JPH06195609A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To realize a high frequency characteristic and a high S/N in a RF band, and to improve a reproducing characteristic by using magnetic reproducing heads with magnetic inductance elements and arranging a RF amplifier on a fixed drum. CONSTITUTION:A pair of magnetic recording heads 20 and a pair of magnetic reproducing heads 21 are oppositely arranged on the fixed drum 4 side of a rotary drum 1. The head 21 is equipped with a magnetic inductance element, and is not equipped with a coil. And, the recorded signal of a magnetic tape 2 is detected by the head 21, is inputted in a RF amplifier circuit 8 arranged on the fixed drum 4. An amplified RF signal is converted to a rectangular wave digital signal by a reproducing and processing circuit 9, and is sent to a digital processing part 11.

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, and more particularly to a rotary head type helical scan type magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art A digital audio tape recorder (DAT), which is an example of a conventional rotary head type magnetic recording / reproducing apparatus of helical scan type, has a rotating drum provided with recording and reproducing magnetic heads. .

For example, the present applicant previously filed Japanese Patent Application No. 4-
The DAT streamer device described in No. (invention title "image data file device") has a pair of recording magnetic heads arranged 180 ° opposite to a rotary drum, and 90 magnetic heads for each recording magnetic head. ° It has a pair of reproducing magnetic heads arranged at different rotational positions and having a step with respect to the rotating surface, and reproduces the track recorded by the recording magnetic head in the recording mode. The playback head can be immediately monitored with a magnetic head.

Each of these magnetic heads is basically of the same construction, in which a gap is formed in a core made of a ferromagnetic material and a winding is wound around the core. Then, by tracing the recorded track of the magnetic tape, the change in the magnetic flux in the vicinity of the gap according to the recording signal is detected and output as an induced electromotive force to the winding.

A detection signal from the reproducing magnetic head is amplified by a preamplifier in the RF band through a rotary transformer, and then is converted into a predetermined reproduction frequency characteristic by a reproduction equalization circuit of an RF reproduction processing circuit. Then, a rectangular wave of a predetermined level is formed in synchronization with a predetermined clock frequency, and digital signal processing is performed.

[0006]

However, in the above-mentioned conventional magnetic recording / reproducing apparatus, the R at the output of the reproducing equalization circuit is increased.
There is a problem that the reproduction code error rate in digital signal processing increases due to the influence of the frequency characteristics and the S / N ratio in the F band, and the reproduction characteristics deteriorate.

Therefore, for example, high sensitivity and high frequency characteristics of the magnetic tape, high output and flattening of the envelope waveform of the detection signal of the magnetic head by mechanically improving the tape contact of the magnetic head, Alternatively, as previously proposed by the present applicant in Japanese Patent Application No. 4- (the title of the invention "digital magnetic recording / reproducing apparatus"), the reproduction equalization equalization characteristic is automatically adjusted so that the reproduction code error rate becomes a predetermined value or less. The frequency characteristics and the S / N ratio in the RF band have been improved from various viewpoints such as increasing the number.

However, it is still not sufficient, and higher frequency characteristics and higher S / N ratio are desired.

Therefore, it is an object of the present invention to provide a magnetic recording / reproducing apparatus having improved reproduction characteristics by realizing high frequency characteristics and high S / N ratio in the RF band.

[0010]

In order to solve the above problems, the present invention has the following configuration.

That is, a rotating drum, a magnetic head disposed on the rotating drum, for detecting a recorded signal of a magnetic tape wound around the rotating drum in a direction different from the rotating direction, and a magnetic head facing the rotating drum. A rotary drum having a fixed drum fixed to a base, a primary winding arranged on the rotating drum, and a secondary winding arranged on the fixed drum; and a secondary winding of the rotary transformer. A magnetic recording / reproducing apparatus comprising: an amplifying means for amplifying a signal voltage according to a recorded signal of a magnetic tape to be induced; and a reproducing means for reproducing the signal amplified by the amplifying means as a predetermined waveform characteristic. Is configured to have a magnetic inductance element arranged so that the inductance value changes according to the change in magnetic flux in the vicinity of the gap, and the amplifying means is fixed drum or It is disposed in the vicinity of.

[0012]

According to the present invention having the above structure, the magnetic head has the magnetic inductance element arranged so that the inductance value changes in accordance with the change in the magnetic flux in the vicinity of the gap. Since it does not, the stray capacitance is reduced, and the low inductance acts. Further, by disposing the amplifying means at the fixed drum or a position in the vicinity thereof, a low impedance is obtained with respect to the rotating drum having the magnetic head as a signal source,
It also acts so as to have a low impedance with respect to the base.

