JP2850324B2 - Magnetic recording / reproducing device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetic recording / reproducing apparatus provided with an image memory.

[Summary of the Invention]

According to the present invention, in a magnetic recording / reproducing apparatus equipped with an image memory, in addition to a state in which an output switch is controlled by a controller, the output switch is set to a state in which a reproduction signal not via the image memory is always output. It can be set to perform noiseless variable-speed playback, and the editing point can be easily searched for at the time of editing.

[Conventional technology]

VTRs equipped with field memories are becoming widespread. FIG. 5 shows an example of the configuration of a conventional VTR reproducing system having a field memory.

In FIG. 5, the recording signal of the tape 51 is
Played on A, 52B. Reproduction signals from the rotary heads 52A and 52B are supplied to a video signal processing circuit 53. In the video signal processing circuit 53, the luminance signal is FM-demodulated, the chroma signal is frequency-converted, and the luminance signal and the chroma signal are synthesized.
An NTSC composite video signal is formed.

The output of the video signal processing circuit 53 is the terminal of the switch circuit 54
It is supplied to A / D converter 55 while being supplied to 54A. The output of the video signal processing circuit 53 is digitized by the A / D converter 55. The output of the A / D converter 55 is supplied to the field memory 56.

The field memory 56 is controlled by the controller 57. The controller 57 is supplied with a mode setting signal from the key switch 58.

The output of the field memory 56 is supplied to the D / A converter 59. The output of the field memory 56 is returned to an analog video signal by the D / A converter 59. D / A converter 59
Is supplied to the terminal 54B of the switch circuit 54.

The switch circuit 54 is controlled according to a setting mode by a switch control signal S11 from the controller 57. The output from the terminal 54C of the switch circuit 54 is output from the output terminal 60.

As described above, when the field memory 56 is mounted on the VTR, special reproduction such as mosaic, solarization, and picture-in-picture can be performed by controlling the address of the field memory 56 and the control of the switch circuit 54. In addition, a noise reducer, a TBC (time base collector), and the like can be configured using the field memory 56, and the image quality can be improved.

Further, when the field memory 56 is used, noiseless variable speed reproduction can be realized without disposing a large number of heads. That is, the VT without the field memory 56
In R, it is necessary to arrange a large number of heads to perform noiseless variable speed reproduction. On the other hand, when the field memory 56 is used, by controlling the address of the field memory 56 and the control of the switch circuit 54, the screen of the noise-free portion is synthesized, so that the noiseless shifting can be performed without disposing a large number of heads. Can play. For example, the noiseless picture search can be realized by replacing a portion that becomes noise for each screen with the signal of the previous screen stored in the field memory 56 when the servo lock is performed at an even-number speed.

However, even when the noiseless picture search is performed using the field memory 56 in this way, since the servo lock is not completed during the transition from the normal playback state or the pause state to the picture search state, a screen without noise is displayed. It is difficult to reproduce.

Therefore, in this type of conventional VTR, during the transition from the normal reproduction state or the pause state to the picture search state, or during the transition from the picture search state to the normal reproduction state or the pause state, until the servo lock is completed. The image immediately before the mode transition starts is stored in the field memory 56, and the image immediately before the mode transition starts is reproduced as a still image. Thus, noiseless reproduction can be realized even during the mode transition period.

That is, in this type of conventional VTR of, as shown in Figure 6, and is switched from the normal reproduction mode to the picture search mode at time T _1.

When the mode is switched at time T _1, it is controlled so that the tape 51 is fed at a rate v ₂ during picture search.
However, the tape 51 from the speed v ₁ in the normal until the speed v ₂ set at the picture search, it is necessary to servo lock time.

In until the servo lock is completed, in order to screen with the noise prevented from being reproduced, the period from the mode is switched at time T ₁ until the servo lock is completed at time T _2, stationary The image is reproduced. That is, the time
Playback screen by T ₁ is taken into the field memory 56.
Then, the switch circuit 54 is switched so that the terminal 54B and the terminal 54C are connected. Accordingly, the playback screen at the time T ₁ is output from the output terminal 60.

If at time T ₂ servo lock is completed, so that the portion of noise on the screen is not output, the switching circuit 54 is switched appropriately.

[Problems to be solved by the invention]

When performing video editing, in order to search for a desired scene, a transition from normal reproduction or pause to picture search, or vice versa, a transition from picture search to normal reproduction or pause is frequently performed. At the time of editing, it is desired that a desired editing point can be searched with high accuracy.

