JP3066153U - Magnetic recording / reproducing device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The setting of the video head switching signal for instructing the switching timing of the video head is performed only once in the adjustment mode performed before the product is shipped. A gap may occur depending on the cause. SOLUTION: When it is detected that a control signal recorded in advance on a video tape is formed with a predetermined control duty, an automatic adjustment process for automatically adjusting a video head switching timing is executed, and a video head switching timing is performed. Can be adjusted 6.5H before the vertical synchronizing signal, and therefore, if this video tape is prepared, the adjustment operation can be easily performed.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a magnetic recording / reproducing apparatus, and more particularly to a magnetic recording / reproducing apparatus that automatically adjusts a switching point for switching a video head.

[0002]

[Prior art]

 Conventionally, as this type of magnetic recording / reproducing apparatus, a technique disclosed in Japanese Patent Application Laid-Open No. 5-41850 is known. In this publication, the magnetic recording / reproducing apparatus generally includes a microcomputer, a servo circuit, a rotating drum having a video head, and a head switch for selecting the predetermined video head. Then, in the adjustment mode, the microcomputer inputs a vertical synchronizing signal and a video head switching signal, and calculates a control amount for setting both signal intervals to 6.5H (H: horizontal scanning period). Here, the head switching switch is included in the servo circuit, and generates a video head switching signal at a timing corresponding to the control amount based on the position detection signal of the rotating drum. Then, the video head is switched and selected based on the video head switching signal.

[0003]

[Problems to be solved by the invention]

 In the conventional magnetic recording / reproducing apparatus described above, the setting of the video head switching signal for instructing the switching timing of the video head is performed only once in the adjustment mode performed before the product is shipped. Depending on the cause, there may be a deviation in the timing of generation of the video head switching signal. If this shift occurs, there is no way for the user to correct it, and the service department must contact the service department such as an after-sales service center for repairs, which is time-consuming and complicated. Was.

The present invention has been made in view of the above-described problem. If a video tape on which a predetermined control signal is recorded is prepared, a switching point of a video head can be set or confirmed. By recording a predetermined control signal on a video tape at the time of recording, it is possible to always maintain an appropriate video head switching point by setting or checking the video head switching point during playback. The purpose is to provide a magnetic recording / reproducing device.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the invention according to claim 1 is a magnetic recording / reproducing apparatus for setting a switching timing of two video heads disposed opposite to a rotating drum, the magnetic recording / reproducing apparatus being mounted on a recording / reproducing mechanism. Control signal detecting means for detecting whether or not a predetermined control signal for activating the video head switching process is recorded in a predetermined area of the video tape, and recording / reproducing while synchronizing with a predetermined video tape loading mechanism. When the rotating drum switching signal output means for outputting a rotating drum switching signal for instructing switching to one of the video heads to be used, and the control signal detecting means detects a predetermined control signal, the video head switching is performed. A switching point system that controls the switching point so that the above-mentioned rotating drum switching signal is output before a predetermined horizontal scanning period of the vertical synchronization signal by processing. It is constituted of and means.

In the invention according to claim 1 configured as described above, by mounting a predetermined video tape on the recording / reproducing mechanism, the switching timing of the two video heads disposed opposite to the rotating drum can be set. A magnetic recording / reproducing apparatus which is set before a predetermined horizontal scanning period of a vertical synchronizing signal can be realized. In such a case, a predetermined control signal for activating the video head switching process is recorded in a predetermined area of a predetermined video tape in advance, and when setting the video head switching timing, the recording / reproducing mechanism of the magnetic recording / reproducing apparatus is used. Installing. The control signal detecting means detects whether or not the predetermined control signal is recorded in a predetermined area of the video tape mounted on the recording / reproducing mechanism.

The rotating drum switching signal output means instructs switching to one of the video heads used for recording / reproduction while synchronizing with a predetermined video tape loading mechanism. When the control signal detecting means detects the predetermined control signal, the switching point control means performs the video head switching processing so that the rotating drum switching signal is output a predetermined horizontal scanning period before the vertical synchronizing signal. Control the switching point.

That is, if a predetermined video tape is mounted, adjustment for setting the switching timing of the video head can be performed. Therefore, if the user has this video tape, adjustment by resetting can be performed at any time. Can be. Here, the control signal may be any signal that is recorded in a predetermined area of the video tape, is readable, and can be identified as a trigger for setting the switching timing of the video head. There is no particular limitation. Therefore, the control signal may be a control signal recorded on a control track in an identifiable manner, or a video signal recorded on a video signal recording track in an identifiable manner, and may be appropriately changed.