[0013]

1 is a schematic configuration diagram of one embodiment of the present invention. Referring to FIG. 1, the configuration of the present invention apparatus which is a rotary head type digital audio tape recorder (R-DAT) will be described. Explain.

In FIG. 1, the rotary drum 1 arranged to face the fixed drum 4 fixed to the base 3 is rotationally driven in the D direction by a drum motor (not shown). On the fixed drum 4 side of the rotary drum 1, a pair of recording magnetic heads 20 and a pair of reproducing magnetic heads 21 are provided.
The recording magnetic head 20 and the reproducing magnet 21 are arranged facing each other by 80 °, and are provided at rotational positions different from each other by 90 °.

The recording magnetic head 2 in the recording mode
Each magnetic head is arranged so as to have a step with respect to the rotating surface so that the track recorded with 0 can be immediately reproduced and monitored by the reproducing magnetic head 21.

The magnetic tape 2 wound around the drums 1 and 4 obliquely to the rotating direction of each magnetic head is driven in the T direction by a tape running mechanism (not shown). Both drums 1,
A rotary transformer 7 having a primary winding 5 and a secondary winding 6 is disposed on the opposing surface of the recording processing circuit 1.
The digital recording signal from 0 is supplied to the recording magnetic head 20 via the rotary transformer 7, and magnetic recording is performed by the helical scan method.

The signal recorded on the magnetic tape 2 is detected by the reproducing magnetic head 21, and the RF amplifying circuit 8 which is an amplifying means provided on a relay substrate (not shown) provided on the fixed drum 4. Is input via the rotary transformer 7 and is amplified with a predetermined amplification gain. Then, the amplified RF signal is made into a rectangular wave digital signal synchronized with a predetermined timing after having a predetermined frequency characteristic in the reproduction processing circuit 9 which is a reproducing means. This digital signal is input to the digital processing unit 11 and subjected to predetermined signal processing such as code error correction.

By the way, the recording magnetic head 20 has a conventionally known structure in which a winding is wound around a core.
The reproducing magnetic head 21 includes a magnetic inductance element (MI
Element) and has no characteristic winding. Therefore, the reproducing magnetic head 21 will be described.

FIG. 2 is a diagram showing the structure of the reproducing magnetic head 21. As shown in FIG. In FIG. 2A, the reproducing magnetic head 2 is used.
1 is two cores 22 made of, for example, ferrite
An insulating member 22 such as a glass member is formed between the ends of a and 22b.
The gap 23 is formed by c and is bonded.

An auxiliary member 24a made of an insulating non-magnetic material such as ceramic is attached to the back surfaces of the other ends of the cores 22a and 22b with an adhesive or the like to ensure the length accuracy of the gap 23. Further, a wire-shaped magnetic inductance element 25 is interposed in a zigzag shape of several turns between the inner sides of the other ends of the cores 22a and 22b. And the MI element 25
Is welded and connected to the inside of each core 22a, 22b by bonding or the like.

In FIG. 2B, the auxiliary member 24b is
It is provided between the inner sides of the two cores 22a and 22b, and is designed to be thinner than that in FIG.

The reproducing magnetic head 2 thus constructed.
1 is a gap 2 corresponding to a recorded signal on the magnetic tape 2.
The magnetic flux change in the vicinity of 3 is set to the two cores 22a, 22b and M.
The magnetic field is composed of the I element 25 and is detected.

Here, FIG. 3 shows a diagram for explaining the MI element of FIG. FIG. 3A is an equivalent circuit of the MI element, and FIG. 3B is an example of the voltage detection circuit.

In FIG. 3A, the MI element 25 is formed of, for example, an amorphous member of FeCoSiB 3.
It is a high-permeability magnetic thin wire having a diameter of 0 μm and is equivalently represented by a series circuit of a resistor R ₀ and a variable inductor L.

That is, the MI element 25 is an element in which the amplitude (or inductance) of the voltage component due to a change in the magnetic flux around the thin wire of the voltage across the voltage changes by several tens of percent when an RF minute current is applied. For example, when the MI element 25 has a length of 5 mm folded back by 10 mm, 10
Inductance is 5 for G (800A / m) magnetic field
It is reduced by 0%.

Then, as shown in FIG. 3B, the resistance R
_{1 to} R ₃ and the variable resistor VR are added to form a Wheatstone bridge circuit, and an AC voltage is excited between the MI element 25 and the variable resistor VR and the resistor R _{1 so} that both ends of the MI element 25 and the resistor V ₃ are excited. To detect the voltage e as a reproduction signal.

