JPH0711842B2 - Magnetic recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic recording device, and particularly to recording an audio signal with PCM audio in which a high frequency bias signal is superimposed on an audio signal is a video signal. The present invention relates to a magnetic recording device suitable for cases where recording is performed.

[Prior Art] An example of a magnetic recording apparatus is disclosed in Japanese Patent Application No. 62-261319. A deep-layer recording system is adopted in this apparatus, and an audio signal in which a high-frequency bias signal is superimposed is recorded in a deep layer portion of the magnetic tape, and a video signal is recorded in a surface layer portion of the magnetic tape. The recorded signal on the magnetic tape is erased by the magnetic field generated by the application of the high frequency erase signal to the erase head.

[Problems to be Solved by the Invention] By the way, in recording and erasing in the case of the above-mentioned deep layer recording method, it is necessary to satisfactorily erase even an audio signal of a deep layer portion of the magnetic tape, and therefore, a high frequency bias signal superimposed on the audio signal is It is necessary to pass a higher level erase current to the erase head.

However, such a large erasing current causes crosstalk in the rotary transformer between the high frequency magnetic field and the high frequency bias signal of the audio signal. Therefore, there is an inconvenience that the audio signal recorded on the magnetic tape after erasing is subjected to intermodulation distortion and the quality of the signal is deteriorated.

Further, the crosstalk of the high frequency magnetic field due to the erase signal and the high frequency bias signal is also generated in the video signal by the rotary transformer, and the intermodulation distortion is also generated in the video signal. As a result, when a video signal of which quality is deteriorated is reproduced, moire occurs on the screen.

As a means for preventing such crosstalk, it is conceivable to add a short ring to the rotary transformer. However, this method has a disadvantage that the cost is increased and crosstalk of another signal occurs due to the reduction of the winding interval of the rotary transformer.

The present invention has been made in view of the above points, and an object thereof is to provide a magnetic recording device capable of effectively preventing crosstalk between signals and improving signal quality. is there.

[Means for Solving the Problems] According to the present invention, an erasing signal, an audio signal on which a high frequency bias signal is superimposed, and a video signal are applied to a corresponding head unit via a rotary transformer, respectively, and magnetic recording is performed by a deep recording method. In the magnetic recording device for carrying out the above, the erasing signal and the high frequency bias signal have a signal output means for commonly outputting at the same frequency, and at least a part of the erasing winding and the voice winding of the rotary transformer and the above The signal output means is connected so that the current directions of the respective windings are opposite to each other.

[Operation] According to the present invention, the erase signal and the high frequency bias signal are signals having the same frequency, and in the rotary transformer, at least some of the windings are energized so that the current directions are opposite to each other. Therefore, the magnetic flux interlinking with the video signal due to the energization of the erase winding and the magnetic flux interlinking with the video winding due to the energization of the audio winding are canceled in the opposite directions.

EXAMPLES Examples of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an embodiment of the magnetic recording apparatus according to the present invention. In the figure, the output side of the audio recording processing circuit 10 to which a recorded audio signal is input from the outside is connected to the input side of the bias superposition circuit 12. The bias signal is input from the bias signal oscillation circuit 14 to the bias superposition circuit 12.

Further, the superposed signal output side of the bias superposing circuit 12 is connected to the stator side audio winding 18 of the rotary transformer 16 and the input side of the audio reproduction processing circuit 20, respectively. Further, the output side of the bias signal oscillation circuit 14 is connected to the stator side erase winding 22 of the rotary transformer 16.

Next, the video recording processing circuit 24 to which the recorded video signal is input
The output side of is connected to the input side of the recording amplifier 26.
The output side of this recording amplifier 26 is
Are connected to the stator side video winding and the input side of the video reproduction processing circuit 30, respectively.

Next, the rotor side erase winding 32 of the rotary transformer 16 is
It is connected to the input side of the erase head 34. In addition, the rotor side voice winding 36 of the rotary transformer 16 is connected to the voice head 38.
It is connected to the signal input / output side of the
Are connected to the signal input / output side of the video head 42.

