JPS63302402A - Rotating magnetic head device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a rotating magnetic head device for a video tape recorder (VTR), and in particular, a rotating magnetic head device for recording and reproducing video and a high-fidelity audio recording and reproducing magnetic head on a rotating body. The present invention relates to a rotating magnetic head device equipped with a head and an erasing magnetic head.

[Conventional technology]

In the VH3 system VTR, a rotating head device in which a high-fidelity audio signal recording and reproducing head is mounted on a rotating body in addition to a magnetic head for recording and reproducing video signals is disclosed in Japanese Patent Application Laid-Open No. 1982-
It is shown in the 53705 publication. In addition, in addition to the video signal recording/reproducing magnetic head, a rotating recording/reproducing/erasing head device was also developed in which a magnetic erasing head was mounted on a rotating body, making continuous shooting and electronic editing easier. 57
It is shown in the publication No.-79783. These devices are
In order to transmit the audio signal or the cancellation signal, both devices are composed of a rotating transformer that has a dedicated signal transmission channel separate from the video signal.

In recent years, there has been a need for a VTR that can perform high-fidelity audio recording and playback as well as rotation erasure for easy splicing and editing. A head device was adopted.

[Problem that the invention seeks to solve]

In recent years, in addition to the above-mentioned functions, some of the rotating magnetic head devices have become more demanding in terms of size and weight. It no longer meets the demand for miniaturization. Therefore, a method has been considered in which a rotary transformer having an audio signal transmission channel as disclosed in Japanese Patent Application Laid-open No. 61-53705 and a rotary transformer having a rotation canceling signal transmission channel as disclosed in Japanese Patent Application Laid-Open No. 57-79783 are integrated. However, a rotating transformer in which dedicated transmission channels are arranged concentrically for video signals, audio signals, and erasing signals has a large outer diameter, and cannot be inserted into a rotating magnetic head device (diameter 62 mg+) for VH3 VTR.

Furthermore, if the distance between each channel is shortened so that the rotary transformer has a diameter that can be inserted, a problem arises in that the transmission performance deteriorates due to a decrease in inductance.

The object of the present invention is to provide a rotating magnetic head having a size of a rotary transformer having a high-fidelity audio function as shown in Japanese Patent Application Laid-open No. 61-53705, which enables the transmission of a rotation erase signal in addition to the transmission of a video signal and a high-fidelity audio signal. The goal is to provide equipment.

When recording high-fidelity audio using a rotating head, it is desirable to superimpose a high-frequency bias current on top of the audio signal from the standpoint of increasing the recording level and eliminating distortion.

It is therefore another object of the invention to record audio signals by means of a rotating head using a high frequency bias method.

[Means for solving problems]

In order to achieve the above object, the rotating magnetic head device of the first invention of the present application has an annular groove in a single rotating transformer that corresponds to each magnetic head of a video recording/reproducing magnetic head and an audio recording/reproducing magnetic head. A fixed and rotating (primary and secondary) coil pair for image coupling and a pair of fixed and rotating coils for audio coupling are provided in each annular groove to be connected to each video recording/reproducing magnetic head and audio recording/reproducing magnetic head, respectively. Wind a pair of rotating coils. As a feature, a fixed and rotating coil pair for erasing signal coupling is wound in the same annular groove in which a pair of fixed and rotating coils for audio coupling are wound, and this coil pair is wound around the rotating erasing head. A portion of the erase signal is also supplied to the audio recording/reproducing magnetic head to provide a high frequency bias effect. Further, a dedicated annular groove for coupled transmission of the erase signal is not provided.

When the audio recording/magnetic reproducing head consists of two heads, it is also possible to supply a high frequency bias signal to only one of them. It is desirable that the wavelength of the erasing signal be an integer fraction of the magnetic gap length of the audio recording/reproducing magnetic head.

In addition to the annular groove in which the fixed and rotating coils for image coupling and audio coupling are wound, the rotating magnetic head device of the second invention of the present application has an annular groove in which a short coil to be short-circuited during reproduction is wound. Has grooves.

During recording, the short coil is used for erasing signal transmission (coupling) and supplies the erasing signal to the rotating erasing head.

Since the annular groove in which the short coil is wound is adjacent to the annular groove in which the audio coupling coil pair is wound, a part of the erase signal is transmitted through the audio coupling coil pair as a high frequency bias to the audio recording and reproducing magnetic field. Superimposed on the head. This case is also similar to the first rotary magnetic head device in that a special annular groove for transmitting erase signals is not provided.

