JP3216553B2 - Magnetic recording device and 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 apparatus and a magnetic recording / reproducing apparatus, and more particularly to a magnetic recording apparatus and a magnetic recording / reproducing apparatus which record digital information on a magnetic tape for a long time by a rotary head and reproduce the digital information.

[0002]

2. Description of the Related Art Heretofore, two rotating heads provided at 180 ° opposite to a cylindrical rotating body (hereinafter referred to as a rotating drum) have been provided on the outer peripheral side surface of the rotating drum by about 180 °.
A helical scan type magnetic recording / reproducing apparatus configured to record and reproduce an information signal on a magnetic tape wound obliquely over a range of angles and running at a constant speed is widely known. In such a magnetic recording / reproducing apparatus, usually, the two rotating heads are different in azimuth angle from each other in order to improve the recording density, and the information signal recording track is provided with a guard band without or with a very narrow guard band. The recording is formed closely on top.

In such a helical scan type magnetic recording / reproducing apparatus, as a recording / reproducing apparatus for recording digital information on a magnetic tape for a long time and reproducing the same, for example, the tape traveling speed is set to one of the standard traveling speed of the normal mode.
There has been known a magnetic recording / reproducing apparatus capable of recording digital information on a magnetic tape for three times as long as the normal mode, with the rotation speed of the rotary drum being the same as the normal mode (Japanese Patent Publication No. 6-18047).

In this magnetic recording / reproducing apparatus, the number of rotations of a rotary drum in which two rotary heads having different azimuth angles are attached to face each other is the same as that in the normal mode. An information signal is recorded and reproduced by forming inclined tracks alternately on the magnetic tape by two rotating heads at a rate of degree. According to this magnetic recording / reproducing apparatus, azimuth recording can be performed in the long-time mode, which is an odd multiple of the recording time in the normal mode.

On the other hand, in order to perform recording in a long mode in which the recording time is an even multiple of the recording time in the normal mode, the number of rotations of the rotary drum and the tape running speed are each reduced by 1 / of the normal mode.
2. Description of the Related Art A recording / reproducing apparatus in which digital information is recorded on a magnetic tape at twice the speed and the drum rotation speed during reproduction is set to be the same as in the normal mode, and only the tape traveling speed is の of that in the normal mode has been known. (Japanese Unexamined Patent Publication No. Hei 8-111059,
JP-A-8-111050).

[0006]

However, the number of rotations of the rotating drum and the tape running speed are respectively reduced by 1 / of the normal mode.
According to a conventional apparatus in which digital information is recorded on a magnetic tape at twice the speed and the drum rotation speed during reproduction is the same as in the normal mode, and only the tape traveling speed is １ ／ of the normal mode, the rotation during reproduction is Since the scanning trajectory of the head is different from the recording track, there is a problem that the error rate of reproduced data is deteriorated.

[0007] The present invention has been made in view of the above points,
It is an object of the present invention to provide a magnetic recording apparatus and a magnetic recording / reproducing apparatus capable of recording and reproducing digital information for a long time which is an even multiple of the recording time in the normal mode with an excellent error rate.

[0008]

In order to achieve the above object, a magnetic recording apparatus according to the present invention comprises a rotating head provided with a first and a second rotating heads having opposite azimuth angles provided opposite to a rotating drum. In the normal mode, the first and second rotating heads are used alternately to form sequential tracks on a magnetic tape which is wound obliquely over a predetermined angle range around the outer peripheral side surface of the drum and travels at a constant speed. In a helical scan type magnetic recording apparatus configured to record a digital information signal, a first magnetic head mounted on a rotary drum at a position separated from a first rotary head by a relative angle θ (however, θ ≠ 180 °). A third rotating head having an azimuth angle different from that of the rotating head is provided. In a long time mode, the rotating speed of the rotating drum is the same as that in the normal mode, and the running speed of the magnetic tape is reduced. Using 1 / (2m) times (m is an arbitrary natural number) of the normal mode, using only the first rotary head and the third rotary head, a digital information signal having a time of 2m times the recording time of the normal mode Is recorded.

