JPH0799561B2 - Magnetic recording / reproducing device - Google Patents

Description

The present invention relates to a magnetic recording / reproducing apparatus for information signals, and more particularly to a digital VTR for television signals.

2. Description of the Related Art The Asians recording method is well known as a high-density recording method for television signals, which is also adopted in the VHS method VTR and the like. In addition, an azimuth recording system using a multi-channel head is adopted in an apparatus for digitally recording a television signal, and tracks sequentially recorded by the multi-channel head are recorded by heads having different cap azimuths between adjacent tracks. Is composed of.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention When digitally recording a television signal, generally 1
It is common to quantize and record at 8 bits per sample, but various methods of bit-compressing and recording in order to lengthen the recording time have been studied. Further, even when the high-definition signal and the NTSC signal are recorded by the same device, the bit rate of the recording signal is different.

When recording signals of various bit rates in this way, the recording head channels are switched, the tape running speed is also changed, and recording is performed so that the recording tracks that are sequentially recorded have different head gap azimuths between adjacent tracks. It is conceivable that a method of configuring the

However, it is not possible to arbitrarily make the gap azimuths different between adjacent recording tracks.

The present invention provides an apparatus for changing the number of recording channels and expanding the conditions for configuring the gap azimuths to be different between adjacent tracks.

Means for Solving the Problems In a rotary head type magnetic recording / reproducing apparatus, K pieces (K is a positive integer of 2 or more) at equal intervals around a rotary head cylinder.
Head blocks, each block of the K head blocks has N (N is a positive integer) magnetic heads, and the N × K (N × K is an even number) magnetic heads are θ ₁
Each of which has two types of gap azimuths of θ and θ ₂ is N · K / 2, and recording tracks are sequentially formed on a magnetic tape which is wound around the rotating cylinder and runs. The recording track is recorded by heads having different gap azimuths between adjacent tracks, and the number of head channels and / or the number of head blocks is changed according to the information amount of the recording signal. As a means for changing the recording time by changing the running speed of the magnetic tape, the number of head blocks used is only 1 block or 2 blocks of K / 2 or less, and 2 mm in each block is 2 m ≦ N. (The integer number of), the tape running speed is selected so that the recording tracks are formed at substantially equal intervals, and the recording tracks are And sets the recording mode to be recorded by different gaps azimuth of the head between adjacent tracks.

Action 2 blocks (K = 2), each block 2 heads (N =
As 2), in an apparatus in which each block is arranged at 180 ° intervals on the cylinder circumference for recording, the head of each block is different from that shown in FIG. 1 in order to make the gap azimuth of the recording track different between adjacent tracks. each theta ₁ as _being arranged in the order of theta ₂ a block theta ₁ head and B
The θ ₁ heads of the block are generally arranged at 180 ° intervals and the mounting heights on the cylinders are almost the same (θ ₂ is also at the same height at 180 ° intervals). In such a device, when recording a signal with half the amount of recorded information, if recording is performed using the θ ₁ head of the A block and the θ ₁ head of the B block, the gap azimuths of adjacent recording tracks are the same. As a result, the effect of azimuth recording cannot be obtained. Further, when the θ ₁ head of the A block and the θ ₂ head of the B block are used, since the head heights are different, the recording track intervals cannot be equally recorded. Therefore, if only the A block of the _two blocks is used and the tape traveling speed is halved by using the θ ₁ and θ ₂ heads of the A block, the gap azimuths of the adjacent recording tracks can be made different from each other, and the azimuth effect can be obtained. It is possible to double the recording density while maintaining it.

By appropriately selecting the number of blocks and the number of heads in the blocks, it is possible to realize long-time recording while the amount of recorded information is small while maintaining the azimuth effect.

Embodiment FIG. 1 An embodiment will be described. FIG. 1 (a) schematically shows a plan view of a cylinder, and a head block A composed of heads a ₁ (azimuth θ ₁ ) and a ₂ (azimuth θ ₂ ) around the cylinder 7 and b ₁ (Azimuth θ ₁ ), b
_The head block B made of ₂ (azimuth θ ₂ ) is arranged at a position of 180 degrees. Fig. 1 (b) shows magnetic tape 8
The recording tracks when recording alternately with the head blocks A and B are shown above. 1,2, ..., 6 are recording tracks, and θ ₁ and θ ₂ are gap azimuths, respectively. There is. A device having a head configuration as shown in FIG.
When recording a signal with half the amount of information and doubling the recording time for the same tape length, temporarily from the A and B head blocks,
If you select heads one by one and try to record with a ₁ and b ₁ heads, the gap azimuth will be the same as θ ₁ and the effect of azimuth recording will not be obtained (the combination of a ₁ and b ₂ is It cannot be taken because the head mounting height is different).