[Effect]

According to the configuration of the rotary magnetic head device of the first and second aspects of the invention, the annular groove around which the audio coupling coil pair or the short coil pair is wound is formed into the annular groove around which the erasure signal coupling coil pair is wound. Since there is no need to newly provide an annular groove that also serves as a groove and transmits an erase signal, the total number of annular grooves is the same as in a device without a rotary erase head, and the rotary transformer can be made smaller and lighter. In addition, since the erasure signal coupling coil pair is wound in the same or adjacent annular groove in which the audio signal coupling coil pair is wound, the erasure signal is generated by magnetic coupling between both coil pairs. A portion of the signal is also supplied to the audio recording/reproducing head and is superimposed on the audio signal, exerting a high frequency bias effect on the audio signal, which is useful for increasing the recording level and reducing distortion.

Note that with the above configuration, the relationship between the number of magnetic heads and the number of annular grooves is as follows. That is, the number of video signal magnetic recording and reproducing heads is β, the number of audio signal magnetic recording and reproducing heads is m, the number of rotating erasing magnetic heads is n, the number of short rings or non-wound vA grooves is k, and When the number of annular grooves is p, the following relationship is obtained: p=ff+m+k m≧n.

In a preferred embodiment, the magnetic gap length of the audio recording/reproducing head is β8, the magnetic gap length of the erasing magnetic head is βa, the recording wavelength of the audio signal on the magnetic tape is λ3, and the wavelength of the erasing signal is λa. When λ, > 13 > λ□ β, −□λ.

In addition, by setting λ to 1/integer of l, the recording level of the audio signal is increased and interference with the erase signal is reduced.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. 1st
The diagram shows the connection between the rotating transformer and magnetic head of a rotating magnetic head device! The relationship between the signal processing circuit and the signal processing circuit is shown. The rotary transformer is circular in shape and has an annular winding insertion groove, and in this figure, a half cross section is shown by a chain line.

The magnetic heads include video magnetic heads la and lb, audio magnetoelectric heads 2a and 2b for high-fidelity audio, and erasing magnetic heads 3a and 3b for flying erase, which are arranged at a predetermined angle on a rotating body. For example, the audio heads 2a and 2b are placed 60'' behind the video heads la and lb, which are spaced 180 degrees from each other.
is arranged, and an erasing head is arranged approximately 90 degrees in front of the image head. Four to five image magnetic heads la and lb are required for the standard recording time mode, long-time recording mode, and special reproduction, but only two are shown in this figure and the others are omitted. Audio magnetic head 2a.

2b performs azimuth recording by changing the azimuth angle. Further, the two erasing magnetic heads 3a and 3b perform advance erasing for each field to perform complete continuous shooting. Therefore, the total number of magnetic heads is 8 to 9.

These magnetic heads are connected to each other via a rotating transformer 4.
It is connected to the signal processing circuits 5, 6.7.

That is, the video signal processing circuits 7a and 7b are connected to the video magnetic heads la and lb, and the audio signal processing circuit 6a.

Reference numeral 6b designates the audio magnetic heads 2a and 2bF, and erase signal generating circuits 5a and 5b designate the erase magnetic head 3a.

3b.

The rotary transformer 4 has a rotary core 4a that rotates together with the magnetic head, and a fixed core 4b that is fixed and connected to a circuit, and has coils 8, 9, 10°, 11, 12, 13, .
These coils 8.9, 10, 11, 12, 13 are placed in the annular groove 15, 16° 17. 18. 19. 20.
．． 14 are respectively connected to the magnetic head and the signal processing circuit, and signals are exchanged between the rotating core 4a and the fixed core 4b.
This is done through magnetic coupling. Moreover, these annular grooves 15~
20 are arranged concentrically in this embodiment, but of course they can be similarly applied to a case where they are arranged in the direction of the rotation axis.

audio magnetic heads 2a, 2b and erase magnetic head 3a,
Rotating coils (secondary coils) 8a, 9a, connected to 3b,
10a and lla are two grooves 15a and 17 of the rotating core 4a.
a, coils 8a and 9a or coils 10a and lla
It is inserted as a pair. On the other hand, the fixed core 4b has these grooves 15a.

