JPS5948443B2 - magnetic recording device - Google Patents

Description

Detailed Description of the Invention The present invention provides a magnetic medium for recording and erasing that is connected to a head motor and rotates by a magnetic medium that is driven to run at a predetermined speed by a capstan that is connected to a capstan motor. A synchronization signal obtained from a reproduction control signal and a video signal of a control signal recorded by the capstan motor in advance along the running direction of the magnetic medium, in which a rotating magnetic head is faced with the latter preceding the former; Alternatively, the head motor is controlled and driven based on a phase comparison output with a rotation detection signal obtained in relation to the rotation axis of the rotary magnetic head for recording and erasing, and the head motor It is controlled and driven based on the phase comparison output with the detection signal, and the recording rotary magnetic head receives the frequency modulated signal by the video signal, and the erasing rotary magnetic head receives the frequency modulated signal. and a magnetic recording device configured to record the frequency-modulated signal by sequentially forming a magnetization locus oblique to the traveling direction on the magnetic medium for each field or frame. In particular, one field or one frame of the above-mentioned frequency modulated signal is recorded by forming one magnetization locus based on the command signal while the magnetic medium is running, and the command signal obtained in this case is Even if the time point at which the data is recorded is arbitrary with respect to the time position of the synchronization signal of the video signal, the recording with the formation of one magnetization locus is surely erased by the erasing magnetic head. It is something.

An example of the present invention will be described below in detail with reference to the drawings.) 1 shows a magnetic tape that is driven to run by a capstan 3 and a pinch roller 4 connected to a capstan motor 2;
As shown in FIG. 2, a track 5 extending in the longitudinal direction is formed on the side edge in the width direction, and a control signal of, for example, 30 pressure is recorded on the track 5, and this control signal is transmitted to the fixed magnetic head HC for control signals. The control signal CT is reproduced as a reproduction control signal CT, and the control signal CT is supplied to a comparator circuit 6.

On the other hand, numeral 10 indicates a video signal source, from which a part of a normal video signal S1 having a two-field one frame structure and a frame frequency of 30 Hz is supplied to a synchronization signal separation circuit 11, from which a synchronization signal VC of, for example, 30H21 is supplied. is obtained and supplied to the comparator circuit 6, and this comparator circuit 6
The phases of the synchronizing signal VC and the control signal CT are compared, and the drive circuit 12 of the motor 2 is controlled by the comparison output B.

Reference numeral 15 indicates a head motor, which drives the recording rotary magnetic heads RHL and RH, which are arranged to maintain a rotation angle of approximately 180°.
The rotary plate 16 is connected to a rotary shaft 17 of a rotary plate 16 on which erasing rotary magnetic heads EHl and EH2 are arranged ahead of each other by a predetermined angle θ.
A rotation detection means 18, which is known per se, is arranged to detect the rotation in relation to the rotation, and a rotation detection signal P obtained from this is arranged.
G is supplied to the comparison circuit 19, while the synchronization signal separation circuit 1
The synchronizing signal VC from 1 is supplied to the comparator circuit 19. The comparator circuit 19 compares the phases of the rotation detection signal PG and the synchronizing signal VC.
0 controls the rotating heads RHl, RH2 and EHL.
, EH2 rotate in phase synchronization with the synchronization signal VC.

The rotating heads RHl, RH2 and EHl, EH2 are connected to the magnetic tape 1, and the rotating heads RHl, RH2 and EHl, EH2 are connected to the magnetic tape 1.
The rotating surface of the magnetic tape 1 is arranged to be in contact with the longitudinal direction (travel direction) of the magnetic tape 1 so as to maintain a predetermined angle ψ.

Also, the video signal S1 from the video signal source 10 is transmitted to the frequency modulator 3.
1, from which a frequency modulated wave S2 by the video signal S1 is obtained, and this modulated wave S2 is supplied to a carrier extraction circuit 32, from which a frequency modulated wave S2 is obtained.
The carrier wave is obtained as the erasing signal SE.

If the modulated wave signal S2 is now supplied to the rotating magnetic heads RHL and RH2, it will generate magnetization oblique to the running direction on the magnetic tape 1 for each frame, as shown in FIG. Trajectories Tl, T2...... are formed and recorded in sequence. "ing.

