JPH0216414Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetic head, and more specifically to a magnetic head for audio control of a video tape recorder. The present invention relates to a magnetic head which has excellent magnetic properties as an audio recording head and at the same time has excellent magnetic properties as an audio reproducing head by arranging the heads in the running direction of the heads, and can be miniaturized.

The recent spread and development of video tape recorders is truly remarkable, and one trend is that they are required to become more and more compact. The biggest problem with miniaturizing video tape recorders is how to increase the signal recording density. If the signal recording density increases, the tape speed decreases, the tape itself becomes smaller, the cylinder becomes smaller, and the entire device becomes smaller and lighter. In practical terms, an appropriate method is to increase the coercive force of the magnetic material used in the tape to increase the recording density. To achieve this, the coercive force of the magnetic material currently used in tapes is about 650 Oersted, but it must be increased to more than 1000 Oersted.
It is required to raise it to 1300-1500 oersted.

The problem when using such a high coercive force tape is how to form a corresponding magnetic head for audio control. One way to do this is to use a material with a saturation magnetic flux density of 10,000 Gauss or more as the core material for the magnetic head, but the material for the magnetic head should have wear resistance, corrosion resistance, magnetic permeability, etc. It is difficult to obtain a suitable core material with a saturation magnetic flux density of 10,000 Gauss or more because of the limitations on . Although some non-quality magnetic materials can be obtained that satisfy all of the properties required for magnetic heads as described above, it cannot be said that they have yet reached the stage of being fully put into practical use.

A conventional magnetic head for voice control has a structure as illustrated in FIG. That is, in the same figure, the magnetic head is placed in case 1, with audio head 2 and control head 3.
Both heads are arranged in a direction perpendicular to the running direction of the tape (indicated by arrow X). In this magnetic head, the audio head 2 is used for both recording and reproducing audio. This method has the advantage of synchronizing the control signal necessary for image recording and reproduction with the audio signal, and can simplify the circuit. However, this conventional magnetic head has the following drawbacks in view of the above-mentioned demand for miniaturization of video tape recorders and the current state of technological progress to meet this demand. In other words, in order to record with high density on a high coercive force tape, the audio head must form a magnetic field in the gap with a size and distribution sufficient to accommodate the high coercive force tape, but this requires a large gap. It requires a long gap length (at least twice the gap length of conventional magnetic heads) and a large gap depth. However, audio heads with such large gap lengths and gap depths have poor playback characteristics, and if you place particular emphasis on playback characteristics, it is necessary to make the gap length extremely small. It was not possible to form the gap magnetic field necessary for audio recording, and this ultimately became a major obstacle to miniaturizing video tape recorders.

The purpose of the present invention is to eliminate the drawbacks of the conventional magnetic head described above, and to provide a magnetic head that can perform high-density recording on a high coercive force tape and can also reproduce the high-density recording well. There is.

In this invention, the audio head of the magnetic head is divided into an audio recording head and an audio playback head, and the centers of both heads are on a line parallel to the tape running direction, and the audio recording head is located in front of the playback head in the tape recording direction. By arranging the audio recording heads as shown in FIG. has achieved its purpose.

Embodiments of the present invention will be described below based on the drawings. FIG. 2 is a diagram showing an example of the magnetic head according to the present invention. In the figure, case 1 includes an audio recording head 2A, an audio playback head 2B,
A control head 3 is housed therein, and the audio recording head 2A and control head 3 are connected in the tape running direction (arrow X) in the same way as conventional magnetic heads.
The audio recording head 2A and the audio reproducing head 2B are arranged with their centers separated by a predetermined distance l on a line parallel to the running direction of the tape. In this example, during recording, the audio recording head 2A and the control head 3 are arranged at right angles to the tape running direction, so audio signals, image signals, and control signals can be recorded in the same manner as before. . During reproduction, the audio reproduction head 2B performs reproduction; in this case, the reproduction of the audio precedes the image by a time t expressed by the following equation.

t=l/υ Here, υ is the running speed of the tape.
Therefore, if the reproduced sound is delayed by a time t using a delay circuit or the like, sound that completely matches the image can be obtained. Also, audio recording head 2
In A, it is possible to perform high-density recording on a high coercive force tape by providing a gap with a sufficiently large length and depth, and in the case of an audio playback head, it is possible to perform high-density recording on a high-coercivity tape. By providing a gap with a shallow depth, high-quality reproduced sound can be obtained.

Furthermore, as shown in FIG. 2, the width of the audio recording head 2A is larger than the track width of the audio reproducing head 2B, so it records widely and reads narrowly. Even if the audio playback head is slightly off-center,
There is no risk of playing back noise recorded nearby.

As described above, the present invention has two audio heads, an audio recording head and an audio playback head, for a magnetic head for audio control of a video tape recorder.
By providing two separate units, it is possible to record extremely high-density audio, and at the same time, it is possible to play back that recording with good performance and without picking up noise. It is clear that it will make a contribution.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating a conventional magnetic head for voice control, and FIG. 2 is a diagram illustrating a magnetic head for voice control according to the present invention. 1...Case, 2...Audio head, 2A...Audio recording head, 2B...Audio playback head, 3...
control head.

Claims (1)

[Scope of utility model registration request] In a magnetic head for audio control of a video tape recorder in which an audio head and a control head are housed in one case, an audio recording head and an audio playback head are separately provided as the audio head, and the center of both heads is The audio recording head is located on a line parallel to the tape running direction, and is located in front of the playback head in the tape recording direction, and the width of the audio recording head is larger than the track width of the audio playback head, and the playback circuit is A magnetic head characterized in that the head is equipped with a delay circuit that delays audio for a predetermined period of time.