The control signal detecting means is not particularly limited, and can be appropriately changed according to a mode in which the control signal is recorded on a video tape. That is, when the control signal is recorded on the video signal track, the control signal may be formed by the video head, and when the control signal is recorded on the control track, the control signal may be formed by the control head. The period before the predetermined horizontal scanning period of the vertical synchronization signal is not particularly limited, and can be appropriately selected depending on the recording mode of the vertical synchronization signal, and may be 6.5 horizontal scanning periods or 7 horizontal scanning periods. It may be.

As described above, when setting the switching point of the video head, a video tape on which a predetermined control signal is recorded may be prepared. Here, when a video tape on which the predetermined control signal is recorded is applied, if the control signal is held in a magnetic recording / reproducing apparatus, the control signal can be reused, which is preferable. is there. Therefore, according to a second aspect of the present invention, in the magnetic recording / reproducing apparatus according to the first aspect, the control signal detecting means stores a mode of a predetermined control signal recorded on the video tape in a predetermined storage area. The configuration includes a control signal storage unit. In the invention according to claim 2 configured as described above, the control signal detection means is provided with a control signal storage means, and when the control signal detection means detects a predetermined control signal, the control signal storage means The mode of the predetermined control signal is stored in a predetermined storage area.

If the mode of the control signal stored in the control signal storage means is recorded in a predetermined area of the video tape at the time of recording, the video tape on which the switching point of the video head can be set can be duplicated. It is suitable. Therefore, the invention according to claim 3 is the magnetic recording / reproducing apparatus according to claim 2, wherein the control signal detecting means changes a mode of a predetermined control signal stored in the control signal storage means at the time of executing a recording operation. In addition to reading, recording is performed in a predetermined area of the video tape attached to the recording / playback mechanism in response to recording. In the invention according to claim 3 configured as described above, the control signal detecting means reads out the form of the predetermined control signal stored in the control signal storing means and performs the recording in response to the recording operation. To record in a predetermined area of the video tape attached to the recording / playback mechanism. That is, if such a predetermined control signal is recorded, it is possible to duplicate a video tape on which a video head switching point can be set. Therefore, a predetermined control signal is recorded in a predetermined area of the video tape recorded by the user, so that the switching point of the video head is set or confirmed every time during reproduction, so that it is always accurate. It is possible to maintain the switching point of the video head.

As a specific example of the above-mentioned predetermined area for recording the predetermined control signal and a mode thereof, the invention according to claim 4 is a magnetic recording / reproducing apparatus according to claim 1. The means is configured to determine that the control signal of the video tape is a predetermined control signal when the control signal has a predetermined control duty. In the invention according to claim 4 configured as described above, a control signal of a video tape used in setting a switching point of a video head is recorded in advance so that a predetermined control duty is formed. When this video tape is mounted on the recording / reproducing mechanism, the control signal detecting means reads out the control signal and determines whether or not the control duty is the above-mentioned. Then, it is determined that the predetermined control duty is a predetermined control signal.

[0013]

[Effect of the invention]

 As described above, the present invention provides a magnetic recording / reproducing apparatus capable of setting or confirming a switching point of a video head if a video tape on which a predetermined control signal is recorded is provided. can do. According to the invention of claim 2, since the mode of the predetermined control signal is stored in the predetermined recording area, it is possible to refer to the mode of the control signal. Further, according to the invention of claim 3, by recording this predetermined control signal on a video tape at the time of recording, the setting or checking of the switching point of the video head is performed every time at the time of reproduction. It is possible to maintain an appropriate video head switching point. Further, according to the invention of claim 4, by forming the control signal with a predetermined control duty, it is possible to easily form a predetermined control signal.

[0014]

[Embodiment of the invention]

 Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram of a video deck to which a magnetic recording / reproducing apparatus according to an embodiment of the present invention is applied. FIG. 1 shows a control system of a video head of the video deck. The control system of the video head generally includes a video tape 1 driven by a predetermined video tape loading mechanism (not shown), video heads 2a and 2b, and rotary transformers 3a respectively connected to the video heads 2a and 2b. , 3b, head amplifiers 4a, 4b respectively connected to the rotary transformers 3a, 3b, a switch circuit 5 for the video heads 2a, 2b for switching to one of the output units of the head amplifiers 4a, 4b, A video signal processing circuit 6 whose terminal is connected to the rotor side of the changeover switch circuit 5, a vertical synchronization signal separation circuit 7 for extracting a vertical synchronization signal from the video signal from the video signal processing circuit 6, a video head 2a, A servo circuit 8 for generating and outputting a video head switching signal to the changeover switch circuit 5 of 2b, and a video output terminal 10 , A rotating drum 11, a permanent magnet 12, a position detecting head 13, a microcomputer 21, and an EPROM 22.