In addition to providing grooves 15b and 17b facing each other in 17a, audio signal processing circuits 5a and 5b and erasure signal generation circuit 5a are provided.
, 5b and fixed coils (primary coils) 8b, 9
b, 10b, llb to coils 8b and 9b or 10b
and llb are inserted as a pair.

Further, in the grooves 19a, 20a of the rotating core 4a and the grooves 19b, 20b of the fixed core 4b, rotating coils (secondary coils) 13a, 14a are connected to the image magnetic heads la, lb and the image signal processing circuits 7a, 7b, respectively. and fixed coil (1
Next coil) 13b.

14b is inserted and arranged. Furthermore, grooves 16a and 15b in which no coils are inserted are in the rotating core 4a and the fixed core 4b.
and a groove 18a into which the short coils 12a and 12b are inserted,
18b, and has a structure that prevents interference between the video signal and the audio signal, and between the audio signals.

The width of the insertion groove of the coils 8, 9, 10, 11, 13, and 14 is approximately 1 mm for the sake of coil insertion, and the width of the protrusion between the coil grooves for magnetic coupling is also approximately 1 mm for the sake of inductance performance.
is necessary. The outer diameter of this rotating transformer is approximately 56 m, which is the size of the center hole through which the rotating shaft passes, approximately 20 mm, plus these groove shapes.
It is m. This size allows the array to be arranged on the rotating magnetic head mounting surface of a VH3 type VTR with a diameter of 62 mm.

In the recording mode, the signals generated by the erase signal generation circuits 5a, 5b and the audio signal processing circuits 5a, 5b are sent to the coils 8a, 9.
a, 10a, and lla.

The signal spectrum of the VH3 system VTR is shown in FIG. The luminance signal and the audio signal are FM, and the color signal is a low frequency conversion carrier color signal. The erasure signal is set to a higher frequency than the video signal band. Therefore, the audio signal and the cancellation signal are superimposed within the fixed core 4b, and the coils 8a, 9a, LOa, lla of the rotating core 4a
In this case, the audio signal (1,3 MH2, 1,7 MH2, frequency deviation ±150 KHz) is biased with the cancellation signal (7 MHz). Figure 3 shows the induced current spectrum in the coils 8a, 9a, 10a, and lla of the rotating core 4a, with 7MHz as the cancellation signal and 1 as the audio signal.
．． This is data obtained using 5MHz.

Therefore, the audio magnetic heads 2a, 2b and the erase magnetic head 3
This superimposed signal is applied to the erasing magnetic heads 3a and 3b, but the erase magnetic heads 3a and 3b are connected to the 7MHz resonant capacitor 213.2.
1b selectively applies only the erase signal, and the audio magnetic heads 2a and 2b magnetically record only the audio signal due to the effect of head gap loss. The magnetic gap length i of the audio magnetic heads 2a, 2b is about ⅓ of the FM audio signal wavelength λ, that is, 1 to 1.2 μm. This recording/reproduction level has a frequency characteristic shown in FIG. 4. From this data, the cancellation signal is 17 dB lower than the audio signal, which poses no practical problem. Also, the magnetic gap length l of the erasing magnetic heads 3a and 3b. is 3~
5 μm, >1. have a relationship of The frequency f of the cancellation signal is f, -172π C(L t) I//L
? ) C: Capacitance: It is sufficient to set each component according to the relationship between the inductance L of the erase magnetic heads 3a and 3b and the inductance of the coils 8a and 10a of the two-rotation transformer 4.As an erase signal, in the case of the above 7MHz, C- 1500pF, LE14-0.
8μHSL? =0.5μH. Wavelength of cancellation signal λ
, then 12>β3>λ, so that only the erase signal acts on the erase magnetic heads 2a and 2b due to the gab loss term and the resonance effect of the capacitors 212 and 21b.

By the way, as is well known, the gap loss is expressed as g: gap length and λ: wavelength, so the reproduced signal becomes the minimum at g/λ - an integer. Therefore, if the erasing signal wavelength is set in relation to an integer ratio (one integer fraction) of the magnetic gab length of the audio magnetic head, interference with the erasing signal can be minimized. Audio magnetic head gab length 1.2μ
m, the most suitable erasure signal is 9.666MHz (
The wavelength λ is 0.6 μm).

By the way, the cancellation signal and the audio signal cause cross-modulation as shown in Figure 3, but the level is about -50d with respect to the cancellation signal.
B, which is acceptable in practice.

