JPH0648561B2 - Rotating head type magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a rotary head type magnetic recording / reproducing apparatus (hereinafter referred to as VTR).
Regarding the VTR), a temporary stop is performed during signal recording, and when the signal recording is restarted after the temporary stop is released, the joints of the recording patterns on the magnetic tape are not disturbed (that is, joint photographing).

[Conventional technology]

Conventionally, in a VTR, a method using a control signal used for feeding control of a magnetic tape has been widely used as a method for performing joint shooting.

FIG. 4 shows a schematic diagram of a tape running system of a VTR which records a control signal on a control track and is used as a signal for controlling magnetic tape running. In FIG. 4, 40 is a supply reel, 41 is a tension arm, 31
Is a full width erasing head, 42 is a drum equipped with the rotary magnetic head 24, 6 is an A / C head (an audio head and a control head are incorporated in the same head assembly), and 43 is a cap driven by a capstan motor 26. Stan shaft, 44 pinch roller, 1 magnetic tape,
46 is a take-up reel.

The magnetic tape 1 is pressed against the capstan shaft 43 by the pinch roller 44 and runs by the rotation of the capstan shaft 43. In the normal recording / reproducing mode, the magnetic tape 1 is sent from the supply reel 40, passed through the tension arm 41 and the full width erasing head 31, and then wound around the drum 42, and then the A / C head 6, and The take-up reel 46 is wound up through the capstan shaft 43.

FIG. 3 is a diagram showing a recording state of a magnetic tape recorded by a helical scan type magnetic recording / reproducing apparatus in which a control track is provided separately from a video signal track. In the figure, on a magnetic tape 1, a video signal track 2 is normally recorded diagonally in units of one field, and a control signal 3 is recorded at regular intervals in the tape running direction. The control signal 3 is used to control tape running so that the video signal rotary magnetic head 24 can accurately scan the video signal track 2 during reproduction. In the following description, a signal before being recorded on the magnetic tape 1 is called a recording control signal, a signal recorded on the magnetic tape 1 is called a control signal 3, and a signal reproduced from the magnetic tape 1 is called a reproduction control signal J.

Normally, the control signal 3 is generated by dividing the vertical synchronizing signal of the video signal to be recorded by 1/2. Therefore, during reproduction, the control head 6 outputs the control signal 3
So that the time at which the video signal rotary magnetic head 24 comes near the start end of the video signal track 2 (that is, the portion where the vertical synchronization signal is recorded) coincides.
The running state of the magnetic tape 1 is controlled.

By the way, at any time during recording, the magnetic tape 1
If the recording phase of the video signal track 2 is different at the joint portion when the recording is paused and started again at an arbitrary timing and recording is started immediately,
There is a problem in that the reproduced image of that portion is disturbed because the inclination angle of is changed. For example, when the magnetic tape 1 is temporarily stopped, the running locus of the video signal rotary magnetic head 24 becomes as shown by the dotted line 4 in FIG.
In order to prevent such a disturbance in the joints of images, the servo control system performs the operation described below.

Now, if there is a pause command during recording, the recording operation is immediately stopped and the magnetic tape 1 is transported in the reverse direction by a certain amount. At that time, the transfer of the magnetic tape 1 is stopped, and the recording standby state is set.

After that, when the temporary stop command is released, the magnetic tape 1 starts running in the forward direction. At this time, the recording operation is not started immediately, but the time point at which the reproduction control signal J from the control track of the magnetic tape 1 is synchronized with the vertical synchronization signal which is the reference of the video signal to be newly recorded, that is, first. When the phase of the recorded video signal track matches the phase of the video signal track to be newly recorded, the mode is switched to the recording mode and the recording operation is restarted. In this way, joint shooting is performed so that the joint between the previously recorded image and the image to be newly recorded is not disturbed.

However, after the temporary stop command is released, the trajectory of the rotary magnetic head drawn on the magnetic tape at the time when the recording mode is switched to the recording mode and the recording operation while the magnetic tape is running in the forward direction is resumed is the temporary stop command. When the recording operation is stopped, the track of the rotary magnetic head drawn on the magnetic tape is shifted back and forth in the tape running direction. There is a portion that overwrites the recording pattern on the magnetic tape that has been recorded, and if it is later displaced, a non-recorded portion will occur. Therefore, when this magnetic tape is reproduced, a visual discomfort is given on the drawing. . To avoid this, the magnetic tape is generally transferred in the reverse direction after the recording operation is stopped by a temporary stop command, and the number of control signals reproduced on the control track during this reverse transfer period is counted and stored. After releasing the pause command, the control signal is reproduced from the control track again and the number is counted, and this number is compared with the stored count number during the reverse transfer period. The recording operation is restarted.

