JPS59193506A - Rotary head type magnetic video recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the simultaneous video recording with two video signals without increasing the number of magnetic heads by setting a >=180 deg. winding angle of a magnetic tape to a rotary cylinder. CONSTITUTION:The winding angle of a magnetic tape 3 is set at >=180 deg. by tape guides 4a and 4b to a rotary cylinder 1. Then the tape 3 is wound around the cylinder 1 via a main winding part theta having a 180 deg. winding angle, a sub-winding part alpha having a prescribed increased winding angle and a margin winding part beta which gives some margin to the winding angle range respectively. With such a winding angle range of the tape 3, both magnetic heads 2a and 2b having a 180 deg. angle space between them touch the part theta alternately for every revolution. In this contact section the 1st video signal is recorded and reproduced by an alternating switch action between both heads 2a and 2b. Thus these heads have contacts with the part alpha earlier than the part theta. In this contact section the 2nd video signal is recorded and reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention provides a rotation method that enables simultaneous recording of a first video signal and a second video signal. The present invention relates to a magnetic recording and reproducing device.

[Butai l]

Conventionally, in the rotary head type magnetic recording/playback device that has been widely used, it is not possible to simultaneously record one video signal while another video signal is being recorded. If there were two or more programs at the same time, only one of them could be recorded.

In addition, in order to eliminate such inconveniences, several proposals have been made for rotary head type magnetic recording and reproducing devices that can record two or more video signals simultaneously; The number of magnetic heads that make up the rotating head is increased according to the number of video signals to be recorded, and these magnetic heads are used to perform helical scanning of the magnetic tape in parallel at the same time to record multiple video signals simultaneously. , had the following drawbacks.

(1) The configuration of the rotating head is complicated.

(2) Multiple video signals are recorded on the magnetic tape by simultaneous parallel helical scanning, one field per field.
In order to record to form the recording tracks of a book, the field phases of multiple video signals must match each other.

(3) When the magnetic tape length is constant, the available recording and playback time decreases in inverse proportion to the number of video signals recorded simultaneously.

(4) Since the recording track of Tsukuda's video signal is interposed between the recording tracks of one video signal, when you try to perform special playback such as slow motion playback, the rotating head will move to the recording track where a different video signal was recorded. Therefore, a meaningful playback video cannot be obtained.

[Purpose of the invention]

An object of the present invention is to eliminate the drawbacks of the prior art described above, to enable simultaneous recording of two video signals having arbitrary field phases without increasing the number of magnetic fields constituting the entire rotary head, and to enable simultaneous recording of two video signals having arbitrary field phases. To provide a rotary throat type magnetic recording and reproducing device which enables special reproduction such as slow motion reproduction without halving the recordable and reproducible time on the magnetic tape used compared to the case where only the entire video signal is recorded. It is in.

[Summary of the invention]

In order to achieve this object, the present invention involves rolling a magnetic tape onto a rotating cylinder with a winding angle of 180 degrees, and rolling the wound magnetic tape onto two pieces of tape placed on the rotating cylinder. In the rotating head type magnetic recording and reproducing device fg, which performs recording and reproducing of video signals by helical scanning each other using a magnetic head, the winding angle of the magnetic tape is 180 degrees, and the winding angle of the magnetic tape is 180 degrees. In the winding angle range, the first video signal is recorded and reproduced by the first recording and reproducing circuit, and in the winding angle range exceeding 180 degrees, the second video signal is recorded by the second recording and reproducing circuit. The feature is that it can be played back.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view of an embodiment of the present invention showing how a magnetic tape is wound around a rotating cylinder. In the figure, 1 is a rotary cylinder, 2α2b is a rotary cylinder 1, and 2α2b is a rotary cylinder 1 placed at an angular interval of 180 degrees. It rotates in the direction of arrow (A) together with the rotating cylinder 1.

To these rotating cylinders 1 and magnetic 1. Do2α, 21
The configuration of No. 5 is equivalent to a throat-type magnetic recording and reproducing device in terms of normal rotation.