As described above, the image immediately before the start of the mode transition is stored in the field memory 56 until the servo lock at the time of the mode transition is completed so that the noise generated during the transition of the reproduction mode does not appear on the screen, When an image just before the mode transition is initiated so that still reproduction, in the period from time T ₁ to time T ₂ in FIG. 6, the screen at the time T ₁ is is reproduced still image. Thus, at time point T ₁ through T _2, what position on the tape 51 is reproduced currently not accurately known. For this reason, at the time of editing, there arises a problem that a desired editing point cannot be accurately searched.

Accordingly, an object of the present invention is to provide a magnetic recording / reproducing apparatus capable of performing noiseless variable speed reproduction and accurately detecting an editing point at the time of editing.

[Means for solving the problem]

According to the present invention, in a magnetic recording / reproducing apparatus having an image memory 6, switch means 4 for selectively extracting a reproduction signal stored in the image memory 6 and a reproduction signal not passing through the image memory 6 is provided. Is a magnetic recording / reproducing apparatus that can be set to a state in which a reproduced signal that is not passed through the image memory 6 is always output.

When the switch means 4 is set to the edit mode,
The state is set such that a reproduction signal that does not pass through the image memory 6 is always output.

The switch means 4 is set to a state in which a reproduction signal that is not passed through the image memory 6 is always output during a transition period during variable speed reproduction.

The switch means 4 is set to the edit mode and to always output a reproduction signal which does not pass through the image memory 4 during a transition period during variable speed reproduction.

[Action]

A switch 13 for constantly outputting a video signal that is not passed through the field memory 6 is provided. When editing,
The switch 13 is turned on. Thereby, at the time of editing, the tape position and the playback screen correspond at the time of mode transition,
Edit points can be searched accurately.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of the present invention. In FIG. 1, a recording signal of a tape 1 is a rotating head.
Played on 2A, 2B. The reproduction signals of the rotary heads 2A and 2B are supplied to the video signal processing circuit 3. In the video signal processing circuit 3, the luminance signal is FM-demodulated, the chroma signal is frequency-converted, and the luminance signal and the chroma signal are synthesized.
An SC composite video signal is formed.

The output of the video signal processing circuit 3 is the terminal of the switch circuit 4.
4A and supplied to the A / D converter 5. The output of the video signal processing circuit 3 is digitized by the A / D converter 5. The output of the A / D converter 5 is supplied to the field memory 6.

The field memory 6 is controlled by the controller 7. The controller 7 receives a mode setting signal from the key switch 8.

The output of the field memory 6 is supplied to a D / A converter 9. The output of the field memory 6 is returned to an analog video signal by the D / A converter 9. D / A converter 9
Is supplied to the terminal 4B of the switch circuit 4. The output from the terminal 4C of the switch circuit 4 is taken out from the output terminal 10.

The switch circuit 4 is controlled by the output of the AND gate 11. When the output of the AND gate 11 is at a low level, for example, the switch circuit 4 is switched so that the terminals 4A and 4C are connected. When the output of the AND gate 11 is at a high level, for example, the switch circuit 4 is switched so that the terminals 4B and 4C are connected.

The AND gate 11 is supplied with the switch control signal S1 from the controller 7 and the forced setting signal S2 from the flip-flop 12. Switch control signal S1
Is low during normal playback or pause, high during the mode transition period until servo lock is completed, and appropriately high during picture search so that no noise appears. ,
It goes low.

The flip-flop 12 is set by the switch 13. When the switch 13 is turned off, the compulsory setting signal S2 from the flip-flop 12 goes high. When the switch 13 is turned on, the forcible setting signal from the flip-flop 12
S2 goes low.

In this embodiment, by setting the switch 13 manually, a noiseless picture search in which noise does not appear on the screen even when the mode is changed when editing is not performed can be realized. Searchable.

