JPH053652B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a video tape recorder, and more particularly to a video tape recorder that employs an FM modulation recording method for audio signals using a rotating head similar to a video head.

[Technical Background of the Invention] Recent video tape recorders (hereinafter referred to as VTRs) have become more sophisticated and multifunctional, and together with the improved performance of videotapes, they have become capable of recording and playing back extremely clear and beautiful color images. Summer. However, since audio signals are recorded using a high-frequency bias recording method using a fixed head similar to audio tape recorders, recording frequency characteristics that depend on the tape running speed and There was a deep desire to improve the sound quality, as wow, flat, and other sounds were becoming increasingly deteriorating.

Recently, an FM modulation recording method for audio signals has been developed that uses a high-speed rotating head unique to video.
High-fidelity video that uses an audio recording method has been commercialized.

[Problems with the Background Art] However, in the conventional FM audio recording described above, an audio band is provided by dividing the frequency band within the video track, and an FM-modulated audio signal is inserted into this audio band and supplied to the video head. Another method is to provide a rotary head exclusively for audio and record the audio and video signals by overwriting them separately, so the audio or video signals can be recorded on the tape once the video or audio signals have been recorded. After writing, I was unable to perform any after-recording operations.

[Object of the Invention] The present invention has been made in view of the above-mentioned points, and it is possible to perform after-recording of only the audio signal (FM modulated audio signal) on a tape on which the FM audio signal of the video signal is recorded. To provide a video tape recorder capable of simultaneously reproducing audio and video signals with a conventional video head.

[Summary of the Invention] The present invention provides a video track having a width narrower than the width of a video track;
A pair of audio recording heads, each having a different gap azimuth angle corresponding to that of the main head, are mounted on a rotating disk at positions facing each other by 180 degrees and separated from the pair of main heads by an arbitrary rotation angle. This makes it possible for the audio recording head to overlay and record an FM audio signal on a portion of a video track on which a video signal has been recorded by the main head, for example.

[Embodiments of the Invention] The present invention will be described in detail below with reference to illustrated embodiments. Here, FIG. 1 is a plan view showing an example of the mounting position of the head of the video tape recorder according to the embodiment, FIG. 2 is an explanatory diagram for explaining the mounting height of each head, and FIG. FIG. 4 is a characteristic diagram showing frequency characteristics, and is a plan view showing a video track drawn according to the present invention.

First, in FIG. 1, reference numeral 1 indicates a drum on which a rotary head is attached, and a pair of main heads 2 _A and 2 _B having mutually different gap azimuth angles are attached at positions facing each other at 180 degrees on the outer periphery of the drum 1. The direction of rotation of this head mounting drum 1 is, for example, arrow D in the figure.
It is set in the direction. and the main head 2
_A , 2 At a forward position 90° away from _B in the direction D,
An audio recording head _3A having the same gap azimuth angle as the main head _2A , and an audio recording head _3B having the same gap azimuth angle as the main head _2B are attached. However, the angle in which the pair of audio recording heads _3A , _3B separate from the corresponding main heads _2A , _2B in the rotational direction can be set arbitrarily, and is not limited to the forward direction, but also the backward direction. It can be attached to any position.

Furthermore, as shown in Fig. 2, the mounting height positions of the main heads _2A and _2B are different from those of the audio recording heads _3A and _3B .
It is installed at a position slightly lower than the height position of the This height difference determines the video track pitch.
T _P is set as T _P ×χ/180, where χ is the mounting angle of the audio recording head with respect to the main head.

In other words, if the heights of the audio recording heads 3 _A , 3 _B and the main heads 2 _A , 2 _B are made the same, the track positions of the audio recording heads 3 _A , 3 _B will be the same as those of the main heads 2 A, 2 _B.
Since it is located below the track position of _2B by the amount expressed by the previous formula, a height difference is provided to make each track position coincide. However, if the audio recording heads 3 _A and 3 _B are installed behind the main heads 2 _A and 2 _B , the audio heads 3 _A and 3 _B should be lower than the main heads 2 _A and 2 _B (the above The height relationship holds true when the running direction of the tape mounted on the rotating head drum at an angle is in the direction of the downward slope; in the opposite case, the height relationship is also reversed.) The VTR according to the embodiment is configured as described above. Next, the operation of the above configuration will be explained. First of all,
An example of the signal spectrum of a VTR on which an audio FM signal is superimposed is from 3.6 [MHz] to 3.6 [MHz], as shown in Figure 3a.
In the spectral gap between the FM luminance signal Y of 4.8 [MHz] and the chroma signal C having a carrier wave of 0.688 [MHz], the FM audio signal on the A channel side with center frequencies of 1.38 [MHz] and 1.68 [MHz] and ,
It is a frequency multiplexed signal in which an audio signal Au consisting of B channel side FM audio signals having center frequencies of 1.53 [MHz] and 1.83 [MHz] is interpolated. In operation, first a video signal is supplied to the main heads _2A and _2B . As a result, each main head _2A ,
Video signals are recorded on the A channel and B channel tracks corresponding to _2B . The spectrum of this video signal is shown in Figure 3b.

