JPH0785282B2 - Magnetic recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to magnetic recording by a plurality of magnetic heads including a flying erase head (hereinafter referred to as FEH) mounted on a rotating drum and a magnetic head for recording information signals. The present invention relates to a magnetic recording device for recording and erasing information signals on a medium.

[Conventional technology]

A well-known video tape recorder (VT
R), but in general VTRs for consumer use have made remarkable progress in miniaturization technology of the VTR itself as the width of the magnetic tape used has changed from 1/2 inch to 8mm. It has become smaller and the rotary transformer is also smaller. On the other hand, the erasing head, which was conventionally fixed to the traveling system, has come to be mounted on the rotating drum even in the VTR for consumer use. Also, many VTRs have adopted a dedicated magnetic head such as a double azimuth head for obtaining good special reproduction. While the rotary transformer is miniaturized in this way, it is necessary to make the rotary transformer multi-channel, and as a result, the occurrence of crosstalk between the channels of the rotary transformer becomes a problem, and it is possible to eliminate this crosstalk. It is becoming important.

In so-called 8mm VTR, using metal tape,
If the FEH is used for erasing, an erasing current several times as large as the recording current of the magnetic head for a normal video signal is required. In the 8 mm VTR, PCM voice recording is also standardized as a format. So the FEH
When the erase signal of is set between several MHz and 10 MHz,
If the crosstalk of the rotary transformer is large during recording, the erasing signal will leak into the PCM recording signal, and the PCM will be lost during playback.
Error rate increases. So, for example, two heads that record and reproduce video PCM signals with a rotary transformer.
If a short ring is provided between the L and R channels and the FEH channel, crosstalk can be almost alleviated. However, in this case, 4 channels are required for the rotary transformer, and if a double azimuth head is used to realize a good still and fine throw, another channel is required, and eventually 5 channels are required for the rotary transformer. .

In addition, the number of VTRs capable of setting a plurality of track pitches has increased in recent years, and the number of heads and the number of channels of a rotary transformer will further increase if a dedicated head for recording / reproducing is provided in these number of track pitches.

Problems to be Solved by the Invention] In a conventional VTR, it is a difficult problem to make crosstalk of a rotary transformer composed of 5 channels or more negligible. Especially in the case of 8 mm VTR, the erasing current is large and the diameter of the drum is also small, so that the erasing current may leak to other than the head during recording and the recording signal may be deteriorated.

The present invention has been made in order to solve various problems as described above, and a magnetic head to which an information signal is not supplied operates due to an erasing signal, which deteriorates the recorded information signal. It is an object of the present invention to provide a magnetic recording device that can prevent the occurrence of the above.

[Means for solving problems]

A magnetic recording apparatus according to the present invention is an apparatus for forming tracks on a recording medium to record an information signal, wherein a plurality of heads for a plurality of recording modes each having a different track pitch, and a plurality of heads among the plurality of heads A recording circuit for supplying an information signal to at least one head, a flying erase head for erasing an information signal recorded on a recording medium, an erasing circuit for supplying an erasing signal to the flying erase head, and the flying erase head. A phase inverting circuit that inverts the phase of the erase signal supplied to the head and supplies the erasing signal to at least one of the plurality of heads to which the information signal is not supplied; the plurality of heads and the flying erase head; The recording circuit and the erasing circuit are electrically coupled to each other and independent channels are used. And a rotary transformer having, in response to said position of the channel in the rotary transformer is used to set the head for supplying an output signal of said phase inverting circuit.

[Work]

In the present invention, at the time of recording, a phase inversion erasing signal corresponding to the amount of the erasing signal supplied to the FEH flowing through the rotary transformer as crosstalk into the magnetic head to which the information signal is not supplied By supplying to the magnetic head which is not supplied, the crosstalk component can be canceled and the information signal to be recorded can be prevented from being deteriorated.

〔Example〕

FIG. 1 is a block diagram showing the configuration of the essential parts of a VTR as an embodiment of the present invention, FIG. 2 is a diagram showing the arrangement of channels of a rotary transformer in the VTR of FIG. 1, and FIG. It is a figure which shows the structure of the magnetic head on a rotating drum.

In FIGS. 1 to 3, F is FEH, R _a and L are magnetic heads having different azimuth angles for recording and reproducing video signals, and also for recording and reproducing PCM signals. The magnetic head R _b is a so-called special reproduction head having the same azimuth angle as R _a . T is a rotary transformer, A _F , A _Rb , A
_L and A _Ra are recording amplifiers of each magnetic head, and I _F , I _Rb ,
I _L and I _Ra are output currents of these recording amplifiers. Further, “FEH osc” is an erasing signal oscillation circuit for supplying to FEH, and “Video REC” is a signal processing circuit for converting a video signal V _IN to be recorded into a recording signal.

In the apparatus configured as described above, at the time of recording, the magnetic heads R _a and L are 30 PG that represent the rotational phase of the magnetic head at the same time or in synchronization with the rotation (magnetic head switching synchronized with the rotational phase of the rotating drum). Signal) causes a recording current to flow alternately. The timing chart of FIG. 4 shows how the recording current flows through the 30PG. The configuration of the magnetic head shown in FIG. 3, the erase current supply to the FEH is as shown in the output current I _F of the constant or Figure 4. Then, the cross-talk of the output current I _F is rotary transformer T, it will also flow through the magnetic head R _b side, thereby causing the problems such as described above. Therefore, a recording amplifier
In reverse phase to the output current I _F from A _Rb, since supplying amount of the output current I _Rb corresponding to the crosstalk of the magnetic head R _b of the output current I _F, the magnetic head R _b of the current output current I The crosstalk of _F is canceled by the output current I _Rb and becomes 0.

