JPH06119601A - Magnetic recording / reproducing device - Google Patents

Abstract

(57) [Summary] [Purpose] Optical signals are transmitted for the purpose of transmitting wideband signals, and optical fibers are used in the transmission line to prevent signal loss during transmission. Another object is to reduce the number of light emitting elements and light receiving elements, facilitate positioning, improve productivity, and realize low cost. According to the present invention, a light emitting element and a light receiving element are provided on a rotating drum having a magnetic head, and correspondingly, a light emitting element and a light receiving element are provided on a fixed drum, and an optical fiber is used for signal transmission between them. It was done by doing so.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a VTR, in which signals are transmitted and received between a magnetic head installed on a rotary drum and the outside of the rotary drum by optical transmission. It is a head device.

[0002]

2. Description of the Related Art Generally, in a VTR, a magnetic tape is helically wound around a drum composed of a rotary drum and a fixed drum coaxial with the rotary drum and having the same diameter, and a magnetic head installed on the rotary drum helically scans the magnetic tape. Then, the recording / reproducing of the signal is performed. Therefore, it is necessary to exchange signals between the magnetic head on the rotary drum and the fixed-side signal processing circuit. Conventionally, a method using a rotary transformer has been used for transmitting signals between the rotating unit and the fixed side.

As a method of replacing with a rotary transformer, JP-A-1-184602, JP-A-1-184603,
As disclosed in Japanese Unexamined Patent Publication No. 1-184604, a method of transmitting and receiving signals by optical transmission has been proposed. For example, in JP-A-1-184602, a light emitting element and a light receiving element are mounted on a rotating drum, and a corresponding light receiving element and a light emitting element are installed on the fixed side (excluding the fixed drum) to exchange signals. The method of doing is disclosed. That is, one of the light receiving element and the light emitting element mounted on the rotating drum is arranged on the rotation axis, and the light emitting element and the light receiving element are provided on the fixed side corresponding to the light emitting element on the rotating side and the light receiving element. One of the fixed-side light receiving element and the light-emitting element is provided on the rotation axis, and from the light-emitting element provided on the rotation side or the fixed side to the light-receiving element provided on the fixed side or the rotation side. Light is transmitted through an optical path that intersects the axis of rotation.

In JP-A-1-184603, both a light emitting element and a light receiving element are installed on a fixed side (excluding a fixed drum), and an MO element (magneto optical device) and an EO element (on a rotating body). An optical modulation element such as an electro-optical device) or an AO element (acoustic optical device) is mounted, and the light from the fixed-side light emitting element is used by the signal read by the magnetic head by the optical modulation element on the rotating drum. Light modulation,
A method is disclosed in which the modulated optical signal is received by the fixed-side light receiving element. According to this method, since the light emitting element is not provided on the rotary drum, there is an advantage that the amount of electric power supplied to the rotary drum can be small. Japanese Patent Laid-Open No. 1-18
In Japanese Patent No. 4604, a light receiving element and a light emitting element are connected by an optical fiber so that one of the light receiving element and the light emitting element can be commonly used by a plurality of magnetic heads, and signals are transmitted and received by optical transmission in a small space. It was made possible.

[0005]

The conventional method of transmitting and receiving a signal between the rotating side and the fixed side by using a rotary transformer has a low coupling coefficient because there is an air gap between the rotating side transformer and the fixed side transformer. Inevitably, there was a problem that the reproduction output deteriorated and the resonance frequency decreased. Further, there is also a problem that the cost is high because precision is required for the processing and assembling of the transformer. Further, there is a problem in that it is not possible to cope with the increase in the number of channels and the reduction in diameter of the drum because a certain distance is required between the channels of the rotary transformer.

As a method for solving these problems, Japanese Patent Application Laid-Open No. 1-184602 discloses a signal transmission system by optical transmission. According to the above method, there is an advantage that the band can be widened as compared with the case where the rotary transformer is used, but since the transmission and reception of the optical signal is performed between the rotating drum and the fixed side, the alignment of the light emitting element and the light receiving element of both is aligned. Since accuracy is required, there is a problem in that productivity is lacking and cost is high.

Further, since light passes through the atmosphere between the light emitting element and the light receiving element, there is a problem that the signal is deteriorated due to scattering or the like. Furthermore, no consideration has been given to power transmission to the light emitting element on the rotating body.

Another method using optical transmission is disclosed in Japanese Unexamined Patent Application Publication No. HEI-1.
No. 184603. However, in the above method, as in the above publication, the problems of alignment between the fixed side and the rotating side and signal deterioration cannot be avoided.

