JPS59204391A - Magnetic reproducing device - Google Patents

Abstract

PURPOSE:To reproduce a sound output signal in variable speed reproduction without varying its frequency by selecting a reproducing output signal with a higher level between main and auxiliary rotary heads. CONSTITUTION:Outputs of sound main rotary heads M1 and M2 and sound auxiliary rotary heads S1 and S2 are amplified by head amplifiers 30-33 and inputted to switches 34 and 35. The switches 34 and 35 select outputs of a main and an auxiliary rotary head which scan on a magnetic head by head switching pulses inputted to an input terminal 39. For example, reproducing output signals of the M1 and M2 obtained at output terminals of switches 34 and 35 are inputted to a switch 36 while a comparison 37 between their levels is made. A comparator 37 operates the switch 36 and a reproducing output signal having a larger level between the M1 and S1 is selected and outputted to an output terminal 38. Consequently, the reproducing output signal having small output level variation is obtained. Further, the reproducing output signal is obtained during variable speed reproduction without varying the frequency of the sound output signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic reproducing apparatus for simultaneously reproducing video and audio, such as a rotating head type azimuth recording type helical scan video tape recorder.

Conventional Structures and Problems There has been an increasing demand in recent years for video tape recorders to have a variable speed playback function for playing back at a tape speed different from that during recording, and various variable speed playback functions for video have been proposed. However, when special reproduction of audio is performed, the conventional method has the disadvantage that it is difficult to understand the content. This will be explained using FIG. FIG. 1 shows video tracks 5 to 11 recorded on a magnetic tape 1. The state of the audio track 2 and the audio head 3 is shown. A conventional method for reproducing audio is to obtain an audio output signal to the audio head 3 by running the magnetic tape 1 in the direction of the arrow 4.

However, in this method, if the running speed of the magnetic tape 1 changes, the frequency of the audio output signal obtained from the audio head 3 changes, so when variable speed playback is performed.

For example, when reproducing a human voice, there is a drawback that the content is difficult to understand.

OBJECTS OF THE INVENTION An object of the present invention is to provide a magnetic reproducing device that can reproduce an audio output signal without changing its frequency during variable speed reproduction.

Structure of the Invention The magnetic reproducing device of the present invention has azimuth angles of V and W, respectively.
and a set of two main rotary heads for video signal reproduction (hereinafter referred to as video main rotary heads) that are 180 degrees apart from each other, and are mounted near the video main rotary heads, and each has an azimuth angle of ■.

A set of two auxiliary rotary heads for video signal reproduction (hereinafter referred to as video auxiliary rotary heads) separated by 1800 mm from each other at W
The video main rotating head and the video auxiliary rotating head are mounted in different positions, and have azimuth angles of M and S, respectively, and are separated by 1800 degrees from each other. (hereinafter referred to as the audio main rotating head)
, an auxiliary rotary head for audio signal reproduction (hereinafter referred to as the "audio auxiliary rotary head") mounted near the audio main rotary head and having azimuth angles M and S, respectively, and 1800 degrees apart from each other; and the video main rotary head. and a first switch means for switching the playback output signal of the video auxiliary rotary head, and a second switch means for switching the playback output signal of the audio main rotary head and the audio auxiliary rotary head, using heads having different azimuth angles. Of the video and audio signals recorded overlappingly on the same track, the video signal is played back by switching the playback output signals of the video main rotary head and the video auxiliary rotary head that have the same azimuth as the head that recorded the video signal. The audio signal is reproduced by switching the playback output signals of the audio main rotary head and the audio auxiliary rotary head having the same azimuth as the head that recorded the audio signal, and the video main rotary head and the video auxiliary rotary head. a second level comparator that compares the reproduction output signal levels of the audio main rotation head and the audio auxiliary rotation head; The output switches the first switch means; the output of the second level comparator switches the second switch means; The main rotating head and the audio auxiliary rotating throat are configured to select and reproduce whichever has a higher level of the reproduction output signal, and the frequency of the audio reproduction output signal does not change even when variable speed reproduction is performed.
In addition, the reproduced output signal does not drop significantly, and variable speed reproduction is possible without producing noise bars on the screen.

