JPH0778845B2 - Rotary head type digital signal recording / reproducing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head type digital signal recording / reproducing apparatus, and particularly, when recording a digital signal on a magnetic tape by a rotary head, it is possible to monitor and record at the same time. The present invention relates to a digital signal recording / reproducing device (after-recording: hereinafter referred to as “after recording”).

2. Description of the Related Art A rotary head system in which digital data containing various information is added to a digital audio signal obtained by pulse code modulation (PCM) of an audio signal, and then recorded and reproduced on a magnetic tape by a rotary head. A digital signal recording / reproducing device (so-called R-DAT) is known.

Among such digital signal recording / reproducing apparatuses, as shown in FIG. 8, a rotary cylinder 1 has a recording rotary head 2a having a plus azimuth angle and a recording rotary head having a minus azimuth angle.
2b are mounted to face each other 180 °, and a reproducing rotary head 3a having a positive azimuth angle and a reproducing rotary head 3b having a negative azimuth angle are 180 ° opposed to each other and rotate with respect to the rotary heads 2a and 2b. There is a head arrangement that is mounted 90 ° ahead of the other.

The rotary cylinder 1 has, for example, a diameter of 30 mm, rotates counterclockwise at 2000 rpm, and the magnetic tape 4 is wound around the rotary cylinder 1 over an angle range of 90 °, and as shown in FIG. It is wound.

Each core width (hw) of the rotary heads 2a, 2b, 3a and 3b is, for example, 1.5 times the track pitch (Tp). During normal recording, digital signal recording tracks are alternately recorded by the rotary heads 2a and 2b at a ratio of two per frame. At this time, the rotary head 2a or 2b immediately before the rotary head 2b or
1/3 of the full width of the track formed by 2a (= (3/2) Tp)
Since the width is overwritten and recorded, the recording tracks of the track pitch Tp are eventually recorded alternately as shown by A and B in FIG. In the track pattern shown in FIG. 10, A schematically shows tracks recorded by the rotary head 2a, and B schematically shows tracks recorded by the rotary head 2b.

By the way, in such a rotary head type digital signal recording / reproducing apparatus, as shown in FIG. 9, the rotary head 5 is a recording rotary head 2a (or 2b), and the rotary head 6 is a reproducing rotary head 3b (or 3a). And the rotating head 3
a, 3b tracks recorded by the rotary heads 2a, 2b,
When the height position is set such that scanning is performed after the 270 ° rotation period of the rotary cylinder 1 has elapsed, the recorded digital signal can be monitored and reproduced immediately after recording the digital signal (this is called "simultaneous monitoring").

On the other hand, the rotary head 5 shown in FIG.
(Or 3b), the rotary head 6 is the rotary head 2a for recording.
(Or 2b) and when the track position scanned and reproduced by the rotary head 5 is set at a height position where the rotary head 6 scans, the recorded track is reproduced after the recorded digital signal is reproduced by the rotary head 5. Another digital signal can be recorded at a position later by the rotary head 6 (this is called "dubbing"). There is post-recording mixing that reproduces a recorded digital signal, mixes an external digital signal with it, and records it again as one kind of this post-recording.

Problems to be Solved by the Invention Even when performing the above-mentioned simultaneous monitoring and dubbing, it is necessary to comply with the existing format of the digital signal recording / reproducing apparatus. Therefore, the simultaneous monitoring is performed with reference to the recording rotary heads 2a and 2b. Rotating head for playback when equipped with functions
Lower the height position of 3a, 3b to the lower fixed drum (shown by 7 in FIG. 9) side, and on the other hand, if the dubbing function is provided, move the height position of the rotary heads 3a, 3b for reproduction away from the lower fixed drum 7. You have to raise it in the direction.

Therefore, conventionally, when the number of reproducing rotary heads is two as shown by 3a and 3b in FIG. 8, it is possible to have only one of the simultaneous monitor function and the post-recording function.