The magnetic tape 44 is moved from the erasing head 34 side at the time of recording / reproducing as shown by an arrow F in the figure. That is, at the time of recording, after the signal already recorded on the magnetic tape is erased by the erase head 34,
Deep recording is performed by the voice head 38. Then, the surface recording of the video signal is performed thereon by the video head 42.
During reproduction, the signals recorded on the magnetic tape 44 are reproduced by the audio head 38 and the video head 42, respectively.

Of the above units, the audio recording processing circuit 10 includes a recording processing system for 2-channel FM audio signals of L and R, a 2-channel PCM audio signal processing system of L and R, and a mixed system of these signals. Respectively, and mixed audio signals are output.

Next, the audio reproduction processing circuit 20 uses the audio recording processing circuit 10
Corresponding to the above, there are respectively provided a reproduction processing system for FM audio signals of two channels L and R and a reproduction system for PCM audio signals of two channels L and R.

The audio head 38 and the video head 42 each have two heads, and a control head (not shown) is provided in addition to the illustrated heads.

Next, the rotary transformer 16 in the above embodiment will be described with reference to FIGS. 2 and 3. In Fig. 2, the rotary transformer 16 is partially broken on the rotor side.
Is shown in its entirety, and FIG. 3 shows an enlarged part of the stator side.

In these figures, the rotary transformer 16 has a stator 50 and a rotor 52, and they are arranged close to each other so that their winding forming surfaces face each other. Rotor 52
It is attached to a motor shaft 54 of a rotary cylinder (not shown) drive motor.

First, the stator side will be described. Each winding 18A-18
B, 22, 28A to 28D are all formed concentrically. Further, a concentric short ring 56 is provided between the audio winding 18B and the video winding 28A.
A short ring 58 is concentrically provided between B and 28C.

On the other hand, the same applies to the rotor side, and each winding 36A-36
B, 32, 40A to 40D are all concentrically formed. A short ring 60 is concentrically provided between the audio winding 36B and the video winding 40A.
A short ring 62 is also provided concentrically between B and 40C.

These respective windings are so arranged that the corresponding ones face each other with the stator 50 and the rotor 52 facing each other as shown in FIG. As shown by arrows FA and FB in FIG. 3, the stator side voice winding 18A and the stator side erasing winding 22 are connected so that the current directions are at least opposite to each other during recording.

Next, the operation of the above embodiment will be described. Magnetic tape
When signal recording is performed on 44, recording signals are input to the audio head 38 and the video head 42, respectively,
The erasing head 34 for erasing the recorded signal of the magnetic head 44.
An erase signal is input to.

In this case, the high frequency bias signal superposed by the bias superimposing circuit 12 on the audio signal output from the audio recording processing circuit 10 and the erasing signal input to the erasing head 34 are, as shown in FIG. Bias signal oscillator circuit 14
Is the output of. That is, the erase signal and the high frequency bias signal of the audio signal are signals having the same fraction. Therefore, the occurrence of intermodulation distortion in the high frequency bias signal due to the erase signal can be effectively prevented.

Next, the magnetic field generated around the winding of the rotary transformer 16 by the erase signal and the high frequency bias signal is as shown by a chain line in FIG. First, winding 18A, 18B,
Magnetic lines of force H, HB, and HC are formed near 22. Here, the magnetic force lines HD by the stator side voice winding 18B in which the high frequency bias signal current flows in the direction of arrow FA and the magnetic force lines HD by the stator side erase winding 22 in which the erase signal current flows in the direction of arrow FB.
Focus on HE.

Considering the influence of these currents on the stator side video winding 28A side, the direction of the magnetic force line HD due to the high frequency bias current and the direction of the magnetic force line HE due to the erasing current are opposite to each other due to the relationship of the current directions. Becomes That is, magnetic force lines due to currents having the same frequency are formed in opposite directions, and as a result, the two act so as to be cancelled.

