JP2752524B2 - Magnetic recording / reproducing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording / reproducing apparatus such as a home video tape recorder and, more particularly, to a magnetic recording / reproducing apparatus for fast-forwarding an unnecessary video portion on a video tape during reproduction.

[0002]

2. Description of the Related Art When a video signal recorded on a video tape is reproduced by a home video tape recorder, CM
In order to automatically fast-forward unnecessary video portions such as (commercial messages), as disclosed in Japanese Utility Model Publication No. 2-33330, a control signal of unnecessary information portions on a video tape is erased. The part where the control signal is not detected during reproduction is fast-forwarded.

[0003]

However, in the above-mentioned conventional configuration, the control signal is erased from the unnecessary portion on the video tape, so that even if it is desired to reproduce this portion later. However, there is a problem that normal reproduction is difficult.

[0004]

In order to solve the above-mentioned problems, a magnetic recording / reproducing apparatus according to the present invention records a video signal in a direction oblique to the longitudinal direction of a video tape,
In a magnetic recording / reproducing apparatus for recording a control signal for regulating a relationship between the video signal and a video head in a longitudinal direction of a video tape, an identification unit for identifying a video necessary for recording and an unnecessary video, and a recording of the video signal A control signal recording means for recording the control signal on the video tape at the same time; and when the identification signal output from the identification means is switched, a predetermined period corresponding to the identification signal is provided.
A duty ratio switching means for switching the duty ratio of the control signal, and detecting the duty ratio of the control signal during reproduction ,
A duty ratio detecting unit that determines a necessary image and an unnecessary image by measuring a period in which the ratio is switched, and an unnecessary image period is a necessary image period according to an output of the duty ratio detecting unit. Control means for controlling the video tape to run at a higher speed.

[0005]

According to the above arrangement, a video signal is recorded in a direction oblique to the longitudinal direction of the video tape, and a control signal for regulating the relationship between the video signal and the video head is recorded in the longitudinal direction of the video tape. In a magnetic recording / reproducing apparatus, identification means for identifying a video necessary for recording and unnecessary video, control signal recording means for recording a control signal on a video tape simultaneously with recording of a video signal, and output from the identification means A duty ratio switching means for switching a duty ratio of the control signal for a predetermined period according to the identification signal when the identification signal is switched , and detecting a duty ratio of the control signal during reproduction; Cut
By measuring the changed period, a duty ratio detection unit that determines a necessary image and an unnecessary image, and a period of the unnecessary image according to an output of the duty ratio detection unit is larger than a period of the required image. Control means for controlling the video tape to run at a high speed, so that when recording a video signal, the identification means discriminates a necessary video from an unnecessary video and a predetermined value corresponding to the identification result. Period
During this time, the duty ratio of the control signal is switched, and the control signal can be recorded simultaneously with the recording of the video signal. As a result, the period during which the duty ratio of the control signal is switched can be measured.
Thus , it is possible to detect a break between a required video and an unnecessary video. Therefore, at the time of reproduction, unnecessary video can be fast-forwarded or fast-forward-reproduced. In addition, since the control signal is also recorded for unnecessary video, normal reproduction can be performed when desired.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

In the magnetic recording / reproducing apparatus of this embodiment, for example, when recording a foreign film program of a television broadcast, the movie itself is in a bilingual broadcast, but a CM that is played on the way is used.
Utilizing that most of (commercial messages) are stereo broadcasts, movies and CMs are distinguished, and only movies are treated as necessary images, and CMs are treated as unnecessary images.

As shown in the block diagram of FIG. 1, the magnetic recording / reproducing apparatus includes an audio multiplex discriminating circuit 1 (identifying means) for outputting an identification signal for identifying a bilingual broadcast or a monaural broadcast and a stereo broadcast, Duty ratio switching circuit 2 (duty ratio switching means) for switching the duty ratio of the control signal according to the identification signal output from the multiplex discriminating circuit 1, and a servo circuit 3 for outputting a reference signal for recording to the duty ratio switching circuit 2 And a control head 4 (control signal recording means) for recording a control signal having a predetermined duty ratio on the video tape 5 based on an output of the duty ratio switching circuit, and detecting a duty ratio of the reproduced control signal. Duty ratio detection circuit 6 (duty Tee ratio detecting means), and a system control circuit 7 (control means) for controlling the video tape 5 to fast-forward or fast-forward playback only during the CM in accordance with the output of the duty ratio detecting circuit 6. .

