JPH07282402A - Device and method for intermittent magnetic recording - Google Patents

Abstract

PURPOSE:To record input signals on a magnetic tape at every accurate time interval and to obtain a continuously reproduced image at the time of reproducing. CONSTITUTION:Switching of a frame memory 4 recording an image signal for each frame, a capstan motor 9 driving a magnetic tape 6, and magnetic heads 2, 20 of a rotary cylinder 1 are all controlled by a system control section 7. When a signal is inputted to the frame memory 4, the system control section 7 drives the capstan motor 9, the magnetic head 2 performs temporarily reproduction. When time information is detected by reproduction, a signal is outputted from the frame memory 4, and recorded in the magnetic tape 6. After finish of recording, the system control section 7 rotates reversely the magnetic tape, and stops the capstan motor 9 in a state in which a part proceeding in the reverse direction of tape rotation from a track recorded by the magnetic head 2 immediately before finish of recording is slid.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermittent magnetic recording apparatus and an intermittent magnetic recording method for intermittent recording, which are used in cameras for monitoring and subjecting slow moving objects to time compression.

[0002]

2. Description of the Related Art Conventionally, in such an intermittent magnetic recording device,
The following have been proposed: When a video signal is input to the apparatus, the capstan motor drives the magnetic tape for one frame of the video signal, and the rotary cylinder is rotated to record the video signal. When recording is completed, so-called "frame drop recording" is performed in which the drive of the magnetic tape is stopped and kept in standby while the rotating cylinder is rotating, and the same operation is repeated.
It is about. However, in this device, due to the start-up characteristics of the capstan motor that drives the magnetic tape, the time from the start-up until the rotation speed reaches the specified speed,
There are variations. Therefore, the magnetic tape drive speeds at the time of recording and at the time of reproduction do not always match, and the magnetic head may not be able to accurately trace the horizontal synchronization signal recorded on the magnetic tape at the time of reproduction.

Therefore, a device shown in FIG. 9 has been proposed.
(See JP-A-60-195780). This is provided with a frame memory (4) and a control unit (100) for controlling the frame memory (4), to which a video signal is input from the outside of the device body (5). The control unit (100) stores the video signal for one frame for each predetermined number of frames of the video signal in the frame memory (4), and at the same time, for each predetermined time, the capstan motor (9).
Rotate and start driving the magnetic tape (6). When the magnetic tape (6) reaches the specified speed, the control unit (100) outputs a plurality of frame unit video signals stored in the frame memory (4) to the magnetic heads (2) and (20), The magnetic heads (2) and (20) write the signal on the magnetic tape (6). When the contents stored in the frame memory (4) are recorded on the magnetic tape (6), the capstan motor (9) is stopped and the same operation is repeated. Since the video signal is recorded after the magnetic tape 6 reaches the prescribed speed, the horizontal synchronizing signal can be accurately traced during reproduction.

[0004]

In the above apparatus, the magnetic tape (6) starts to record a frame after reaching the specified speed. However, due to the starting characteristic of the capstan motor 9, the time from when the capstan motor 9 is stopped to when it reaches the specified speed is not always constant. Therefore, the distance intervals between the frames recorded on the magnetic tape 6 are not always constant, and it is not possible to cope with the case where information is required at continuous accurate time intervals during reproduction.
It is an object of the present invention to continuously record frames at accurate time intervals on a magnetic tape and obtain continuous information during reproduction.

[0005]

In an intermittent magnetic recording apparatus, a time signal generating means for issuing time information to be recorded in a signal track of a magnetic tape (6) and a memory means for storing an input signal at regular intervals. As well as issuing a control signal,
In response to the transmission of the control signal, the drive means is actuated, and the magnetic heads (2) and (20) are reproduced, and the magnetic heads (2) and (20) are reproduced. After detecting the time information, the signal stored in the memory means is called and the recording control means for recording the signal on the magnetic tape (6) and the track (60) on the magnetic tape (6) by the recording control means.
After recording, the drive means is reversed and the magnetic tape
(6) is reversely run, and the magnetic head (2) is provided with a stop control means for stopping the drive means in a state where the magnetic head (2) slides on a portion closer to the tape reverse direction than the track (60).