Also, in the reproduction mode, audio signals are induced in the coils 8a, 10a, but there is no practical problem due to the gap loss effect of the capacitors 21a, 21b and the erasing magnetic heads 3a, 3b.

FIG. 5 shows a second embodiment. In this embodiment, there is one erasing magnetic head 3 and a rotating transformer 4a.

4b erasure signal coils 3a, 13b and audio signal coil 9
The same grooves 15a and 15b of a and 9b are arranged as shown in the figure.
Although the arrow A section is omitted in this figure, the video signal system is similar to that of the first embodiment. Also groove 18a, 1
8b, 16a, 16b, short coil 12a, 12b
This is to prevent crosstalk between audio signals and between audio signals and video signals. Note that even if no short coil is inserted as in the crosstalk prevention grooves 16a and 16b, a certain degree of effect can be expected.

By the way, in the case of the second embodiment, the audio magnetic head 2a performs bias recording using an erase signal, but the audio magnetic head 2b performs non-bias recording, and both audio magnetic heads 2a,
2b has a different recording method.

FIG. 6 shows 7 MHz as the cancellation signal and 1.0 MHz as the audio signal.
The bias recording and reproducing characteristics when the frequency is 5 MHz are shown. From the data in FIG. 6, the audio signal reproduction level depends on the bias current and can be made equal to the reproduction level when no bias is applied. Therefore, both audio magnetic heads'la
, 2b allows the audio signal reproduction level to be set in a well-balanced manner. That is, when the bias current is 100 mA, the same reproduction level as when no bias is applied can be obtained. Secondary coil 9a:
If the winding ratio of the primary coil 8b is 1:2 or 1:3, the primary current from the erase signal generation circuit required to give a bias current of 100 mA to the head is 50 mA or 33 mA, and these are It can be set arbitrarily based on the design.

Note that this embodiment uses one erasing head, but the erasing head width is wide enough to erase more than 2 fields (2 fields) in one scan.
tracks or more) are being erased.

FIG. 7 is a diagram showing a third embodiment. The audio magnetic heads 2a, 2b include audio signal processing circuits 6a, 6b and coils 9a, 9b of rotary transformers 4a, 4b.

11a and llb. The erasing magnetic head 3 includes an erasing signal generating circuit 5 and the coil 9a.

a coil 10a placed between 9b, lla, and llb;
It is connected to lQb.

In recording mode, the erase signal is sent from coil 1°b.
Audio signal coils 9a and 9b are transmitted to the erasure signal coil 10a and magnetically coupled.

It is also transmitted to 11a and 11b. Coil 10a.

Since the iob and coils 9a, 9b, lla, and llb are equally isolated, there are two audio magnetic heads 2a.

The applied bias signal (erase signal) of the audio magnetic heads 2b is the same, and the recording and reproducing levels of both the audio magnetic heads 2a and 2b are the same.

Application of the audio signal to the erasing magnetic head 3 occurs in the same manner, but only the erasing signal is selectively applied to the erasing magnetic head 3 by the resonant capacitor 21 as in the first embodiment.

In the regeneration mode, the switch 30 is closed and the coil 10b is short-circuited. Therefore, the effect of preventing crosstalk between audio signals induced in both audio magnetic heads 2a and 2b can be obtained.

As described above, in the rotating magnetic head device of each embodiment, the number of erase magnetic heads is n, the number of audio magnetic heads is m, the number of video magnetic heads is β, and the number of crosstalk prevention grooves (with and without short coils). k, the number p of annular grooves in the rotary transformer is p-1! +m+, and m and n have a relationship of m≧n.