The control signal is recorded in the longitudinal direction of the video tape 5 in order to regulate the relationship between the video signal and the video head (not shown). The control signal is reproduced to operate the servo circuit 3. By doing so, the video signal recorded in a direction oblique to the longitudinal direction of the video tape 5 is accurately reproduced by the video head.

Usually, the duty ratio of the control signal is set to 60% as shown in the waveform diagram of FIG. That is, the ratio between the positive pulse 8 and the negative pulse 9 is 60% of one cycle between the positive pulses 8.8. In addition,
In this embodiment, the duty ratio of the control signal is 6
The state of 0% is called logic "0".

On the other hand, when a control signal is used to record an index used for cueing or the like, the duty ratio of the control signal corresponding to the part where the index is to be recorded is 2 as shown in the waveform diagram of FIG.
It is set to 7.5%. That is, the positive pulse 8.8
The period between the positive pulse 8 and the negative pulse 9 is 2
It is 7.5%. In this embodiment, a state in which the duty ratio of the control signal is 27.5% is referred to as logic "1".

The duty ratio switching circuit 2 switches the duty ratio of the reference signal input from the servo circuit 3, and changes the logic of the control signal to be recorded according to the identification signal output from the audio multiplex discrimination circuit 1. Is switched to “0” or “1”. Note that the relationship between the video signal and the video head is regulated by the positive pulse 8 in FIGS. 2 and 3, and is not related to the logic of the control signal.

The duty ratio switching circuit 2 of the present embodiment
In the above, when the identification signal of the audio multiplex discrimination circuit 1 is switched from a signal indicating bilingual broadcasting to a signal indicating stereo broadcasting, the duty ratio switching circuit 2 is set to logic "
1 "is transmitted by 3 bits. Conversely, when the identification signal switches from a signal indicating stereo broadcasting to a signal indicating bilingual broadcasting, 5 bits of logic" 1 "are transmitted. When there is no change in the identification signal, logic "0" is continuously transmitted.

In the above configuration, when a bilingual Western movie program is recorded, a movie section and a CM section are alternately recorded on the video tape 5 as shown in FIG. At this time, the logic of the control signal is such that the logic "0" is continuously recorded in the section of the movie or the CM as shown in the numeral string 10 in the figure corresponding to the area of the video tape 5. However, at the boundary between the movie and the CM, a logical "1" appears, and at the boundary where the movie is switched to the CM, three bits of logic "1" are recorded. On the contrary, at the boundary where the CM is switched to the movie, the logic "1" is recorded. 1 "is recorded in 5 bits.

Therefore, when the video tape 5 is reproduced,
When the duty ratio is detected from the control signal reproduced by the control head 4 in the duty ratio detection circuit 6 (FIG. 1), the logic of the control signal can be known, and thereby the boundary between the movie and the CM can be determined. . Also, by counting the number of bits of logic "1", it can be determined whether the boundary is a boundary where the movie is switched to the CM or a boundary where the CM is switched to the movie.

The system control circuit 7 controls the magnetic recording / reproducing apparatus so that the video tape 5 is fast-forwarded or fast-forward-reproduced only during the CM section in accordance with the output of the duty ratio detection circuit 6.

