JPH0765307A - Device for recording/reproducing video signal - Google Patents

Abstract

PURPOSE:To provide a digital VTR having compatibility with conventional analog VTR. CONSTITUTION:The same video signal from an input terminal 1 is modulated by an analog recording modulation circuit 33 and a digital recording modulation circuit 34, and is recorded on a magnetic tape 51 by heads 42, 43. The analog recording modulation circuit 33, a control signal processing circuit 32, a capstan control circuit 31, the head 41 for control and a capstan 52 are made to be the same as the conventional analog VTR. Thus, a helical track recording a recorded analog signal is reproduced by the conventional analog VTR. The helical track recording a digital signal is provided on the guard band of the helical track recording the analog signal, and a digital video signal is recorded on the track. Thus, the magnetic tape recorded by the digital VTR is reproduced even by the conventional analog VTR as it is.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording / reproducing apparatus for digitally recording a video signal, and more particularly to a digital recording / reproducing apparatus which maintains compatibility with a conventional VHS type or 8 mm type analog recording / reproducing apparatus.

[0002]

2. Description of the Related Art Since a conventional digital VTR (video tape recorder) records image information without compression, it requires a recording medium (magnetic tape) having a larger area than that of an analog VTR. Therefore, analog VTR
Recording and reproducing digital image information was performed using a cassette tape of a larger size. Due to recent advances in image compression technology, a digital VTR capable of recording a moving image for a long time in a cassette having a size similar to that of a conventional analog VTR is being put into practical use.

[0003]

Currently, hundreds of millions of analog VTRs are in widespread use throughout the world.
Since R is recorded in a completely different format from the analog VTR, even if a cassette of the same size as the analog VTR is used, the cassette tape recorded by the digital VTR cannot be reproduced as it is by the analog VTR. There were issues to be solved. The present invention is intended to provide a digital VTR which can be recorded in a tape format which can be reproduced as it is by a conventional analog VTR.

[0004]

A helical track for recording an analog signal and a helical track for recording a digital signal are provided in a guard band on an existing magnetic tape for an analog VTR and the same video signal is provided. Is modulated into an analog recording signal and a digital recording signal, and the analog recording signal is recorded on a helical track for analog signal recording.
The signals are recorded in the same format so that they can be reproduced even in the conventional analog VTR, the same tracking is performed, and the digital recording signal is recorded on the helical track for recording the digital signal.

[0005]

[Function] Looking at the analog signal recording track,
Since the size and recording format of the cassette tape and the tracking of the cassette tape are the same as those for the conventional VTR, they can be reproduced as they are by the existing VTR. A digital recording signal compressed by a conventional image compression technique such as DCT variable length coding is recorded on the digital signal recording track provided in the guard band of the analog signal recording track.

[0006]

FIG. 1 shows the circuit configuration of a video signal recording / reproducing apparatus showing an embodiment of the present invention.

An analog video signal input from the analog video input terminal 1 is recorded and modulated by the analog recording modulation circuit 33 into the same format as the existing analog VTR, and the analog recording head 42 is used to record an analog signal on the magnetic tape 51.・ Record on the track. The azimuth (head azimuth) of the analog recording head 42 is the same as that of the existing analog VTR. As a result, the recorded analog recording signal can be reproduced by the conventional analog VTR.

Analog video signal input terminal The analog video signal input from the terminal 1 is also applied to the A / D conversion circuit 14, where it is converted into a digital video signal. This digital video signal is subjected to digital recording modulation suitable for digital recording in the digital recording modulation circuit 34,
The output is applied to the digital recording / reproducing head 43 to record a helical signal for recording an analog signal on the magnetic tape 51.
Recording is performed on helical tracks for digital signal recording provided between the tracks. The azimuth of the digital recording / reproducing head 43 (the azimuth angle of the head) is set to a value different from the azimuth of the analog recording head 42 so as to cause an azimuth loss, and the crossing with the analog track
Talk is reduced.