[0006]

When the memory means stores the input signal, the drive means causes the magnetic tape (6) to run by the control means, and the magnetic head (2) is in a reproducing state. The recording control means, after detecting the time information recorded on the magnetic tape (6), calls the signal stored in the memory means to record the track (60) on the magnetic tape (6). After the signal is recorded, the stop control means reverses the driving means to cause the magnetic tape (6) to run in the reverse direction, and the track (60) recorded immediately before by the magnetic head (2).
As a result, the drive means is stopped in a state where it slides on a portion closer to the tape reverse direction. The above operation is repeated every time the memory means stores the input signal at regular intervals.

[0007]

Since the input signals stored in the memory means at regular intervals are recorded on the magnetic tape (6), the time when each input signal is actually recorded depends on the starting characteristics of the driving means. Magnetic tape (6) even if the gaps occur
The input signal is recorded at the exact time intervals. Therefore, during reproduction, it is possible to obtain information recorded at accurate time intervals. Further, when recording the signal stored in the memory means, the magnetic tape (6) that has been moved back and stopped once is reproduced, and after the time information recorded on the magnetic tape (6) is detected, ,Record. After the recording is completed, the magnetic tape (6) is rotated in the reverse direction, and the magnetic tape (6) is stopped in a state where the magnetic head (2) slides on a portion near the tape reverse direction from the track (60) recorded immediately before. In preparation for recording the next input signal. Therefore, the interval between the tracks recorded on the magnetic tape (6) can be narrowed, and continuous images can be obtained during reproduction.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 1, the rotary cylinder (1) has two different azimuth angles as in the conventional case.
Two magnetic heads (2) and (20) are provided at symmetrical positions with the center of the rotary cylinder (1) interposed therebetween. A capstan motor (9) for driving the magnetic tape (6) is arranged beside the rotary cylinder (1), and a control head (90) is installed between the rotary cylinder (1) and the capstan motor (9). ) Is provided. The control head 90 records a control signal on the lower side of the magnetic tape 6 or reproduces the recorded control signal.

A video signal is input to an input terminal (50) provided on the apparatus body (5), and the video signal is an A / D converter (51).
After being converted into a digital signal by the frame memory
Input in (4). The video signal output from the frame memory (4) in response to the signal from the timing circuit (40) described later is returned to the analog signal by the D / A converter (52), and the video signal processing circuit (8) Entered in. The video signal processing circuit (8) applies a recording current to the magnetic head based on the video signal.
(2) Sends to the (20) and outputs a video signal from the current reproduced by the magnetic heads (2) and (20).

As is well known in the reproduction signal processing circuit (3), the reproduction video signal output from the video signal processing circuit (8) is subjected to FM demodulation of the video signal and then the video signal and time information are obtained. , To the monitor (91) and the system controller (7). The drive timing of the capstan motor (9) is controlled by the system control unit (7) composed of a microcomputer. That is, the system control section (7) outputs a signal SX for driving the capstan motor (9), a signal SY for stopping, and a signal SZ for reversing. The system control unit (7) also generates time information representing the time in seconds and outputs it to the timing circuit (40) provided between the system control unit (7) and the frame memory (4). The system control section (7) issues a control signal to the timing circuit (40) at regular intervals. The timing circuit (40) receives the control signal and issues the control signal SC so that the frame memory (4) records the video signal and the time information at regular intervals, and at the same time, outputs the video signal and the time information to the frame memory. The system control unit (7) is informed that the data has been stored in (4). The system control section (7) also detects the time information from the reproduction signal processing circuit (3) and issues a control signal SD so as to output the information stored in the frame memory (4). Magnetic head
(2) records the video signal and time information output from the frame memory (4) on a magnetic tape (6), or a magnetic tape
Play from (6).

