JPH11161926A - Rotary head type magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the control signal of program searching information or the like from a subcode area at the time of a high speed search by arranging a first head and a second head so that the phase difference between amplitude cycles of reproduced envelopes from both heads at the time of the search satisfies a specific relation. SOLUTION: When the amplitude cycle of a reproduced envelope, a reproducable time width at the time of the search and the time width of the subcode area recorded on a tape to be searched are respectively defined as Bperi, Btime and SUBtime and DETp is defined to be DETp=(Btime-SUBtime)×2π/Bperi, the heads are arranged so that the phase difference between amplitude cycles of reproduced envelopes from both heads at the time of the search satisfies DETp<=X<=2π-DETp when DETp is not larger than π and satisfies 2π-DETp<=X<=DETp when the DETp is larger than π. Moreover, even when the searching speed is changed, a reproducing probability can be maintained to some extent by setting the phase difference to 180 degrees.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head type magnetic recording / reproducing apparatus for controlling a control signal necessary for high-speed reproduction and high-speed cueing at the time of high-speed running of a tape such as a high-speed cue of a digital VTR. The present invention relates to a recording / reproducing apparatus having a detecting means suitable for reading the data.

[0002]

2. Description of the Related Art In a rotary head type magnetic recording / reproducing apparatus, a signal or time indicating a head recorded in a track is displayed in order to perform heading or the like in a high-speed tape running at the time of a search at a normal reproduction speed or higher. It is necessary to correctly reproduce a control signal such as a signal to be reproduced.

Conventionally, as a method of reproducing data at the time of high-speed tape running at the time of searching, a method of reproducing data by controlling a relative speed between a head and a tape in a recording track direction and a method of simplifying control of drum rotation have been conventionally known. Therefore, there is a method in which the number of rotations of the drum is made the same as during recording, and as a result, data is reproduced without controlling the relative speed between the head and the tape to be constant.

The above-mentioned drum rotation speed is made equal to that at the time of recording,
In the method where the relative speed between the head and the tape is not controlled to be constant, it is not necessary to control the number of rotations of the drum, but the relative speed between the head and the tape is changed by the search, and the head is different from the time of recording or normal reproduction. And the relative speed between the tape and the tape. As a result, the frequency characteristics of the waveform equalizer required for digital signal reproduction and the capture range and lock range of the PLL must be changed. The method of controlling the relative speed in the recording track direction to a constant value is used.

As a method for keeping the relative speed between the head and the tape constant, Japanese Patent Publication No. 44744/1993 discloses output information of both reel rotation period detecting means by means of a rotation detecting means of a take-up reel and a rotation detecting means of a supply reel. Based on this output, the double speed ratio to the normal tape speed is calculated, and based on this output, the number of rotations of the rotating drum is controlled so that the relative speed between the tape speed and the rotating head is almost constant. A method for keeping the relative speed of the motor constant has been proposed.

[0006]

During a search in which the relative speed between the head and the tape is controlled to be constant, the trajectory of the head takes a trajectory different from the trajectory of the recording track. In general,
The VTR performs azimuth recording using two types of heads having different azimuth angles. Therefore, as for the reproduction signal at the time of the search, an output is obtained only for the track where the azimuth angle of the reproduction head and the recording track match, and the reproduction output is not obtained for the track where the azimuth angle does not match due to azimuth loss. A bead-like waveform signal such as an abacus ball is obtained. The range in which data can be actually detected in this bead-like waveform depends on the margin of the system such as C / N. However, if it is assumed that the amplitude can be correctly reproduced up to about half the amplitude peak of the bead waveform, for example, When the head runs on the tape, about half of the time being searched cannot be reproduced on the time axis.

