JPH0944803A - Magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a magnetic recording and reproducing device to reproduce a signal up to a range of a high frequency band at the time of reproducing by applying a designated voltage level to the central point dividing the winding of a rotary transformer, providing a pair of record amplifiers so that a recording current is made to individually flow through each winding to suppress a counter electromotive force at the time of recording. SOLUTION: In the case of recording, an output current from a recording amplifier 4 flows through a head winding 2 corresponding to an input recording signal, and an output current from a recording amplifier 5 flows through a head winding 3. These amplifiers 4, 5 are in opposite phase to each other and a sum of the recording currents from the recording amplifiers 4, 5 flows through the winding 2 and 3, and this recording signal is supplied to a rotary magnetic head 1 to be recorded on a magnetic tape. Also, in the case of reproducing, the signals on the magnetic tape are picked up by the rotary magnetic head 1 and outputted as reproduced signals of an mutually opposite phase via the head windings 2 and 3. These reproduced signals are sent to a reproducing amplifier 10 forming a differential amplifier through capacitors 8, 9 to be amplified and outputted outside.

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 magnetic recording / reproducing apparatus for recording / reproducing signals corresponding to a magnetic tape via a rotary magnetic head.

[0002]

2. Description of the Related Art The structure of a magnetic recording / reproducing circuit section in a conventional magnetic recording / reproducing apparatus is shown in FIGS. 2 (a) and 2 (b). 2A shows the structure of the recording / reproducing input / output independent type magnetic recording / reproducing circuit section, and FIG. 2B shows the recording / reproducing input / output shared type magnetic recording / reproducing circuit section. It is a composition.

Usually, in a magnetic recording / reproducing apparatus for recording / reproducing a signal on / from a magnetic tape by a rotary magnetic head, a signal amplified by a recording amplifier is supplied to a reproducing amplifier via a rotary transformer and amplified by the reproducing amplifier. The reproduced signal thus reproduced is taken out.

In the input / output independent type magnetic recording / reproducing circuit section shown in FIG. 2A, the recording signal amplified and output by the recording amplifier 20 is output from the head winding 19 included in the rotary magnetic head 18. The head winding 19 is connected to one end, and the other end of the head winding 19 is connected to a power supply (power supply voltage: V _cc ). On the other hand, the input terminal of the regenerative amplifier 16 is connected to one end of a head winding 13 included in the rotary magnetic head 12 via a capacitor 14, and the other end of the head winding 13 is connected to a power supply (power supply voltage: V _cc ). It is connected. In the recording / reproducing circuit unit, at the time of recording, the input recording signal is amplified by the recording amplifier 20 and supplied to the rotary magnetic head 18 via the head winding 19 and recorded on the corresponding magnetic tape. At the time of reproduction, the signal on the magnetic tape is taken out by the rotary magnetic head 12, supplied to the reproduction amplifier 16 through the head winding 13, amplified by the reproduction amplifier 16 and output to the outside as a reproduction output signal. To be done.

Next, in the shared input / output type magnetic recording / reproducing circuit section shown in FIG. 2B, the recording signal amplified and output by the recording amplifier 28 is output to the rotary magnetic head 2.
2 is connected to one end of a head winding 23, and the other end of the head winding 23 is connected to a power supply (power supply voltage: V _cc ). The input to the regenerative amplifier 26 is a capacitor 24
Is connected to one end of the same head winding 23 as the recording amplifier 28, and the other end of the winding 23 is a power supply (power supply voltage: V _cc ).
It is connected to the. In the recording / reproducing circuit unit, at the time of recording, the input recording signal is amplified by the recording amplifier 28, supplied to the rotary magnetic head 22 via the head winding 23, and recorded on the corresponding magnetic tape. During reproduction, the signal on the magnetic tape is taken out by the rotary magnetic head 22, and the head winding 23 and the capacitor 2
4 is supplied to the reproduction amplifier 26, amplified by the reproduction amplifier 26, and output to the outside as a reproduction output signal.

In the input / output independent type recording / reproducing circuit section shown in FIG. 2A and the input / output common type recording / reproducing circuit section shown in FIG. 2B, the former input / output independent type is used. In this case, although it is advantageous in the frequency characteristic as compared with the shared input / output type, it is disadvantageous in terms of cost because the magnetic heads are separately required for recording and reproduction. On the other hand, in the case of the latter input / output shared type, the output capacity of the recording amplifier and the input capacity of the reproduction amplifier are combined to increase the capacity, so that the required frequency characteristic is ensured when reproducing the high frequency signal. There is a problem that it becomes difficult.