By thus configuring the Wheatstone bridge circuit, the voltage component due to the resistance R ₀ of the MI element is canceled and the detection sensitivity is improved. In this embodiment, the voltage detection is performed by the Wheatstone bridge circuit, but the present invention is not limited to this.

Here, a specific circuit configuration of the device of the present invention in FIG. 1 will be described with reference to FIGS. 4 and 5 shown below. The circuits shown in both figures have terminals 47 ₁ , ... 47 ₁₂ and terminals 48 1.
Electrical connection is made by connecting ₁ , ..., 48 ₁₂ with a wire harness or the like.

FIG. 4 shows each magnetic head 20 in FIG.
21 to RF amplifier circuit 8. In the figure
Reference numeral 30 denotes a relay substrate arranged on the fixed drum (4).
Terminal 47₁₁Power supply voltage V_CCBut terminal 47_Five,47₆
Interval 47₇And terminal 47_6,47 ₇Bias oscillator circuit between
The AC bias voltages vb1 and vb2 from (Fig. 5) are
Each comes in as described below.

The signal voltage from the reproducing magnetic head 21 is
Resistor R _4, ... etc. R _6, and resistors R _7, ... is detected by a Wheatstone bridge circuit 33 constituting each like R _9, is amplified by the preamplifier IC32 with two-channel RF amplifier circuit 8, the terminal 47 _{8 ,} is output from the 47 _9. The output from the preamplifier IC 32 is switched so as to be alternately output by the switching pulse Sp entering at the terminal 47 ₁₀ .

FIG. 5 shows the reproduction processing circuit 9 and the recording processing circuit 10 of FIG. Terminals 45 ₁ , 45 ₃ and terminals 45
Reference numeral ₆ is connected to the digital processing unit 11 of FIG. 1, and a switching pulse Sp from a synchronizing circuit (not shown) is input to the terminal 45 ₆ and supplied to the circuits of FIGS. 4 to 5.
Further, a power supply circuit (not shown) is connected between the terminals 45 ₈ and 45 ₉ , and the power supply voltage V _CC enters the terminal 45 ₈ and is supplied to the circuits of FIGS.

[0032] Incidentally, the incoming recording digital signals R _e from the digital processing unit 11 to a terminal 45 _1, the recording equalizer circuit 17, recording amplifier 18 and 19 (or the recording processing circuit 10) is a predetermined process in After that, a digital recording signal is supplied to the recording head (20) and magnetically recorded on the magnetic tape (2).

On the other hand, in the reproduction processing circuit 9, the output signal from the preamplifier IC (32) is generally output to the terminals 48 ₈ and 48 _9.
An amplifier 34, a detection circuit 35, a reproduction equalization amplifier 36, a comparator 37, and a counter 38, which come in through the circuit, and output a reproduction digital signal Pb to a terminal 45 ₃ . Further, the reproduction processing circuit 9 includes a transformer 4
The bias oscillation circuit 39 supplies high-frequency AC bias voltages vb1 and vb2 to the Wheatstone bridge circuit 33 via 0.

The terminals 45 ₂ and 45 ₇ are connected to the recording equalization circuit 17 and the reproduction equalization amplifier 3 from a control unit (not shown).
A control signal for controlling the frequency equalization characteristics of 6 comes in and is controlled so as to have predetermined frequency equalization characteristics. The control unit is also connected to terminals 45 ₄ and 45 ₅ .

The circuit operation of the above-described device of the present invention shown in FIGS. 4 to 5 will be described with reference to the waveform chart of FIG. FIG. 6 shows the waveform of each part of the circuit shown in FIG. 4 to FIG. 5, and the same reference numerals are given in each figure.

That is, FIG. 6A shows the recording digital signal R _e coming into the terminal 45 ₁ , and FIGS.
(F) is a waveform of each part of the reproduction system.

[0037] When reproducing the recorded digital signal R _e recorded on the magnetic tape 2 by the reproducing magnetic head 21, the inductance of the MI element of the reproducing magnetic head 21 if there is no change in the magnetic field intensity in the vicinity of the gap (magnetic flux) 6 does not change, and as shown in FIG. 6B, the amplitude value of the signal a output from the amplifier 34 does not change and the envelope waveform becomes flat (T ₁ , ... T ₁₀ ).

Further, upon detecting a change in the magnetic field intensity corresponding to each edge portion of the recording digital signal R _e (flux), signal a inductance is small in MI element in accordance with the degree of change in the pre-amplifier IC32 It is output from the amplifier 34 via.