Magnetic tape 6 is wound around the rotating cylinder 1 and runs in the direction of the arrow (b), 4a, 41! l is magnetic chi 16
This is a tape guide for regulating the winding angle around the 0-rotation cylinder 1. In a normal rotating head type magnetic recording/playback device, the Q7 guide regulates the winding angle of the magnetic tape around the rotating cylinder to approximately 180 degrees, and the guide 7 controls the winding angle of the magnetic tape around the rotating cylinder to approximately 180 degrees. Recording and reproduction of one video signal is performed by alternately nihelically scanning the magnetic tape, but in the present invention, the tape guides 4α, ah
The winding angle of the magnetic tape 3 on the rotating cylinder 1 is 18
It is increased from 0 degrees, and in the embodiment shown in FIG.
The magnetic tape 3 includes a main winding part θ having a winding angle of 180 degrees, a sub winding part α having a predetermined increased winding angle, and an allowance winding part β to give some margin to the winding angle range. is wound around the rotating cylinder 1.

By setting the winding angle range of the magnetic tape in this manner, two magnetic heads 2a, 2 having an angular interval of 180 degrees from each other can be set.
h alternately contacts the main winding portion θ every rotation,
In the contact section between the two magnetic heads 2a and 26, the first video signal can be recorded and reproduced by alternating switching operations of the two well-known magnetic heads 2a and 26.
2A comes into contact with the sub-winding section α before coming into contact with the main winding section θ, and in the present invention, recording and reproduction of the second video signal is performed in this contact section, as will be described later. be exposed.

Figure 2 shows the magnetic tape 3 wound in the state shown in Figure 1.
It shows a scanning locus pattern on the magnetic tape 3 that occurs when helical scanning is performed using all the magnetic heads 2α and 2h. In the figure, the scanning trajectory fll, +
21, +31... are magnetic heads 2α, 2
These are the main winding part θ and the sub-winding part α of the magnetic tape 3 in FIG. 1 for each scanning locus.

Scanning section θ corresponding to each extra winding portion β.

It has α and β. Note that arrows (a) and (b) indicate the rotation direction of the magnetic heads 2α, 2b and the running direction of the magnetic tape 6, which correspond to FIG. 1, respectively.

FIG. 3 is a block diagram showing an embodiment of a recording circuit system in a rotary head type magnetic recording/reproducing apparatus according to the present invention.
is the first video signal input section.

Reference numeral 7 denotes a first frequency modulator that frequency modulates the first video signal input from the first video signal input section. 6 is a second video signal input section; 8 is a second video signal f input from the second video signal input section; A/D for A/D conversion;
The memory has two storage sections that alternately store the second video signal A/IJ) converted by the converter 8 for each field. 13 is a write control unit that controls the write operation of the memory 9 based on the vertical synchronization signal of the second video signal;
The second video signal converted from A/7) is written alternately for each field into the two storage units. 1
4 is a predetermined phase relationship with the vertical synchronization signal of the first video signal? The read control unit 14 controls the read timing of the memory 9, and the read control unit 14 controls the magnetic head 2α at the sub-winding portion α of the magnetic tape shown in FIG.

The second video signal stored alternately in the two storage sections of the memory 9 at a timing such that the second video signal 2h can sequentially record the second video signal.
The video signal sound is read out while being time-compressed alternately during the non-writing period. This is a second frequency modulator that frequency modulates the second video signal read from the 10-digit memory 9. 11 and 12 are switching units each operated by a switching control signal (not shown) that is in phase synchronization with the vertical synchronization signal of the first video signal;
a and 2b are the two magnetic heads on the rotating cylinder shown in FIG. 7
The first video signal output from the frequency modulator 10 and the second video signal output from the second frequency modulator 10 are switched and supplied reciprocally, respectively.

Next, the operation of such a recording circuit system will be explained with reference to an operation waveform diagram shown in FIG. In FIG. 4, (a) shows the first video signal inputted from the input section 5, and (b) shows the second video signal inputted from the input section 6, each field A of the first video signal.

B, C, D, . . . and each field α, A, c, d, . . . of the second video signal have an arbitrary phase relationship with each other.

The first video signal is frequency modulated by the first frequency modulator 7, and is passed through a switching section 11.12 that performs a switching operation in phase synchronization with the vertical synchronization signal of the first video signal, for each field of the first video signal. alternately to magnetic, J de 2α
, 2b.

Although not particularly shown, the rotational phases of the magnetic heads 2α and 2h are controlled in phase by the vertical synchronization signal of the first video signal using a well-known Herad servo system. ...see Figure 4), (
As shown in FIG. 1), recording is performed alternately each time the magnetic heads 2α, 2h come into contact with the main winding portion θ (see FIG. 1) of the magnetic tape.