In the present invention, recording in the normal mode is performed by using only the first and third rotary heads so that tracks are alternately formed by the first and third rotary heads having different azimuth angles. It is possible to record a digital information signal for 2 m times as long as the time.

Here, the running speed of the magnetic tape in the normal mode is set to v _S , the track pitch is set to Tp, the running speed of the magnetic tape in the long time mode is set to v, and
Number of rotations of the rotating drum from the start of recording on the first track
The third rotating head is visually adjacent to the second track
Rotation of the rotating drum to indicate whether to start recording the next track
When the number is n (where n is a natural number), the following equation is used: h = Tp − [(v / v _S ) ｛(θ / 180) + 2n−
It is desirable to attach the first and third rotary heads to the rotary drum at a relative height h expressed by 2 [Tp], since a digital information signal recording track pattern having the same track pitch as in the normal mode can be formed.

In the magnetic recording / reproducing apparatus of the present invention, the first and third rotary heads are used to set the rotation speed of the rotary drum to the same as in the normal mode, as in the case of recording.
In addition, the running speed of the magnetic tape is set to 1 / (2
m) (where m is an arbitrary natural number), so that the recording track trace and the scanning trajectory of the rotary head during reproduction can be matched.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a head mounting arrangement of an embodiment of a magnetic recording apparatus and a magnetic recording / reproducing apparatus according to the present invention. In the figure, a rotating surface such as a bottom surface of a cylindrical rotating drum 10 that rotates counterclockwise in the figure by a drum motor (not shown) has rotating heads for video signals (hereinafter, also referred to as video heads) SP1, SP2, EP1 and EP2
, Audio signal rotating heads (hereinafter also referred to as audio heads) A1 and A2, and a flying erase head ER
And extra audio head E for long time mode
A is attached and fixed.

Each of the video heads SP1 and SP2 is a video head for a normal mode (hereinafter also referred to as a standard time mode), and has a track width of 58 μm, for example.
The video head SP1 has a gap of an azimuth angle (this is + 6 °) inclined 6 ° clockwise with respect to the track width direction.
Have gaps with an azimuth angle of 6 ° counterclockwise with respect to the track width direction (referred to as -6 °), which are mounted on the rotating drum 10 at the same height opposite to each other. Have been.

The video heads EP2 and EP1 are triple-mode video heads constituting a double azimuth head together with the video heads SP1 and SP2, and their track width is, for example, about 19 μm. The azimuth angle is -6 °, and the video head EP1 has an azimuth angle of + 6 °. These are mounted on the rotating drum 10 so as to face each other and to precede the video heads SP1 and SP2 in the rotation direction.

Further, at a position preceding the double azimuth head by the video heads SP1 and EP2 by 43 ° in the rotational direction, a track width of 32 μm and an azimuth angle of +30
The first audio head A1 having a track width of 32 μm and a second azimuth angle of −30 ° is disposed at a position facing the audio head A1.
Audio head A2 is arranged on the rotating drum 10 at the same height position as the audio head A1. Further, a flying erase head ER, which is a rotating head for erasing, is disposed at a position ahead of the second audio head A2 by 90 ° in the rotating direction.

The above-described head arrangement is based on, for example, existing VHS
This is a well-known head arrangement in a helical scan type magnetic recording / reproducing apparatus of the (registered trademark) type. In the present embodiment, in addition to this, at a position following the first audio head A1 by 270 ° in the rotation direction. , A1 has the same track width of 32 μm, but has a different azimuth angle of −30 ° from A1, and is characterized in that it is fixed at a predetermined height position to be described later.