Here, if the tape speed is halved by using the heads a ₁ and a ₂ of only the A block, the recording tracks on the tape 8 have the gap azimuths of θ ₁ and θ ₂ as shown in FIG. It can be configured to alternate.

A signal processing circuit for such recording is shown in FIG. In FIG. 2, a case where recording is performed by four heads as shown in FIG. 1B will be described first. The tape shall be wound around the cylinder 180 °. 9 is for example NTSC
A signal input terminal, 10 is an A / D converter, and 11 is an error correction coding circuit.

The two outputs of the error correction coding circuit 11 are one to the modulator 13 through the contact P of the electronic switch 12 and the other to the modulator 14.
Be led to. The output of the modulator 13 is guided to the recording amplifier 17 through the contact P of the switch 15, and the output of the modulator 14 is switched.
It is guided to the recording amplifier 18 through 16 contact points P.

The outputs of the recording amplifiers 17 and 18 are alternately recorded on the tape by the heads a ₁ and a ₂ (head block A) and the heads b ₁ and b ₂ (head block B) through the switches 19 and 20 (switches 19 and 20). Are alternately switched to the contacts P and Q every half rotation of the cylinder).

Next, the signal processing when the amount of recorded information is halved will be described. The NTSC signal input to the input terminal 9 is converted into a digital signal by the A / D converter 10, guided to the bit compression circuit, the bit rate is reduced to half, and the error correction coding circuit is guided. The output of the error correction coding circuit is guided to the modulator 13 through the contact Q of the switch 12.
The output of the converter 13 is first led to the memory circuit through the contact Q of the switch 15, and when the recording information for one track is stored, it is led to the recording amplifier 18 through the contact Q of the switch 16. Further, the output of the modulator 13 is guided to the recording amplifier 17 by switching the contact of the switch 15 to the P side when the information for one track is stored in the memory circuit. This is repeated for each track of information amount.

Further, in this case, the switches 19 and 20 are both connected to the P side, and the outputs of the recording amplifiers 17 and 18 are heads respectively.
Recording is performed on the tape via a ₁ and a ₂ to form a recording pattern as shown in FIG. Due to the operation of the switch 15 and the memory circuit, the recording signals are simultaneously supplied to the a ₁ and a ₂ heads during the period when the head block A is in contact with the tape to record on the tape.

FIG. 3 is a second concrete example, and as shown in FIG.
This is a case where a head block A composed of _two heads a ₁ , a ₂ and a ₃ and a head block B composed of heads b ₁ , b ₂ and b ₃ are arranged 180 degrees apart on the cylinder circumference. . Usually, as shown in FIG. 3B, recording tracks are alternately formed by head blocks A and B, and tracks are alternately formed by heads having a gap azimuth of θ ₁ and θ ₂ . In this case, as a condition for reducing the number of head channels and alternately forming the recording tracks of the gap azimuths θ ₁ and θ ₂ , there are methods shown in FIGS. 3C and 3D. The method of (iii) is close to the method used in VHSVTR like conventionally (recorded alternately by using only b ₁ head of a ₁ head and B blocks of the A blocks) course possible method is. Third
In the method shown in FIG. 4D, only the a ₁ and a ₂ heads of block A (a ₂ and a ₃ heads may be used) are used for recording, and the tape speed is 1/3. The signal processing in this case can also be realized by the same method as in the case of FIG.

FIG. 4 shows another specific example. FIG. 4 shows an example in which (a) the number of head blocks K = 2 and the number of heads in one block N = 4. When the amount of information is the largest, as shown in (b), all the heads of both A and B head blocks are used to form 8 tracks by one rotation of the cylinder.

On the other hand, when the amount of information is halved, combinations such as (c) and (d) are possible. (C) uses only the _four heads (a ₁ , a ₂ , a ₃ , a ₄ ) on the A block side,
4 tracks are formed by one rotation of the cylinder.
(D) uses the two heads a ₁ and a ₂ of the A head block and the two heads b ₁ and b ₂ of the B block to form four tracks with one rotation of the cylinder.

When the amount of information becomes 1/4, for example, two tracks are formed by one rotation of the cylinder by using only the _two heads a ₁ and a ₂ of the A block (e).

