JPS6126904A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To improve the quality of sound signals by using an exclusive having a different azimuth from those of a pair of heads which record video signals to record the code modulated sound signals to a guard band and using different heads to reproduce the video and sound signals respectively. CONSTITUTION:The video signals are applied to a terminal 17 and amplified by a recording amplifier 27 via a video signal processing circuit 26 set at the recording side. These amplified video signals are recorded to a magnetic tape through rotary heads 4 and 5. While the sound signals applied to a terminal 28 are amplified by a recording amplifier 30 via a signal processing circuit 29 at the recording side and recorded to the magnetic tape through rotary heads 6 and 7. Heads 4 and 5 are set at adverse azimuth 180 deg. to each other, and heads 6 and 7 have different azimuths from those of heads 4 and 5. Then heads 6 and 7 performs the PCM recording to a guard band between video signal tracks. In a reproduction mode the video signals are reproduced by heads 4 and 5; while the sound signals are reproduced by heads 6 and 7 respectively. This can improve the quality of the sound signals for recording and reproducing.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention is directed to a rotating head type video device that enables recording and reproduction of an audio signal by rotation and code modulation (hereinafter referred to as PGM) in addition to a video signal. The present invention relates to magnetic recording and reproducing devices such as tape recorders (hereinafter referred to as VTRs).

Structure of the Conventional Example and its Problems In the conventional VTR, the video signal was sent to a rotating head, and the audio signal was sent to a fixed head, and each was recorded on a dedicated track on a magnetic tape. However, as the length of time for VTRs increases, the tape running speed has become slower, and in this case, the frequency characteristics and frequency characteristics of the audio signal deteriorate, resulting in the problem that high-quality reproduced sound cannot be obtained. In order to obtain high-quality reproduced sound even at low tape speeds, there is a method of modulating and recording an audio signal on the video track of a VTR. This is a method in which the audio signal is frequency-modulated and recorded in the band between the frequency-modulated luminance signal and the carrier color signal that is low-frequency converted. There is a method in which the signal is recorded using a rotating head dedicated to audio. Since the audio signal is recorded in FM mode, it is not only possible to remove large gaps and have good quality, but also has the advantage that the sound quality does not deteriorate even if the tape running speed is reduced, making it suitable for long-term VTR audio recording. This is one powerful method.

However, in recent years, there have been many opportunities to come into contact with high-quality audio sources such as compact discs and audio PCM broadcasts via broadcasting satellites, and there has been a growing consensus that the above-mentioned VTR audio recording system is not fully satisfactory. The main points are that head switching noise occurs, the distortion rate is high, and after-recording is impossible.

PCM recording of audio is a good way to eliminate these problems, but current consumer VTRs do not have the recording density to record PCM wideband audio signals added to video signals. .

There is a recently developed example of a PGM audio recording system for VTRs. This uses a broadcast VTR with one rotating head, and as shown in Figure 1, a PCM audio signal track 3 is placed in a guard band (non-recording space) 2 between video tracks 1.
This is a method of recording and reproducing using a separate head. With this method, wideband PCM audio signals can be sufficiently recorded and reproduced, and high-quality reproduced sound can be obtained.

However, it is difficult to apply the above-described method as is to a consumer VTR that employs the azimuth recording method. This is because, while the above-mentioned broadcasting VTR has a sufficiently large guard band width, a consumer VTR basically does not have a guard band as shown in FIG. Recent consumer VTRs have been designed to last longer and can now be switched between standard mode (2 hours for VH8 VTRs) and long-time mode (6 hours), and the rotary head is used in both modes. In the standard mode, a guard band exists as shown in an enlarged view in FIG. This guard band is narrow, less than 30 μm, so if you try to record PCM and audio signals on this guard band, the video signal and PCM audio signal will be distorted due to tracking errors due to head width variations, mounting position variations, etc. They interfered with each other, making it impossible to reproduce high-quality video and audio. Furthermore, in broadcast VTRs, the video tracks on both sides of the guard band have the same azimuth angle d;
In a consumer VTR, for example, the azimuth angle is reversed, and it is not easy to set the azimuth angle of the PCM audio signal recording head.

OBJECT OF THE INVENTION The purpose of the present invention is to solve the above-mentioned problems, and to improve the quality of the audio signal by enabling PCM recording and playback of the audio signal in a narrow guard band in an azimuth recording type consumer VTR. It is an object of the present invention to provide a magnetic recording and reproducing device that can be significantly improved.