A magnetic tape 15 is wound on the outer peripheral side surface of the rotary drum 10 obliquely and over an angle range of about 180 °, and is held in a fixed direction by being sandwiched by capstans and rollers (not shown). It is made to run. Thus, when recording a video signal in the normal mode,
For example, a standard system color video signal such as the NTSC system is separated into a luminance signal and a carrier chrominance signal, the luminance signal is frequency-modulated, and the carrier chrominance signal is in a frequency region lower than the frequency-modulated luminance signal band. The video heads SP1 and SP2 alternately form video tracks on the surface layer of the magnetic tape 15 and record the signals obtained by frequency conversion and frequency division multiplexing of these two signals, and
The frequency-modulated audio signal is transmitted to the audio head A.
1 and A2 alternately form and record an audio track prior to recording of a video track in the deep portion of the magnetic tape 15 alternately. That is, a video track is formed on the audio track. At the time of reproduction, reproduction is performed using the video heads SP1 and SP2 and the audio heads A1 and A2 in the same manner as at the time of recording.

In the triple mode, the video heads EP1 and E2 are replaced by the video heads EP1 and E2.
P2 is used and 1/3 of the tape running speed in the normal mode
On the magnetic tape 15 traveling at twice the traveling speed, a video track having a track pitch of about 19 μm is formed, and an audio track having a track pitch of about 19 μm is formed using the audio heads A1 and A2. As a result, recording for three times as long as in the normal mode can be performed. At the time of reproduction, reproduction is performed using the video heads EP1 and EP2 and the audio heads A1 and A2 in the same manner as during recording.

In the helical scan type magnetic recording / reproducing apparatus having the above-described configuration, during recording of digital data in the normal mode, only the audio heads A1 and A2 are used as rotary heads for recording digital data, respectively. Digital data recording tracks are sequentially formed at a pitch of 29 μm. In addition,
At the time of digital data recording in the normal mode, the rotation speed of the rotary drum 10 is, for example, 30 rps, which is the same as the speed at the time of video signal recording / reproduction, and the tape traveling speed is at the time of video signal recording / reproduction in the standard time mode. 16.67 mm / s, which is の of the above.

Here, this embodiment is characterized in that digital data is recorded and reproduced twice as long as in the normal mode. In the long time mode, the rotation speed of the rotary drum 10 is the same as that during video signal recording / reproduction, for example, 30 rps.
In addition, the tape traveling speed of the magnetic tape 15 is set to 8.34 mm / s, which is 1/2 the speed at the time of digital data recording in the normal mode, and in this state, the audio head A1 and the extra head are moved. Audio head E
Digital data is recorded and reproduced by using only A as a rotary head for digital data.

Here, in the long time mode, the rotating drum 10 has the same 30 rps as in the video signal recording / reproduction.
The rotation of the rotating drum 10 is controlled as in the prior art.
The speed is controlled by a known means based on a speed detection signal from a frequency generator (FG) proportional to the rotation speed of a drum motor rotating, and the rotation phase of the rotating drum is detected by a known pickup head. The rotation detection pulse having a repetition frequency of 60 Hz
The frequency is divided by 2 to 30 Hz. At the time of recording with the frequency-divided pulse, for example, 30 Hz is obtained by dividing the vertical synchronization signal of 60 Hz by 1/2.
Is compared with a 30 Hz reference signal from an oscillator during reproduction, and the rotational phase of the drum motor is controlled by the obtained phase error signal.

The tape running speed of the magnetic tape 15 is controlled, for example, by a speed control based on a speed detection signal having a frequency proportional to the rotation speed of the capstan motor, and an output of an oscillator when the capstan rotation detection signal is recorded. The signal is controlled by a known capstan motor speed and phase control method based on a phase control based on a phase error signal obtained by comparing the phase with a reproduction control signal from the magnetic tape 15 during reproduction. Although not shown in FIG. 1, a control pulse having a constant period is recorded on the magnetic tape 15 by a fixed control head and reproduced.