On the other hand, in order to provide both functions at the same time, two rotary heads for reproduction are provided at different height positions in the axial direction of the rotary cylinder 1, and a total of four rotary heads for reproduction and two rotary heads for reproduction are provided. The rotary heads 2a and 2b for recording may be arranged in the rotary cylinder 1. However, in this case, the number of rotary heads is large, the mechanism around the rotary heads is complicated, head mounting accuracy is required, and height adjustment is difficult and costly.
In addition, the rotary transformer also needs to be designed with stricter consideration of the influence of signals from other channels. Further, in order to perform post-recording mixing, at least 2.5 frames are required as a period from signal reproduction to recording.

The present invention has been made in view of the above points, and provides a rotary head type digital signal recording / reproducing apparatus having both a simultaneous monitoring function and an after-recording function including after-recording mixing, without increasing the number of rotating heads. With the goal.

Means for Solving the Problems The rotary head type digital signal recording / reproducing apparatus of the present invention comprises:
It comprises a head mechanism having a structure as shown in FIGS. 1 and 2, a first recording / reproducing means for simultaneous monitoring, and a second recording / reproducing means for post-recording.

In the above head mechanism, as shown in FIG. 1, a first rotary head HA1 having a first azimuth angle and a second rotary head HB1 having a second azimuth angle are arranged on the rotary cylinder 10 so as to face each other. A third rotary head HA2 having a first azimuth angle and a fourth rotary head HB2 having a second azimuth angle, which are mounted at an angular interval of °, face each other on the rotary cylinder 10, and The third rotary head HA2 is mounted so as to precede the first rotary head HA1 at an angular interval of approximately 90 ° in the rotational direction. The above-mentioned first to fourth rotary heads HA1, HB1, HA2, HB2 are all rotary heads for both recording and reproduction.

Further, the rotary heads HA1 and HB1 are mounted on the first rotary surface 11 of the rotary cylinder 10 as shown in FIG. 2, and the rotary heads HA2 and HB2 are adjusted to the data processing time during dubbing mixing. For the first surface of revolution 11.
5Tp (however, Tp is track pitch) tape guide 1
It is mounted on the second rotating surface 12 of the rotating cylinder 10 located in the direction away from 3. In FIG. 1, reference numeral 14 is a magnetic tape, which is wound around a rotary cylinder 10 over a predetermined angle range, and is guided along a tape guide 13 and is wound obliquely.

The first recording / reproducing means records the digital signal on the magnetic tape 14 by alternately using the third and fourth rotary heads HA2 and HB2 as recording heads at the time of simultaneous monitoring. The rotary heads HA1 and HB1 are used as reproducing heads.

The second recording / reproducing means includes third and fourth rotary heads H.
A2 and HB2 are alternately used as reproducing heads to reproduce recorded digital signals, and the first and second rotary heads H
A1 and HB1 are alternately used as recording heads to newly form a digital signal recording track having a track pitch Tp.

Action At the time of simultaneous monitoring, the first recording / reproducing means causes the third
The rotary heads HA2 and HB2 are used as recording heads, respectively, as shown by REC in the figure, and the rotary heads HA1 and HB1 are used as reproducing heads, as shown by PB in the figure, for recording and reproduction.

Two digital signal recording tracks, one for each, are recorded and formed on the magnetic tape 14 at a track pitch Tp by the rotary heads HA2 and HB2 per one rotation period of the rotary cylinder 10. On the other hand, the rotary heads HA1 and HB1 are 4.
Since it is mounted at a position lower by 5 track pitches, the scanning positions of HA1 and HB1 are located on the tape downstream side by 4 track pitches than the recording digital signal recording track position by HA2 and HB2. This means that the digital signal recording track recorded by the rotary head HA2 is subsequently scanned by the rotary head HA1 having the same azimuth angle,
This means that the recorded digital signal is reproduced (the same applies to the rotary heads HB2 and HB1). Therefore, the first
The recording / reproducing means allows simultaneous monitoring.