That is, as is clear by referring to the configuration of the recording / reproducing circuit section shown in FIGS. 2A and 2B, the load impedance of the recording amplifier is the inductance L, and the load impedance is The higher the frequency of the recording signal is in the high frequency band, the larger the value.
When recording a signal on a magnetic tape, it is necessary to pass a current through a rotary transformer to magnetize the magnetic head. However, if the value of the current flowing into the magnetic head is the same, the frequency of the recording signal is When the value is high, the value of the output voltage amplitude (back electromotive force) is large. This causes one problem. The amplitude of the output voltage mentioned above cannot be infinitely increased and is limited by the D range. In other words, when a current is passed through the inductance L corresponding to the winding of the rotary transformer, the voltage amplitude (back electromotive force) is generated.
Is generated, and the counter electromotive voltage V _out is represented by the following equation.

V _out = 2πfLI (1) In the above formula (1), L = about 4 μH and f = 16 MH
With z and I = 25 mA _pp , the frequency of the recording signal is 16 M
Assuming that the current flowing into the inductance L is 25 mA and the current is 25 mA, in this case, the counter electromotive voltage V _out is given by the following equation.

V _out = 10V _pp (2) Therefore, in the case of the recording / reproducing circuit section formed by the semiconductor integrated circuit having the standard value of the power supply voltage V _cc of about 5V, it obviously operates. The state will be saturated. This is one of the problems in the conventional recording / reproducing circuit section, and is related to the problem that the recording current is distorted when recording a recording signal. As a measure against this, the actual situation is that the rectangular wave of the back electromotive voltage is operated so that the rising and falling edges are in a gentle state. Is less, the smaller the value). Further, at the time of reproduction, especially in the case of a shared input / output type, it is difficult to secure the frequency characteristic with respect to the reproduction signal, so that the magnetic head for recording / reproduction must be used independently. Create constraints.

FIG. 4 shows an example of the recording current waveform (C) and the counter electromotive voltage waveform (D) in the recording / reproducing circuit section of the conventional embodiment.

[0011]

In the recording / reproducing circuit section of the above-described conventional magnetic recording / reproducing apparatus, in the case of the input / output independent recording / reproducing circuit section, the magnetic heads are respectively for recording and reproducing. Therefore, there is a drawback that the cost is high because of the necessity of the above.

Further, in the case of the input / output type recording / reproducing circuit section, the output capacity of the recording amplifier and the input capacity of the reproducing amplifier are combined, so that a frequency characteristic required when reproducing and outputting a high frequency signal is obtained. However, it is difficult to secure

An object of the present invention is to solve the above-mentioned problems in the input / output independent type recording / reproducing circuit section and the input / output common type recording / reproducing circuit section, thereby achieving low cost and effective recording / reproducing up to a high frequency band. It is to provide a magnetic recording / reproducing apparatus capable of

[0014]

A magnetic recording / reproducing apparatus of the present invention is a magnetic recording / reproducing apparatus for recording / reproducing a signal corresponding to a magnetic tape via a rotary magnetic head, and is included in the magnetic recording / reproducing apparatus. A rotary magnetic head that is commonly used for recording and reproducing as a recording / reproducing circuit section, and a first recording amplifier in which a recording signal output section is connected to a first terminal of a head winding included in the rotary magnetic head. A second recording amplifier having a recording signal output section connected to a second end of a head winding included in the rotary magnetic head; and a first head winding included in the rotary magnetic head. And at least a regenerative amplifier to which a replay signal input section is connected.

The head winding included in the rotary magnetic head is divided into a first head winding and a second head winding at the center position of the head winding. A predetermined power supply voltage may be supplied to the center connection point of the first and second head windings.

[0016]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an input / output type recording / reproducing circuit unit according to an embodiment of the present invention. As shown in FIG. 1, the input / output shared recording / reproducing circuit unit in this embodiment includes a rotary magnetic head 1 including head windings 2 and 3, recording amplifiers 4 and 5, resistors 6 and 7, It comprises capacitors 8 and 9, a differential amplifier type regenerative amplifier 10, and a constant current source 11. FIG.
As shown in FIG. 1, one end of the head winding 2 included in the rotary magnetic head 1 is connected to the output of the recording amplifier 4 and one input of the reproduction amplifier 10, and one end of the head winding 3 is connected. The output part of the recording amplifier 5 and the other input part of the reproduction amplifier 10 are connected to. And head winding 2
The center point of the winding to which the head winding 3 and the head winding 3 are connected is connected to a power supply (power supply voltage: V _cc ).

In FIG. 1, at the time of recording, the output current of the recording amplifier 4 flows into the head winding 2 and the output current of the recording amplifier 5 flows into the head winding 3 in response to the input of the recording signal. Inflow. The recording amplifiers 4 and 5 are in a mutually opposite phase operation state, whereby the recording currents in-phase added by the recording amplifiers 4 and 5 flow into the head winding 2 and the head winding 3, and the recording signal is Rotating magnetic head 1
And recorded on a magnetic tape. At the time of reproduction, the signal on the magnetic tape is taken out by the rotary magnetic head 1 and is output as a reproduction signal having a mutually opposite phase relationship via the head winding 2 and the head winding 3.
These reproduction signals are supplied to the input section of the reproduction amplifier 10 forming a differential amplifier via the capacitors 8 and 9, respectively, amplified, and output to the outside as a reproduction output signal.