Next, the operation at the time of recording digital data in the long time mode twice as long as the normal mode will be described with reference to FIGS.
It is explained together with. First, when the first audio head A1 starts scanning on the magnetic tape 15, as shown schematically at 21 in FIG. Since scanning is performed on the area 15, digital data is recorded while forming a first track. During this period, no signal is input to all the heads on the rotating drum 10 other than the first audio head A1.

Therefore, until the first audio head A1 completes the scanning on the magnetic tape 15 and further the 90 ° rotation period of the rotary drum 10 has elapsed, signal recording is performed as schematically shown at 22 in FIG. Nothing is performed, and when the 90 ° rotation period has elapsed, the extra audio head E
A reaches the scanning start position of the magnetic tape 15 and starts to scan the magnetic tape 15. As a result, during the subsequent 180 ° rotation period of the rotary drum 10, the extra audio head EA scans over the magnetic tape 15 as shown schematically at 23 in FIG.
Is formed and recorded. During this period, no signal is input to all the heads other than the extra audio head EA on the rotating drum 10.

When the extra audio head EA finishes scanning the magnetic tape 15, the flying erase head ER starts scanning the magnetic tape 15, and again when the rotating drum 10 rotates 270 °, the first erase again. The audio head A1 reaches the position where the magnetic tape 15 starts scanning.

Here, the extra audio head E
After the scanning of the magnetic tape 15 is completed, the flying erase erase head ER, the second erase head ER and the second audio head A1 reach the scanning start position of the magnetic tape 15 after the rotary drum 10 rotates 270 °. Audio head A
2. The video heads EP1 and SP2 scan on the magnetic tape 15, respectively. During this period, no digital data is input to these heads. Therefore, signal recording is not performed as schematically shown at 24 in FIG. I can't.

From the point in time when the rotary drum 10 rotates 270 ° and the first audio head A1 returns to the scanning start position of the magnetic tape 15, the first audio head A1 starts.
Represents the rotation period of the rotary drum 10 by 180 °, the magnetic tape 15
The top is scanned, during which digital data is formed and recorded on a third track, as shown schematically at 25 in FIG.

Hereinafter, in the same manner as described above, the normal mode 1
A first audio head A1 and an extra audio head EA on a magnetic tape 15 running at a speed of 1/2 times
Thus, two digital data recording tracks are formed alternately for two rotations of the rotating drum 10. Here, since the first audio head A1 and the extra audio head EA have different azimuth angles as described above, adjacent digital data recording tracks are recorded at different azimuth angles. In addition, since the running speed of the magnetic tape 15 is 倍 times that of the normal mode, it is possible to record for a long time twice the recording time of the normal mode.

Next, a method for setting the track pitch of the long-time mode digital data recording track to be the same as the track pitch of the normal mode digital data recording track will be described. And the lower end of the first rotary head for forming a one track one, the difference between the height position of the lower end of the second rotary head to form one track before the h, the tape running speed v _S The track pitch of two tracks obtained when the rotary drum makes one rotation in the normal mode is Tp, and the tape running speed is v
The relative angle between the mounting positions of the first audio head A1 and the extra audio head EA used in the long time mode is θ (where θ ≠ 180 °),
Assuming that the rotating drum rotates n times (where n is a natural number) until the number of rotating heads starts recording, the difference h in height position for forming the track pitch Tp in the long-time mode is as follows. Required.

First, the track pitch Tp in the normal mode
Is formed when the rotation angle of the rotary drum is 180 °, the track width Hs formed when the rotation angle is θ is expressed by Hs = Tp (θ / 180) (1) Also, the tape running speed v _{S in the} normal mode
The relationship between the track width Hs at the time of (1) and the track width H formed at the same rotation angle θ at the tape running speed v in the long time mode is as follows: H = Hs (v / v _S ) (2) It is represented by Therefore, the following equation is obtained by substituting the equation (1) into the equation (2).