Structure of the Invention The magnetic recording and reproducing apparatus of the present invention is a rotary head type video tape recorder in which the tape speed and head width are set so that a guard band exists between video signal tracks by a pair of rotary heads having opposite azimuths. A code-modulated audio signal is recorded on the guard band using a dedicated head with a different azimuth angle than the head that records the video signal.
The video signal and the audio signal are respectively reproduced by separate heads, and thereby the quality of the reproduced audio signal can be significantly improved.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 3 is a diagram showing a video signal track pattern of a VTR which is currently popular for consumer use, with a indicating a standard mode and b indicating a long time mode. For example, in the VH8 system, one track pitch in the standard mode is 58 μm, and in the long time mode it is 19.3 μm, which is one third of that. Normally, video signals in standard mode and long-time mode are often recorded using the same head, and in that case, for example, the video head width is about 30 μm.
selected.

Therefore, in the standard mode, approximately 28
There is a guard band 12.14 on the order of μm. However, in the case of the long-time mode, the video head width becomes larger than the track pitch, so a guard band cannot be formed.

The present invention enables POM recording of audio only in the standard mode in which a guard band is available, and the audio recording in the long-term mode is performed by conventional FM audio recording using a fixed head method or a rotating head.

Now, in order to perform audio PGM recording on the guard bands 12 and 14 of FIG. 3, another dedicated head is used, and the head position is determined so that its scanning locus is on the guard band. FIG. 4 shows an example of head arrangement.

A is a diagram showing the arrangement of heads on the rotating cylinder 8, and the image heads 4 and 6 are in opposite azimuths and are located at 1 sd' from each other.

Audio PGM recording is performed using dedicated heads 6 and 7.
The heads 6 and 7 are arranged so as to form an angle θ with the imaging heads 4 and 7, and are also arranged with a height shifted by h from the reference plane as shown in b. By appropriately setting the angle θ and the step height shown in FIG. 4, the scanning loci of the dedicated heads 6 and 7 can be aligned with the guard band shown in FIG.

Now, the wider the track width of the dedicated head for audio PGM recording, the higher the S/N can be, but if it straddles the video tracks on both sides, the signal on the video track may be erased (during recording) or picked up ( during playback) and cause mutual interference. In order to suppress this interference, it is effective to set the azimuth angle of the dedicated head to a different azimuth angle from the azimuth angle of the video heads on both sides to reduce the interference caused by crosstalk between the audio PGM (audio PGM) rack and the video track. be. In the example shown in Figure 3 B, video track L11 +6°,
Since the video track R13 has an azimuth angle of 16°, the azimuth angle of the dedicated head is set to a larger azimuth angle than the azimuth angle of the video track, such as 3d or 4ts°, so that the azimuth angle is different from both adjacent tracks.

Also, in order to make the azimuth loss as large as possible, the audio P
It is desirable to record the CM signal in a relatively high frequency band (because short wavelengths have a large azimuth loss).

FIG. 5 is a diagram for explaining another embodiment of the present invention,
The positional relationship between the standard mode track pattern and the dedicated head for recording audio PCM in its guard band is shown. - For a, set the track width of the dedicated head 9 to be a little narrower than the width of the guard band 120, and set the mounting angle θ and the step of the dedicated head 9 so that it is close to the video track R13 side and away from the video track L11 side. . And dedicated head 9
The azimuth angle of is the azimuth angle of video track R13 (-6
The azimuth angle (10 α°) is opposite to the angle (10 α°). With this configuration, even if the head width or head height deviates somewhat from the set value, the crosstalk between the video track R and the audio PCM track is small and mutual interference does not occur. In other words, when the head 9 shifts downward in the figure, the azimuth angle between the video track R and R is opposite, so the azimuth loss becomes very large, and when it shifts upward, the guard band remains, so the azimuth loss becomes very large. There will be no crossover. In this example, since the azimuth angle of the dedicated head 9 may be small, there is an advantage that the head is easy to manufacture.

In example b, the track width of the dedicated head 10 is made narrower than the guard band 12, and the mounting angle θ and step are set so that the center line of the dedicated head is approximately at the center of the guard band so as not to intersect the video tracks on both sides. do. in this case,
(Audio PGM) A slight guard band remains between the rack and the video track, making it resistant to track misalignment due to head width or head installation dimensional errors. Further, the azimuth angle of the dedicated head does not need to be so greatly different from the video tracks on both sides (for example, it is possible to set the azimuth angle to σ, and in that case, manufacturing of the head becomes extremely easy).