Therefore, the magnetic flux interlinking with the stator-side video winding 28 due to the erasing current or the high frequency bias current is significantly reduced, and the crosstalk between them is favorably reduced. These actions are the rotary transformer 16
The same applies to the rotor side of.

As described above, according to this embodiment, the following effects can be obtained.

(1) Crosstalk is satisfactorily reduced even though it is a flat plate rotary transformer.

(2) Since crosstalk is reduced, the winding intervals of the rotary transformer can be reduced, and the overall size of the device can be reduced.

(3) If the size is the same as the conventional one, it is possible to widen the winding interval, thereby improving the performance.

Next, a case where the rotary transformer is a coaxial type will be described with reference to FIG. In this case as well, the current directions of the voice winding 70 and the erase winding 72 are opposite, as in the case of the flat plate described above. Here, the direction of the magnetic flux interlinking with the video winding 74 when the erase current is applied to the erase winding 72 is indicated by the arrow FC
The direction of the magnetic flux interlinking with the video winding 74 when the high frequency bias current is applied to the audio winding 70 is indicated by arrow FD.

Then, since the current directions are opposite to each other as described above, the magnetic flux directions FC and FD are also opposite to each other, and both act so as to be cancelled.

Next, in order to further reduce the crosstalk with respect to the video signal, as shown in FIG. 1, a signal trap circuit 80 formed by a parallel circuit including a coil and a capacitor may be used. The signal trap circuit 80 has circuit constants set so as to have a trap effect with respect to a high frequency bias signal or an erase signal, and is connected in series to at least one of the video windings 28 and 40 of the rotary transformer 16. It

The present invention is not limited to the above embodiment. For example, in the above embodiment, the erase winding is provided between the voice windings. However, as described above, the erase signal is a signal larger than the high frequency bias signal superimposed on the audio signal. Therefore, in order to balance the number of flux linkages with the video winding by these signals and cancel the influence, it is better to talk the audio winding closer to the video winding and speak the erase winding from the video winding. From this point of view, the arrangement of each winding may be set. In addition to the arrangement, the number of turns of each winding may be taken into consideration.

[Effect of the Invention] As described above, according to the present invention, the frequency of the erase signal and the frequency of the high-frequency bias signal superimposed on the audio signal are made to coincide with each other, and the winding of these signals in the rotary transformer is matched. Since the energization direction to the is set to be reverse at least for a part, the cross modulation distortion due to the crosstalk with respect to the video signal is reduced, and it is possible to favorably prevent the generation of moire on the reproduced video.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention, FIG. 2 is a perspective view showing a partially broken external view of the rotary transformer in the embodiment, and FIG. 3 is a part of the rotary transformer shown in FIG. FIG. 4 is an enlarged perspective view, and FIG. 4 is a main sectional view showing an embodiment of a coaxial type rotary transformer. 10 ... Voice recording processing circuit, 12 ... Bias superposition circuit, 14
...... Bias signal oscillator circuit, 16 ...... Rotary transformer, 18,18A, 18B ...... Stator side voice winding, 22 …… Stator side erasing winding, 24 …… Video recording processing circuit, 28,28A to 28D
...... Stator side video winding, 32 ...... Rotor side erasing winding, 34
...... Erasing head, 36, 36A, 36B ...... Rotor side voice winding, 38
...... Voice head, 40, 40A-40B …… Rotor-side video winding, 4
2 …… Video head, 44 …… Magnetic tape, 50 …… Stator, 52 …… Rotor.

Claims (1)

[Claims] 1. A magnetic recording apparatus for applying a deletion signal, an audio signal on which a high-frequency bias signal is superimposed, and a video signal to a corresponding head portion via a rotary transformer to perform magnetic recording by a deep recording method. At least a part of the erasing winding and the voice winding of the rotary transformer and the signal outputting means have a signal output means for commonly outputting the erasing signal and the high frequency bias signal at the same frequency. The magnetic recording device is characterized in that the currents are connected so that the directions of the currents are opposite to each other.