In the present invention, the tape on which only the video signal has been recorded as described above is further subjected to audio recording. That is, for example, while viewing the video recorded during video recording, audio may be inserted into the video via the audio recording heads 3 _A and 3 _B using line input or microphone input means, or while listening to audio information. It is possible to add video information or to insert an audio source completely unrelated to the video, such as an FM broadcast signal. The spectrum of this audio signal (FM signal) is shown in Figure 3c. In this way, when a video signal and an audio signal are recorded separately, the spectrum of the recorded signal ultimately becomes
It will look like figure a. A track recorded in this manner is shown in FIG.

In FIG. 4, A and B indicate the video tracks recorded by the main head _2A and the audio recording head _3A , and the main head _2B and the audio recording head _3B, respectively, and approximately midway along each track. Audio tracks 4 _A and 4 _B are formed by audio recording heads 3 _A and 3 _B in this section. In other words, the audio tracks 4 _A and 4 _B are overwritten on the previously recorded video signal.

When a tape on which tracks are formed as shown in FIG. 4 is played back (played by the main heads 2 _A and 2 _B ), the playback signal becomes a multiplexed signal with a spectral structure as shown in FIG. 3 a. conventional FM
The signals of audio tracks _4A and _4B can be played back simultaneously with the video signal using the same configuration as the playback circuit of a VTR that uses the audio recording method (the gap azimuth angle of the audio recording heads _3A and _3B is The same azimuth angle as heads 2 _A and 2 _B ).

In the above description of this embodiment, the audio FM signal is later recorded over the tape on which only the video signal is recorded, but while the video signal is being recorded in the main heads _2A and _2B , the video signal is simultaneously recorded in the rear. The audio signal (FM modulated audio signal) may be recorded in an overlapping manner using the audio recording head provided.

Furthermore, according to the configuration of this embodiment, by performing highly accurate tracking, it is also possible to replace only the audio track on the recorded tape by overwriting it (after-recording).

In addition, as another embodiment, the present invention may be applied to combinations of heads that do not correspond to each other, that is, the azimuths of the main head 2 _A and the audio recording head 3 _B , and the azimuths of the main head 2 _B and the audio recording head 3 _A are made the same. You can perform an after-recording operation, which is the effect of Further, the present invention can also be applied to a VTR using a perpendicular magnetic recording system.

[Effects of the Invention] As explained above, according to the present invention, an audio recording head whose width is narrower than the width of a video track can transfer an audio signal to a part of a video track where a video signal is recorded. Since recording is done in the form of overwriting, it is possible to perform after-recording between the audio signal and the video signal.
This has the advantage that it is possible to reproduce FM audio signals and video signals using a circuit similar to the reproduction circuit of the conventional FM audio recording system.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of the head arrangement of the video tape recorder according to the present invention, FIG. 2 is an explanatory diagram for explaining the installation height position of the head according to the present invention, and FIG. FIG. 4 is a characteristic diagram showing the frequency characteristics of the reproduced signal, and is a diagram showing a track pattern drawn by the present invention. 2 _A , 2 _B ...Main head, 3 _A , 3 _B ... Audio recording head, 4 _A , 4 _B ... Audio track.

Claims (1)

[Claims] 1 Recording an audio signal in the form of overwriting on a part of the video track whose width is narrower than the width of the video track, whose gap azimuth angles differ depending on the gap azimuth angle of the main head, and where the video signal is recorded. A pair of audio recording heads,
A video tape recorder mounted on a rotary disk at 180° opposing positions and separated from the pair of main heads by an arbitrary rotation angle.