On the other hand, the second video signal is converted into an appropriate A/D converter 8.
/D converted, it is supplied to the memory 9, and under the control of the write control unit 13, its respective fields α, h, c, cl
As shown in Figure 4 (c) and (e), ...... is 1
Each field is alternately written and stored in two storage sections of the memory 9. The 902 memory storage units perform read operations alternately under the control of the read control unit 14 during the write period, and the read second video signal is transmitted to the second frequency modulator 10. frequency modulated,
The switching unit 11.12 alternately supplies the first video signal from the first frequency modulator 7 to the magnetic heads 2α and 2A between the supply periods, but this second video signal is supplied to the magnetic heads 2α and 2A alternately. , must be carried out at the timing when the magnetic healds 2α and 2h come into contact with the sub-winding portion α of the magnetic tape in FIG. 1, and within the contact period. For this reason, in this embodiment, the read control unit 14
The read timing of each field of the second video signal from the memory 9 is controlled with a predetermined phase relationship with the vertical synchronization signal of the video signal of the second video signal.
The reading of each field is performed at a high speed corresponding to a relatively short contact period between the magnetic heads 2α, 2h and the sub-winding portion α of the magnetic tape 3, so that the readout is completed within a relatively short contact period.

In this way, the vertical synchronization signal of the first video signal has 1
The magnetic field whose rotational phase is controlled by
b, each field α, h, c of the second video signal
, d... are supplied alternately during the contact period with the sub-winding part α of the magnetic tape, as shown in FIG. ',mosquito,
c', d'... can be recorded together.

FIG. 5 is a block diagram showing an embodiment of a reproducing circuit system in a rotary helical type magnetic recording and reproducing apparatus according to the present invention.
α, 2b Id, the magnetic head mounted on the rotary cylinder, 15.16 is a switching unit whose switching is controlled by a switching control signal output from the switching control unit 20, and the switching unit 15.16 is During the half-rotation period during which the magnetic head 21Z fully scans the main winding portion θ of the magnetic tape (see FIG. 1), the magnetic head 2b scans the main winding portion θ of the magnetic tape at the solid line position in FIG. During the half-rotation period, it is alternately switched to the dotted line position in the figure. Therefore, the first video signal recorded on the main winding portion θ of the magnetic tape is transmitted to the magnetic heads 2α, 2A.
The second video signal, which is sequentially taken out from the output line p for each field and recorded in a time-compressed manner on the sub-winding part α of the magnetic tape (see Figure 1), is transferred to the magnetic tape. Radiation 2α and 2h are used to sequentially take out each field from the output line p.

17 is a memory having two storage units; 21 is memory 1;
7, the write control unit 21 controls the write operation of the memory 17 based on the switching control signal output from the switching control unit 20,
The video signal of plan 2 taken out to the output line P is alternately input into 1702 memory units for each field.

Reference numeral 18 denotes an output signal switching unit which selects between the first video signal taken out from the output line p and the second video signal taken out from the output #+P and read out after being temporarily stored in the memory 17. frequency modulator 19 by selectively switching either one of the
input.

22 is a read control unit for the memory 17, and the read control unit 22 reads 1 from the 1702 storage units.
The time-compressed second video signals scanned alternately for each field are time-expanded so as to have a regular field period in the non-writing period, and are sequentially and alternately read out. In order to perform such alternate readout, the readout control unit 22 controls the readout of the next field at each end of each field of the second video signal read out from the memory 17 and demodulated by the demodulator 19. Configured to start.

Next, the operation of such a reproduction circuit system will be explained with reference to the operation waveform diagram shown in FIG.

In FIG. 6, (A) and (B) are video signals reproduced by the magnetic heads 2 (Z, 2h), respectively.

B, C, D... are each field, α', or C of the first video signal which is alternately reproduced by the magnetic head 2α, 2h VC from the main winding part θ of the magnetic tape. '.

d' . . . indicates each field of the time-compressed second video signal which is alternately reproduced by the magnetic heads 2α and 2b from the sub-winding portion α of the magnetic tape. The video signals reproduced by the magnetic heads 2α and 2h are switched by the switching units 15 and 16 as described above, and the output line P receives the first video signal as shown in FIG. 6(c). Each field A.

