JP3102176B2 - Magnetic recording / reproducing device - Google Patents

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 helical scan type magnetic recording / reproducing apparatus of a rotary head type has a rotary drum provided with magnetic heads for recording and reproduction. .

For example, the applicant of the present invention has previously filed Japanese Patent Application No.
The DAT streamer device described in the issue No. (name of the invention, "image data file device") has a pair of recording magnetic heads arranged 180 ° opposite to a rotating drum, and a pair of recording magnetic heads 90. ° a pair of reproducing magnetic heads arranged at different rotation positions and arranged so as to have a step with respect to the rotation surface, and reproduce a track recorded by the recording magnetic head in the recording mode. It is configured so that reproduction monitoring can be immediately performed by the magnetic head for use.

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

[0005] A detection signal from the reproducing magnetic head is amplified by a preamplifier in the RF band via a rotary transformer, and then given a predetermined reproducing frequency characteristic by a reproducing equalizing circuit of an RF reproducing processing circuit. Then, it is synchronized with a predetermined clock frequency to be a rectangular wave of a predetermined level, and is subjected to digital signal processing.

[0006]

However, in the above-mentioned conventional magnetic recording / reproducing apparatus, R
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.

For this reason, for example, high sensitivity and high frequency characteristics of a magnetic tape, high output and flattening of an envelope waveform of a detection signal of a magnetic head by mechanically improving the contact of the magnetic head with the tape, Alternatively, as previously proposed by the present applicant in Japanese Patent Application No. Hei 4- (Title of Invention: "Digital Magnetic Recording / Reproducing Apparatus"), the reproduction equalization characteristics are automatically adjusted so that the reproduction code error rate becomes a predetermined value or less. For example, the frequency characteristics and the S / N ratio in the RF band have been improved from various aspects.

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

SUMMARY OF THE INVENTION 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 a high S / N ratio in an RF band.

[0010]

In order to solve the above-mentioned problems, the present invention has the following constitution.

That is, a rotating drum, a magnetic head disposed on the rotating drum and 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 transformer having a fixed drum fixed to the base, a primary winding disposed on the rotating drum, and a secondary winding disposed on the fixed drum; and a secondary winding of the rotary transformer. A magnetic recording / reproducing apparatus comprising: amplifying means for amplifying a signal voltage corresponding to a recorded signal of a magnetic tape induced; and reproducing means for reproducing a signal amplified by the amplifying means as predetermined waveform characteristics. Having a magnetic inductance element arranged so that the inductance value changes in accordance with a change in magnetic flux near 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-described 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 near the gap. Therefore, the stray capacitance is reduced and the inductance is reduced. Further, by disposing the amplifying means at the fixed drum or at a position near the fixed drum, the impedance is made low with respect to the rotating drum on which the magnetic head as the signal source is disposed,
It also acts on the base to have a low impedance.

[0013]

FIG. 1 is a schematic block diagram of an embodiment of the present invention. Referring to FIG. 1, the structure of a rotary head type digital audio tape recorder (R-DAT) of the present invention is shown. Will be explained.

In FIG. 1, a rotary drum 1 disposed opposite a fixed drum 4 fixed to a base 3 is driven to rotate in a direction D 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 respectively.
The recording magnetic head 20 and the reproducing magnet 21 are arranged at an angle of 90 ° different from each other.

In the recording mode, the recording magnetic head 2
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 reproduced and monitored immediately by the reproducing magnetic head 21.

The magnetic tape 2 wound on the drums 1 and 4 at an angle to the rotation direction of each magnetic head is driven in the T direction by a tape running mechanism (not shown). Both drums 1,
4, a rotary transformer 7 having a primary winding 5 and a secondary winding 6 is disposed on a surface facing 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 the magnetic recording is performed by the helical scan method.

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

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

FIG. 2 is a diagram showing the configuration of the reproducing magnetic head 21. As shown in FIG. In FIG. 2A, the reproducing magnetic head 2
Reference numeral 1 denotes two cores 22 formed of, for example, ferrite or the like.
a, 22b, an insulating member 22 such as a glass member.
A gap 23 is formed by c and bonded.

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

FIG. 2B shows that the auxiliary member 24b is
This is provided between the inner sides of the two cores 22a and 22b, and is made thinner than FIG.

The reproducing magnetic head 2 thus configured
1 is a gap 2 corresponding to a recorded signal on the magnetic tape 2.
3 near the two cores 22a, 22b and M
This is to detect the induction to the magnetic circuit including the I element 25.

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

In FIG. 3A, the MI element 25 is formed of an amorphous member of, for example, FeCoSiB.
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 whose amplitude (or inductance) of a voltage component due to a change in a thin-line circumferential magnetic flux of a voltage between both ends changes by several tens% due to an external magnetic field when a high-frequency minute current is applied. For example, if the MI element 25 has a 5 mm length with a 10 mm turn,
The inductance is 5 for the magnetic field of G (800 A / m).
It decreases by 0%.

Then, as shown in FIG.
Ends with ₁ to R ₃ and the variable resistor VR is added to constitute a Wheatstone bridge circuit, MI device 25 and the variable resistor VR and the resistor R ₁ MI element 25 excites the AC voltage between the resistor V ₃ To detect the voltage e as a reproduction signal.

By configuring the Wheatstone bridge circuit in this way, 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 case where the voltage detection is performed by the Wheatstone bridge circuit is shown, but the present invention is not limited to this.

Here, a specific circuit configuration of the device of the present invention shown in FIG. 1 will be described with reference to FIGS. The circuit shown in both figures, terminals 47 _1, ... 47 ₁₂ and the terminal 48
_1, is connected to ... 48 ₁₂ electrically by connecting such a wire harness.