On the other hand, a control signal such as a head signal is recorded for a predetermined length at a track position in a format. Therefore, in order to reproduce the head and other control signals during the search, the head and other control signals must be within the reproducible reproduction signal amplitude level range (this reproducible reproduction signal amplitude level is, for example, the above-described beads). The time range is equal to or more than の of the amplitude of the waveform.) If the search speed is about several tens of times the speed of normal playback, the number of abacus beads is small, so the reproducible range is any location on the recording track, that is, the format position where the control signal such as the head signal is recorded. It is possible to lock the possible amplitude level range in the bead-like reproduced signal. However, if the search speed is several hundred times faster than that during normal playback, the number of abacus beads increases, and the time period range of the bead waveform that satisfies the reproducible amplitude level becomes shorter. Sometimes it becomes difficult to lock the range of the reproducible amplitude level to any location on the recording track. Therefore, it is impossible to constantly reproduce a control signal such as a head signal. Even when a high-speed search is performed in a system equipped with a plurality of heads, it is difficult to lock the range of the reproducible amplitude level to an arbitrary position on the recording track, and as a result, the reproducible range between the plurality of heads Is difficult to control the phase of the recording track. At this time, depending on the track format and the search speed, for example, at a certain search speed in a system equipped with a plurality of heads, both the traveling locus of the first head on the recording track and the traveling locus of the second head on the recording track are both heads. In some cases, it is not possible to travel in a recording track area necessary for reproducing a control signal such as a duck, and as a result, a control signal such as a head signal cannot be reproduced.

Hereinafter, the above problem will be described in more detail.

In a rotary head type magnetic recording / reproducing apparatus,
When the relative speed between the head and the tape is obtained, the relative speed Vr
Is the rotational speed of the drum at the time of reproducing and searching Vh,
Assuming that t is the tape running speed at the time of reproduction and search, Vhl is the rotational speed of the drum at the time of recording, Vtl is the tape running speed at the time of recording, and θ ₀ is the track angle at the time of still, Vr = K1 × Vh−K2 × Vt (Equation 1) K1 = (Vhl−Vtl × cos θ ₀ ) / K3 (Equation 2) K2 = (Vhl × cos θ ₀ −Vtl) / K3 (Equation 3) K3 = Square root (Vhl ² + Vtl ² −2Vhl × Vtl) × cos θ ₀ ) (Equation 4).

Here, the tape speed Vt at the time of search is represented by a multiple of the tape speed Vtl at the time of recording, that is, a multiple speed at the time of recording, and N is a double speed ratio to the tape speed at the time of recording. = Vtl × N (Equation 5) Rotational peripheral speed Vh of drum during playback or search
From the above (Equation 1) to (Equation 5), the relationship between and the tape double speed is obtained by Vh [N] = (Vrl + K2 × N × Vtl) / K1 (Equation 6).

Here, the relative speed Vrl between the head and the tape
Uses the same control method during search as during recording, so that Vh and Vt in (Equation 1) are Vhl and Vt, respectively.
A constant Vrl = K1 × Vhl−K2 × Vtl where 1 is substituted.

Next, a reproducible time width at the time of search is obtained.

In general, at the time of search, the reproduction envelope of the reproduction signal has a bead shape. Now, when the number of beads Bnum at the time of the N-times search is obtained, it is given by the following equation: Bnum = | (N × Vhl / Vh) −1 |

At this time, the bead cycle Bperi is as follows: Bperi = (Lr × sin θr) / (Vh × Bnum × sin θ ₀ ) (Equation 8) Here, Lr is the effective track length on the tape format, and θr is the track angle shown on the tape during recording.

Next, the fact that there is a portion where data cannot be correctly detected in search data detection will be specifically described with reference to FIG.

FIG. 2A is a diagram showing the trajectory of the head on the track pattern formed on the tape during the reverse search. In this tape, track patterns are formed from A azimuth tracks (tracks indicated by oblique lines in the figure) and B azimuth tracks (tracks indicated by white in the figure). Arrows in the figure indicate the locus of the A azimuth head corresponding to the A azimuth track.
As shown in this figure, at the time of high-speed search, the head moves across a plurality of tracks.

FIG. 2B is a diagram showing a reproduction envelope obtained from the head locus shown in FIG. 2A.
As shown in this figure, the reproduction envelope is in a bead shape, the reproduction amplitude level of the A azimuth head in FIG. 2A is maximum at the position T1, and the reproduction amplitude level of the reproduction envelope is minimum at the position T2. .

Here, as an example, if the track pitch and the width of the reproducing head are the same and data can be reproduced at a reproduction signal level equal to or more than 1/2 of the maximum reproduction amplitude level during reproduction, N times The reproducible time width Btime during the search is as follows: Btime = Bperi / 2 (Equation 9) In other words, the reproducible time is 再生 the reproduction time. FIG. 2B shows the bead period Bpe.
ri and a reproducible time width Btime.

Next, a description will be given of whether or not a subcode in which a control signal such as a head signal is recorded can be reproduced.