As shown in FIG. 3, the video signal processing circuit (8) amplifies the video signal converted into a recording current in the recording mode and sends it to each magnetic head (2) (20), and also in the reproduction mode. Then, the reproduction signals from the magnetic heads (2) and (20) are amplified (see Japanese Patent Laid-Open No. 5-300464). That is, the video signal processing circuit (8) outputs the input video signal to the recording signal processing unit.
After performing a well-known pre-emphasis process in (80), it is amplified in the recording amplifier (82), and a recording current is sent to each magnetic head (2) (20) through the changeover switches (84) (85). . In the reproduction mode, the reproduction signals from the magnetic heads (2) and (20) are transmitted through the changeover switches (84) and (85) to the reproduction amplifier (83).
Is reproduced by the reproduction signal processing section (81).

A changeover switch (86) is provided between the recording signal processing section (80) and the recording amplifier (82).
(86) and changeover switches (84) and (85) are system control unit (7)
Can be switched by. When the changeover switch (86) is ON, the changeover switches (84) and (85) change the recording signal to each magnetic head.
(2) Switch to flow to (20), changeover switch
When (86) is turned off, the changeover switches (84) (85) close the electric path between the magnetic heads (2) (20) and the reproduction amplifier (83).
Which magnetic head (2) (20) is to be recorded and reproduced by the system control unit (7) is issued from the rotary cylinder (1).
Although it is determined based on the G pulse (not shown) and the control signal, this is a known technique and its detailed description is omitted.

FIG. 2 shows the track format of one frame recorded by the magnetic head (2). The truck
(60) is formed diagonally to the tape running direction,
(60) A time signal area (61) in which time information is recorded on the upper part, and a control signal area (63) below the time signal area (61)
Video signal areas (62) in which video signals are recorded are provided above each. Note that the time information can be represented by another method, for example, by converting the time information into a low-frequency signal,
It goes without saying that a method of recording according to (62) can be considered.

(Intermittent Recording) The operation of intermittent recording will be described below with reference to FIGS. 1, 4, and 5 to 7. FIG. 4 is a timing chart of this embodiment, in which the vertical axis represents the track of the magnetic tape (6) and the horizontal axis represents time. The shaded area in FIG. 4 (a) shows a frame recorded every 30 seconds. Figure 5
7 to 7 are flowcharts showing the operation of the system controller (7). In the present embodiment, one frame is recorded every 30 seconds, but it goes without saying that the recording interval of each frame can be set arbitrarily. Video signals are continuously input to the input terminal (50). Here, the time information of an arbitrary frame A is set to 0 second, the frame 30 seconds after the frame A is set to B, and the frame 30 seconds after the frame B is set to C. Further, for convenience of explanation, it is assumed that the frame A is recorded by the magnetic head (2) of the two magnetic heads (2) (20).

When a video signal is to be recorded, the magnetic head (2) is first put into a reproducing state, the presence or absence of time information is confirmed, and then recording is performed. To record a signal on an unrecorded tape, follow the procedure below. System control unit (7)
Stores the frame A in the frame memory (4) via the timing circuit (40), drives the capstan motor (9) (S1), and reproduces it with the magnetic head (2) (S2). ). Since the unrecorded tape is being reproduced, the system control unit (7) detects that the reproduction signal from the magnetic head (2) does not include time information (S
3). The system control unit (7) switches the changeover switches (86), (84) and (85) of the video signal processing circuit (8) to the recording mode (S).
At the same time as 9), the frame A is called from the frame memory 7, the frame A is recorded on the magnetic tape 6 by the magnetic head 2 (S10), and then the capstan motor 9 is stopped.
The rotating cylinder (1) keeps rotating. When the frame A is recorded on the magnetic tape (6) in advance, the frame A is reproduced (S2), so the system control unit (7) detects the time information from the reproduction signal processing circuit (3). Then, (S3), it is detected that the time is 0 second, and the drive of the capstan motor (9) is stopped (S4).