H = (v / v _S ) · Tp (θ / 180) (3) Here, the track width Hn obtained by n rotations (where n is a natural number) of the rotating drum in the long-time mode is expressed by the following equation. expressed.

Hn = (v / v _S ) · Tp (360 n / 180) = (v / v _S ) · Tp · 2n (4) Therefore, the total width of the track that advances by n rotations and the rotation angle θ in the long-time mode H is represented by the following equation.

H = (v / v _S ) · Tp ｛(θ + 360n) / 180)｝ (5) Here, if 0 ≦ θ ≦ 360, the first rotation can be expressed only by θ. Since 360n / 180 must be set to 0, the total width H of the track traveling at the rotation angle θ of the nth rotation can be rewritten as follows.

H = (v / v _S ) · Tp {(θ + 360 (n−1)) / 180)} (6) Here, the total width H of the track is the track pitch T
If p is less than p, it is necessary to correct the height by the difference h between the height positions of the lower ends of the two rotary heads, and Tp = H + h (7) Therefore, the following equation is obtained by substituting equation (6) into equation (7) and rearranging for h.

[0036]

(Equation 1)Where v = (1/2) v_S, Θ = 270 °, Tp = 2
9 (μm) and extra audio head
EA and the first audio head A1 each within one rotation
Since recording starts, n = 1, and these values are
When substituted, h = 7.25 (μm). Also here
Then the first rotating head is extra audio
In the head EA, the second rotary head connects to the first audio.
As shown in FIG. 3, extra
The audio head EA is the first audio head A1
The lower end of the head by 7.25 μm.
By attaching it, even in long-time mode, normal mode
Azimuth recording track with the same track pitch of 29 μm
Can be formed.

At the time of reproduction, the rotating drum 10
Is set to, for example, 30 rps, and the tape traveling speed of the magnetic tape 15 is set to a traveling speed that is 1/2 times that of digital data recording in the normal mode. In this state, only the audio head A1 and the extra audio head EA are used. To reproduce digital data.

Therefore, according to this embodiment, the relative speeds between the tape and the head during recording and during reproduction are the same, so that during reproduction, the audio head A1 and the extra audio head EA are each identical to the recording track mark. Trajectory of the recording head is different from that of the recording track as in the prior art, and the error rate does not deteriorate at all. Digital data can be reproduced twice as long as in the normal mode. In this embodiment, the existing rotary drum 10 can be used as it is.

It should be noted that the present invention is not limited to the above-described embodiment, and it is possible to similarly perform long-time recording / reproducing of an even multiple of the recording time of the normal mode such as 4 times or 6 times. Further, in FIG. 2, the recording period of one rotary head is set to 180 °, but the period during which the rotary head scans the magnetic tape may be longer than 180 °.

In FIG. 1, the positions of the flying erase head ER and the extra audio head EA may be exchanged. In this case, the formation of the digital data recording track by the extra audio head EA is started after a rotation period of 270 ° from the end of the formation of the digital data recording track by the first audio head A1, and after the formation of the recording track is completed. After the 90 ° rotation period, recording of the digital data recording track by the first audio head A1 is started.

In this case, θ = 90 ° in the equation (8),
Since n = 2, h = −7.25 μm. Therefore, the extra audio head EA is mounted at a position where the lower end of the head is lower than the first audio head A1 by 7.25 μm, so that the extra audio head EA can be used for a long time. In the mode, an azimuth recording track having the same track pitch of 29 μm as in the normal mode can be formed.

[0042]

As described above, according to the present invention,
A track is alternately formed by the first rotary head and the third rotary head having different azimuth angles,
A digital information signal can be recorded for 2 m times the recording time in the normal mode, and a digital information signal recording track pattern having the same track pitch as in the normal mode can be formed.