H defined by the "HD Digital VCR Council"
In the D specification, a format for recording subcode data in the area at the end of each track is defined for a control signal area (hereinafter referred to as a subcode area) such as a head at the time of a search as in the standard shown in FIG. Have been. here,
Subcode area for recording subcode for each track
e, an area Video for recording video information, an area Audio for recording audio information, and an area ITI for recording track information. In this track format, the subcodes are formed integrally at the upper part in FIG.

Referring to FIG. 4, a description will be given of the state of reproduction of the sub-code areas (shaded portions in the figure) formed in this manner at the time of search. Although the subcode area, track angle, and the like are different from the standards shown in FIG. 3, they are expressed for convenience because they do not contribute to the essence of the present patent.

When the subcode area is reproduced by two heads A and B azimuth heads, the phase of the subcode area and the trajectory of the head cannot be controlled as described above. 4), the data in the subcode area 52 of the A azimuth track 50 cannot be reproduced as shown by the A azimuth reproduction envelope in FIG. 4B. The B azimuth head trajectory 54 is determined by the positional relationship between the A azimuth head and the B azimuth head. In the B azimuth head trajectory shown in FIG. 4A, the data of the subcode area 52 of the B azimuth track 51 is shown in FIG. As shown by the B azimuth reproduction envelope in c), reproduction cannot be performed similarly to the A azimuth head.

Accordingly, the search speed and the positional relationship between the azimuth heads A and B for obtaining the results shown in FIG.
With the azimuth head, the data in the subcode area cannot be reproduced.

As a method of improving the possibility of detecting a control signal such as a head at the time of such a search, for example, a DAT (Digital Audio Tape Recorder)
In the high-speed search, a four-head cylinder mechanism is provided with a signal processing circuit in which two pairs of heads having phases different from each other by 180 ° are arranged at positions shifted from each other by 90 °, so that the lack of the reproduced signal during the head gap period is eliminated. There is known a method of reducing the data size and improving the data detection accuracy at the time of search (JP-A-2-154303, JP-A-6-162423). 1 here
The 80 ° phase and the 90 ° phase are the phases of the reproduction signal at the time of normal reproduction, and four heads are provided on the outer peripheral portion of the drum at equal intervals (the center angle is every 90 °). (A, A ′, B, B ′)).

This method aims to improve the probability of data reproduction at the time of search by newly providing a head dedicated to reproduction at the time of search in addition to the head used for normal reproduction. No consideration is given to search conditions such as the search speed. For this reason, depending on the search conditions, there is a possibility that data reproduction in the subcode area cannot be performed for both the A and B azimuth heads.

In this method, two heads are added to improve the reliability of search or normal reproduction even though normal recording / reproduction is performed with two heads, thereby increasing the cost and complicating the apparatus. There is also a problem. In particular, as in the home digital VCR described later, A,
B azimuth heads 2 each (A1, A2, A3, A
In the rotary head type magnetic recording / reproducing apparatus which performs normal recording / reproducing by using the method 4), the method of newly adding a head as described above requires a large number of heads (for each head used for normal recording / reproducing). On the other hand, if one head is added, a total of eight (A1, A1 ', A2, A2', B1, B
1 ', B2, B2'), the device becomes very complicated.

The present invention has been made in order to solve the above-mentioned problems of the conventional rotary head type magnetic recording / reproducing apparatus. In the present invention, a control signal such as heading information from a subcode area during a high-speed search is transmitted. It is an object of the present invention to provide a rotary head type magnetic recording / reproducing apparatus capable of detecting with high probability.

[0028]

According to a first aspect of the present invention, there is provided a rotary head type magnetic recording / reproducing apparatus comprising at least two heads including a first head and a second head. In the apparatus, the amplitude cycle of the playback envelope is Bperi, the time width that can be played back during the search is Btime, the time width of the subcode area recorded on the tape to be searched is SUBtime, and DETp = 2π (Btime−SUBtime) / Bp
eri, the first head and the second head perform DETp ≦ X ≦ 2π when the phase difference X of the amplitude period of the reproduction envelope from the first head and the second head at the time of search is DETp or less. Satisfy DETp, and DETp
Is larger than π, the arrangement is such that 2π−DETp ≦ X ≦ DETp.

According to a second aspect of the present invention, there is provided a rotary head type magnetic recording / reproducing apparatus having at least two heads including a first head and a second head. The second head and the second head are arranged such that the phase difference between the amplitude periods of the reproduction envelopes from the first head and the second head at the time of the search becomes substantially π.