FIG. 6 is a block diagram of essential parts of an embodiment of the present invention. In the figure, a video signal is applied to a terminal 17, passed through a recording side video signal processing circuit 26, amplified by a recording amplifier 27, and recorded on a magnetic tape through rotary heads 4 and 5. The recording-side video processing circuit 26 frequency-modulates the luminance signal, performs low frequency conversion on the carrier color signal, and frequency-multiplexes the signal. Next, the audio signal given to the terminal 28 is transmitted to the recording side audio signal processing circuit 2.
9 and is amplified by the recording amplifier 30, and the rotary head 6°7
recorded on magnetic tape. The recording side audio signal processing circuit 29 performs code modulation (PGM) on the audio signal, converts the code into a format that is easy to record, and applies, for example, a frequency modulation signal.

Next, the time of reproduction will be explained. The azimuth angle of the video signal and digitized audio signal recorded on magnetic tape was changed.

Playback using each dedicated head.

The video signal is reproduced by rotary heads 4 and 5, and amplifier 1
After being amplified at step 8, the signal is input to a reproduction side video signal processing circuit 20, demodulated into a 1-element video signal, and outputted to a terminal 21. The audio signal is reproduced by rotary heads 6 and 7 and is passed through amplifier 22
After being amplified, the signal is input to the reproduction side audio signal processing circuit 24, decoded to the original audio signal, and outputted to the terminal 25.

Effects of the Invention As detailed above, the present invention provides a rotary head type VTR in which a guard band exists between tracks having different azimuth angles on which video signals are recorded. The code-modulated audio signal is recorded using different dedicated heads, and the video signal and audio signal are played back using separate heads, allowing PCM recording and playback of the audio signal with almost no interference to the video signal. possible. Therefore, compared to the reproduced audio signal in a conventional VTR, the frequency characteristics are 1.

It is possible to reproduce high-quality audio signals with significantly improved performance such as distortion rate and wow and flutter.

Furthermore, when performing PCM on an audio signal, it is easy to distribute digital data so that data is not placed near the time of head switching, and thereby it is possible to prevent noise from occurring at the time of head switching. Furthermore, by passing a recording current only through the dedicated head, it is possible to perform after-recording, which was impossible with conventional FM audio recording, making it possible to realize a VTR with extremely excellent sound quality and full after-recording function.

[Brief explanation of the drawing]

FIG. 1 shows a track pattern in a broadcasting VTR, FIG. 2 shows a track pattern in a conventional consumer azimuth recording VTR, and FIG. 3a. b is an enlarged view of the track pattern of the azimuth recording type in different modes, FIG. FIG. 6, which is a diagram showing the positional relationship, is a configuration diagram of the main parts of the above embodiment. 11.13...mark/video track, 12.14...
・・Guard band, 15.16・・River video truck,
4゜6...Rotary head for video signal, 6,7...
... Rotating head exclusively for audio PGM, 8... Rotating cylinder, 9°1o... Rotating head exclusively for audio PCM, 29... Audio processing circuit, 24...・
...Audio processing circuit. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure @ Figure 2■ Deuwo Tora Sofu (Ni) Figure 4 (Otoshi) of White (3) (b) Figure 5 Stone Figure

Claims (4)

[Claims] (1) The video signal is recorded on the guard band of a rotary head video tape recorder in which the tape speed and head width are set so that a guard band exists between the video signal tracks by a pair of rotary heads having opposite azimuths. A magnetic recording and reproducing apparatus characterized in that a code-modulated audio signal is recorded by a dedicated head having a different azimuth angle from a pair of heads, and the video signal and the audio signal are reproduced by separate heads, respectively. . (2) When recording an audio signal code-modulated by a dedicated head on a guard band between video tracks recorded by a pair of rotary heads having opposite azimuths, the azimuth angle between the track by the dedicated head and the video track is Claim 1, characterized in that the positions and azimuth angles of the respective heads are set so that when the heads are in opposite directions, they are brought close to each other, and when the azimuth angles are in the same direction, they are separated. magnetic recording and reproducing device. (3) When recording an audio signal code-modulated by a dedicated head in a guard band between video tracks recorded by a pair of rotating heads having mutually opposite azimuths, the azimuth angle of the dedicated head is used to record the video signal. Claim 1, characterized in that the heads are set at equal angles to each other, and the positions of the heads are set so that the track by the dedicated head is approximately at the center of the guard band. The magnetic recording/reproducing device according to item 1. (4) In a rotary head type VTR having a standard recording mode and a long-time recording mode, a track capable of recording a code-modulated audio signal is provided between tracks on which a video signal is recorded only for the standard recording mode, and a track capable of recording a code-modulated audio signal is provided. 2. The magnetic recording and reproducing apparatus according to claim 1, wherein the magnetic recording and reproducing apparatus is configured to record the recorded audio signal using a dedicated head different from the head for recording the video signal.