[Problems to be solved by the invention]

Since the conventional VRT is configured as described above, the contact between the tape and the roll head becomes unstable at the time of rising from the stop of the tape running or at the time of the reverse rotation in the forward direction. If sufficient accuracy control is not performed, the control signal reproduction during the transition of the above-mentioned running becomes unstable, and the overriding period increases or a non-recorded part occurs, which causes visual discomfort during signal reproduction. There was a problem.

The present invention has been made to solve the above-mentioned problems, and does not require mechanical accuracy control during a transition such as a rise from a stop of tape running, and a VTR with high joint shooting accuracy. Aim to get.

[Means for solving problems]

The VTR according to the present invention records an image signal recording / reproducing means for recording or reproducing an image signal by a rotary magnetic head, a magnetic tape traveling control means for controlling traveling of a magnetic tape in a forward or reverse direction, and an image signal recording / reproducing means. A rotary head type magnetic recording / reproducing apparatus equipped with an operation mode switching means for switching to an operation mode or a reproducing operation mode and a full width erasing head, and a position signal recording means for recording a position signal on a magnetic tape using the full width erasing head, and a full width Provided on the supply reel side with respect to the erasing head,
When a position signal reproducing means for reproducing a position signal and a magnetic tape pause command are input, the magnetic tape running control means causes the magnetic tape to run in the forward direction and the image signal recording / reproducing means to record an image signal. The position signal is recorded by the position signal recording means while continuing the forward running for a predetermined time, and then the image signal recording / reproducing means is switched to the reproducing operation mode by the operation mode switching means. When a magnetic tape temporary stopping means for moving the magnetic tape in a reverse direction by a predetermined amount and then temporarily stopping it and a temporary stop canceling command for canceling the temporary stop of the magnetic tape are input, the magnetic tape running control means moves the magnetic tape in order. Image signal by the operation mode switching means in correspondence with the position signal reproduced by the position signal reproducing means. Switching the recording and reproducing means to a recording mode of operation, in which a magnetic tape pause release means for restarting the recording operation of the image signal.

[Action]

In the present invention, since the position signal is recorded or reproduced during the forward running of the magnetic tape in the stable running state,
When the recording is resumed, the position of the magnetic tape in the longitudinal direction is accurately determined, and since the full-width erasing head is also used for recording the position signal, the structure of the device is simplified. Further, since the position signal reproducing device is provided on the supply reel side with respect to the full-width erasing head, the position signal is erased immediately after being reproduced at the time of joint shooting, and there is no adverse effect on the audio signal or the like.

Example of Invention

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 shows a timing chart. The embodiment of FIG. 1 will be described with reference to the timing chart of FIG. At the time of normal recording, the switch 21 and the image signal processing circuit 22 are controlled by the control signal A from the system control circuit 20, and F outputted from the image signal processing circuit 22 is controlled.
The M-modulated image signal is recorded on the magnetic tape by the rotary magnetic head 24, and the erasing signal generating circuit 30 is controlled to erase the recording signal on the magnetic tape by the full width erasing head 31. At this time, the magnetic tape running control circuit 25
The capstan motor 26 is controlled by the control signals B and B ′ from the system control circuit 20 so that the magnetic tape is fed at a constant speed in the forward direction. When the temporary stop command is given, the switch 28 is turned on for the time T ₀ by the control signal D output from the system control circuit 20. The position signal generating circuit 29 is a circuit that continuously generates a signal that is phase-synchronized with the rotation of the rotating drum. The gate time T ₀ of the switch 28 is selected to be an integral multiple of the cycle of the continuous cycle signal output from the position signal generating circuit 29. In FIG. Is set to pass through. The signal that has passed through the switch 28 is an erase signal generation circuit 3 that generates a fixed frequency signal.
The erasing signal is recorded on the magnetic tape by the full-width erasing head 31 by superimposing it on the output signal of 0 and using the erasing signal as an AC bias.