In either case of FIG. 4, recording tracks are alternately formed by heads having different gap azimuths of θ ₁ and θ ₂ . Of these, the method (d) is an extension of the conventional method and is not within the scope of the present invention.

FIG. 5 shows another embodiment of the present invention (when K = 3 and N = 4).
Is shown. As shown in FIG. 5 (a), the head blocks A, B, and C each have four heads (θ ₁ , θ _2).
Gap azimuth heads are arranged alternately)
The blocks of A, B, and C are 120
They are arranged at intervals. In this case, when the amount of information is the largest, as shown in (b), all the heads of blocks A, B, and C sequentially form tracks, and one track of the cylinder forms 12 tracks. On the other hand, when the amount of information is halved, each 2 of each block of A, B, C as shown in (c)
By sequentially forming recording tracks with one head (for example, a ₁ , a ₂ ; b ₁ , b ₂ ; C ₁ , C ₂ ), _one track of the cylinder forms 6 tracks.

When the information amount becomes 1/3, as shown in (d), four recording tracks are formed by one cylinder rotation by using the _four heads a ₁ , a ₂ , a ₃ , a ₄ of the A head block. Further, when the amount of information becomes 1/6, for example, two tracks are formed by one rotation of the cylinder using only the _two heads (a ₁ , a ₂ ) of the A block. In any of these cases (c), (d), and (e), the recording tracks have gap azimuths θ ₁ and θ ₂
It becomes a track recorded alternately by the head of (e). Of these, the method (3) is an extension of the conventional technology and is not within the scope of the present invention.

FIG. 6 shows a concrete example when K = 4 and N = 3. In FIG. 6 (a), the head blocks A, B, C, and D are each composed of three heads, and the gap azimuths are arranged in the order shown in the drawing. Also, A, B, C,
Ds are placed 90 degrees apart. In this case, when the amount of information is the largest, as shown in (b), all the heads of the head blocks A, B, C, and D are used to sequentially form tracks, and one track of the cylinder forms 12 tracks. The amount of information
When it becomes 1/3, for example, only two blocks of head blocks A and C are used as shown in (C), and A and C are used.
4 tracks per cylinder revolution using only each two heads of the block.

When the amount of information becomes 1/6, for example, recording is performed using only _two heads (a ₁ , a ₂ ) of one head block A, and recording is performed only on two tracks by one cylinder rotation. Yes (D). These (b), (c),
(D) In either case, the recording tracks are alternately formed by the heads having the gap azimuths θ ₁ and θ ₂ . FIG. 7 is a diagram for explaining an embodiment in the case of K = 4 and N = 4. In FIG. 7A, head block A,
Each of B, C and D consists of 4 heads,
Heads with a gap azimuth of θ ₁ and θ ₂ are arranged in the order shown in the figure. The head blocks A, B, C and D are arranged at 90 degree intervals. In this case, when the amount of information is the largest, all the heads of the head blocks A, B, C, and D are used to sequentially form tracks, and 16 tracks are formed by one cylinder rotation as shown in (b).

When the amount of information is half, the methods shown in (c) and (d) are adopted. In (c), eight tracks are formed by one rotation of the cylinder by using four heads of each of the two head blocks A and C. Method (d) is A,
Using each head block of B, C, and D, two heads (for example, a ₁ , a ₂ ;
b ₁ , b ₂ ; C ₁ , C ₂ ; d ₁ , d ₂ ) are sequentially recorded, and one track of the cylinder forms eight tracks.

When the amount of information becomes 1/4, the method shown in (e) or (f) will be adopted. In the method (e), two tracks of each of the head blocks A and C are used to form four tracks by one cylinder rotation. In the method (f), only the head block A is used, and four tracks of A block are used to form four tracks by one cylinder rotation.

Furthermore, when the amount of information becomes 1/8, the method of (G) is adopted. In the method (g), tracks are formed using only two heads of the head block A (for example, a ₁ and a ₂ ), and one track of the cylinder forms two tracks. In any of the methods shown in FIGS. 7B to 7G, the recording tracks formed by the heads having the gap azimuths θ ₁ and θ ₂ are alternately and sequentially formed. Of these, the method (d) is an extension of the conventional technique and is not within the scope of the present invention.