〔Effect of the invention〕

As described above in detail, the rotating magnetic head' device of the present invention can be used as a video recording/reproducing magnetic head, an audio recording/reproducing magnetic head, or an audio recording/reproducing magnetic head.
In a device equipped with an erase magnetic recording/playback head and equipped with high-fidelity audio recording/playback and splicing/editing functions, the rotary transformer that transmits and receives signals to and from each magnetic head includes a rotary transformer for transmitting erase signals. A dedicated annular groove for winding the coil pair is not provided, but an annular groove for audio signal coupling (transmission) or an annular groove for audio signal coupling (transmission) is not provided between channels. Since the annular groove created to prevent crosstalk is also used as the winding part of the erase signal coupling (transmission) coil pair, the total number of annular grooves in the rotary transformer does not change much compared to a device without a rotary erase head. Without this, it is possible to reduce the size and weight of the rotary transformer and, by extension, the rotary magnetic head device. In addition, since the pair of erasure signal coupling coils is wound in the same or adjacent annular groove in which the pair of coils for audio signal coupling is wound, the erasure signal can be transmitted through the magnetic coupling between both coil pairs. Since a part of the signal is superimposed on the audio signal and exerts a high frequency bias effect on the audio signal, it is possible to increase the recording level and reduce distortion.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a first embodiment of a rotary magnetic head device of the present invention, FIG. 2 is a frequency spectrum diagram of each signal in the embodiment of the present invention, and FIG. 3 is a diagram of induced current in a coil of a rotary transformer. 4 is a frequency characteristic diagram of the magnetic recording/reproducing head, FIG. 5 is a block diagram of the second embodiment of the rotating magnetic head device of the present invention, and FIG. 6 is for explaining the second embodiment. FIG. 7 is a configuration diagram of a third embodiment of the rotary magnetic head device of the present invention. la, lb......Video recording/reproducing magnetic head, 2a, 2b......Audio recording/reproducing magnetic head, 3.3a, 3b...... Erase magnetic head, 4...Rotating transformer, 4a...
...Rotating transformer rotating core, 4b...
・Rotating transformer fixed core, 5.5a, sb...
... Erasing signal generation circuit, 6a, 6b...
・Audio signal processing circuit, 7a, 7b...Video signal processing circuit, 8a, 9a, 10a, lla, 12a
, 13a. 14a... Rotating coil of rotating transformer,
8b. 9b, 10b, llb, 12b, 13b, 14b...
...... Fixed coil of rotating transformer, 15a, 16
a, 17a, 18a, 19a, 20a...
Annular groove of rotating core, 15b, 16b, 17b, 18b
, 19b, 20b...... Annular groove of fixed core Fig. 1 Fig. 2 Fig. 3 ITI Kainu (formerly Fig. 4 Fig. 5 Fig. 6 Fig. 7)

Claims (4)

[Claims] (1) In a rotary magnetic head device in which a video recording/reproducing magnetic head, an audio recording/reproducing magnetic head, and an erasing magnetic head are provided in a rotating part and transmitting/receiving signals via a rotating transformer, the rotating transformer is connected to the video recording/reproducing magnetic head. A pair of video coupling coils and a pair of coils for audio coupling connected to the magnetic head and the audio recording/reproducing magnetic head for each magnetic head, and a plurality of circles around which the pair of video coupling coils and the pair of audio coupling coils are individually wound. Further, the rotary transformer has a pair of erasing signal coupling coils connected to the erasing magnetic head wound in the same annular groove as the pair of audio coupling coils. A rotating magnetic head device characterized in that a part of the signal is supplied to an audio recording/reproducing magnetic head so that the audio signal is bias-recorded using the erasing signal. (2) The rotary magnetic head device according to claim 1, wherein the audio recording/reproducing magnetic head is comprised of two heads, and a part of the erase signal is supplied as a bias signal to only one of the heads. . (3) The rotary magnetic head device according to claim 1, wherein the wavelength of the erasing signal is set to an integer fraction of the magnetic gap length of the audio recording/reproducing magnetic head. (4) In a rotating magnetic head device in which a video recording/reproducing magnetic head, an audio recording/reproducing magnetic head, and an erasing magnetic head are provided in a rotating section and transmitting and receiving signals via a rotating transformer, the rotating transformer is configured to operate the video recording/reproducing magnetic head. A pair of coils for video coupling and a pair of coils for audio coupling connected to the magnetic head and the audio recording/reproducing magnetic head separately for each magnetic head, a pair of short coils that are short-circuited during reproduction, the pair of coils for video coupling, and the pair of coils for audio coupling. The rotary transformer includes a plurality of annular grooves around which the pair of coils and the short coil pairs are individually wound, and further includes an annular groove around which the pair of audio coupling coils is wound, and a plurality of annular grooves around which the pair of short coils are wound. At the same time, the pair of short coils is used as a pair of erase signal coupling coils connected to the erase magnetic head during recording, thereby supplying a part of the erase signal to the audio recording/reproducing magnetic head. A rotating magnetic head device characterized in that an audio signal is bias-recorded using the erasure signal.