After the recording of the position signal on the magnetic tape is completed as described above, the switch 21 is switched by the control signal A of the system control circuit 20 to interrupt the recording of the image signal on the magnetic tape by the rotary magnetic head 24, and The erasing of the recording signal on the magnetic tape by the full width erasing head 31 is stopped. After that, the capstan motor is once stopped by the control signal B from the system control circuit 20 via the magnetic tape running control circuit 25. After that, the capstan motor 26 is rotated in the reverse direction to reversely transfer the magnetic tape for a predetermined time and then stopped. When the temporary stop command is released, the magnetic tape running is activated by the control signals B and B'from the system control circuit 20 to transfer the tape in the forward direction. At this time, in the magnetic tape running control circuit, reproduction is performed from the control head 32 so that the recording pattern on the magnetic tape recorded before the temporary stop command is input and the trajectory drawn by the rotary magnetic head 24 on the magnetic tape match. The capstan motor 26 based on the control signal obtained via the control recording / reproducing circuit 33,
Control tape running. The amount of time to reversely transfer the magnetic tape when a pause command is input is set so that the control system can be fully settled within this time when the magnetic tape running is controlled based on the control signal after the magnetic tape running is started. Has been done. When the position signal recorded on the magnetic tape is reproduced by the position signal reproducing head 34, the position signal reproducing circuit 35 shapes the reproduced position signal and sends it to the (F) system control circuit 20. The system control circuit 20 switches the control signal A to the signal recording mode based on the reproduced position signal, and the recording of the image signal on the magnetic tape is restarted by the control signal A.

〔The invention's effect〕

As described above, according to the present invention, it is not necessary to generate or record a signal on the magnetic tape during a transition such as inversion, stop or start of the magnetic tape, and moreover, the signal recording restart position on the magnetic tape can be accurately grasped. Therefore, it is possible to provide a VTR which does not require the conventional mechanical precision management and has high joint shooting precision.

In the case of a VTR in which a commercially available audio signal is FM-modulated by a rotary magnetic head and deeply recorded on a magnetic tape, a position signal recorded by a full width erasing head causes a significant disturbance to the audio signal. . However, according to the present invention, the position signal reproducing head 34 is provided with respect to the full width erasing head 31 on the supply reel side, specifically, between the supply reel and the full width erasing head. After the position signal recorded on the magnetic tape is reproduced by 34, erasing is performed by the full width erasing head 34 including the area on the magnetic tape where the position signal is recorded, and the recorded position signal is erased. Therefore, there is no interference.

[Brief description of drawings]

FIG. 1 is a block circuit diagram showing an embodiment of a VTR according to the present invention, FIG. 2 is a timing chart diagram in the embodiment of the present invention shown in FIG. 1, and FIG. 3 is a connection in a conventional example. FIG. 4 is a diagram showing a relationship between a recording pattern on the magnetic tape and a locus drawn on the magnetic tape by the rotary magnetic head at the time of shooting, and FIG. 4 is a schematic diagram of a magnetic tape running system of a general VTR. 24 ... Rotating magnetic head 25 ... Magnetic tape running control circuit 29 ... Position signal generating circuit 31 ... Full width erasing head 34 ... Position signal reproducing head 35 ... Position signal reproducing circuit A considerable part is shown.

Claims (2)

[Claims] 1. A recording operation of an image signal recording / reproducing means for recording or reproducing an image signal by a rotary magnetic head, a magnetic tape traveling control means for controlling traveling of a magnetic tape in a forward or reverse direction, and the image signal recording / reproducing means. A rotary head type magnetic recording / reproducing apparatus equipped with an operation mode switching means for switching to a mode or a reproduction operation mode and a full width erasing head, and position signal recording means for recording a position signal on the magnetic tape by using the full width erasing head. Provided on the supply reel side with respect to the full width erasing head,
When the position signal reproducing means for reproducing the position signal and the temporary stop command for the magnetic tape are inputted, the magnetic tape running control means moves the magnetic tape in the forward direction and the image signal recording / reproducing means makes the image signal. The recording operation is continued for a predetermined time, the position signal is recorded by the position signal recording means while the forward traveling is continued, and then the image signal recording / reproducing means is switched to the reproducing operation mode by the operation mode switching means. When the magnetic tape running control means transfers the magnetic tape in a reverse direction by a predetermined amount and then temporarily stops, and a temporary stop cancel command for canceling the temporary stop of the magnetic tape is input. , The magnetic tape running control means runs the magnetic tape in the forward direction, and the position signal playing means plays the magnetic tape. Magnetic tape temporary stop release means for switching the image signal recording / reproducing means to the recording operation mode by the operation mode switching means in response to the position signal and restarting the recording operation of the image signal. Head type magnetic recording / playback device. 2. A full width erasing means for erasing the magnetic tape using a full width erasing head after reproducing the position signal recorded on the magnetic tape by the position signal reproducing means. A rotary head type magnetic recording / reproducing apparatus according to claim 1.