Although various concrete examples of the present invention have been described above, the idea of the present invention can be applied to other various developments. Further, the present invention relates to a method of forming a recording track with heads having different gap azimuths sequentially in a rotary head type magnetic recording / reproducing apparatus having a plurality of head blocks composed of a plurality of head groups. When recording a signal having a small amount of information or a signal obtained by compressing the bit rate of the information with respect to the maximum amount of information that can be recorded, the number of head blocks used for recording is reduced to half or less, and a head used at the time of recording is used. In block
It is characterized by using 2 m (m is an integer) heads for recording so that the gap azimuth of tracks to be recorded is different between adjacent tracks.

In FIGS. 3 to 7, the order of the heads in each head block does not necessarily represent the order in the angular direction, but rather, the height of the head mounted around the rotary head cylinder (the rotational axis direction). Of height).

Effect of the Invention As described above, in the present invention, the recording density can be doubled while maintaining the azimuth effect. Further, it is possible to realize long-time recording when the amount of recorded information is small while maintaining the azimuth effect.

[Brief description of drawings]

FIG. 1 is an explanatory view of a head arrangement and a recording track pattern in the apparatus of the first embodiment of the present invention, FIG. 2 is a circuit block diagram of the apparatus, and FIG. 3 is an apparatus of the second embodiment of the present invention. 4 is an explanatory view of a head arrangement and a recording track pattern in FIG. 4, FIG. 4 is an explanatory view of a head arrangement and a recording track pattern in the apparatus of the third embodiment of the present invention, and FIG. 5 is a fourth embodiment of the present invention of the present invention. FIG. 6 is an explanatory diagram of the head arrangement and recording track pattern in the apparatus of the example, FIG. 6 is an explanatory diagram of the head arrangement and recording track pattern in the apparatus of the fifth embodiment of the present invention, and FIG. 7 is the sixth embodiment of the present invention. FIG. 7 is an explanatory diagram of a head arrangement and a recording track pattern in the example. 9 ... Input terminal, 10 ... A / D terminal, 11 ... Error correction coding circuit, 12 ... Electronic switch, 13, 14 ... Modulator, 15,
16,19,20 …… Switch, 17,18 …… Recording amplifier.

Claims (7)

