JPS6231868B2 - - Google Patents

Description

[Detailed description of the invention] In a so-called helical scan type VTR, a magnetic tape is transported at a speed different from normal,
There are devices that provide special effects such as slow playback, double speed playback, and still playback.

In such a device, in addition to a first group of magnetic heads for performing normal recording and reproduction on a rotating head drum, a second group of magnetic heads is provided, the mounting portion of which is provided with an electromechanical transducer, such as a bimorph plate. , when the magnetic tape is being transported at a speed different from normal, the second magnetic head group is displaced in the width direction of the track to perform tracking correction;
I am trying to play special effects.

That is, FIG. 1 is a plan view of the rotary head drum 10, and in the figure, magnetic heads 1a and 1b for normal recording and reproduction are provided at positions 180 degrees apart from each other, and magnetic heads 2a and 1b for special effect reproduction are provided. 2b are provided at positions trailing the heads 1a and 1b at a predetermined angle in the direction of rotation (arrow A), respectively. And this rotating head drum 10
The magnetic tape 20 is wound over an angular range of approximately 180 degrees around the circumferential surface.

FIG. 2 is a side view of a head attached to a bimorph plate, with the head 2 attached to one end of the bimorph plate 3, and the other end of the bimorph plate 3 attached to a support 4. When a voltage is applied to the bimorph plate 3 through the terminal 5, the bimorph plate 3 is bent, and one end of the bimorph plate 3 is displaced up and down as shown by arrow B.

The deviation between the scanning locus of the track and the head when the magnetic tape 20 is transferred at a speed different from normal speed is corrected by displacing the bimorph plate 3 described above, so that a good output signal is always obtained. ing.

In this device, a rotary transformer is used for inputting and outputting signals to and from the rotating head drum.
That is, in FIG. 3, the rotating head drum 10
4 rotor side coils 6a, 7a, 6b, 7b
are provided with heads 1a, 2a, 1b, respectively.
2b is connected. In addition, stator side coils 8a, 9a, 8 are placed at positions facing each of the coils 6a to 7b.
b, 9b are provided. And when recording, signal source 1
A signal from the head 1 is supplied to coils 8a, 8b through recording amplifiers 12a, 12b and recording contacts R of switches 13a, 13b, and is supplied to heads 1a, 1b through coils 6a, 6b. Also, during normal playback, the signals from the heads 1a and 1b are sent to the coil 6.
a, 8a, 6b, 8b, switch 13a, 13b
The output signal is taken out through the regeneration contact P and the regeneration amplifiers 14a and 14b. Furthermore, when playing special effects, the signals from the heads 2a, 2b are transmitted to the coils 7a, 9a, 7.
The signals from the control signal source 16 are supplied to the bimorph plates 3a, 3b through slip rings 17a, 17b.

However, in this case, since the rotary transformer is provided in an extremely narrow area within the rotary head drum, there is a risk that crosstalk may occur between the coils as shown by arrow C. When such crosstalk occurs, for example, when recording, head 1
A part of the recording signal supplied to heads a and 1b is sent to head 2.
When crosstalk occurs on the a and 2b sides, unnecessary signals are recorded over the recorded track, resulting in deterioration of the recorded signal. Furthermore, when the reproduction signals from the heads 2a and 2b mix with the reproduction signals from the heads 1a and 1b due to crosstalk during normal reproduction, a ghost appears on the reproduction screen.

In view of these points, the present invention is intended to prevent the above-mentioned trouble due to crosstalk from occurring. An embodiment of the present invention will be described below with reference to the drawings.

That is, in the present invention, during normal recording and reproduction, a large voltage is applied from the control signal source 16 to the control terminal 5 of the bimorph plate 3, thereby causing the bimorph plate 3 to bend significantly as shown in FIG.

Therefore, during normal playback, head 2 and magnetic tape 2
The abutting angle with zero deviates from 90 degrees, opening a gap and increasing spacing loss. Therefore, even if crosstalk occurs during recording, the recorded signal will not deteriorate due to overlapping recording, and during normal playback, the level of the playback signal from heads 2a and 2b is extremely low, so the playback screen No ghosting occurs.

In this manner, according to the present invention, it is possible to eliminate interference caused by crosstalk in a VTR that performs special playback as described above.

[Brief explanation of the drawing]

Figure 1 is a plan view of the rotating head drum, Figure 2 is a side view of the magnetic head equipped with a bimorph plate, and Figure 3 is a side view of the magnetic head equipped with a bimorph plate.
The figure is a configuration diagram of a rotary transformer, and FIG. 4 is a diagram for explaining the present invention. 1a and 1b are magnetic heads for normal recording and reproduction; 2
a, 2b are magnetic heads for special effect reproduction, 3a, 3
b is a bimorph plate, 10 is a rotating head drum, 1
6 is a control signal source, and 20 is a magnetic tape.

Claims (1)

[Claims] 1 A first magnetic head group that performs normal recording and reproducing, and a second magnetic head group that performs a different type of recording and reproducing in which an electromechanical transducer made of a bimorph plate is provided at the attachment part of each head. The recording head is equipped with a rotary head drum, and by transmitting signals between the magnetic heads on the rotary head drum and the recording/reproducing amplifier using rotary coil means, recording can be performed on the magnetic tape wound around the circumferential surface of the rotary head drum. In a VTR that performs playback,
A control signal source for displacing the viamorph plate by a predetermined amount is provided, and during the period when the first magnetic head group is performing recording/reproducing, the control signal source is operated to displace the viamorph plate by a predetermined amount. By displacing the electromechanical transducer by the predetermined amount, the spacing loss between the second magnetic head group and the magnetic tape is increased, and the cross of the recording/reproducing signal generated through the rotating coil means is A VTR designed to reduce talk interference.