In this case, the capstan motor 2 generates a synchronization signal V obtained from the reproduction control signal CT based on the control signal recorded on the track 5 at the side edge of the magnetic tape 1 and the video signal S1 as described above.
Since it is controlled and driven by the phase comparison output B with C, the magnetization trajectory . Tl, T2...... are extended with a constant positional relationship with the sequential reference positions of control signals on the magnetic tape 1 recorded on the side edges of the magnetic tape 1. . Also, erasing magnetic heads EHI and EH2
are the recording magnetic heads RHI and RH2, respectively, as described above.
However, according to the angle θ, these positions are scanned before the magnetization trajectories Tl, T2, etc. are formed. Perhaps the rotation axis 1 for the magnetic heads RHI and RH2, respectively? is offset in the axial direction. Now the erasing magnetic head EH
If the erasing signal SE is supplied to I and EH2, the recording by forming the magnetization locus by the magnetic heads RHI and RH2 will be surely erased by the erasing magnetic heads EHI and EH2. be. Since the above is the same as in conventional magnetic recording devices, further detailed explanation regarding the above-mentioned configuration will be omitted. However, in the present invention, in the above-mentioned configuration, the frequency modulator 31 The modulated wave S2 is supplied to the recording magnetic heads RHI and RH2 through the recording gate circuit 34R, and the erasing signal SE from the carrier extraction circuit 32 is supplied to the erasing rotary head EHI through the erasing gate circuit 34E. and EH2, and the gate circuits 34R and 34E.
is controlled based on the command signal CM from the command signal source 35 by the gate signals GR and GE having the waveforms described below obtained from the gate signal forming circuit 36 having the configuration described below, to generate the modulated wave S2. One frame corresponds to one magnetization locus that is recorded on the recording magnetic heads RHI and RH2. This is obtained from the erased state.

The gate signal forming circuit 36 is constructed as described below with reference to FIG. That is, the command signal C from the command signal source 35
As shown in FIG. 4A, M is obtained as a rectangular wave having a width of 1 to 2 times the time of one frame (1/30 sec) of the video signal S1 from a desired point in time, and this command signal CM is a rectangular wave. On the other hand, the reproduction control signal CT from the magnetic head HC mentioned above is supplied to the waveform shaping circuit 3T, from which the reproduction control signal CT based on the reproduction control signal CT is supplied.
A pulse train CT' of Hz as shown in FIG. 4B is obtained, which is supplied to the delay circuit 38, from which a pulse train P1 delayed by, for example, about 10 msec with respect to the pulse train CT' as shown in FIG. 4C is obtained. This is the circuit Q1 mentioned above.
Therefore, as shown in FIG. 4D, from the circuit Q1,
It is turned on by one pulse that arrives only after the command signal CM of the pulse train P1 is obtained, and the command signal C of the pulse train P1 is turned on.
A rectangular wave R1 that is turned off is obtained by one pulse that arrives only after M is no longer obtained.

In reality, the rectangular wave forming circuit Q1 has a J-K type flip-flop configuration, and the delay circuit 38 is constructed using a monostable circuit. The rotation detection signal PG mentioned above is supplied to a waveform shaping circuit 39 similar to the circuit 37 mentioned above, from which a pulse train P3 of 30 Hz as shown in FIG. is supplied to a delay circuit 40 similar to that of FIG. 4F, and from this, as shown in FIG.
A pulse train P2 whose phase is advanced by an angle θ between 2 is obtained, and this is supplied to a rectangular wave forming circuit Q2 similar to the circuit Q1 described above.
1 is supplied, and therefore from this circuit Q2, 5 as shown in FIG. 4G.
As shown in FIG.
A rectangular wave R2 which is turned off by the pulse that arrives only when the signal 1 is no longer obtained can be obtained.