According to a third aspect of the present invention, there is provided a rotary head type magnetic recording / reproducing apparatus according to the first aspect, wherein the first and second heads perform a search at a maximum search speed. When the phase difference X of the amplitude period of the reproduction envelope is equal to or smaller than DETp, DETp
If ≤X≤2π-DETp is satisfied and DETp is larger than π, the setting is made so as to satisfy 2π-DETp≤X≤DETp.

According to a fourth aspect of the present invention, there is provided a rotary head type magnetic recording / reproducing apparatus as set forth in the second aspect, wherein the first and second heads at the time of a search at a maximum search speed are used. It is arranged so that the phase difference of the amplitude period of the reproduction envelope becomes substantially π.

According to a fifth aspect of the present invention, there is provided a rotary head type magnetic recording / reproducing apparatus according to the first or second aspect, wherein a variable means for varying a search speed, And a head moving means for changing a distance between the first head and the second head.

A rotary head type magnetic recording / reproducing apparatus according to claim 6 is the rotary head type magnetic recording / reproducing apparatus according to any one of claims 1 to 5, wherein the first head and the second head are usually It is arranged at a position where a recording / reproducing operation is possible.

The operation of the present invention will be described below. In the present invention, the first head and the second head are arranged such that the phase difference between the amplitude period of the reproduction envelope of the first head and the amplitude period of the reproduction envelope of the second head at the time of search falls within a predetermined range. . As a result, it is possible to improve the reproduction probability of the subcode (head information and the like) during the search.

The phase difference is set to 180 °. As a result, even if the search speed changes, the reproduction probability can be maintained to some extent.

On the basis of the maximum search speed, the reproduction probability can be improved under the condition that the reproduction of the subcode is most difficult.

Further, if the head position is made variable, the probability that the subcode can be reproduced by either the first head or the second head can be improved regardless of the change in the search speed.

If the head position is set to a position where normal recording and reproduction can be performed, both recording and reproduction and search can be realized by the same head.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary head type magnetic recording / reproducing apparatus according to the present invention is characterized by the arrangement of heads in a rotary head type magnetic recording / reproducing apparatus having, for example, the configuration shown in FIG. The arrangement of the heads improves the probability that information recorded in the subcode area of the tape can be reproduced at the time of search. In addition,
In the following embodiment, basically, “HD digital VC
R Council ”for home digital VCs
The description will be made based on R, but is not limited to this.

First, the HD-D / D
Tables 1 and 2 below show the specifications of the VTR [when the video signal is NTSC] and the recommended values.

[0041]

[Table 1]

[0042]

[Table 2]

FIG. 25 shows the search double speed N and the drum peripheral speed V when the HD-D / VTR specifications and recommended values are used.
The relationship of h is shown for reference.

The features of the present invention will be described below.

(A) First, the problem that the possibility of reading information from the subcode area is low can be solved by changing the arrangement of the A azimuth head and the B azimuth head, that is, the reproduction probability can be improved. The points will be described.

A specific description will be given with reference to FIG. FIG.
(A) is a figure which shows the locus | trajectory of the head on the track pattern formed in the tape at the time of a reverse search. In this tape, a track pattern is formed from an A azimuth track 50 and a B azimuth track 51. Each track is provided with a subcode area 52. Here, the arrangement of the azimuth head is shown in FIG.
Is different from that shown in FIG.
The A azimuth head and the B azimuth head pass through the locus indicated by 54, respectively.

FIGS. 5B and 5C respectively show FIG.
Arrows 53 and 54 in FIG.
It is a figure showing a reproduction envelope when an azimuth head passes. As shown in FIG. 5C, the reproduction envelope from the B azimuth head is the same as that of FIG.
The information recorded in the subcode area 52 cannot be reproduced from here. On the other hand, in the reproduction envelope from the azimuth head A shown in FIG. 5B, since the signal amplitude from the subcode area 52 is equal to or more than の of the maximum amplitude, the information recorded in the subcode area 52 can be reproduced. .

As described above, by setting the arrangement of the A azimuth head and the B azimuth head specially in accordance with the search condition, it is possible to reproduce the subcode area with either the A or B head.

(B) Next, how to arrange the heads will be described.