The control signal processing circuit 32 generates a control signal for tracking the magnetic tape 51, and the control signal recording / reproducing head 4 generates the control signal.
1 is applied to the magnetic tape 51 to record on a control signal recording track which is a linear track of the magnetic tape 51. This control signal is the linear of the existing analog VTR.
This is the same as the control signal when recording on a track, and the same tracking is performed. The capstan control circuit 31 receiving the control signal from the control signal processing circuit 32 is arranged so that the relationship between the recording position of the control signal and the recording position of the analog track is exactly the same as that of the existing analog VTR. Tracking is performed by controlling the drive of the magnetic tape 52 to adjust the running of the magnetic tape 51.

When reproducing the analog-recorded and digital-recorded magnetic tape 51 according to the configuration of FIG. 1, the digital recording / reproducing head 43 reads data from a track for recording a digital signal on the magnetic tape 51, and the digital demodulating circuit 35 digitally reproduces the data. The video signal is demodulated, the digital video signal is output to the digital video signal output terminal 4 as it is, and the analog video signal is output to the analog video signal output terminal 3 via the D / A conversion circuit 13. Control signal processing circuit 3 in which a control signal is read from the control signal recording track on the magnetic tape 51 by the control signal recording / reproducing head 41.
In No. 2, a signal is sent to the capstan control circuit 31 to control the capstan 52 to align the position of the helical track and adjust the running of the magnetic tape 51.

FIG. 2 shows an example of the arrangement of recording tracks on the magnetic tape 51 according to the circuit configuration of FIG.
Analog signal recording tracks (AT) 101-103 and digital signal recording tracks (DT) 111-113
Are alternately arranged so as to be recorded by a helical track, and a control signal recording track 121 which is a linear track is arranged at the edge of the magnetic tape 51.

On the control signal recording track 121 and the analog signal recording tracks 101 to 103,
Since a signal of the same format as the existing analog VTR is recorded in the same positional relationship as the reproduction ranges 151 and 152 of the analog VTR, even when reproducing from the magnetic tape 51 with the existing analog VTR, the reproducing head is for recording the analog signal. The tracks 101 to 103 can be accurately followed. The reproducing head of the conventional analog VTR at this time sequentially scans the reproducing ranges 151 and 152 of the analog VTR, but the guard bands between the analog signal recording tracks 101 to 103 in the case of the conventional analog VTR are sequentially scanned. In this range, which is the part of (1), the digital signal recording tracks 111 and 112 are also included. However, the azimuth of the digital recording / reproducing head 43 when writing the digital recording signal on the magnetic tape 51 is different from the azimuth of the analog recording head 42 which is set to be the same as the analog recording head of the existing analog VTR. When reproducing with an existing analog VTR, due to azimuth loss, the data of the digital signal recording tracks 111 to 113 are not reproduced, but only the video signals of the analog signal recording tracks 101 to 103 are reproduced, so that a good reproduced image is obtained. Can be obtained.

FIG. 3 shows each reproduction range 15 of the analog VTR.
An example is shown in which two digital signal recording tracks 111, 112 and 113, 114 are recorded in 1, 152, respectively. Also in this case, the control signal recording track 121 and the analog signal recording tracks 101-
The positional relationship of 103, the format of the recording signal, and the azimuth conform to the standard of the existing analog VTR. The azimuth at the time of recording of the digital signal recording tracks 111 to 115 is the analog signal recording track 101.
Different from the azimuth at the time of recording of No. 103 to No crosstalk occurs, a good image can be reproduced by the conventional analog VTR. Between adjacent digital signal recording tracks 112 and 113 or 114 and 11
Crosstalk between the tracks 5 and 5 can also be avoided by appropriately setting the azimuths of the digital signal recording tracks 112, 114 and 111, 113, 115.

FIG. 4 shows an analog V of the existing VHS system.
TR indicates the arrangement of recording tracks compatible with those having so-called high-fidelity audio tracks. A conventional audio fidelity audio track has an audio track recorded on an analog video track, and an audio signal recording track (AUT) 131 to an analog signal recording tracks 101 to 103. By recording 133, the conventional VHS system high-fidelity audio.
Digital V compatible with those with tracks
TR can be configured.

