JPS61271602A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To apply the efficient drive of a preamplifier without the need of a slip ring by irradiating the light from an external light source to a solar battery provided to the outer wall of a rotary drum and applying the electromotive force of said battery to the reproduction preamplifier in the rotary drum. CONSTITUTION:In irradiating the light from an external power supply 13 to the solar battery 12 installed to the outerwall of the rotary drum, an electromotive force is produced from the battery 12 and fed to the preamplifier 20 installed in the rotary drum. Thus, a reproducing signal from a magnetic head 4 is amplified by the amplifier 20 and its output is extracted from a rotor side coil 25b of a rotary transformer 25 to the outside of the rotary drum. On the other hand, since the light source 13 is not lighted at the recording of a signal, no electromotive force is generated and a recording signal inputted from the transformer 25 into the rotary drum is not inputted to the amplifier 20 but inputted directly to a head 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a magnetic recording and reproducing S! which reproduces signals recorded on a magnetic recording medium using a rotating head. More specifically, the present invention relates to a magnetic recording and reproducing apparatus in which a reproducing preamplifier for pre-amplifying a reproduced signal is mounted on the rotary head.

(Prior Art) In magnetic recording and reproducing devices such as VTRs, video signals are generally recorded and reproduced using a rotating head. Recently, it has been known that a rotary transformer is mounted on the rotary head, and signals are input and output using the rotary transformer in order to improve the S/N ratio.

Furthermore, since the playback signal is minute, the playback preamplifier is placed close to the head of the rotating head in order to improve the problem of noise being affected when the playback signal passes through the low retransformer. A device is known in which a reproduction signal is preamplified by a reproduction preamplifier and then output to a rotary transformer.

However, in the above-mentioned apparatus, a slip ring is used to supply driving power to the reproduction preamplifier from outside the rotary head, and therefore problems such as quality deterioration due to wear of the slip ring occur.

Further, when the driving power is supplied, as the slip ring rotates, noise is generated due to fluctuations in the contact state between the slip ring and the jaw brush, and this causes a problem in that the noise becomes important in the reproduced signal.

(Purpose of the Invention) The present invention was made to solve the above problems, and it is possible to supply power to the reproduction preamplifier in the rotary head without using a slip ring, and the reproduction signal is free from noise. It is an object of the present invention to provide a magnetic recording/reproducing device that is less likely to be affected by.

(Structure of the Invention) The magnetic recording/reproducing device of the present invention includes a solar cell arranged on the outer wall of a rotating drum constituting a rotating head, and irradiates the solar cell with light from a light source placed outside the rotating head. It is characterized in that the electromotive voltage generated in the solar cell is supplied as a drive voltage to a reproduction preamplifier in the rotary head, and the preamplifier preamplifies the reproduction signal q.

('R, bright effect) According to the magnetic recording/reproducing 5A device of the present invention, an electromotive force is generated in the solar cell arranged on the outer wall of the rotating drum, and this electromotive force is used to drive the reproducing preamplifier arranged inside the rotating drum. Since the drive voltage is supplied and the slip ring which was conventionally required because power was supplied from outside the rotating drum is not required, there is no risk of failure due to *U or poor contact of the slip ring.

<Actual rotation mode> Hereinafter, one embodiment of the present invention will be described using the drawings.

FIG. 1 is a schematic diagram showing a loading mechanism of a magnetic recording/reproducing apparatus according to an embodiment of the present invention.

This loading mechanism has a built-in supply reel 2 that supplies the magnetic tape 1, an erasing head 3 that erases all the signals recorded on the magnetic data 71, and a magnetic head 4, and records video signals on the magnetic tape 1 using a helical method. A rotating drum 5 for reproduction, an audio erasing head 6 for erasing only the audio signals recorded on the magnetic tape 1, an audio recording/reproducing head 7 for recording and reproducing audio signals on the magnetic tape 1, and a rotating drum 5 for moving the magnetic tape 1 at an accurate speed. A capstan 8 and a pinch roller 9 for feeding the magnetic tape 1, and a take-up reel 10 for winding the magnetic tape 1 are arranged in this order in the direction in which the magnetic tape travels during reproduction and recording.