Here, the rotating drum 11 has the video heads 2a and 2b mounted opposite to each other at, for example, 180 ° symmetrical positions, and has the rotary transformers 3a and 3b and the permanent magnets 12 for position detection. . The position detection head 13 is a position detection head for extracting a pulse signal from the permanent magnet 12 as a position detection signal. FIG. 2 shows the positions of signals such as the vertical synchronizing signal Sv on the video track, and FIG. 3 shows the timing of the video head switching signal Ss and the vertical synchronizing signal Sv. When a video cassette mounted on a video deck is reproduced, a video signal recorded on a video tape 1 reproduced by a video head 2a or 2b is amplified by a head amplifier 4a or 4b via a rotary transformer 3a or 3b. Is done. The amplified video signal is input to a video signal processing circuit 6 via a switching circuit 5 which is switched for each field by a video head switching signal. The video signal processed by the video signal processing circuit 6 is output from the video output terminal 10 and is also input to the vertical synchronizing signal separation circuit 7 where the vertical synchronizing signal is separated and input to the servo circuit 8. This vertical synchronizing signal becomes a reference signal for the reproducing system. On the other hand, a predetermined position of the rotating drum 11 is detected by the permanent magnet 12 and the position detecting head 13.

Here, the microcomputer 21 receives a vertical synchronization signal from the vertical synchronization signal separation circuit 7 and a video head switching signal from the servo circuit 8. The microcomputer 21 calculates a control amount for controlling the interval between these two signals to 6.5H as shown in FIGS. 2 and 3, and adjusts the VCR body when adjusting the switching point. Mode and execute the automatic adjustment process described later. The automatic adjustment process is performed by the microcomputer 21 by notifying the microcomputer 21 from the video signal processing circuit 6 that has read out a control signal formed with a predetermined control duty recorded on the control track of the video tape 1. Be executed. Here, the control duty of the control track read by the video signal processing circuit 6 is stored in the EPROM 22 and is used in the control duty duplication processing described later.

The servo circuit 8 has an input terminal connected to the vertical synchronizing signal separating circuit 7, the microcomputer 21 and the position detecting head 13, and a video head generated based on a position detecting signal from the position detecting head 13. The switching signal is output to the changeover switch circuit 5 and the microcomputer 21 in accordance with the control amount from the microcomputer 21 by changing the timing so that the interval from the vertical synchronizing signal becomes 6.5H before.

FIG. 4 shows a schematic aspect of the video tape 1 used for the automatic adjustment as described above. Referring to FIG. 1, a video tape 1 has an audio track area 1a, a video track area 1b, and a control track area 1b. An audio signal is recorded in the audio track area 1a, and the video track area 1b mainly has an audio signal. A video signal is recorded. In the control track area 1c, a control signal having a predetermined control duty is recorded.

FIG. 5 is a diagram schematically showing a recording mode of a control signal having a predetermined control duty recorded in the control track area 1c. In the figure, a control track area 1c has control tracks 1b1 to 1bn recorded at a predetermined constant interval, and a control signal is provided at a predetermined position of the control tracks 1b1 to 1bn so as to have a predetermined control duty. Is formed. The control duty is obtained by recording the magnetism of the S pole and the N pole at a predetermined ratio. The microcomputer 21 obtains the control duty read by the video signal processing circuit 6, and obtains the S duty at the predetermined ratio. Then, it is determined whether or not the N pole has been recorded, and if it has been recorded, an automatic adjustment process is executed.

Next, the operation of the video deck according to an embodiment will be described. In the figure, the vertical synchronizing signal separated by the vertical synchronizing signal separation circuit 7 during reproduction is input to the microcomputer 21. On the other hand, when the video signal processing circuit 6 reads the data recorded in the control tracks 1b1 to 1bn and detects a control signal having a predetermined control duty, it outputs a notification signal notifying the servo circuit 8 of the detection. I do. Based on this signal, the servo circuit 8 generates a video head switching signal and outputs it to the switching switch circuit 5 and the microcomputer 21. As shown in FIG. 3, the microcomputer 21 having received the vertical synchronizing signal and the video head switching signal as described above has a period of 6.times. From the rising of the video head switching signal Ss to the falling of the vertical synchronizing signal Sv. The control amount is calculated so as to be 5H (approximately 413 μsec), the servo circuit 8 is controlled based on the calculation result to control the timing of the video head switching signal, and the video head switching point at the time of reproduction is automatically adjusted. I do.

The operation described above is performed by the microcomputer 21 by setting the VCR body in the adjustment mode (that is, the switching point can be adjusted only in this mode). Thereafter, when the microcomputer 21 releases the adjustment mode, the microcomputer 21 stores the control amount of the servo circuit 8 in the EPROM 22 and stores the control duty mode in the EPROM 22.