According to the present invention, using the first and third rotary heads, the rotation speed of the rotary drum is set to the same speed as in the normal mode as in the case of recording, and the running of the magnetic tape is performed. Speed is 1 / (2m) times of normal mode (however,
m is an arbitrary natural number), so that the recording track trace matches the scanning trajectory of the rotating head at the time of reproduction. The digital data can be reproduced for even-number times of the high-quality normal mode without causing any deterioration in the error rate, and the existing rotating drum can be used as it is.

[Brief description of the drawings]

FIG. 1 is a head mounting layout diagram of an embodiment of a recording / reproducing apparatus of the present invention.

FIG. 2 is a schematic diagram illustrating a recording operation according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a height positional relationship of a head attachment according to an embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 10 rotating drum 15 magnetic tape SP1, SP2 normal mode video head (video head) EP1, EP2 triple mode video head (video head) A1 first audio rotary head (audio head) A2 second audio rotation Head (audio head) ER Rotating head for erasing (flying erase head) EA Extra audio head

Claims (2)

(57) [Claims] A first rotating head provided opposite to the rotating drum and having a different azimuth angle; the first rotating head and the second rotating head being obliquely wound around an outer peripheral side surface of the rotating drum over a predetermined angle range and traveling at a constant speed; A helical scan type magnetic recording apparatus configured to record a digital information signal by forming a sequential track by using the first and second rotary heads alternately in a normal mode in a normal mode. A third rotary head having an azimuth angle different from that of the first rotary head, which is mounted on the rotary drum at a position separated from the first rotary head by a relative angle θ (where θ ≠ 180 °), In the long time mode, the rotation speed of the rotating drum is set to the same rotation speed as the normal mode, and
The running speed of the magnetic tape is set to 1 / (2
m) times (where m is an arbitrary natural number)
The digital information signal is recorded for 2 m times as long as the recording time in the normal mode by using only the rotating head and the third rotating head, and the magnetic tape in the normal mode is recorded.
The running speed of the loop is v _S , the track pitch is Tp, and
The running speed of the magnetic tape in the long time mode is represented by v,
Before the start of recording of the first track by one rotary head
At what number of rotations of the rotary drum the third rotary head is
Start recording on the second track adjacent to the first track
N (where n is
Is a natural number), the following equation is given: h = Tp − [(v / v _S ) ｛(θ / 180) + 2n−
The first and third rotating heads at a relative height h expressed by 2 [Tp].
Is attached to the rotating drum . 2. A rotating drum, which is diagonally wound over an outer circumferential surface of the rotating drum over a predetermined angle range by first and second rotating heads having different azimuth angles provided opposite to the rotating drum and running at a constant speed. In the normal mode, the first and second rotary heads are alternately used to form sequential tracks on the magnetic tape to record and reproduce digital information signals. In the apparatus, a third rotation having an azimuth angle different from that of the first rotary head, which is mounted on the rotary drum at a position separated from the first rotary head by a relative angle θ (where θ ≠ 180 °). A head is provided, in the long-time mode, the rotation speed of the rotary drum is set to the same rotation speed as that in the normal mode both during recording and reproduction, and the running speed of the magnetic tape is set to the 1 / (2m) times the normal mode (where, m is an arbitrary natural number)
Using only the first rotary head and the third rotary head, recording and reproducing the digital information signal for a time 2 m times longer than the recording time in the normal mode ,
The running speed of the magnetic tape of the serial normal mode v _S, track
The magnetic pitch in the long-time mode, where Tp is the pitch
Is the traveling speed of the first rotating head,
How many rotations of the rotating drum from the start of recording or playback of the rack
The third rotating head is visually adjacent to the first track
Indicates whether to start recording or playback of the second track
The number of rotations of the rotating drum is n (where n is a natural number)
Then, the following equation h = Tp − [(v / v _S ) ｛(θ / 180) + 2n−
The first and third rotating heads at a relative height h expressed by 2 [Tp].
Is attached to the rotary drum .