Next, when recording / reproducing is performed by the second recording / reproducing means, the rotary heads HA1 and HB1 as shown by REC in FIG.
Recording heads are used as recording heads, respectively, and rotary heads HA2 and HB2 are used as reproducing heads as shown by PB in the figure for recording and reproducing.

Rotating heads HA2 and H per one rotation period of the rotating cylinder 10
By B2, one digital signal is reproduced from each of the two digital signal recording tracks having a track pitch Tp.
On the other hand, the rotary heads HA1 and HB1 are compared to HA2 and HB2.
Since it is mounted at a position lower by 4.5 track pitches, the scanning positions of the rotary heads HA1 and HB1 are HA2 and H2.
It is located 4 tape pitches downstream from the playback track position by B2. This means that the track position of the digital signal reproduced by the rotary head HA2 is subsequently scanned by the rotary head HA1 having the same azimuth angle and another digital signal is recorded (for rotary heads HB2 and HB1). The same).

Therefore, by the second recording / reproducing means, it is possible to perform post-recording for recording another digital signal at the track position reproduced by traveling.

In addition, the first and second rotary heads HA1 and HB1 are mounted at positions lower than the third and fourth rotary heads HA2 and HB2 by 4.5 track pitches in accordance with the data processing time during dubbing mixing. Has been. Therefore, the number of RAMs used for the after-recording processing can be minimized, and the RAM utilization efficiency can be improved by eliminating the RAM non-operation period.

Simultaneous monitoring is performed during the 90 ° rotation period of ∠imk shown in FIG. 2, and the perpendicular line e indicates the recording start position. See also ∠jml
The post-recording is performed in the 90 ° rotation period of, and the perpendicular line f shows the recording start position at that time. Here, the distance between the rotating surface 11 and the intersection X is equal to the distance between the rotating surface 12 and the intersection Y.

As described above, according to the present invention, simultaneous monitoring and post-recording can be selectively performed by the four rotary heads.

Embodiment FIG. 5 is an explanatory view of a positional relationship between a head and a track according to an embodiment of the present invention. In the figure, A ₁ , A ₂ , A ₃ , A ₄ are digital signal recording tracks of channel A (plus azimuth angle) recorded by the rotary head HA 1 or HA ₂ , and B ₁ , B ₂ , B ₃ are rotary heads HB 1 Or, in the B channel (minus azimuth angle) digital signal recording track recorded by HB2, the recording tracks are track pitch Tp (here, 13.6 μm, for example, in the order of A ₁ → B ₁ → A ₂ → ... → A ₄ → ... ) Is formed. The head arrangement of the rotary heads HA1, HA2, HB1 and HB2 is as described in FIGS. 1 and 2, respectively, but the core width is 20.4 which is 1.5 times the track pitch Tp as an example.
It is selected to be μm.

Hereinafter, the simultaneous monitor and the post-recording will be sequentially described.

At the time of simultaneous monitoring At the time of simultaneous monitoring, the first recording / reproducing means operates based on an external instruction input, and a digital signal is supplied to use the rotary heads HA2 and HB2 as recording heads respectively, and the rotary heads HA1 and HB1 are reproduced. Connect to the system. If all the four rotary heads HA1, HB1, HA2 and HB2 are at the same height, the rotary cylinder 10
Since it advances by 0.5 track pitch every 90 ° rotation period of, → → → → → → → →… in Fig. 5 (A) and (B)
The rotary head is positioned on the magnetic tape in the order shown by. 5A shows the position of the rotary head HA2, B shows the position of the rotary head HB2, A of FIG. 5B shows the position of the rotary head HA1, and B shows the position of the rotary head HB1. Show.

Further, since the rotary heads HA2 and HB2 are respectively used as recording heads, as shown in FIG. 5 (A), they are partially overwritten and the tracks A ₁ , B ₁ , A ₂ , ... Are track pitch T.
Recording is sequentially formed with p. The rotary heads HA1 and HB1 shown in FIG. 5 (B) are used as reproducing heads.