By the way, since the relay substrate 30 is disposed on the fixed drum (4) and the reproducing magnetic head 21 has no winding and has a low inductance, it can have a low impedance and a high impedance. A high gain amplification can be performed with an S / N ratio. For example, the combined inductance of the reproducing magnetic head 21 as viewed from the secondary winding 6 side of the rotary transformer 7 can be set to 1 μH or less, whereas it is several μH in the magnetic head having the conventional winding. .

Further, since the output impedance to the amplifier 34 can also be made low, the amplifier 34 can also perform amplification with a high S / N ratio. Further, since the reproducing magnetic head 21 has no winding, the stray capacitance is extremely small, and the head output signal can have a high frequency characteristic.

The signal a having the above-mentioned high frequency characteristic and high S / N ratio
Is subjected to envelope detection in the detection circuit 35 to obtain a signal b (see FIG. 6).
(C)), the reproduction equalizing amplifier 36 sets a predetermined value.
The signal is amplified by the frequency equalization characteristic and becomes a signal c (Fig. 6 (D)).
It At this time, for example, in the digital processing unit (11),
The terminal 45 is arranged so that the raw code error rate becomes a predetermined value or less. ₇
Externally controlled by the control signal from the control unit described above via
Variable control of the impedance of the transistor
The frequency equalization characteristic of the reproduction equalization amplifier 36 is controlled appropriately.
Be done.

Further, in the comparator 37, the rectangular wave signal d (FIG. 6 (E)) of a predetermined level is synchronized with the predetermined clock frequency, and then the counter 38 sets 1
The frequency is divided by 2 and output as a reproduced digital signal Pb (FIG. 6 (F)) from the terminal 45 ₃ to the digital processing section (11).

As described above, according to this embodiment, the reproducing magnetic head having the magnetic inductance element and requiring no winding is used, and the RF amplifier requiring the high gain is arranged on the fixed drum. As compared with the case where a reproducing magnetic head that requires a conventional winding is used, a high frequency characteristic and a high S / N ratio can be obtained, so that there is an advantage that the signal reproducing characteristic can be improved.

In this embodiment, the RF amplifying circuit 8 which is the amplifying means is arranged on the fixed drum 4. However, if the RF impedance circuit 8 can be constructed on the base 3 near the fixed drum 4 to have a low impedance, it is not limited thereto. Not.

In the present embodiment, an example in which the present invention is applied to R-DAT has been described. However, the present invention is applied to video tape recorders (VHS, beta, 8 mm video, etc.) of each method by the helical scan method. Even if
It goes without saying that the same effect as the above can be obtained.

[0046]

As described above, according to the present invention, since the magnetic head does not require a head winding, stray capacitance can be reduced and high frequency characteristics can be improved, and the magnetic head has a low inductance. In addition, the amplifying means has a low impedance with respect to the magnetic head and the base, and S /
Since the N ratio can be improved, the reproducing characteristic can be improved.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a reproducing magnetic head 21 of FIG.

FIG. 3 is a diagram for explaining the magnetic inductance element 25 of FIG.

FIG. 4 is a specific circuit configuration diagram (1) of the device of the present invention in FIG.

FIG. 5 is a specific circuit configuration diagram (part 2) of the device of the present invention in FIG.

FIG. 6 is a waveform diagram of each part of the circuits of FIGS.

[Explanation of symbols]

 1 rotating drum 2 magnetic tape 4 fixed drum 7 rotary transformer 8 RF amplifier (amplifying means) 9 reproduction processing circuit (reproducing means) 21 reproducing magnetic head (magnetic head) 25 magnetic inductance element

Claims (1)

[Claims] 1. A rotary drum, a magnetic head disposed on the rotary drum for detecting a recorded signal of a magnetic tape wound around the rotary drum in a direction different from the rotating direction, and the rotary drum. A rotary drum having a fixed drum which is fixed to a base so as to face the fixed drum, a primary winding arranged on the rotating drum, and a secondary winding arranged on the fixed drum; An amplifying means for amplifying a signal voltage according to the recorded signal of the magnetic tape induced in the secondary winding of the transformer, and a reproducing means for reproducing the signal amplified by the amplifying means as a predetermined waveform characteristic. In the above magnetic recording / reproducing apparatus, the magnetic head includes a magnetic inductance element arranged so that the inductance value changes according to a change in magnetic flux in the vicinity of the gap. Magnetic recording and reproducing apparatus according to claim amplifying means that is disposed on the fixed drum or vicinity thereof.