0 Furthermore, the rectangular wave R2 obtained in this way and the pulse train P mentioned above
2 is supplied to a rectangular wave forming circuit Q3 similar to circuits Q1 and Q2, and after the rectangular wave R2 of the pulse train P2 is obtained from this circuit Q3 as shown in FIG. A rectangular wave R3 which is turned off by the pulse that arrives only when P2 is no longer obtained is obtained, and this is supplied to the rectangular wave forming circuit Q4 together with the rectangular wave R2.

An example of this circuit Q4 is an inverting circuit 41 which inverts a rectangular wave R3 to obtain a rectangular wave R3' as shown in FIG. 41, and one period of a pulse train P2 as shown in FIG. This square wave R4 is shown to be supplied to the gate circuit 34E described above as the erase gate signal GE. In addition, the above-mentioned rectangular wave R1 and pulse train P
3 is supplied to a rectangular wave forming circuit Q5 similar to the circuits Q1 to Q3, and as shown in FIG. When the rectangular wave R1 is no longer obtained, a rectangular wave R5 which turns off with the arriving pulse is obtained, and this rectangular wave R5 is supplied to the rectangular wave forming circuit Q6, from which, as shown in FIG. 4L, It is turned on by the pulse that arrives only after the rectangular wave R5 of the pulse train P3 is obtained, and the pulse train P3
When the square wave R5 is no longer obtained, a rectangular wave R6 that turns off is obtained by the pulse that arrives for the first time, and this rectangular wave R6 is
An inverting circuit 43 which obtains a rectangular wave R6' as shown in FIG.
The rectangular waves R6' and R5 are supplied to a rectangular wave forming circuit Q7 consisting of an AND circuit 44 which obtains a rectangular wave R7 having a section width of one period of the pulse train P3 as shown in FIG. The rectangular wave R7 obtained in this way is the recording gate signal G.
The signal R is supplied to the gate circuit 34R described above.

The above is an example of the configuration of the present invention. According to this configuration, when the command signal CM is obtained from the command signal source 35 at a desired time, the gate signal forming circuit 36 generates rotations as shown in FIG. 4 J and N. Gate signals GR and GE are obtained, each having a period width of one period based on the pulses P3 and P2 based on the detection signal PG, and the width of these one period is exactly one frame of the video signal S1. Therefore, one cycle of the video signal S1 is recorded on the magnetic tape 1 by forming one magnetization locus.

In this case, since the gate signal GR is phase-advanced with respect to the gate signal GE by a time period corresponding to the angle θ between the recording magnetic head and the erasing magnetic head, one magnetization trajectory by the magnetic head is generated. The recorded data is reliably erased by an erasing magnetic head. In this case, the time point at which the command signal CM is obtained is as shown in FIG.
Even if it is between the 1st pulse of the pulse train P2 and the pulse of the pulse train P3 which is obtained with a delay of a time corresponding to the angle θ between the recording magnetic head and the erasing magnetic head, or otherwise. Even if the erasing gate signal GE is erased, the erasing gate signal GE is always obtained as a signal that advances the recording gate signal GR by an amount corresponding to the angle θ between the recording magnetic head and the erasing magnetic head. Incidentally, the rectangular wave forming circuit Q1 is omitted, so the rectangular wave R1 is not applied and the command signal C is used instead.
If M is supplied to the rectangular wave forming circuits Q2 and QQ5 and thereafter, the time point at which the command signal CM is obtained is as described above, when this is obtained and the pulse 1 of the pulse train P2 is obtained, and then the command signal CM is obtained between the magnetic head for recording and the magnetic head for erasing. In the state shown in the figure between the pulses of the pulse train P3 obtained with a delay of time corresponding to the angle, the recording gate signal GR has a phase-advanced relationship with the erasing gate signal GE as shown by the dotted line, and therefore erasing occurs. This results in the inconvenience that the modulated wave is recorded on a position that is not erased by the magnetic head. However, with the configuration described above, such inconvenience will not occur at all. The above description is merely an example of the present invention; for example, the comparator circuit 6 of the capstan motor 2 may output a phase comparison between the reproduction control signal CT and the rotation detection signal PG. Moreover, the pulse train P1 supplied to the rectangular wave forming circuit Q1 is a pulse train based on the synchronization signal VC or the rotation detection signal PG, and the pulses P2 and P3 supplied to the rectangular wave forming circuits Q2 and Q5 are used as reproduction control signals. Further, in some cases, the delay circuit 38 may be omitted.

