce time-compressed audio signals. (2. In claim 1, there is provided means for recording a pilot signal in at least a portion of the entire area of the track recordable by the auxiliary head that overlaps with the recording track recorded by the main head. 1. During reproduction. A magnetic recording/reproducing apparatus characterized in that tracking control is performed using the pilot signal reproduced by the main head.