FIG. 5 shows a configuration in which not only an analog video signal but also a digital video signal is input to the digital video signal input terminal 2 in addition to the circuit configuration of FIG. Input selector switch 21, which can be switched in conjunction with each other,
When 22 is tilted to the a side, the configuration is the same as in FIG.
When tilted to the side b, the digital video signal is recorded from the digital recording / modulating circuit 34 by the digital recording / reproducing head 43 for recording the digital signal on the racks 111-115. At the same time, the digital video signal becomes an analog video signal in the D / A conversion circuit 11, and the analog video signal can be recorded on the analog signal recording tracks 101 to 103 by the analog recording head 42 from the analog recording modulation circuit 33.

[0016]

As is apparent from the above description, since the analog video signal is recorded on the magnetic tape in the same standard as the existing VHS system or 8 mm system analog VTR,
The magnetic tape produced by the device according to the present invention can be reproduced on an existing analog VTR. Therefore, the effect of the present invention is extremely large.

[Brief description of drawings]

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

FIG. 2 is a layout diagram of recording tracks on a magnetic tape according to the present invention.

FIG. 3 is another layout diagram of recording tracks on the magnetic tape according to the present invention.

FIG. 4 is still another layout of recording tracks on the magnetic tape according to the present invention.

FIG. 5 is a circuit configuration diagram showing another embodiment of the present invention.

[Explanation of symbols]

1 analog video signal input terminal 2 digital video signal input terminal 3 analog video signal output terminal 4 digital video signal output terminal 11, 13 D / A conversion circuit 14 A / D conversion circuit 21, 22 input selector switch 31 capstan control circuit 32 control signal processing circuit 33 analog recording / modulating circuit 34 digital recording / modulating circuit 35 digital demodulating circuit 41 control signal recording / reproducing head 42 analog recording head 43 digital recording / reproducing head 51 magnetic tape 52 capstan 101-103 analog signal recording track (AT ) 111-115 Digital signal recording tracks (D
T) 121 control signal recording tracks 131 to 133 audio signal recording tracks (AU
T) 151,152 Playback range of analog VTR

 ─────────────────────────────────────────────────── (72) Inventor Hironori Akasaka 4-36-19 Yoyogi, Shibuya-ku, Tokyo Inside Graphics Communication Laboratories, Inc. (72) Inventor Toshifumi Sakaguchi 4-36 Yoyogi, Shibuya-ku, Tokyo No. 19 in Graphics Communications Laboratories, Inc. (72) Inventor Tomoyuki Shindo 4-36-19 Yoyogi, Shibuya-ku, Tokyo Incorporated in Graphics Communications Laboratories (72) Inventor, Watanabe Yuzumi Tokyo 4-36-19, Yoyogi, Shibuya-ku, Tokyo Within Graphics Communications Laboratories, Inc.

Claims (7)

[Claims] 1. An analog helical track (101) for analog video signals on a magnetic tape (51).
To 103) for recording in analog recording means (33,
42) and a digital helical track provided between the analog helical tracks of the video signal in digital form.
Digital recording / reproducing means (14, 34, 43, 35) for recording / reproducing on the tracks (111-115), and tracking means (32 for tracking the analog and digital helical tracks on the magnetic tape. , 31, 41, 52). 2. The video signal recording / reproducing apparatus according to claim 1, wherein the tracking means is substantially the same as the tracking means of an existing analog video tape recorder. 3. A video signal recording / reproducing apparatus according to claim 1, wherein the analog helical track has a modulated audio signal recorded thereon in an overlapping manner. 4. The video signal recording / reproducing apparatus according to claim 1, wherein the analog recording means is substantially the same as the analog recording means of an existing analog video tape recorder. 5. The analog recording means, wherein the azimuth when recording on the analog helical track is substantially the same as the azimuth of an existing analog video tape recorder. 3 or 4 video signal recording / reproducing apparatus. 6. The distance between the analog helical tracks is substantially the same as the distance between the helical tracks of an existing analog video tape recorder.
3, 4 or 5 video signal recording / reproducing apparatus. 7. The azimuth when the digital recording / reproducing means records on the digital helical track is set to a value different from the azimuth when the analog recording means records on the analog helical track. 2. The azimuth loss is set to obtain
2, 3, 4, 5 or 6 video signal recording / reproducing apparatus.