As another method, Japanese Patent Laid-Open No. 1-1846
There is a method disclosed in Japanese Patent Laid-Open No. 04. In the case of the above method, since the light passes through the optical fiber, there is less signal deterioration than the above method. However, there is a problem in that the productivity is poor because it is necessary to process the shape of the optical fiber into a shape along the circumference of the drum.

Further, in the above conventional example, all the heads and the optical paths (signal transmission paths) have a one-to-one correspondence, and in the case of a system mounted on a plurality of head rotating bodies, a light emitting element,
A plurality of light receiving elements, modulation elements, etc. must be mounted on the rotating body, and there is a problem that it cannot be applied to a small diameter drum.

[0011]

In view of the above problems, the present invention provides a light emitting element and a light receiving element on a rotating drum having a magnetic head, and correspondingly provides a light emitting element and a light receiving element on a fixed drum. The signal transmission between the two is performed using an optical fiber.

Further, a signal dividing circuit for dividing a recording signal into bands and allocating it to a plurality of magnetic heads, and a signal synthesizing circuit for synthesizing the signals from the respective band-divided heads are mounted on the rotary drum.

Further, electric power is transmitted from the fixed drum side to the rotating drum side by a rotary transformer.

[0014]

Therefore, according to the present invention, the optical signal transmission path between the rotary drum and the fixed drum is constituted by an optical fiber.
It becomes possible to transmit without deteriorating the signal.

Further, by mounting a circuit having a function of dividing and synthesizing signals on the rotary drum, it becomes possible to perform signal transmission between the heads of a plurality of channels and the fixed drum by one round-trip optical path. . That is, the number of light emitting elements and light receiving elements can be reduced, and power saving and space saving can be achieved.

Further, since the signal is first transmitted from the rotary drum to the fixed drum, the handling after the integrated assembly of the rotary drum and the fixed drum becomes easy.

Further, by supplying electric power to the rotary drum by using the rotary transformer, electric power sufficient to operate the light emitting element can be obtained.

[0018]

FIG. 1 shows a magnetic head device according to a first embodiment of the present invention, which comprises a rotary drum 1 and a fixed drum 2. On the rotating drum 1, a magnetic head 7,
8 is provided, and signals are recorded and reproduced by obliquely scanning the magnetic tape wound around the drums 1 and 2. The magnetic heads 7 and 8 are connected to the signal amplifier 10, the signal amplifier 10 is connected to the signal division circuit 12, and the signal division circuit 12 is connected to the light receiving element 5. Magnetic head 7,8
Is also connected to the signal amplifier 11, the signal amplifier 11 is connected to the signal combining circuit 13, and the signal combining circuit 13 is connected to the light emitting element 3. On the fixed drum 2, the light emitting element 4,
A light receiving element 6 is provided. Rotating shaft 1 of rotating drum 1
An optical fiber 9 is provided in the optical fiber 5, and the central axis of the optical fiber 9 is installed so as to coincide with the center of rotation of the rotary drum 1. The rotary transformer 14 is used to transmit electric power to the rotary drum.

Referring to FIG. 2, the light emitting elements 3 and 4 of this embodiment are
The shapes of the light receiving elements 5 and 6 and the optical fiber 9 will be described. The light emitting element 3 on the rotary drum 1 has a circular shape, and the light receiving element 5 has a concentric circular shape surrounding the light emitting element 3. On the other hand, the light receiving element 6 on the fixed drum 2 has a circular shape, and the light emitting element 4 has a concentric circular shape surrounding the light receiving element 6. The optical fiber 9 includes the light emitting elements 3 and 4,
It has a concentric circular shape matching the shapes of the light receiving elements 5 and 6. Therefore, the light from the light emitting element 3 on the rotating drum 1 reaches the light receiving element 6 on the fixed drum 2 through the inside 9a of the optical fiber. Light from the light emitting element 4 on the fixed drum 2 reaches the light receiving element 5 on the rotating drum 1 through the outer side 9b of the optical fiber. At this time, the centers of the light emitting elements 3 and 4, the light receiving elements 5 and 6, and the optical fiber 9 are all the rotating drum 1.
Since it is installed so as to be on the central axis of rotation, the positional relationship among the light emitting elements 3 and 4, the light receiving elements 5 and 6, and the optical fiber 9 does not change even when the rotating drum 1 is rotating.
Signals can be exchanged smoothly. In this case, the light emitting element 3 and the light receiving element 5 and the light emitting element 4 and the light receiving element 6 may have the opposite shapes.

In this embodiment, the optical fiber 9 is installed in the rotary shaft of the rotary drum 1, but it is not always necessary to install it in this place. For example, a structure in which a plurality of optical fibers are arranged along the inner side of the drum as in the example described in JP-A-1-184604 may be adopted.