Thus, according to the present embodiment, the rotary heads HA1 and HB1 are 4.
Because 5 is provided below the track pitch HA2, HB2, as shown in the FIG. 5 (C), the rotary head in which the track A ₃ slides on the magnetic tape immediately after being recorded by the rotary head HA2 HA1 scans the track a ₁ of the same azimuth angle are previously recorded, for reproducing the already recorded digital signal.

Thereafter, similarly, the rotary heads HA1 and HB1 scan on the tracks already recorded by the rotary heads HA2 and HB2 having the same azimuth angle and reproduce the recorded digital signals, so that simultaneous monitoring can be performed.

At the time of after-recording, the rotary heads HA2 and H are driven by the second recording / reproducing means.
B2 is connected to a reproducing system, respectively, and rotary heads HA1 and HB1 are connected to a recording system to input a digital signal to be recorded.

Here, at the time of after-recording mixing, three random access memories (RAM) for main data, each having a capacity for storing one frame of digital data (main data), are provided in the digital signal recording / reproducing apparatus. As shown by RAM in FIG. 6A, the reproduced digital data for one frame reproduced from two tracks is written, the error is corrected by reading the reproduced digital data, and the writing is performed again within one frame period. Of 1
In the frame period, the error-corrected stored digital data is read out, mixed with the external information signal through the D / A converter, and then written again as a digital mixing signal through the A / D converter. And next 1
During the frame period, as shown in FIG. 6, the digital mixing signal read from the RAM is encoded and then supplied to the recording rotary head for recording (writing).

As described above, in order to perform post-recording mixing for reproducing the recorded digital signal, mixing the external information signal with the recorded digital signal, and recording again, three RAMs and at least
2.5 frame period is required. That is, as indicated by the circled numbers in FIG. 6, reproduction and recording are sequentially performed by each rotary head, but the digital signal reproduced by the rotary head with the first plus azimuth angle (here, HA2) Thirdly, the digital signal of the next track reproduced by the rotary head with negative azimuth angle (here, HB2) that slides on the magnetic tape is mixed with the external information signal, and then the tenth magnetic tape is produced. With a rotating head with a positive azimuth angle (here, HA1) that slides
It is sufficient that the twelfth rotary head (here, HB1) that slides on the magnetic tape can be used for recording.

On the other hand, if it is assumed that the rotary heads HA1, HB1, HA2 and HB2 are all mounted at the same height position, the rotary head HA2, which is a reproducing head, based on the tracking signal of the recorded magnetic tape during dubbing mixing. HB2
Shows a scanning locus such that the track center coincides with the head center, as shown in FIG.
→→→→ ... → as shown in FIGS.
The rotary head slides on the magnetic tape in the order shown as → →. Here, A in FIG. 5 (D) indicates the position of the rotary head HA2 used as the reproducing head, B indicates the position of the rotary head HB2 used as the reproducing head, and A and B in FIG. 5 (E) indicate The positions of the rotary heads HA1 and HB1 used as recording heads are shown.

According to this embodiment, however, the rotary heads HA1 and HB1 are provided below the HA2 and HB2 by 4.5 track pitches, respectively, as described above. As shown in FIG. 5E instead of FIG. 5E, the rotary head HA1 that slides on the magnetic tape 10th scans on the track A ₁ and slides 12th on the magnetic tape. rotary head HB1 of the track B ₁
Will scan over.

Therefore, as can be seen from FIGS. 6 and 5, the digital signals for a total of one frame reproduced from the A ₁ and B ₁ tracks by the rotary heads HA2 and HB2 are the tenth magnetic signals after being mixed with the external information signal. Rotary head H sliding on tape
Recording is performed again on the same recording tracks A ₁ and B ₁ by the rotary head HB1 which slides on A1 and the 12th magnetic tape.