FIG. 6 shows the subcode area to be reproduced and N
FIG. 10 is a diagram showing a relationship of a reproducible time width at the time of double search.
Here, when the time width of the sub-code to be reproduced is fixed, the phase of the bead period is set to 0 at the position shown in FIG. 6A, and the phase is sequentially changed to the phase = 2π in FIG. It shows the positional relationship between the playback envelope and the subcode area (hatched portion in the figure) 61 to be played back during the search. In addition,
In this figure, the period of the reproduced beads during the N-times search is Bperi, and the reproducible time width is Btim in the same manner as described above.
e, and the time width of the subcode to be reproduced is SUB
time.

FIG. 7 is a diagram for explaining a phase range and a time range in which the subcode area 61 can be reproduced when the phase is set as shown in FIG. Here, as described above, the track pitch and the reproduction track width are the same,
It is assumed that the read data is reproduced when an amplitude level equal to or more than 1/2 of the maximum reproduction amplitude level is obtained. Further, the time point of the phase 0 is set to time 0.

FIG. 7 shows that the subcode can be reproduced from the phase 0 in FIG. 6 to the DETp phase shown below. DETp = 2π (Btime−SUBtime) / Bperi (Equation 10) Also, at time 0 to (Btime−SUBtime), it can be seen that reproduction is possible if the head accesses the subcode area 61.

On the other hand, while the phase is between DETp and 2π (time Btime to Bperi), data cannot be reproduced even if the head accesses the subcode area 61.

When such a phenomenon is applied to FIGS. 4 and 5 described above, in the state of FIG. 4, the phase relationship between the A and B heads and the subcode area is both 2π from DETp, and the data of the subcode area is Playback is not possible,
On the other hand, in the state of FIG.
And the data in the subcode area can be reproduced,
It can be seen that the B head was at 2π from the phase DETp and was in a state where the data in the subcode area could be reproduced. Thus, whether or not the information in the subcode area can be reproduced is determined by the phase relationship between the head and the subcode area.

Here, when both the heads A and B pass through the subcode area, the probability that at least one of the heads reproduces the data in the subcode area is higher than that of each of the A and B heads. That is, the reproducible phases of the subcode area do not overlap. FIG.
FIG. 4 is a diagram for explaining conditions for preventing overlap. Now, assuming that the subcode can be reproduced by the A azimuth head as shown in FIG. 8A, the B azimuth head is different from the A azimuth head in FIG.
It is sufficient that the phase relationship is as shown in FIG. Therefore, the phase difference between the amplitude periods of the reproduction envelope during the search by the A azimuth head and the B azimuth head is DE.
If Tp to (2π-DETp), the reproducible phases of the subcode area by the A and B azimuth heads do not overlap.

As described above, when the search is performed at a predetermined search speed, the phase difference X of the amplitude cycle of the reproduction envelope by the A and B azimuth heads at the predetermined search speed is obtained.
If DETp ≦ X ≦ (2π−DETp) (Equation 11), the probability of reproducing the data in the subcode area becomes higher.

Incidentally, the search speed may be changed depending on the rotary head type magnetic recording / reproducing apparatus. Also,
When the search is started or stopped, the search speed changes. In such a case, that is, when the search speed changes, Bpe
ri and Btime change. Then, FIG.
The phase relationship between the A azimuth head and the B azimuth head indicated by changes. As shown in FIG. 8 (d), in order to prevent the overlapping of the reproducible range by the A azimuth head and the B azimuth head as much as possible and to improve the reproduction probability of the subcode even with such a change in the phase relationship, as shown in FIG. , A and B azimuth heads are desirably shifted by 180 ° (π) from each other in the phase of the amplitude cycle of the reproduction envelope during the search at a predetermined search speed. Here, it is desirable that the predetermined search speed is set to a maximum search speed at which reproduction of the subcode is most difficult (the number of accessible subcode areas is the smallest).

In the above description, basically, the period Bperi of the reproduced beads and the reproducible time width during the N-times search are represented by B
As a relation of time, when an amplitude level equal to or more than 1/2 of the maximum reproduction amplitude level is obtained, the read data is reproduced, and the track pitch Tp and the reproduction track width HEA are obtained.
The case where Dw is equivalent was considered. Next, other cases will be described. That is, the reproduction track width HEADw
And the track pitch Tp is assumed to be 2 × Tp>HEADw> Tp (Equation 12) (where 2 × Tp> HEADw is a condition in which adjacent tracks are not reproduced).