B, C, D, . . . , and the output line p, as shown in FIG. cl'... is obtained.

If the output signal switching unit 18 is now switched to the solid line position in FIG. 5, each field A, B, and C of the first video signal obtained on the output line P+.

D... is input as is to the frequency demodulator 19, demodulated, and becomes a reproduced output.

On the other hand, when the output signal switching unit 18 is switched to the dotted line position in FIG. 5, each field α', b',
c', d', . During these non-writing periods, the signals α, h, I? are read out alternately with time expansion and have regular field periods as shown in FIG. 6(E). , d, .

In the explanation so far, it has been assumed that the memory 9 in the recording circuit system and the memory 17 in the reproduction circuit system are separate, but by using an appropriate switching circuit, a single memory can be connected to the recording circuit system and the reproduction circuit. It goes without saying that it can also be used for both systems.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the winding angle f180 of the magnetic tape with respect to the rotating cylinder is
By simply increasing the number of magnetic heads, it is possible to simultaneously record the first video signal and the second video signal without increasing the number of magnetic heads, and once the second video signal is stored in the memory, , the magnetic head scans the increased winding angle range of the magnetic tape with appropriate time compression and reading;
Since the second video signal is for recording, simultaneous recording is possible even if the second video signal has an arbitrary field phase with respect to the first video signal, and the second video signal is time-compressed. Since the amount of magnetic tape required to record and play back the second video signal is reduced by that amount, even if the first and second video signals are recorded simultaneously, the recording and playback time of the magnetic tape used is halved. There's nothing to do.

Furthermore, since the first video signal is recorded in a track pattern similar to that of a J-type magnetic recording and reproducing device for one normal rotation within a 180 degree winding angle range of the magnetic tape, when reproducing it, is produced in slow motion using a method similar to that used in ordinary rotating head type magnetic recording and reproducing devices.

Special playback such as high-speed search can be easily performed.

Therefore, according to the present invention, it is possible to provide a rotary head type magnetic recording and reproducing device which has an excellent simultaneous recording function and has the drawbacks of the prior art described above.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the present invention showing how the magnetic tape is wound around a rotary cylinder. FIG. 2 is a plan view of the magnetic tape wound in the state shown in FIG. FIG. 3 is a block diagram showing an embodiment of the recording circuit system according to the present invention, FIG. 4 is a timing chart showing its operation, and FIG. 5 is a diagram showing the scanning locus pattern when scanning. FIG. 6 is a block diagram showing an embodiment of the reproducing circuit system in FIG. 6, and is a timing chart showing its operation. 1... Rotating cylinder 2α, 2b... Magnetic helad 6... Magnetic tape 4α, 4h... Tape guide 5... First video signal input section 6... Second video signal input Part 9.17...Memo +), 13.21.
...Write control section 1/1.22...Read control section 1 i, 12.15.16...Switching section 18
...Output signal switching section 20...Switching control section A 1 Figure 2 Figure A (B) Izu 45

Claims (1)

[Claims] (1) A rotating cylinder on which two magnetic heads are mounted, a magnetic tape winding means for winding a magnetic tape around the rotating cylinder at a winding angle as large as 180 degrees, and a first recording/reproducing circuit for recording and reproducing the first video signal in order by the two magnetic heads in the winding angle range; 2 magnetic heads sequentially
1. A rotary head type magnetic recording and reproducing device, comprising: a second recording and reproducing circuit for recording and reproducing video signals of the present invention. +21% In claim (1), the second recording and reproducing circuit comprises a memory having two storage units;
a write control section that alternately writes a second video signal for each field into two storage sections of the memory; and a write control section that causes the two magnetic heads to write the second video signal alternately for each field of the magnetic tape in a winding angle range exceeding 180 degrees. A recording circuit system comprising a readout control unit that time-compresses and alternately reads out the second video signals stored in the two storage units of the memory at timings so as to sequentially record the second video signals. , and a memory having two storage sections, and one of the magnetic tapes in the two storage sections of the memory.
a write control unit that alternately writes time-compressed fc second video signals that are sequentially reproduced from a winding angle range exceeding 80 degrees; and a write control unit that time-expands the second video signal from two storage units of the memory. What is claimed is: 1. A rotary type magnetic recording and reproducing apparatus characterized by having a reproducing circuit system comprising a readout control section that alternately reads data.