JPH0757205A - Magnetic recording/reproducing device - Google Patents

Abstract

PURPOSE:To improve performance and to reduce the cost by providing an oscillation means in a rotary cylinder. CONSTITUTION:Magnetic heads 25a, 25b and an erase head 27 are mounted on a rotary drum, and these magnetic heads are switched and controlled by a control signal transmitted through a rotary transformer 24, and the magnetism on a recording medium is erased by an AC signal generated from an oscillator 20. Then, the oscillator 20 is mounted on the rotary transformer 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus in which a plurality of magnetic heads and their peripheral circuits are mounted on a rotary cylinder and electric power is supplied to them.

[0002]

2. Description of the Related Art Conventionally, there is known a magnetic recording / reproducing apparatus characterized in that a plurality of magnetic heads and circuits are mounted on a rotary cylinder and electric power is supplied into the rotary cylinder. An example thereof is the device disclosed in Japanese Patent Laid-Open No. 64-62801. This will be described with reference to FIG.

In FIG. 3, the rotation erasing heads 2a and 2b arranged ahead of the rotary heads 1a and 1b are connected to the AC signal rectifier 51 by the rotation erasing head connection switches 63a and 63b. At the time of recording, the recording signal detecting means 63 connects and holds the rotation erasing switches 63a and 63b so that a part of the AC signal transmitted to the AC signal generator 50 is applied to the rotation erasing heads 2a and 2b. .

When the VTR is put into operation, the rotary cylinder portion 17 surrounded by the broken line rotates. Further, an AC signal is generated from the AC signal generator 50, added to the fixed side coil 52b of the rotary transformer, transmitted to the rotation side coil 52a, and added to the AC signal rectifier 51 as an AC signal (P). The AC signal (P) is rectified by the AC signal rectifier 51, stabilized to a predetermined voltage (V), and output from the power supply + Vcc and the ground GND to the recording / reproducing amplifiers 3, 4 and the recording signal detecting means 63. Supply power. If the VTR is in the reproduction state, the reproduction signals from the rotary heads 1a and 1b are
It is individually amplified by the regenerative amplifier 4 and added to the rotary coils 53a and 54a of the rotary transformer, and fixed coils 53b and 54b.
And is added to the subsequent video signal processing circuit.

In the recording state, the recording signal is transmitted to the rotary coils 53a and 54a of the rotary transformer and applied to the recording / reproducing amplifiers 3 and 4 and the recording signal detecting means 63. The recording signal detecting means 63 operates so that the recording signal is detected and the rotation erasing connection switches 63a and 63b keep the connection. Then, a part of the AC signal (P) applied to the AC signal rectifier 51 is supplied as an erase signal to the rotary erase heads 2a and 2b through the rotary erase head connection switches 63a and 63b, and the corresponding magnetized track of the magnetic tape is recorded. to erase. Further, the recording signals input to the recording / reproducing amplifiers 3 and 4 are amplified by the recording amplifier 3 and applied to the rotary heads 1a and 1b, respectively.

However, in the above magnetic recording / reproducing apparatus, AC signals for power supply and erasing are transmitted by the rotary transformer. The AC signal for power supply and erasing has a higher level than the video and audio signals, and crosstalk from the AC signal to the video and audio signals causes deterioration in image quality and sound quality due to crosstalk.

[0007]

As described above, in the conventional magnetic recording / reproducing apparatus, the erasing AC signal is transmitted by the rotary transformer. The AC signal for erasing has a higher level than the video and audio signals, and crosstalks from the AC signal to the video and audio signals in the rotary transformer, which causes deterioration in image quality and sound quality. Further, since the rotary transformer is used for erasing, it causes a cost increase. An object of the present invention is to improve the performance and reduce the cost by providing the oscillation means in the rotary cylinder.

[0008]

In order to achieve the above object, according to the present invention, at least a plurality of recording heads, erasing heads and oscillating means are mounted on a rotating cylinder,
Recording between the fixed side of the magnetic recording / reproducing device and the rotating cylinder
It is characterized by comprising a rotary transformer capable of transmitting a reproduction signal and means for supplying a power supply voltage into the rotary cylinder.

[0009]

With the above-mentioned means, the oscillating means is operated at the time of recording to generate the erasing signal, whereby the rotary transformer for the erasing signal can be reduced. Also, since the large level erase signal is not transmitted by the rotary transformer, crosstalk from the erase signal to the video / audio signal is eliminated,
The performance can be improved.

[0010]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a circuit diagram showing an embodiment of the present invention. In FIG. 1, slip rings 11a, 11
The power supply voltage Vb is supplied to the rotary cylinder portion 12 via b. At this time, the control signal Cs including information such as head switching and recording / reproducing switching is modulated by the modulator 13, superposed on the power supply voltage Vb, and then the rotary cylinder section 12 is controlled.
Supply to. The control signal Cs is separated into the power supply voltage Vb and the control signal Cs by using the LPF 14 and the capacitor C1. The control signal Cs is demodulated by the demodulator 15 and then separated by the separator 16 into a head switching signal HS and a recording / reproducing switching signal R / P, and a mode signal MD indicating the current state such as special reproduction and joint shooting. Separate each.