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

FIG. 2 shows the video main rotating head v1 attached to the rotating cylinder 20. ■2. Video auxiliary rotating head W1. W2
, audio main rotating head M1. M2, audio auxiliary rotating head S
1 shows the state of S2. video main rotating head v
1 and V2. The video auxiliary rotary heads W1 and W2 are each +6°, for example.

It is a rotating head with azimuth angles of -6°, -6°, and +6°, and the video main rotating heads v1 and ■2 are 18σ with respect to each other.
apart, the video auxiliary rotating heads W1 and W2 are also 180 degrees apart from each other.
They are mounted on the same plane of the rotary cylinder 2o at a distance of 1°, and rotate together with the rotary cylinder 20 in the direction of the arrow 27.

Also, the video main rotating head v1 and the video auxiliary rotating head W1. What are the video main rotating head v2 and the video auxiliary rotating head W2?

They are respectively located apart by a distance corresponding to, for example, one horizontal opening signal period.

Audio main rotating head M1. M2. Audio auxiliary rotating head 31
．． 32 is, for example, +45°, -45°, -45°.

It is a rotating head with an azimuth angle of +45°.

Their positional relationship is the video main rotating head V1 mentioned above.
．． V2, video auxiliary rotary head W1. This is the same positional relationship as W2. In this case, the audio main rotating heads M1, M
2 and video main rotating head V1. V2゜Voice auxiliary rotating head S1. S2 corresponds to the video auxiliary rotary heads W1 and W2. Further, the audio main rotary head M1 and the video main rotary head v1 are located, for example, 9o0 apart.

Video main rotating head V1. V2 and video auxiliary rotary head W1. W2 is the audio main rotary head M1°M2 and the audio auxiliary rotary head S1. The mounting height is determined so that it scans on the same track as S2.

On the other hand, the magnetic tape 23 is guided by guide posts 21 and 22, wound around the rotary cylinder 20 in a 1800 Ω shape or more, and is run in the direction of an arrow 26 by a capstan 24 and a pinch roller 25.

FIG. 3(,) shows the track pattern of the magnetic tape 23. As shown in FIG. 50 to 57 indicate tracks in which video signals and audio signals are recorded in an overlapping manner.For example, even-numbered tracks are tracks in which video signals are recorded in an overlapping manner with an azimuth of +6° for all video signals and +45° for audio signals, and odd-numbered tracks are for video signals. The tracks are recorded in an overlapping manner at an azimuth of -6° and an azimuth of -45° for the audio signal. Further, 58 represents the playback track locus during 5x speed playback.

For example, assume that the heads scanning the reproduction head locus 58 are the audio main rotary head M1 and the audio auxiliary rotary head S1. During playback, the output appears on the head with the same azimuth as during recording, so the audio main rotary head M1 with an azimuth of +46° receives the audio signals of even tracks, and -
The audio auxiliary rotary head with an azimuth of 45° reproduces audio signals of odd-numbered tracks, but does not reproduce video signals. In FIG. 3(a), the hatched portion is reproduced by the audio main rotary head M1, and the cross-hatched portion is reproduced by the audio auxiliary rotary head S2.

The rewritten reproduction signals at this time are shown in Figure 3(b) and (
C), which represent the reproduction output signals of the audio main rotary head M1 and the audio auxiliary rotary head S1, respectively. FIG. 3(b), (In step C, there is a point where the level of the reproduced output signal becomes zero. This is changed to the higher level of the reproduced output signal of the audio main rotary head M1 and the audio auxiliary rotary head S1 using a switch means. By switching, a reproduced output signal as shown in FIG. 3(d) can be obtained.This switching method will be explained with reference to FIG.