That is, as shown in the flow chart of FIG. 5, first, in step 1 (hereinafter abbreviated as S1), the section of the movie is played back at a normal playback speed, and only the section of the CM is fast-forwarded or fast-forwarded. When so-called "skip" is selected, the system control circuit 7 is set to the reproduction mode, and normal reproduction starts. Then, the duty ratio detection circuit 6 (FIG. 1) uses the logic "
Normal reproduction is continued until three bits of 1 are counted (S2) When three bits of logic "1" of the control signal are detected, it is a boundary where movie is switched to CM.
The system control circuit 7 is switched from the reproduction mode to the fast forward mode, and fast forward or fast forward reproduction of the CM is started (S3). Then, the fast-forward or fast-forward reproduction is continued until the duty ratio detection circuit 6 detects 5 bits of control signal logic "1" (S4). When 5 bits of logic "1" of the control signal are detected, CM
Since this is the boundary where the movie is switched to the movie, the system control circuit 7 is switched from the fast-forward mode to the playback mode, and normal playback of the movie starts again (S5). Then, the process returns to step 2, and the above operation is repeated.

As described above, in the present embodiment, the movie and the CM are discriminated based on the duty ratio of the control signal. Therefore, only the movie is automatically played back normally without any manual operation, and the CM is fast-forwarded or Fast forward playback is possible. In addition, since the control signal is recorded as usual, the CM can be normally reproduced as needed.

In the above-described embodiment, in the bilingual broadcast of a foreign film program, a case has been described in which only a movie is treated as a necessary video and a CM is treated as an unnecessary video. However, the present invention is not limited to this.

[0020]

As described above, the magnetic recording / reproducing apparatus of the present invention, as described above, the identification means for distinguishing the video necessary for recording from the unnecessary video, and records the control signal on the video tape simultaneously with the recording of the video signal. Control signal recording means;
Duty ratio switching means for switching the duty ratio of the control signal for a predetermined period according to the identification signal when the identification signal output from the identification means is switched, and detecting the duty ratio of the control signal during reproduction And the duty ratio is switched.
Duty cycle detecting means for determining a required video and an unnecessary video by measuring a period of time required, and an unnecessary video interval is faster than a required video interval according to an output of the duty ratio detecting means. And control means for controlling the video tape to run so that, when recording a video signal, the discriminating means discriminates a necessary video from an unnecessary video, and a predetermined value corresponding to the identification result. Period
During this time, the duty ratio of the control signal is switched, and the control signal can be recorded simultaneously with the recording of the video signal. As a result, the period during which the duty ratio of the control signal is switched can be measured.
Thus , it is possible to detect a break between a required video and an unnecessary video. Therefore, at the time of reproduction, unnecessary video can be fast-forwarded or fast-forward reproduced, and the unnecessary video can be normally reproduced when desired because the control signal is recorded.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a magnetic recording / reproducing apparatus of the present invention.

FIG. 2 is a waveform diagram of a control signal of logic “0”.

FIG. 3 is a waveform diagram of a control signal of logic “1”.

FIG. 4 is an explanatory diagram showing the correspondence between the arrangement of a movie section and a CM section on a video tape and the logic of a control signal.

FIG. 5 is a flowchart for explaining an operation when “unnecessary viewing” of an unnecessary video is performed.

[Explanation of symbols]

Reference Signs List 1 audio multiplex discriminating circuit (identifying means) 2 duty ratio switching circuit (duty ratio switching means) 4 control head (control signal recording means) 5 video tape 6 duty ratio detecting circuit (duty ratio detecting means) 7 system control circuit (control means) )

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 15/087 101 G11B 15/02 355

Claims (1)

(57) [Claims] 1. A magnetic recording / reproducing apparatus for recording a video signal in a direction oblique to a longitudinal direction of a video tape and recording a control signal for regulating a relationship between the video signal and a video head in a longitudinal direction of the video tape. An identification means for identifying a video necessary for recording and an unnecessary video, a control signal recording means for recording a control signal on a video tape simultaneously with recording of a video signal, and an identification signal output from the identification means being cut off. A switching means for switching a duty ratio of the control signal for a predetermined period according to the identification signal when the switching is performed, and detecting a duty ratio of the control signal during reproduction , and determining a period during which the duty ratio is switched. measure
By doing so, a duty ratio detecting means for distinguishing a required video from an unnecessary video, and an unnecessary video section is reproduced at a faster speed than a required video section in accordance with an output of the duty ratio detecting means. A magnetic recording / reproducing apparatus, comprising: control means for controlling the vehicle to run.