The head switching signal HS is sent to the playback output switching circuit 17, the recording / playback switching signal R / P is sent to the recording / playback switching circuit 18, and the mode signal MD indicating the current state is
It is sent to the recording / reproducing power supply generator 19 and the oscillator 20, respectively.
The recording / reproducing power supply generator 19 generates a recording voltage RV during recording, a reproducing voltage PV during reproducing, and an erasing voltage EV when the erasing head needs to operate, according to a signal indicating the current state. To do. Recording voltage RV
Is a recording amplifier 21 and recording / reproducing switches 22a and 22b.
Send to. The reproduction voltage PV is used as the reproduction amplifiers 23a and 23b.
To the recording / reproducing switch 22c. The erase voltage EV is
Send to oscillator 20. When the operation of the erasing head is necessary,
The oscillator 20 generates a signal for erasing according to the signal indicating the current mode.

Recording / reproducing switches 22a, 22b, 22c
Is set to short-circuit when a voltage is applied. When the recording / reproducing power source generator 7 generates the recording voltage RV, the recording / reproducing switches 22a and 22b are short-circuited, and the reproducing voltage P
When V is generated, the recording / reproducing switch 22c is short-circuited.

At the time of reproduction, the recording / reproduction switching circuit 18 connects the rotary transformer 24 and the reproduction output switching circuit 17. Also,
The recording / reproducing switches 22a and 22b are opened, and the recording / reproducing switch 22c is short-circuited. The signals reproduced by the magnetic heads 25a and 25b are amplified by the reproduction amplifiers 23a and 23b and input to the reproduction output switching circuit 17. The reproduction output switching circuit 17 selects a reproduction signal according to the head switching signal. The selected reproduction signal is transferred to the recording / reproduction switching circuit 1
Input / output terminal 2 via rotary transformer 24
Output to 6.

At the time of recording, the recording / reproducing switching circuit 18 connects the rotary transformer 24 and the recording amplifier 21 by a recording / reproducing switching signal. A recording voltage R is output from the recording / reproducing power source generator 19.
Since V is generated, the recording / reproducing switches 22a and 22b are short-circuited and the recording / reproducing switch 22c is opened. The recording signal input through the rotary transformer 24 is amplified by the recording amplifier 21 through the recording / reproducing switching circuit 18,
It is sent to the magnetic heads 25a and 25b. When the operation of the erasing head 27 is necessary, the oscillator 20 generates an erasing signal and sends it to the erasing magnetic head 27.

In this embodiment, the oscillator 20 provided on the rotary transformer side is operated to generate the erasing signal at the time of recording, so that the erasing signal rotary transformer 24 can be reduced. Since it is not necessary to transmit the erase signal having a large level through the rotary transformer 24,
The occurrence of crosstalk from the erase signal to the video / audio signal also disappears.

FIG. 2 is a circuit diagram showing another embodiment of the present invention. In this embodiment, the LPF 14 and the capacitor C1 of FIG. 1 are deleted, the input of the recording / reproducing power generator 19 and the slip rings 11a and 11b are directly connected, and the control signal CS including information such as head switching and recording / reproducing switching is
Modulation is performed by the modulator 13 and is supplied to the demodulator 15 through the rotary transformer 24 'and directly supplied from the demodulator 15 to the head switching signal HS and the recording / reproducing switching signal R / P, and special reproduction and joint shooting. Signal MD indicating the state of
In addition, the structure of the separated parts is different from that of FIG.

A recording / reproducing power source generator 19 during recording and reproduction
The generation timings of the recording voltage RV, the reproduction voltage PV, the erasing voltage EV, and the like generated from the above are exactly the same as those in FIG. Further, the head switching signal HS and the recording / reproducing switching signal R which are separately output by the demodulator 15
/ P, and the mode signal MD indicating the current state such as special reproduction and joint shooting, the operation is exactly the same as in FIG.

In this embodiment, although the control signal CS is transmitted by the rotary transformer 24 ', the level of the control signal CS is smaller than the level of the erasing signal ES, and the control signal CS is converted into a video / audio signal. There is almost no crosstalk. Therefore, even if the control signal is transmitted by the rotary transformer 24 ', it does not cause deterioration of image quality and sound quality.

[0019]

As described above, according to the present invention, the oscillating means is operated at the time of recording to generate the erasing signal, so that it is not necessary to use the rotary transformer for the erasing signal, and the rotary transformer is used. It is possible to eliminate crosstalk from the erasing signal to the video / audio signal.

[Brief description of drawings]

FIG. 1 is a circuit diagram for explaining an embodiment of a magnetic recording / reproducing apparatus of the present invention.

FIG. 2 is a circuit diagram for explaining another embodiment of the present invention.

FIG. 3 is a circuit diagram for explaining a conventional magnetic recording / reproducing device.

[Explanation of symbols]

 20 ... Oscillator 24, 24 '... Rotating transformer 25a, 25b ... Magnetic head 27 ... Erase head

Claims (3)

[Claims] 1. A magnetic recording / reproducing apparatus comprising: a rotary cylinder having at least a plurality of magnetic heads and oscillating means mounted thereon; and means for supplying a power supply voltage to the rotary cylinder. 2. A plurality of magnetic heads are mounted on a rotary drum, and these magnetic heads are switched and controlled by a control signal transmitted via a rotary transformer to generate magnetism on a magnetic medium from an AC signal oscillating means. In the magnetic recording / reproducing device which is erased by the alternating signal, the alternating signal oscillating means is mounted on the rotating drum. 3. A rotary cylinder is provided with at least a plurality of recording heads, erasing heads, and oscillating means, and recording / reproducing signals can be transmitted between the stationary side of the magnetic recording / reproducing apparatus and the rotating cylinder. A magnetic recording / reproducing apparatus comprising a rotary transformer and means for supplying a power supply voltage into a rotary cylinder.