FIG. 5 is a schematic block diagram of amplifiers A _F , A _Rb , A _L , and A _Ra for realizing the timing chart of FIG.
M _1, MM ₂ is a monostable multivibrator, F / F will flip-flop, switch SW _1, SW ₂ is ON control input is High level
The switches SW ₃ and SW ₄ are analog switches that turn on when the control input is at low level, A _{1 to} A ₄ are amplifiers, R ₁ and R ₂ are resistors that form a voltage divider circuit, and A ₅ is for inverting the phase. , IN is an inverter, and the same reference numerals as those in FIG. 1 indicate the same or corresponding portions.

In the amplifier configured as described above, 30PGHi
At the gh level, the first half has two mono multivibrator MMs
₁ and MM ₂ and flip-flop F / F work, switch SW ₁ and SW
₂ is closed and the erase signal supplied to FEH and the current corresponding to the amount of the erase signal cross-talking to the magnetic head R _b and the phase of the erase signal is inverted, the magnetic head R supply to _b . Second half opens switch SW _1, SW _2, the output current I _F, I _Rb is cut off, also switch SW ₃ is O
At FF, the switch SW ₄ is turned on, the output current I _Ra flows, and recording is performed.

Next, when 30PG is at Low level, in the first half, two mono multivibrators MM ₁ and MM ₂ and flip-flop F / F work.
Switch SW _1, SW ₂ opens, the output current I _F, I _Rb does not flow. In the latter half, the switches SW ₁ and SW ₂ are closed, and the erase signal supplied to the FEH and the current corresponding to the amount by which the erase signal crosstalks to the magnetic head R _b , and the phase of the erase signal is inverted. Supplies to the magnetic head R _b . At this time, switch SW ₄ is OFF and switch SW ₃ is ON.
The output current I _L flows and recording is performed.

Further, FIG. 6 shows a circuit diagram of a specific example of the phase inverting circuit A ₅ . In FIG. 6, Q is a transistor, R _{5 to} R ₈ are resistors, and C _{1 to} C ₂ are capacitors, and the frequency characteristic of this circuit should be almost flat with respect to the input signal band.

In the above-mentioned embodiment, the channel adjacent to the channel of the rotary transformer for the erase head FEH is the channel for the special reproduction head R _b , but it may be the channel for other heads. is there. For example, when a dedicated recording / reproducing head is provided for each of a plurality of track pitches as described above, a channel of a rotary transformer for a recording / reproducing head corresponding to a track pitch other than the recording track pitch is adjacent to a channel for FEH. At this time, the same effect can be obtained by supplying the output of the above-mentioned phase inversion circuit to this channel.

〔The invention's effect〕

As described above, the present invention is provided with the phase inverting circuit for inverting the phase of the erase signal supplied to the flying erase head, and at the time of recording, the inverted erase signal obtained by inverting the phase of the erase signal is supplied to the magnetic head not supplied with the information signal. Since the magnetic head to which the information signal is not supplied is activated by the erasing signal and the information signal recorded by the magnetic head is deteriorated by the erasing signal, it is possible to prevent deterioration of the recorded information signal. A recording device is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the essential structure of a VTR as an embodiment of the present invention, FIG. 2 is a diagram showing the arrangement of channels of a rotary transformer in the VTR of FIG. 1, and FIG. 3 is a diagram of FIG. FIG. 4 is a diagram showing the structure of the magnetic head on the rotary drum of the VTR, FIG. 4 is a timing chart showing the timing of FIG. 1, and FIG. 5 is a VTR of FIG. 1 for realizing the timing chart of FIG. FIG. 6 is a circuit diagram showing a concrete example of the amplifier, and FIG. 6 is a circuit diagram showing a concrete example of the phase inverting circuit in FIG. In Figure, F represents _{FEH, L, R a, R} b is a magnetic head, T is a rotary _{transformer, A F, A L, A} Ra, A Rb amplifiers for recording, "F
"EH OSC" is an FEH erasing signal oscillation circuit "Video REC" is a signal processing circuit for converting a video signal V _IN into a recording signal, MM ₁ and MM ₂ are mono multivibrator, and F / F is a flip-flop, A _{1 to} A ₄ are amplifiers, and A ₅ is a phase inverting circuit.

Claims (1)

[Claims] 1. An apparatus for forming information tracks by forming tracks on a recording medium, comprising a plurality of heads for a plurality of recording modes having different track pitches, and at least one head of the plurality of heads. A recording circuit for supplying an information signal to the recording medium, a flying erase head for erasing the information signal recorded on the recording medium, an erasing circuit for supplying an erasing signal to the flying erase head, and a flying erase head A phase inverting circuit for inverting the phase of the erase signal, and supplying the same to at least one of the plurality of heads to which the information signal is not supplied; the plurality of heads and the flying erase head; the recording circuit and the erasing A circuit that electrically connects the circuits and has independent channels. And a Lee transformer, according to the position of the channel in the rotary transformer, the magnetic recording apparatus characterized by setting the head for supplying an output signal of said phase inverting circuit.