In addition, impedance rollers 1 are provided before and after the rotating drum 5.
1a and 11b are arranged. Furthermore, a solar cell 12 is arranged on the upper surface of the rotating drum 5.

This solar cell 12 converts light energy from a light source 13 placed above the rotating drum 5 into electrical energy. A fixed drum 14 is disposed below the rotating drum 5, and both drums 5 and 14 are connected to one another as shown in FIG.
It is formed to form two cylinders. Further, as shown in FIG. 2, a rotary transformer 25 is disposed between the drums 5 and 14, and is configured to efficiently input and output signals between the drums 5 and 14. There is. That is, a recording signal from a signal generator (not shown) is input to the fixed drum 14 and then transferred to the rotary transformer 25.
The signal is inputted to the magnetic head 4 in the rotating drum 5 via.

On the other hand, the reproduction signal read by the magnetic head 4 is transmitted to the fixed drum 14 via the preamplifier 20.0 and the Taly transformer 25.
The signal is then output to the reproduction signal processing section.

FIG. 3 shows a recording/reproducing signal system circuit disposed within the rotating drum and a circuit for supplying a driving voltage to a preamplifier.

The solar cell 12 is irradiated with light from the light source 13.
An electromotive voltage is generated at the preamplifier 20, and a preamplifier driving voltage is supplied to the power input terminals 21 and 22 of the preamplifier 20.

Moreover, when an electromotive force is generated in the solar cell 12, this solar cell 12
The relay 23 connected in parallel to is activated, and the relay terminal 24a and the relay terminal 24b of the signal switching section 24 are connected.

The above-mentioned light source 13 is turned on only when a signal is reproduced, so that the reproduced signal from the magnetic head 4 is input to the preamplifier 20 via the signal switching section 24 of the relay, and is voltage amplified by the preamplifier 20. The signal is input to the rotor-side coil 25a of the rotary transformer 25, and then output from the stator-side coil 25b to the outside of the rotating drum.

On the other hand, since the light source 13 is not turned on during signal recording, no electromotive voltage is generated in the solar cell 12, so the relay circuit 23 is not activated and the relay terminal 24c and the relay terminal 2
4b is kept connected.

As a result, the recording signal input into the rotary drum via the rotary transformer 25 is input directly to the magnetic head 4 without being input to the preamplifier 20.

That is, the signal switching unit 24 is operated to allow input of only the reproduced signal to the preamplifier 20.

According to this embodiment, noise can be reduced compared to a conventional device that uses a slip ring to supply an AC voltage for driving a preamplifier from the outside, and the S/N ratio is 1 to 1.2 dB. A reasonably good reproduction signal can be obtained.

J5, it is desirable to select a solar cell 12 that can generate an appropriate electromotive voltage depending on the drive voltage of the preamplifier used.

Although the above embodiment describes the case where a magnetic head for both recording and reproduction is used, the apparatus according to the present invention may also use a magnetic head for reproduction only.

[Brief explanation of the drawing]

1 is a schematic diagram showing a loading mechanism of a magnetic recording/reproducing apparatus according to an embodiment of the present invention, FIG. 2 is a side view of the rotating drum shown in FIG. 1, and FIG. 3 is a diagram showing the rotation of the rotating drum shown in FIG. FIG. 2 is a circuit diagram showing a recording/reproducing signal system circuit and a preamplifier drive voltage supply circuit built into the drum. 4... Magnetic head 5... Rotating drum 12.
...Solar cell 13...Light source 20...
・Preamplifier 25...Rotary transformer?
V

Claims (1)

[Claims] A rotating drum comprising a built-in magnetic head that reads signals recorded on a magnetic recording medium and a preamplifier that amplifies the read signal from the magnetic head, and operating power is supplied to the preamplifier provided on the rotating drum. A magnetic recording/reproducing device comprising: a solar cell to be supplied; and a light source provided outside the rotating drum to irradiate the solar cell with light.