After the capstan motor 9 is stopped (S4), the system control unit (7) switches the changeover switches (86) (84) (85).
Switch to playback mode (S5), capstan motor
Reverse (9) and run the magnetic tape (6) in reverse.
(S6). After elapse of a predetermined time or after retreating for a predetermined length (S7),
The rotation of the capstan motor (9) is stopped and it waits until the next drive (S8). This predetermined time or length is sufficient for the magnetic tape (6) to move until the magnetic head (2) slides in the tape reverse direction from the track (60) on which the frame A is recorded. It is time or length and is determined empirically. This time or length is measured by a timer or a counter (neither is shown). At this time, the rotary cylinder (1) continues to rotate. That is, the magnetic head (2) (20)
Keeps sliding on the tape portion closer to the tape reverse direction than the portion where the frame A is recorded.

In FIG. 6, the system control unit (7) waits an appropriate interval, for example, 30 seconds after the frame A is stored or when it is detected that the time information is 0 seconds (S11). , Issues a control signal to the timing circuit (40). The frame memory (4) stores the video signal of the frame B in response to the control signal SC from the timing circuit (40) (S12). At the same time, the system control unit (7) rotates the capstan motor (9) in the tape winding direction (S1
3). At this time, the magnetic head (2) remains in the reproducing state.
Immediately after receiving the control signal from the system control unit (7), the capstan motor (9) is in the run-up period in which the rotational speed is accelerated, and the magnetic tape was reversed after the previous recording.
Send out (6).

When the magnetic tape (6) runs, the magnetic head
(2) passes through the track (60) on which frame A is recorded,
The recorded time information is detected from the track (60).
When the system control unit (7) detects that the magnetic head (2) has passed the track on which the frame A is recorded, based on the information from the reproduction signal processing circuit (3) (S14), it directs it to the timing circuit (40). Generates control signal SD and outputs the frame memory
The frame B is called from (4) (S15). At the same time, the system control unit (7) also records the frame B and the time information on the magnetic tape (6) with a magnetic head (20) different from the magnetic head (2) reproducing the track (60). Operate the selector switches (86) (84) (85) of the video signal processing circuit (8)
(S16, S17).

When the frame B is recorded on the magnetic tape (6) by the magnetic head (20), as shown in FIG. 7, the capstan motor (9) is stopped (S18) and the process returns to step S5. Repeat the operation of. That is, the capstan motor
(9) is reversed and the magnetic head (20) stops the capstan motor (9) while sliding on the part of the magnetic tape (6) closer to the tape reverse direction than the track on which the frame B is recorded. Then, the recording standby state of the next frame C is set.
Hereafter, whether a stop signal is input from outside the device body (5),
Or until the magnetic tape (6) is recorded over the entire length (S1
9), the frame memory (4) stores video signals in the order of frame C and frame D every 30 seconds.

In FIG. 4, the frame B is a magnetic tape.
The time t1 from the recording of (6) to the recording of the frame C and the time t2 from the recording of the frame C to the magnetic tape (6) to the recording of the frame D are not always the same. do not do. This is the system control unit as described above.
(7) sends a signal to start or stop the capstan motor (9), and then the capstan motor (9) actually
The time it takes to start and stop the capstan motor
The stop / start characteristics of (9) are not uniform because they vary. That is, the time from the standby state of the magnetic heads (2) and (20) until the track is reproduced is not constant. However, in this embodiment, the frame stored in the frame memory (4) exactly every 30 seconds is the magnetic tape (6).
Since each frame is recorded on the magnetic tape 6, the video signal can be accurately obtained every 30 seconds at the time of reproduction even if the time intervals at which the frames are recorded on the magnetic tape 6 are different.