FIG. 9 is a diagram for explaining this. FIG.
(A) is a figure which shows the movement locus 55,56 of a head.
FIG. 9B shows a reproduction envelope at the time of search when the track pitch and the head width are the same (corresponding to the locus 56 in FIG. 9A). This is the example described with reference to FIG. FIG. 9C is a diagram showing a reproduction envelope at the time of search when the head width is 1.5 times the track pitch (corresponding to the locus 55 in FIG. 9A). Comparing the two, it can be seen that the regenerated bead cycle is the same for both (b) and (c). At this time, assuming that the reproducible reproduction signal level is の of the maximum amplitude level, the relationship between the reproduction bead period Bperi and the reproducible time width Btime in the N-times search is Btime> in FIG. 9C. Bperi / 2 (Equation 13)

Further, when it is assumed that the reproducible reproduction signal level can be set to be equal to or less than 1/2 of the maximum amplitude level, N
The relationship between the period Bperi of the reproduced beads at the time of the double search and the reproducible time width Btime is (Equation 13).

Further, when the time width SUBtime of the subcode to be reproduced has a relationship of (Btime-SUBtime)> Bperi / 2, the reproducible phase DE is obtained from (Equation 10).
Tp is DETp = 2π × (Btime−SUBtime) / Bperi> π (Equation 14), and the reproducible phase DETp is larger than π.

As described above, the reproducible phase DETp is π
If it becomes larger, the phase condition represented by Expression (11) changes. FIG. 10 is a diagram for explaining the phase condition. Now, assuming that the sub-code can be reproduced by the A azimuth head as shown in FIG. 10A, the B azimuth head is different from the A azimuth head in FIGS. 10B and 10C.
What is necessary is just to have the phase relationship as shown in FIG. In short, if the phase difference X of the amplitude period of the reproduction envelope at the time of the search by the A azimuth head and the B azimuth head is (2π−DETp) ≦ X ≦ DETp (Equation 15), both the reproducible areas overlap. However, when both of the A and B azimuth heads have passed through the subcode area, it is possible to perform reproduction with at least one of the furnaces.

In this case as well, the phase of the amplitude cycle of the reproduction envelope of the A and B azimuth heads is 180 °.
It is desirable to make the difference by (π), since it is possible to cope with a change in the search speed.

In the above description, the arrangement between the two heads having different azimuth angles has been described. However, the present invention is not limited to this. The same effect can be obtained even if two heads having the same azimuth angle are arranged in the above relationship.

(C) Next, based on the above phase relationship,
The positional relationship between the A and B heads during the N-times search is obtained. Here, a case where the phases of the amplitude periods of the reproduction envelopes of the A and B azimuth heads differ by 180 ° (π) will be described.

Head Locus at Search First, the angle of the head locus Srundeg (hereinafter referred to as a search head run angle) at the time of search is obtained as Srundeg [N] = θ ₀ + Gsearch [N] (Equation 16). Here, θ ₀ is the above-mentioned still angle, Gse
rch is an angle shown below. Gsearch [N] = cos ⁻¹ (GA / GB) (Equation 17) where GA = (D × π / 2) − ((D × π × Vt) / (2 × V
h)) × cos θ ₀ GB = Square root ((D × π / 2) ² +
((D × π × Vt) / (2 × Vh))) 2 -2 × (D ×
π / 2) × ((D × π × Vt) / (2 × Vh)) × co
sθ ₀ ) Here, D is the drum diameter, Vh is the peripheral speed of the drum at the time of search, Vt is the tape speed at the time of search, and θ ₀ is the track angle at the time of still.

At this time, Vh is expressed as follows from (Equation 6): Vh = (Vr + K2 × N × Vtl) / K1 (Equation 18)

The HD-D / VTR shown in Tables 1 and 2 above
FIG. 26 shows the relationship between the search speed and the search head run angle: Srundeg [N] when the specifications and the recommended values are used.

The positions of the A and B heads at the time of recording will be described using the HD-D / VTR specifications and the recommended values.
A1, A2 of azimuth and B1, B2 of B azimuth head
Use a head. As these arrangements, for example, FIG.
As shown in FIG. 1A, A1 head, A2 head and B1
The head and the B2 head are arranged 180 ° opposite to each other, and A
There is a method in which one head, A2 head, B1 head, and B2 head are orthogonal to each other at 90 °. Alternatively, although called a pair head, there is a method of mounting the A1 and B1 heads and the A2 and B2 heads close to each other. However, even in this case, the A1 head and the A2 head and the B1 head and the B2 head are generally arranged to be 180 ° opposite to each other.