FIG. 6 is a flowchart showing the contents of the automatic adjustment processing for video head switching executed by the microcomputer 21. In the figure, when the reproduction of the video tape inserted in the video deck is started, the control tracks 1b1 to 1bn at predetermined positions for instructing the execution of the automatic adjustment process of the video head are read (step S100). Then, it is determined whether or not the control signal recorded on the control tracks 1b1 to 1bn is a control signal having a predetermined control duty (step S105). Here, if the control signal has a predetermined control duty, the microcomputer 21 shifts to an automatic adjustment mode for setting a switching point of the video head (step S115), and the microcomputer 21 executes the above-described arithmetic processing to execute the above-described arithmetic processing. The switching timing is set to 6.5H (step S120). When the setting is completed, the control duty is stored in the EPROM 22 (step S125).

FIG. 7 is a flowchart showing the control duty duplication processing executed by writing the control duty executed by the microcomputer 21 on the video tape. As shown, when the video tape 1 is mounted on the video deck, the control tracks 1b1 to 1bn at predetermined positions are read (step S200). Then, it is determined whether or not the read data recorded on the control tracks 1b1 to 1bn is a control signal having a predetermined control duty (step S205). Here, if the control duty is the predetermined control duty, the control duty duplication processing ends, and the switching point of the video head is set in the automatic adjustment processing described above. On the other hand, if the predetermined control duty has not been recorded, the control duty stored in the EPROM 22 is read out in step S125 (step S110) and recorded on the control tracks 1b1 to 1bn (step S215). As a result, when the video tape is reproduced thereafter, the above-described automatic adjustment processing is executed.

As described above, when it is detected that the control signal pre-recorded on the video tape is formed at a predetermined control duty, an automatic adjustment process for automatically adjusting the switching timing of the video head is executed, Since the switching timing of the video head can be adjusted so as to be 6.5H before the vertical synchronizing signal, the adjustment work can be easily performed by preparing this video tape. In addition, since the above-described control duty mode is stored in the EPROM 22 and read out from the EPROM 22 to a video tape at the time of recording and recorded as a control signal, a video tape capable of starting automatic adjustment of the switching timing of the video head is provided. It becomes possible to duplicate.

[Brief description of the drawings]

FIG. 1 is a block diagram of a video deck to which a magnetic recording and reproducing apparatus according to an embodiment of the present invention is applied.

FIG. 2 is a diagram showing a position of a vertical synchronization signal on a video signal track area.

FIG. 3 is a diagram illustrating timings of a vertical synchronization signal and a video head switching signal.

FIG. 4 is a schematic configuration diagram showing a schematic configuration of a video tape.

FIG. 5 is a configuration diagram showing a schematic configuration of a control track area.

FIG. 6 is a flowchart showing the contents of an automatic adjustment process for video head switching executed by the microcomputer 21;

FIG. 7 is a flowchart showing the control duty duplication processing executed by writing the control duty executed by the microcomputer 21 on a video tape.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Magnetic tape 2a, 2b ... Video head 3a, 3b ... Rotary transformer 4a, 4b ... Head amplifier 5 ... Changeover switch circuit 6 ... Video signal processing circuit 7 ... Vertical synchronization signal separation circuit 8 ... Servo circuit 11 ... Rotating drum 12 ... Permanent magnet 13 Position detecting head 21 Microcomputer 22 EPROM

Claims (4)

[Utility model registration claims] 1. A magnetic recording / reproducing apparatus for setting a switching timing of two video heads disposed opposite to a rotating drum, wherein the video head is switched to a predetermined area of a video tape mounted on a recording / reproducing mechanism. Control signal detecting means for detecting whether or not a predetermined control signal for starting processing is recorded; and switching to one of the video heads used for recording / reproduction while synchronizing with a predetermined video tape loading mechanism. A rotating drum switching signal output means for outputting a rotating drum switching signal for instructing the control signal; and
A switching point control means for controlling a switching point so that the rotating drum switching signal is output before a predetermined horizontal scanning period of a vertical synchronizing signal by the video head switching process. . 2. The magnetic recording / reproducing apparatus according to claim 1, wherein the control signal detecting means stores a mode of a predetermined control signal recorded on the video tape in a predetermined storage area. A magnetic recording / reproducing apparatus comprising: 3. The magnetic recording / reproducing apparatus according to claim 2, wherein the control signal detecting means reads out a mode of a predetermined control signal stored in the control signal storage means at the time of executing a video recording operation, and performs the video recording. A magnetic recording / reproducing apparatus for recording data in a predetermined area of a video tape mounted on a recording / reproducing mechanism in correspondence with the above. 4. The magnetic recording / reproducing apparatus according to claim 1, wherein the control signal detecting means determines that the control signal of the video tape is a predetermined control signal when the control signal has a predetermined control duty. A magnetic recording / reproducing apparatus characterized by the above-mentioned.