As described above, in this embodiment, the rotary heads HA1 and HB1 are mounted at positions lower than the rotary heads HA2 and HB2 by 4.5 track pitches in accordance with the data processing time at the time of post-recording mixing. Therefore, as described above, the number of RAMs used for post-recording mixing can be minimized to three, and the non-operation period of RAMs can be eliminated to make R
The use efficiency of AM can be improved.

When performing post-recording mixing, the rotary head H
When A2 and HB2 are exchanged, the reproduced signal and the recorded signal are
As shown in the figure, four RAMs are required as shown in the figure, but according to the present embodiment, the number of RAMs is as small as three,
Moreover, there is no non-operation period of the RAM shown by X in FIG.
Effective use of AM can be achieved.

As described above, according to the present invention, after-recording and simultaneous monitoring can be performed with a minimum number of rotary heads without using rotary heads dedicated for after-recording and simultaneous monitoring.
Moreover, the post-recording mixing can be performed by using the minimum number of RAMs, and the features are that the configuration can be inexpensive and the RAMs can be effectively used.

[Brief description of drawings]

FIG. 1 is a diagram showing a head arrangement configuration of the present invention, FIG. 2 is a diagram showing a height positional relationship of each rotary head in the present invention, and FIGS. 3 and 4 are respectively for simultaneous monitoring in the present invention and FIG. 5 is a diagram for explaining the function of the rotary head during dubbing, FIG. 5 is a diagram for explaining the positional relationship between the head and the track of one embodiment of the present invention, and FIG. 6 is an example of the operation of the RAM during dubbing mixing of the present invention FIG. 7 is an explanatory diagram of an embodiment, FIG. 7 is an explanatory diagram of an example of an operation of a RAM during post-recording mixing with another head arrangement configuration, FIG. 8 is a diagram showing an example of a conventional head arrangement, and FIG. FIG. 10 is an explanatory diagram of a head arrangement configuration during dubbing and simultaneous monitoring, and FIG. 10 is a diagram showing an example of a track pattern. HA1, HB1, HA2, HB2 ...... Rotary head, A ₁ ~ A ₃ ,, B ₁ ~ B ₃ ......
Truck, 10 …… Rotating cylinder.

Claims (1)

[Claims] 1. A first rotary head for recording / reproducing both having a first azimuth angle and a second rotary head for recording / reproducing having a second azimuth angle different from the first azimuth angle. The digital signal recording tracks are mounted on the same first rotating surface of the cylinder at an angular interval of 180 °, and the digital signal recording tracks are mounted on the magnetic tape running while being wound around the rotating cylinder over a predetermined angle range. A rotary head type digital signal recording / reproducing apparatus for alternately recording and forming a track pitch Tp by a rotary head and reproducing the same, comprising a third rotary head for recording / reproducing both having the first azimuth angle and the second azimuth. A fourth rotary head for recording / playback that has a corner and a tape guide of 4.5 Tp with respect to the first rotary surface of the rotary cylinder according to the data processing time during dubbing mixing. The second rotary heads are mounted on the second rotary surfaces located farther away from each other and face each other, and the third rotary head precedes the first rotary heads at an angular interval of approximately 90 ° in the rotational direction. And a head mechanism attached so as to simultaneously use the third and fourth rotary heads as recording heads during simultaneous monitoring to form digital signal recording tracks on the magnetic tape at a track pitch Tp. First recording / reproducing means for reproducing the digital signal of the digital signal recording track immediately after being recorded by the third and fourth rotary heads by alternately using the first and second rotary heads as reproducing heads. During the after-recording, the third and fourth rotary heads are alternately used as reproducing heads to reproduce recorded digital signals on the magnetic tape, By alternately using the first and second rotary heads as recording heads, another digital signal is recorded at the digital signal recording track position previously reproduced by the third and fourth rotary heads, and the track pitch is obtained. A rotary head type digital signal recording / reproducing apparatus comprising: second recording / reproducing means for newly forming a Tp digital signal recording track.