JPS6360681A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To eliminate a large quantity of memories and to attain voice reproduction executing an intermittent time base inversion processing by rotating a head faster than a tape in the same direction as that of tape running. CONSTITUTION:Rotary heads 2 and 3 are fitted to a rotating drum 1 at the intervals of 180 deg., and the tape 4 is wound on the periphery of the drum for 180 deg.. A motor 7 rotates the drum 1 so that it rotates heads 2 and 3. An electronic switch control signal 9 is generated at every 180 deg. of the output from a generator 8, and an electronic switch 5 is driven so as to switch the signals of the heads 2 and 3. With synchronizing with the control signal 9, a generator 10 generates a gain control signal, and a gain control circuit 6 controls the output from the switch 5 and controls visually and accoustically the discontinuous part of the signal. Reversed running tape is reproduced with the heads rotating the signal of the voice track in the same direction as tape running at speed twice as fast as that of tape running when the time base of a video signal is set in the reversed direction to a normal reproducing mode.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing apparatus having a mode of reproducing the tape by running it in the opposite direction.

[Summary of the Invention] A magnetic recording and reproducing device that enables reverse time axis reproduction of video signals, comprising a rotating drum around which a tape is wound at a predetermined angle, a rotating head attached to the drum and capable of reproducing audio signals; By providing a drive circuit that rotates the head faster than the tape in the same direction as the tape running direction, audio can be reproduced with a simple configuration.

[Prior Art] As a function of a video tape recorder (VTR), there is a mode in which the tape is played back in the opposite direction.

At this time, the time axis of the video signal is reversed and an erect image (same as standard reproduction) is obtained as one screen, so that the effect of time axis reversal can be obtained.

On the other hand, when the time axis is reversed, the content of the audio signal changes from music to
The words become meaningless.

Therefore, a method has been proposed in which all audio signals during reverse reproduction on a VTR are intermittently reproduced in the forward direction on the time axis.

Figure 2 shows the relationship between time t and tape playback position when the tape is running in the opposite direction in this proposed method.The broken line is the position on the tape for audio playback when nothing is being done, and the solid line is , this is an example in which an audio signal is stored in a memory and played back every T seconds. In the playback shown by the solid line, the audio signal becomes normal from the beginning to the end of the tape over time.

[Problems to be Solved by the Invention] Such a proposed method requires a plurality of memories for storing one second of data in FIG. 2 for intermittent time axis reversal operations.

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetic recording and reproducing apparatus capable of reproducing audio by performing intermittent time axis reversal processing without using a special memory.

[Means for solving problems] One aspect of the present invention is to achieve such objects.

and a rotating drum around which the tape is wrapped at a predetermined angle.

A rotating head that is attached to this drum and can reproduce audio signals, and a rotary head that runs in the same direction as the tape running direction.
It is characterized by the provision of a head drive means that rotates the tape faster than the running speed of the tape.

[Function] In the present invention, by providing a driving means for rotating the rotating head in the same direction as the tape running direction and faster than the tape running speed, it is possible to perform intermittent time axis reversal without requiring a large capacity memory. It becomes possible to play back the audio that causes the processing to take place.

[Example code] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 shows an example of a rotary head having a tape winding angle of 180 degrees, and two rotary heads 2 and 3 are provided on a rotary drum 1 having a radius of r, separated by 180 degrees.

Further, when the tape 4 is wound 180 degrees and the speed of the tape 4 when playing in reverse is in the direction of the arrow vaIl/S, the rotation of the drum 1 is 2van/s.
The relationship between the tape running and the signals on the tape reproduced by the rotary head is as shown by the solid line in FIG.

For example, in Figure 3, the pattern on the tape is t in the forward direction.
7. tel t, in reverse playback, fixed head 2
, 3, the time axis is reversed as t, , tilt t. As shown in Fig. 2, the head 2 rotating in the same direction as the tape running at twice the speed of the tape running is ttt tel.
t, and reproduce the signal. In Figure 3, ttt tut
t is the amount of 90° winding, but head 2 has 180° winding.
'Play this signal with rotation.

Here, 180° winding takes the running time of the tape in minutes T
When it comes to engineering.

T□=□. During this time, the rotating head reproduces at a speed of 2v/S, resulting in an intermittent signal of T1/2.