Further, every time one frame is recorded, the magnetic tape (6) is reversely run, the magnetic tape (6) is returned, and when recording the next frame, the magnetic head (2) is moved immediately before. Recording is started after the recorded frame is played back. Therefore, the intervals between the tracks on the magnetic tape (6) can be narrowed, and continuous images can be obtained during reproduction.
The present embodiment is useful in the case where the image information for every fixed time is required accurately, for example, in the case of detecting the chemical reaction of a substance. Although the frame memory (4) records one frame at a time, a plurality of frames may be stored at one time.

In such a magnetic recording / reproducing apparatus, the video signal recorded by one magnetic head (2) is half the horizontal synchronizing frequency, for example, 262.5 lines in the NTSC system. There are many. The word "field" is often used to indicate a video signal at half the horizontal synchronizing frequency. Therefore, in interpreting the scope of the claims,
The term "frame" should be understood to include both "frame" and "field" as the case may be.

In this embodiment, the device for performing only the intermittent recording is used. However, for example, as shown in FIG.
A changeover switch (54) that can be operated by the user may be provided in front of (0) so that both normal recording and reproduction and intermittent recording can be performed. That is, when the changeover switch (54) contacts the contact (54a), normal recording and reproduction are performed, and the changeover switch (54)
When (54) contacts the contact (54b), intermittent recording is started. The specified speed of the magnetic tape (6) is 3.3 cm / sec in the NTSC system, but it can be changed according to the purpose of use and the broadcasting system. Furthermore, the device body
It goes without saying that the information input to (5) may include an audio signal and the like in addition to the video signal.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or limiting the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

[Brief description of drawings]

FIG. 1 is a block diagram of an intermittent magnetic recording device.

FIG. 2 is a diagram showing tracks on a magnetic tape.

FIG. 3 is a block diagram showing the inside of a video signal processing circuit.

FIG. 4 is a timing chart of the intermittent magnetic recording device.

FIG. 5 is a flowchart showing the operation of the system control unit.

FIG. 6 is a flowchart of the above.

FIG. 7 is a flowchart of the above.

FIG. 8 is a block diagram of an intermittent magnetic recording device according to another embodiment.

FIG. 9 is a diagram showing a conventional intermittent magnetic recording device.

[Explanation of symbols]

 (2) Magnetic head (6) Magnetic tape (60) Track

Claims (2)

[Claims] 1. A rotary cylinder (1) comprising a plurality of magnetic heads (2) (20), a drive means for running a magnetic tape (6), and an input signal once stored for every predetermined number of frames. In the intermittent magnetic recording device for recording the output signal from the memory means on the magnetic tape (6) by intermittently driving the driving means, the time information to be recorded on the magnetic tape (6). And a time signal generating means for emitting a time signal so that the memory means stores the input signal at regular intervals.
Time information is generated from the control signal that emits a control signal, activates the drive means in response to the transmission of the control signal, and puts the magnetic head (2) into a reproduction state, and the reproduction signal from the magnetic head (2). When detected, after switching the magnetic head (2) to the recording mode,
A magnetic tape is called by calling a signal stored in the memory means.
(6) recording control means for recording the signal, and after the recording control means records the track (60) on the magnetic tape (6), the driving means is reversed to cause the magnetic tape (6) to run backward. An intermittent magnetic recording device characterized by comprising stop control means for stopping the drive means in a state where the magnetic head (2) slides on a portion closer to the tape reverse direction than the track (60). 2. An input signal is stored in the memory means at regular time intervals, the driving means is operated, the magnetic head (2) is brought into a reproducing state, and time information is detected from the reproduced signal and then stored in the memory means. The recorded signal is called to record a track (60) on the magnetic tape (6), and after the recording is completed, the magnetic tape (6) is run in the reverse direction so that the magnetic head (2) reverses the tape from the track (60). An intermittent magnetic recording method in which the driving means is stopped while sliding at a position closer to the direction.