In addition, although the case where one frame of the video signal is recorded has been described above, it is also possible to record one field of the video signal by setting the frequency of the control signal, synchronization signal and rotation detection signal to 60 Hz. , or a pair of one magnetic head for recording and one magnetic head for erasing, and the video signal is transferred to the second magnetic head.
The present invention may be applied to the case where each field is recorded one field at a time, and various other modifications may be made.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an example of a magnetic recording device according to the present invention, FIG. 2 is a diagram showing a pattern of magnetization locus of a magnetic tape,
FIG. 3 is a system diagram showing essential parts of the present invention, and FIG. 4 is a waveform diagram for explaining the same.

Claims (1)

[Scope of Claims] 1 (A) A magnetic medium that is driven to run at a predetermined speed by a capstan that is connected to a capstan motor, and a recording and erasing rotating magnetic medium that is connected to a head motor and rotates. The heads are brought into contact with each other in such a manner that the latter precedes the former, and the capstan motor records in advance a synchronization signal obtained from a reproduction control signal and a video signal of a control signal recorded along the running direction of the magnetic medium. The head motor is controlled and driven based on a phase comparison output with a rotation detection signal obtained in relation to the rotation axis of the rotary magnetic head for recording and erasing, and the head motor is driven by the synchronization signal and the rotation detection signal. The recording rotary magnetic head is controlled and driven based on the phase comparison output of the video signal, and the recording rotary magnetic head receives a frequency modulated signal by the video signal, and the erasing rotary magnetic head receives a frequency modulated signal by the carrier wave of the frequency modulated signal. The frequency modulated signal was recorded by sequentially forming a magnetization locus oblique to the traveling direction on the magnetic medium for each field or frame. In the magnetic recording device, (B) the frequency modulated signal and the erasing signal pass through the recording and erasing gate circuits controlled by the recording and erasing gate signals from the gate signal forming circuit, respectively; (C) The gate signal forming circuit generates a rectangular wave having a width of 1 to 2 times the time of one field or one frame of the video signal. and a first pulse train having a period of one field or one frame of the video signal based on a command signal consisting of the above, and any one of the playback control signal, the synchronization signal, and the rotation detection signal. a first rectangular wave forming circuit that obtains a first rectangular wave that turns on with a pulse that arrives only after a command signal is obtained;
ii) the first rectangular shape of the second pulse train based on the second pulse train having a period of one field or one frame of the video signal based on the first rectangular wave and the synchronization signal or rotation detection signal; (iii) a second rectangular wave forming circuit that generates a second rectangular wave that turns on with a pulse that arrives only after the wave is obtained; (iv) a third rectangular wave forming circuit that obtains a third rectangular wave that turns on with a pulse that arrives only after the second rectangular wave of the second pulse train is obtained; and (iv) the second and third rectangular waves. (v) a fourth rectangular wave forming circuit that obtains a fourth rectangular wave as the erasing gate signal having a time width of one field or one frame of the video signal based on the wave;
The rotation magnetic head for recording and erasing has a period of one field or one frame of the video signal based on the first rectangular wave and the synchronization signal or the rotation detection signal, and the angle of the rotating magnetic head for recording and erasing with respect to the second pulse train. The third step is delayed by a time corresponding to the interval.
A fifth pulse train that is turned on by a pulse that arrives only after the first rectangular wave of the third pulse train is obtained based on the pulse train of
(vi) obtaining the fifth rectangular wave of the third pulse train based on the fifth rectangular wave and the third pulse train; (vii) a sixth rectangular wave forming circuit that generates a sixth rectangular wave that turns on with a pulse that arrives for the first time; and (vii) one field or one frame of the video signal based on the fifth and sixth rectangular waves. A seventh method for obtaining a seventh rectangular wave as the recording gate signal having a time width and delayed with respect to the fourth rectangular wave by a time corresponding to the angular spacing of the recording and erasing rotary magnetic head. A magnetic recording device comprising: a rectangular wave forming circuit;