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows the circuit configuration of this embodiment.

First, the flow of signals during recording will be described with reference to FIG. During recording, a recording signal is transmitted to the light emitting element 4 on the fixed drum 2, and the light emitting element 4 emits light in response to the recording signal. The light generated by the light emitting element 4 passes through the optical fiber 9 and reaches the light receiving element 5 on the rotary drum 1. The light receiving element 5 sends an output corresponding to the received light to the signal dividing circuit 12. The signal division circuit 12 frequency-divides the input recording signal and sends it to the DA converter 15 to convert the signal into an analog signal.
The analog signal is sent to the magnetic heads 7 and 8 after being sent to the amplifier 10.

Next, the signal flow during reproduction will be described with reference to FIG. The reproduction signals of the magnetic heads 7 and 8 are amplified by the amplifier 11 and then sent to the AD converter 16 and converted into digital signals. After that, the signal is sent to the signal synthesizing circuit 13 and the playback signals of the magnetic head 7 and the magnetic head 8 are synthesized, and then sent to the light emitting element 3, and the light emitting element 3 emits light according to the sent signal and passes through the optical fiber 9. The light receiving element 6 on the fixed drum 2 is reached.

In this embodiment, paying attention to the characteristics of the optical transmission system capable of transmitting a wide band signal as compared with the rotary transformer, the head signals of a plurality of channels are transmitted by one optical path during recording and reproduction. This has the effect of saving space and power.

[0025]

According to the present invention, since the signal is transmitted between the rotary drum and the fixed drum and further the signal is transmitted by using the optical fiber, the accuracy of mounting the drum is not required and the productivity is improved. Does not deteriorate.

Further, according to the present invention, the transmission of head signals of a plurality of channels is carried out by one optical path for recording and reproducing, respectively, so that the number of light emitting elements and light receiving elements can be reduced, thus saving It has the effect of space saving and power saving.

Further, according to the present invention, since electric power is transmitted to the rotary drum by the rotary transformer, stable and sufficient electric power can be supplied.

[Brief description of drawings]

FIG. 1 is a front view of a magnetic head device according to a first embodiment of the invention.

FIG. 2 is a perspective view showing the shapes of an optical fiber, a light receiving element, and a light emitting element according to the first embodiment of the present invention.

FIG. 3 is a block diagram of a recording process of a magnetic head device according to a second embodiment of the invention.

FIG. 4 is a block diagram of a reproducing process of the magnetic head device according to the second embodiment of the invention.

[Explanation of symbols]

1 ... Rotating drum, 2 ... Fixed drum, 3, 4 ... Light emitting element,
5, 6 ... Light receiving element, 7, 8 ... Magnetic head, 9 ... Optical fiber, 10, 11 ... Amplifier, 12 ... Signal band division circuit,
13 ... Signal band addition circuit, 14 ... Rotary transformer,
15 ... DA converter, 16 ... AD converter.

Claims (5)

[Claims] 1. A rotator equipped with a magnetic head, a light emitting element and a light receiving element, and a rotator equipped with at least the light receiving element and the light emitting element which are arranged to correspond to the light emitting element and the light receiving element and transmit optical signals. A magnetic recording / reproducing apparatus comprising a fixed portion coaxial with and having substantially the same diameter, and transmitting an optical signal between the rotating body and the fixed portion by an optical fiber. 2. The magnetic recording / reproducing apparatus according to claim 1, wherein a central axis of the optical fiber coincides with a rotation axis of the rotating body. 3. A rotating body having a plurality of magnetic heads, a light emitting element and a light receiving element mounted thereon, and at least a light receiving element and a light emitting element corresponding to the light emitting element and the light receiving element arranged to transmit an optical signal. It is composed of a fixed part having the same diameter as that of the rotary body and having the same diameter, and the signal transmission from the plurality of magnetic heads to the fixed part and the signal transmission from the fixed part to the rotary body are respectively performed by one optical path. Magnetic recording / reproducing device. 4. A plurality of magnetic heads, a light emitting element, a light receiving element,
A rotating body equipped with a signal amplifier, a circuit for converting a digital signal into an analog signal, a circuit for converting an analog signal into a digital signal, a signal processing circuit for band-dividing a recording signal, and a signal processing circuit for synthesizing a band-divided reproduction signal. And a magnetic recording / reproducing device, which comprises a fixed portion coaxial with and having the same diameter as the rotating body on which the light-receiving element and the light-emitting element are mounted and which are arranged to transmit an optical signal at least corresponding to the light-emitting element and the light-receiving element. apparatus. 5. The magnetic recording / reproducing apparatus according to claim 1, wherein electric power is transmitted to the rotating body by using a rotary transformer.