In the case of the recording / reproducing circuit section in this embodiment, the output voltage V of the recording amplifier 4 shown in FIG.
_out (1) is the head winding 2 when the frequency of the recording signal is f
Is represented by L ₁ and the recording current flowing through the head winding 2 is represented by I ₁ , which is represented by the following equation.

V _out (1) = 2πfL ₁ I ₁ (3) Here, by comparing the equation (1) with the equation (3), the following conditional expression is obtained. To be

I = I ₁ …………………… (4) L ₁ = L / 2 ……………… (5) V _out (1) = V _out / 2 (6) As is apparent from the equation (6), the output voltage V of the recording amplifier 4 in the input / output circuit section of the present embodiment.
The amplitude of _out (1) is reduced to 1/2 of the amplitude of the output voltage V _out of the input / output circuit unit in the conventional embodiment. This is clearer than the fact that the head winding included in the rotary magnetic head is divided into the head winding 2 and the head winding 3. This also applies to the case of the corresponding recording amplifier 5, and as a result,
It is not necessary to record the rising and falling edges of the rectangular wave of the back electromotive force at the time of recording as in the conventional case, and the optimum magnetic recording function is realized.

On the other hand, regarding the frequency characteristic of the regenerative amplifier 10 at the time of reproduction, assuming that the capacitance at the input part of the regenerative amplifier 10 is C as in the conventional example, the frequency f _u (corresponding to the index of the upper limit frequency of the frequency characteristic concerned) 1) is expressed by the following equation.

F _u (1) = 1 / {2π (L ₁ C) ^1/2 } (7) On the other hand, input / output sharing type recording in the conventional embodiment shown in FIG. 2 (a). In the reproducing circuit section, the input capacitance is C
The frequency f _u corresponding to the index of the upper limit frequency of the frequency characteristic is expressed by the following equation.

F _u = 1 / {2π (LC) ^1/2 } (8) Equation (5) is introduced into Equation (7), and Equations (7) and (8) ) as is apparent by comparing the expression, f _u
(1) and between the f _u, the following relationship holds.

F _u (1) = (2 ^1/2 ) f _u ………………………………………………………………………………………………………………………………………………………………………………………… (9) The frequency characteristic according to the embodiment is shown, and B shows the frequency characteristic according to the conventional embodiment.

That is, it can be seen that the frequency characteristic of the recording / reproducing circuit section in the present embodiment is extended by a factor of 2 ^1/2 as compared with the frequency characteristic of the conventional input / output type recording / reproducing circuit section. . Therefore, according to the present invention, it is possible to reproduce and output even a signal in a higher frequency band during reproduction, and it is possible to suppress the amplitude of the counter electromotive voltage during recording. .

[0027]

As described above, the present invention is applied to a magnetic recording / reproducing apparatus including a rotary magnetic head and a rotary transformer to supply a predetermined voltage level to the center position where the winding of the rotary transformer is divided. Then, by arranging a pair of recording amplifiers so as to individually supply a recording current to each winding, at the time of recording,
It is possible to suppress the amplitude of the counter electromotive voltage, and it is possible to reproduce and output a signal in a higher frequency band during reproduction.

[Brief description of drawings]

FIG. 1 is a block diagram showing a recording / reproducing circuit unit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a recording / reproducing circuit unit in a conventional embodiment.

FIG. 3 is a diagram showing a comparative example of frequency characteristics in the embodiment of the present invention and the conventional embodiment.

FIG. 4 is a diagram showing waveforms of a recording current and a counter electromotive voltage in a conventional embodiment.

[Explanation of symbols]

 1, 12, 18, 22 Rotating magnetic head 2, 3 Recording amplifier 4, 5, 20, 28 Recording amplifier 6, 7, 21, 29 Resistance 8, 9, 14, 15, 24, 25 Capacity 10, 16, 26 Playback Amplifier 11, 17, 27 Constant current source 13, 19, 23 Head winding

Claims (2)

[Claims] 1. A magnetic recording / reproducing apparatus for recording / reproducing a signal corresponding to a magnetic tape via a rotary magnetic head, and as a recording / reproducing circuit unit included in the magnetic recording / reproducing apparatus, a rotation commonly used for recording / reproducing. Type magnetic head, a first recording amplifier having a recording signal output section connected to a first end of a head winding included in the rotary magnetic head, and a head winding included in the rotary magnetic head A second recording amplifier, to which a recording signal output section is connected, and a reproduction signal input to the first terminal and the second terminal of the head winding included in the rotary magnetic head. A magnetic recording / reproducing apparatus comprising at least a reproducing amplifier to which a unit is connected. 2. A head winding included in the rotary magnetic head is divided into a first head winding and a second head winding at a center position of the head winding, and these head windings are formed. The magnetic recording / reproducing apparatus according to claim 1, wherein a predetermined power supply voltage is supplied to the center connection points of the first and second head windings.