FIG. 4 shows a block diagram of a switch circuit portion in an embodiment of the present invention. In the figure, the outputs of the audio main rotary heads M1, M2 and the audio auxiliary rotary heads S1, 32 are amplified by head amplifiers 3.about.33, respectively, and input to switches 34 and 35. The switches 34 and 35 switch the magnetic tape 23 in response to a head switching pulse indicating the rotational phase of the rotary cylinder 20 inputted to the input terminal 39.
Select the output of the audio main rotary head and the audio auxiliary rotary head that are scanning above. obtained at the output terminals of switches 34 and 35. For example, the reproduced output signals of the audio main rotary head M1 and the audio auxiliary rotary head S1 are input to the switch 36, while the levels are compared by the level comparator 37. The level comparator 37 switches the switch 36, and the one having the higher reproduction output signal level of the audio main rotary head M1 and the audio auxiliary rotary head S1 is selected and output to the output terminal 3B. As a result, a reproduced output signal with relatively little variation in output level as shown in FIG. 3(d) can be obtained.

Moreover, even if the tape speed changes, the relative speed between the rotary head and the tape hardly changes, so it is possible to obtain a reproduced output signal whose frequency does not change with changes in tape speed.

Effects of the Invention As is clear from the above description, two aspects of the present invention can be applied to video signals and audio signals recorded on the same track.

The audio signal is transmitted by two sources: the audio main rotating head and the audio auxiliary rotating head.
By reproducing the video signal using two sets of heads: a video main rotating head and a video auxiliary rotating head, there is no change in frequency even during variable speed playback, and the level remains unchanged. It is possible to obtain a sound-output signal that does not cause extreme deterioration and to obtain a playback screen in which no noise bars appear. Moreover, the video and audio signals only need to be recorded overlappingly using heads with different azimuth angles.

It can be realized with a simple configuration since it does not require a complete circuit for electrically multiplexing and separating signals.

Note that the above explanation has been made regarding the audio signal.

As for the video signal, the video main rotating head V1. By selecting and reproducing the larger reproduction output signal of V2 and the video auxiliary rotary heads W1 and W2, a reproduction screen without noise bars can be obtained during variable speed reproduction.

Also, the above explanation took 5x speed playback as an example, but
If playback is performed at other speeds, (b) and (
Only the period at which the reproduced output signal becomes zero shown in C) changes, and two similar effects can be achieved. Furthermore, for the same reason, the same operation can be performed when the tape is fed intermittently.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a track pattern of a conventional magnetic tape, FIG. 2 is a schematic diagram showing the configuration of a rotary head mounting 9 of an embodiment of the present invention, and FIG. 3(a) is a schematic diagram showing the track pattern on the magnetic tape and the reproducing head locus in Embodiment 1 of the present invention, and FIG. 3(b)
), (C) l (d) is a waveform diagram of an audio output signal in an embodiment of the present invention, and FIG. 4 is a circuit block diagram of a switch means in an embodiment of the present invention. vl, v2... Video main rotating head, Wl,
W2... Video auxiliary rotating head, Ml, M2
...Audio main rotating head, Sl, S2...
・Voice assisted rotating bellybutton)", 34.35.36...
・Switch, 37・Old level comparator. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2? 4 Figure 3 2/

Claims (1)

[Claims] A set of two first main rotary heads for video signal reproduction, which have azimuth angles v and W, respectively, and are installed in the vicinity of the first main rotary head and are separated by 1800 degrees from each other, and have azimuth angles v and W, respectively. A set of two first auxiliary rotary heads for video signal reproduction, which are separated by 180 degrees from each other, and the first main rotary head and the first auxiliary rotary head are mounted at different positions and have different azimuth angles. M and S each have 1
a set of two second main rotary heads for audio signal reproduction separated by 800 mm, and installed near the second main rotary head,
and a set of two second auxiliary rotary heads for audio signal reproduction with azimuth angles M and S, respectively, and 180° apart from each other;
a first switch means for switching reproduction output signals of the first main rotary head and the first auxiliary rotary head; and a second switch means for switching reproduction output signals of the second main rotary head and the second auxiliary rotary head. and a second rubel comparator for comparing reproduction output signal levels of the first main rotation head and the first auxiliary rotation head, and a comparison of reproduction output signal levels of the second main rotation head and the second auxiliary rotation head. A second level comparator is provided, the output of the first level comparator switches all of the first switch means, the output of the second level comparator switches the second switch means, and the output of the second level comparator switches the second switch means. The reproduction output signal of the first auxiliary rotary head and the second main rotary head and the second auxiliary rotary head are selected for reproduction. Features a magnetic reproducing device.