FIG. 4 shows each magnetic head 20, FIG.
21 to RF amplifier circuit 8 are shown. Smell
Reference numeral 30 denotes a relay board provided on the fixed drum (4).
And terminal 47₁₁Is the power supply voltage V_CCIs the terminal 47_Five,47₆
Interval 47₇And terminal 47_6,47 ₇Bias oscillation circuit between
The AC bias voltages vb1 and vb2 from FIG.
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 IC32 is switched to be outputted alternately by the switching pulse Sp coming to the terminal 47 _10.

FIG. 5 shows the reproduction processing circuit 9 and the recording processing circuit 10 of FIG. Terminals 45 ₁ and 45 ₃ and terminal 45
₆ is connected to the digital processing unit 11 of FIG. 1, the switching pulse Sp from the synchronizing circuit (not shown) to the terminal 45 _6-entering, is supplied to the circuit of FIG. 4 to FIG.
Further, between the terminals 45 _8, 45 ₉ power supply circuit (not shown) is connected, the power supply voltage V _CC is incoming to the terminal 45 ₈ is supplied to the circuit of FIG. 4 to FIG.

[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 magnetic recording is performed on the magnetic tape (2).

On the other hand, the reproduction processing circuit 9 large short, output signal terminal 48 ₈ from the preamplifier IC (32), 48 ₉
An amplifier 34 for incoming via, a detection circuit 35, a reproduction equalizing amplifier 36, and more become the comparator 37 and the counter 38, which is configured to output a reproduced digital signal Pb to the terminal 45 _3. Further, the reproduction processing circuit 9 includes a transformer 4
A bias oscillating circuit 39 for supplying high-frequency AC bias voltages vb1 and vb2 to the Wheatstone bridge circuit 33 through the oscillating circuit 33.

[0034] Note that the terminal 45 ₂ and the terminal 45 _7, reproduction equalizing amplifier 3 and the recording equalizer circuit 17 from the control unit (not shown)
Control signals for controlling the frequency equalization characteristics of Nos. 6 and 7 are received, and each is controlled to have a predetermined frequency equalization characteristic. The control unit is also connected to terminal 45 _4, 45 _5.

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

[0036] That is, FIG. 6 (A) is a recording digital signal R _e incoming to the terminal 45 _1, FIG. 6 (B) ~
(F) shows the 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) Does not change, and as shown in FIG. 6B, the amplitude waveform 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 The signal is output from the amplifier 34 via the amplifier 34.

By the way, the relay substrate 30 is provided on the fixed drum (4), and since the reproducing magnetic head 21 has no winding and low inductance, it can have a low impedance. High gain amplification can be performed at the 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, compared to several μH for a magnetic head having a conventional winding. .

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

The signal a having the above high frequency characteristic and high S / N ratio
The signal b (FIG. 6)
(C)), a predetermined value is set by the regenerative equalization amplifier 36.
The signal c (FIG. 6 (D)) amplified by the frequency equalization characteristic
You. At this time, for example, the digital processing unit (11)
The terminal 45 is controlled so that the raw code error rate becomes a predetermined value or less. ₇
Via the control signal from the control unit
Variable control of transistor impedance
Thus, the frequency equalization characteristic of the regenerative equalization amplifier 36 is appropriately controlled.
It is.

Further, in the comparator 37, a rectangular wave signal d (FIG. 6 (E)) having a predetermined level is synchronized with a predetermined clock frequency, and then the counter 38 outputs 1
/ 2 divided has been reproduced digital signal Pb output from the terminal 45 ₃ as (FIG. 6 (F)) the digital processor to (11).

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

In this embodiment, the RF amplifying circuit 8 as the amplifying means is provided on the fixed drum 4. However, the present invention is not limited to this configuration as long as the low impedance can be formed on the base 3 near the fixed drum 4. Not.

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

[0046]

As described above, according to the present invention, the magnetic head does not require a head winding, so that the stray capacitance is reduced and the high frequency characteristics can be improved, and the magnetic head has a low inductance. Also, the amplifying means has low impedance with respect to the magnetic head and the base,
Since the N ratio can be improved, there is a feature that the reproduction characteristics can be improved.

[Brief description of the 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 view for explaining the magnetic inductance element 25 of FIG. 2;

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

FIG. 5 is a specific circuit configuration diagram (part 2) of the device of the present invention in FIG. 1;

FIG. 6 is a waveform chart of each part of the circuits of FIGS. 4 and 5;

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-165410 (JP, A) JP-A-4-337502 (JP, A) JP-A-58-12105 (JP, A) JP-A-60-1985 29905 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 5/02

Claims (1)

(57) [Claims] 1. A rotating drum, a magnetic head disposed on the rotating drum and detecting a recorded signal of a magnetic tape wound around the rotating drum in a direction different from the rotating direction, and the rotating drum A rotary drum having a fixed drum opposed to the fixed drum and fixed to a base, a primary winding disposed on the rotating drum, and a secondary winding disposed on the fixed drum; Amplifying means for amplifying a signal voltage corresponding to the recorded signal of the magnetic tape induced in the secondary winding of the transformer; and reproducing means for reproducing the signal amplified by the amplifying means as predetermined waveform characteristics. In the magnetic recording / reproducing apparatus, the magnetic head has a magnetic inductance element arranged so that an inductance value changes in accordance with a change in magnetic flux near the gap. Magnetic recording and reproducing apparatus according to claim amplifying means that is disposed on the fixed drum or vicinity thereof.