FIG. 4 shows the distribution of the reverse rotation reproduction signal. In the figure, (
a) is the readout signal from the playback head with respect to time t; in head 2, during period T4/2, titl, 1. , then switch to head 3 and press t4t tel t
, and then head 2 plays back fltf, ,f. During the period T1/2, audio is played back in the normal direction. (b) is a gain control signal that suppresses clicks that may occur at discontinuous portions that occur every T1/2. Then, 5ms or more is desirable.

FIG. 1 shows a circuit configuration of an embodiment of a magnetic recording/reproducing apparatus according to the present invention, and 5 is an electronic switch.

6 is a gain control circuit, 7 is a drum rotation motor, 8 is a drum rotation signal generator, 9 is an electronic switch control signal, and 10 is a gain control signal generator.

In the figure, as mentioned above, the rotating heads 2 and 3 are attached to the rotating drum 1 with an interval of 180 degrees, and
A tape 4 is wound around the circumferential surface of the rotating drum 1 over a length of 180''.

Further, the drum 1 is rotated by a drum rotation motor 7, thereby rotating the heads 2 and 3.

An electronic switch control signal 9 is generated every 180 degrees of the output of the drum rotation signal generator 8, and the electronic switch 5 is driven to switch the signals of the heads 2 and 3.

In synchronization with this control signal 9, a generator 10 generates a gain control signal as shown in FIG. auditory and perceptual suppression.

FIG. 5 shows a case where the tape is wound so that the corner is close to 360', and the reproduced signal in this case is shown in FIG. 6(a), and the gain control signal is shown in FIG. 6(b).

It is physically impossible for the winding to have a corner of 360', so the angle is 360'''-0. In FIG.
...ttz is played back and the position P is reached.

However, the tape running speed is assumed to be van/s, and the rotational speed of the head 2 is assumed to be 2VCITl/s. The tape running time T2 for one rotation of the drum is T2=□■. Therefore, the time for one rotation of the drum, that is, the head, is T2/2. As is clear from FIG. 6, there is no signal reproduction during the rotation time of 0, and the rise and fall of the control signal in FIG. 6(b) also avoid the time θ.

If the radii of the drums in Figure 3 and Figure 5 are the same, T2 valve 2
T.

Therefore, with 3600 windings, if the drum has the same radius, the intermittent playback time can be made longer, and if the intermittent playback time is made equal, the radius of the drum can be made smaller. However, as shown in FIG.

Regeneration between the start and end of winding (the rotation angle θ) is no longer possible.

In this way, in reverse tape playback, when the time axis of the video signal is in the opposite direction to the normal playback mode, the audio track signal is moved in the same direction as the tape running at 2 times the tape running speed.
By playing with a rotating head that rotates at twice the speed,
During this time, the audio signal in the forward direction is reproduced, and by switching the head, the audio signal in the forward direction can be reproduced for a short time regardless of whether the tape is running in the reverse direction. In order to eliminate clicks caused by switching the reproduction signal, the gain of the reproduction audio signal at the time of signal switching is controlled so that the rise and fall τ are 5 ms or more.

[Effects of the Invention] As described above, according to the present invention, it is possible to perform intermittent forward playback of an audio signal when the tape is running in reverse, without providing a special memory circuit.

[Brief explanation of drawings]

FIG. 1 is a circuit configuration diagram of an embodiment of the magnetic recording/reproducing apparatus according to the present invention, FIG. 2 is a diagram showing the relationship between the time when the tape runs backwards and the tape reproducing position, and FIGS. 3 and 5 are respectively The tape winding is a diagram showing an example of a rotating head with an angle of 180° and 360°, and Figures 4 and 6 are similar to Figures 3 and 5, respectively.
It is a figure which shows the distribution of the reverse rotation reproduction signal in a figure. 1... Rotating drum, 2.3... Rotating head, 4... Tape. 7...Drum rotation motor. Patent applicant: Clarion Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 1 →

Claims (1)

[Claims] In a magnetic recording and reproducing device that enables reproducing video signals in reverse time axis when reproducing the tape with the tape traveling in the opposite direction,
a rotating drum around which the tape is wound at a predetermined angle; a rotating head that is attached to the rotating drum and capable of reproducing audio signals; What is claimed is: 1. A magnetic recording and reproducing device comprising a rotating head drive means.