[Claims] 1. Four head blocks are arranged at equal intervals around a rotary head cylinder, and each block of the four head blocks has N magnetic heads (N is a positive integer). Each head has 2N heads each having two types of gap azimuths of θ ₁ θ ₂ and sequentially forms recording tracks on a magnetic tape which is wound around the rotating cylinder and runs. A device configured such that formed recording tracks are recorded by heads having different gap azimuths between adjacent recording tracks, and the number of head channels and / or the number of head blocks is changed according to the information amount of the recording signal. Of the two head blocks at 180 degree intervals as a means to change the recording time by changing the running speed of the magnetic tape as well as the Recording is performed by using only 2m heads (m is a positive integer of 2m ≦ N) and multiplying the tape running speed by about 4m / 4N (= m / N) that when recording with 4N heads. A magnetic recording / reproducing apparatus comprising at least means for increasing a time by about N / m and satisfying conditions that gaps azimuths of recording heads between adjacent recording tracks are different from each other. 2. Two head blocks are arranged around the rotary head schilling at a positional interval of 180 °, and each of the two head blocks has two magnetic heads, and these four heads have θ ₁ and θ _{2 respectively.} The magnetic head has two different gap azimuths, and the magnetic head has different gap azimuths between adjacent tracks of the recording tracks sequentially formed on the magnetic tape which is wound around the rotating cylinder and runs. The recording track is configured to be recorded by a head and has a function of changing the number of head blocks to be used according to the amount of information of a recording signal and changing the running speed of the magnetic tape to change the recording time. A magnetic recording / reproducing apparatus configured so that data is recorded by heads having different gap azimuths between adjacent tracks. 3. Two head blocks are arranged around the rotary head shilling at a positional interval of 180 °, and each of the two head blocks is composed of three magnetic heads, and these six magnetic heads have a total of θ ₁ Each of the magnetic heads has two kinds of gap azimuths of θ and θ ₂ , and the magnetic head is wound around a rotating cylinder and sequentially formed on a running magnetic tape. It is configured to record with heads of different gap azimuths, and has a function of changing the number of head blocks to be used according to the amount of information of a recording signal and changing the recording time by changing the magnetic tape speed, And a magnetic structure in which recording tracks are recorded by heads with different gap azimuths between adjacent tracks. In the recording / reproducing apparatus, a first mode of recording (or reproducing) using all heads of two head blocks and a second mode of recording (or reproducing) using only two adjacent heads of one head block. A magnetic recording / reproducing apparatus characterized by being configured to switch between modes. 4. Two head blocks are arranged around the rotary head shilling at a positional interval of 180 °, and each of the two head blocks is composed of four magnetic heads, and these eight magnetic heads have a total of θ. Each of the magnetic heads has four kinds of gap azimuths of ₁ and θ ₂ , and the magnetic head is formed between recording tracks which are successively formed on a magnetic tape which is wound around a rotating cylinder and runs. It is configured to record with heads with different gap azimuths, and has the function of changing the number of head blocks used according to the amount of information of the recording signal and changing the recording time by changing the magnetic tape speed. In addition, the magnetic tracks are configured so that the recording tracks are recorded by heads with different gap azimuths between adjacent tracks. In the recording / reproducing apparatus, a first mode in which recording (or reproduction) is performed by using all the heads of two head blocks and a second mode in which recording (or reproduction) is performed by using only four heads of one head block A magnetic recording / reproducing apparatus characterized by being configured to switch between modes. 5. Three head blocks are arranged around the rotary head shilling at a positional interval of 120 °, and each of the three head blocks is composed of four magnetic heads, and these twelve magnetic heads have a total of θ _1. Each of the magnetic heads has two kinds of gap azimuths of θ and θ ₂ , and the magnetic head is wound around a rotating cylinder and sequentially formed on a running magnetic tape between adjacent tracks of recording tracks. It is configured to record with heads of different gap azimuths, and has a function of changing the number of head blocks to be used according to the amount of information of a recording signal and changing the recording time by changing the magnetic tape speed, And a magnetic structure in which recording tracks are recorded by heads with different gap azimuths between adjacent tracks. In the recording / reproducing apparatus, a first mode of recording (or reproducing) using a total of 12 heads of 3 head blocks, and recording (or reproducing) using 4 heads of 1 head block among 3 head blocks. A second mode for reproducing) and a third mode for recording (or reproducing) using only two adjacent heads of one head of the three head blocks. 2. A magnetic recording / reproducing apparatus, characterized in that it can be switched between the second and third modes. 6. Four head blocks are arranged around the rotary head schilling at a positional interval of 90 °, and each of the four head blocks is composed of three magnetic heads, and these 12 magnetic heads have a total of θ ₁ And 6 with two gap azimuths of θ ₂ and 6 respectively,
The magnetic head is configured so that recording is performed by heads having different gap azimuths between adjacent tracks of recording tracks that are sequentially formed on a magnetic tape that is wound around a rotating cylinder and that runs according to the amount of information of a recording signal. It has a function to change the recording time by changing the magnetic tape speed while changing the number of head blocks to be used, and the recording tracks are recorded by heads with different gap azimuths between adjacent tracks. In the magnetic recording / reproducing apparatus described above, a first mode of recording (or reproducing) using a total of 12 heads of four head blocks, two heads having different azimuth angles adjacent to the first head block, Two adjacent heads of a second head block, which is provided at a distance of approximately 180 ° from the two heads. Adjacent second mode, and one head block to be recorded (or reproduced) with two
Magnetic recording / reproducing apparatus having a third mode of recording (or reproducing) using one head, and being configured to switch the first, second, and third modes. 7. Four head blocks are arranged around the rotary head shilling at a positional interval of 90 °, and each of the four head blocks is composed of four magnetic heads, and these 16 magnetic heads have a total of θ ₁ And 8 having two types of gap azimuth, θ ₂ respectively.
The magnetic head is constructed so that recording tracks sequentially formed on a magnetic tape wound around a rotating cylinder and recorded are recorded by heads having different gap azimuths and used according to the amount of information of a recording signal. It has the function of changing the recording time by changing the number of head blocks and the magnetic tape speed, and it is a magnetic structure in which recording tracks are recorded by heads with different gap azimuths between adjacent tracks. A total of 16 head blocks in the recording / playback device
First mode for recording (or reproducing) using four heads, recording using four heads in the first head block and four heads in the second head block provided at 180 ° intervals (Or reproduction) second mode, third mode of recording / reproduction using two adjacent heads of the first head block and adjacent heads of the second block provided at an interval of 180 ° A fourth mode in which recording and reproduction are performed using only four heads of one head block, and a fifth mode in which recording (reproduction) is performed using only two adjacent heads of one head block, A magnetic recording / reproducing apparatus configured to switch and use at least two modes among the first, second, third, fourth, and fifth modes.