That is, the switch 13 is turned off except during editing, and the switch 13 is turned on during editing. When the switch 13 is off, the forced setting signal S2 from the flip-flop 12
Is high level. Therefore, the switch control signal S1 from the controller 7 is supplied to the switch circuit 4 via the AND gate 11. As described above, the switch control signal S1 is at a low level during normal reproduction or pause, during a mode transition period, is at a high level until servo lock is completed, and during a picture search, a noise portion is generated. It becomes high level and low level appropriately so as not to appear. And the switch circuit 4
For example, when the output of the D gate 11 is at a low level, the switch circuit 4 is switched so that the terminals 4A and 4C are connected. When the output of the AND gate 11 is at a high level, for example, the switch circuit 4 is connected to the terminals 4B and 4C. It is switched so that 4C is connected. Therefore, during the mode transition period, the screen stored in the field memory 6 is reproduced as a still image, and a screen with noise is not reproduced. When the servo lock is completed, the switch circuit 4 is switched by the switch control signal S1.
Can be appropriately switched, and noiseless variable speed reproduction can be performed.

At the time of editing, the switch 13 is turned on. When the switch 13 is turned on, the forcible setting signal from the flip-flop 12
S2 is set to low level. When the compulsory setting signal S2 is set to low level, the output of the AND gate 11 is always at low level regardless of the switch control signal S1 from the controller 7. When a low level is supplied to the switch circuit 4, the switch circuit 4 is switched so that the terminals 4A and 4C are always connected. If the switch circuit 4 is always switched to the terminal 4A side, still reproduction is not performed even during the mode transition period, so that an edit point can be accurately searched.

FIG. 2 shows a second embodiment of the present invention. In FIG. 2, the same portions as those of the embodiment are denoted by the same reference numerals. In this embodiment, the switch 13 is shared with the edit switch. That is, a VTR intended for video editing is provided with an editing switch. The edit switch switches the characteristics of the video signal correction circuit in order to cope with image quality deterioration during dubbing.

In FIG. 2, the switch 13 is turned off except during editing, and turned on during editing. When the switch 13 is off, the output of the flip-flop 12 is set to high level, and when the switch 13 is on,
The flip-flop 12 is set to low level. The output of flip-flop 12 becomes AND gate 1 as forced setting signal S2
1 and is supplied to the correction circuit 20 of the video signal processing circuit 3 as a correction value switching signal.

Except during editing, the edit switch 13 is turned off. When the edit switch 13 is off, the output of the flip-flop 12 goes high, and the video signal processing circuit 3
The correction circuit 10 has the characteristics at the time of normal operation. The normal characteristic is a characteristic in which the high frequency range is slightly emphasized in order to improve the reproduction screen. At this time, the compulsory setting signal S2 goes high. Therefore, the switch control signal S1 from the controller 6 is supplied to the switch circuit 4 via the AND gate 11. For this reason, during the mode transition period, the screen stored in the field memory 6 is reproduced as a still image, and a screen with noise is not reproduced.

When editing, the edit switch 13 is turned on.
When the edit switch 13 is turned on, the output of the flip-flop 12 goes low. When the output of the flip-flop 12 is at the low level, the correction circuit 20 of the video signal processing circuit 3 has the characteristics at the time of editing. The characteristics at the time of editing are characteristics in which the high-frequency characteristics are flattened in order to prevent image quality deterioration due to editing. Also, at this time, the forced setting signal S2 from the flip-flop 12 becomes low level, so that regardless of the switch control signal from the controller 7, AND operation is always performed.
The output of the gate 11 goes low. Therefore, the switch circuit 4 is switched so that the terminals 4A and 4C are connected. As a result, the editing point can be accurately searched even during the mode transition period.

FIG. 3 shows a third embodiment of the present invention. In the first and second embodiments described above, when the switch 13 is turned on, not only the mode transition period, but also the switch circuit 4 is switched so that the terminals 4A and 4C are always connected. On the other hand, in the third embodiment, when the switch 13 is turned on, the switch circuit 4 is switched so that the terminals 4A and 4C are connected only at the time of mode transition.

That is, in FIG. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals. The output of the flip-flop 12 is switched by the switch 13. When the switch 13 is turned off, the output of the flip-flop 12 goes high. When the switch 13 is turned on, the flip-flop
12 outputs go low. The output of the flip-flop 12 is inverted and supplied to the NAND gate 21.

Further, a mode transition period signal S3 is extracted from the controller 7, and this mode transition period signal S3 is output from the NAND gate 21.
Is supplied to the other input terminal. This mode transition period signal S3, as shown in FIG. 4, for example, is switched from the normal mode to the picture search mode, a high level between t ₁ ~t ₂ until the servo lock is completed.

A forced setting signal S2 is obtained from the NAND gate 21, and the forced setting signal S2 is supplied to the AND gate 11.

Except during editing, the switch 13 is turned off, and the output of the flip-flop 12 becomes high level. Therefore, the forced setting signal S2 output from the NAND gate 21 is always at the high level regardless of the mode transition signal S3. NAND gate
When the forced setting signal S2 output from 21 is set to the high level, the switch control signal S1 from the controller 7 is supplied to the switch circuit 4 via the AND gate 11 as it is. Thus, during the mode transition period, the screen stored in the field memory 6 is reproduced as a still image.

At the time of editing, the switch 13 is turned on. Switch circuit
When 13 is turned on, the output of flip-flop 12 goes low. When the output of the flip-flop 13 becomes low level, the mode transition signal S3 is inverted and output from the NAND gate 21. That is, when the switch 13 is turned on, the between time t ₁ ~t ₂ in Figure 4 A, forcing the signal S2 output from the NAND gate 21 becomes low level. When the compulsory setting signal S2 goes low, the output of the AND gate 11 goes low regardless of the switch control signal S1 from the controller 7. Therefore, time points t _{1 to} t ₂
During the mode transition period, the terminal 4A of the switch circuit 4 and the terminal
4C is connected, and a video signal not passing through the field memory 6 is output from the output terminal 10. As a result, the edit point can be accurately searched.

In the third embodiment shown in FIG.
When the switch 13 is turned on and the switch 13 is turned on, the characteristics of the correction circuit of the video signal processing circuit may be switched. In the above-described embodiment, the composite video signal is stored in the field memory. However, the component video signal may be stored. Further, a frame memory may be used without using the field memory.

〔The invention's effect〕

According to the present invention, the switch 13 for constantly outputting a video signal not passing through the field memory 6 is provided, and this switch 13 is turned on at the time of editing. As a result, at the time of editing, the tape position and the playback screen correspond to each other at the time of mode transition, and the editing point can be accurately searched. By turning off the switch 13 except when editing, a still image is reproduced at the time of mode transition, and noiseless variable speed reproduction can be performed.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a block diagram of a second embodiment of the present invention, FIG. 3 is a block diagram of a third embodiment of the present invention, FIG. FIG. 5 is a timing chart used for explaining a third embodiment of the present invention, FIG. 5 is a block diagram of a configuration of a conventional VTR reproducing system, and FIG. 6 is a graph used for explaining a conventional VTR. Explanation of main symbols in the drawing 4: switch circuit, 6: field memory, 7: controller, 1
2: flip-flop, 13: switch.

Claims (3)

(57) [Claims] 1. A video reproducing means for reproducing a video signal from a magnetic recording medium, an image memory for storing a video signal reproduced from the video reproducing means, a reproduced signal stored in the image memory, and the image memory Switch means for selectively taking out a reproduction signal which is not passed through; mode input means provided with an input for setting a normal reproduction mode and a variable-speed reproduction mode; and an image memory based on an input from the mode input means. In the normal playback mode, the playback signal is set to the playback signal side not passing through the image memory. In the variable speed playback mode, the playback signal side not passing through the image memory and the playback signal side stored in the image memory are appropriately set. In the mode transition period, it is set to the reproduction signal stored in the image memory. Control means for generating a switch control signal for controlling the switch means, forcible input means for forcibly setting a reproduction signal stored in the image memory during a mode transition period so as not to be output, and input from the forcible input means. Switch compulsory setting means for compulsorily setting the switch means so as to always be set to a reproduction signal side not passing through the image memory regardless of the switch control signal from the control means based on Characteristic magnetic recording / reproducing device. 2. The video reproducing means is provided with an image correction circuit for giving the reproduced video signal an optimum characteristic during normal reproduction and an optimum characteristic during editing, based on an input from the forcible input means. When the switch means is forcibly set to the reproduction signal side which does not pass through the image memory regardless of the switch control signal from the control means, the characteristics of the image correction circuit are set to the optimum characteristics at the time of editing. 2. The reproducing apparatus at the time of magnetic recording according to claim 1. 3. The control means generates a mode transition signal corresponding to a mode transition period, and the switch forcible setting means controls the control based on an input from the forcible input means during the mode transition signal. 2. The switch means is forcibly set so as to always be set to a reproduction signal side not passing through the image memory irrespective of the switch control signal from the means.
The magnetic recording and reproducing apparatus according to claim 1.