When the A1 and B1 heads and the A2 and B2 heads are mounted close to each other, the positions of the B1 and B2 heads (in this case, A
FIG. 11B shows the relationship between the mounting angle positions of the heads 1 and 1 or the mounting angles of the heads A2 and B2) and the mounting height. That is, the height of the mounting of the B1 and B2 heads is 9
At the 0 ° phase position, it is mounted at the same height as A1 or A2, and at the 0 ° phase it is higher than the A1 or A2 head by the track pitch. Here, A1, B1, A2, and B2 are 90
Although they are provided at intervals, the present invention is not limited to this, and it is sufficient that A1 and B1 can access tracks adjacent to each other and A2 and B2 can access tracks adjacent to each other during recording and reproduction.

Position of A / B Head on Track Pattern FIG. 12 is a diagram showing the state of the mounting position of the A / B head on the drum when viewed from the track pattern. In this figure, each track angle on the tape is a track angle θr. Now, assuming that A1 head is O points A1 track, B1 head in the extension of the track angle or drum lead angle theta ₀ line during still the position O point A1 head, 90 ° phase position described above (Fig. At the point R, the height is the same as the height of the A1 head on the drum. Further, the point P at a height corresponding to the track pitch Tp on a line perpendicular to the drum lead angle θ ₀ from the point O is the position shown in FIG.
This corresponds to the 0 ° phase position described above.

Therefore, when the A1 head is at the point O of the A1 track, the B1 head must be located on the line segment PR in order for the B1 head to access the B1 track adjacent thereto. For example, it is desirable to position at an arbitrary L1 length at the Q point position on the line segment PR.

Head trajectory during search and mounting phase of A / B head Head trajectory angle during search (hereinafter referred to as search head run angle): Srundeg is described in the above “1. The head trajectory at the time of search "and the angle Srundeg of the head trajectory at the time of search as shown in the section" Search trajectory N ".

The relationship between the head trajectory during the search and the mounting phase of the A / B head will be described with reference to FIG. FIG. 13 shows that at a certain search speed N, the A1 head is passing the entrance O of the subcode area of the A1 azimuth track at the head locus angle Srundeg at the time of the search. The phase when the A1 head passes through the point O corresponds to the position of the phase 0 in FIG.

On the other hand, assuming that the position of the B1 head has a phase difference of 180 ° (π) from the amplitude period of the reproduction envelope of the A1 head, as described above. In FIG. 13, B
The trajectory of one head is, for example, B1srn-1, B1srn-
2 is required.

The position at which the B1 head is attached to the A1 head is determined as described with reference to FIG. That is, in the case of FIG. 13, A1 head when in the position of the point O, from point O Doramuri - P point position of de angle theta ₀ on the vertical line (on Yd axis) at a track pitch Tp and the above-mentioned FIG. The B1 head is located on the line segment PR formed at the point R indicated by 12.

Accordingly, for example, the B1 head is moved to the point B1s.
When passing over rn-1, the B1 head must be disposed at the intersection S1 on the line segment PR with the line segment passing through the point B1srn-1 at the head locus angle Srundeg at the time of search. When the B1 head passes over the point B1srn-2, the B head is disposed at the intersection S2 on the line segment PR with the line segment passing through the point B1srn-2 at the head locus angle Srundeg at the time of search. There must be.

In FIG. 13, when the point O where the A1 head is located is the origin position of the (Xt, Yt) axis on the tape pattern, the positions of the points B1srn-1 and B1srn-2 that the B1 head wants to pass through are determined. (B1srnXt (n), B
1srnYt). Here,
n is a track in which the B azimuth head track in the Xt axis direction from the point O is positive, and the B azimuth head track in the −Xt axis direction from the point O is negative. That is, n = -1 is the point B1.
srn-1, n = -2 is the point B1srn-2.

The value of the point B1srn (n) on the Xt axis is as follows: B1srnXt (n) = (Tp × cos θr / tan θr) + (2 × Tp / sin θr) × (n−1) (Equation 19) Since the point B1srn (n) on the Yt axis does not depend on n, it can be expressed as B1srnYt = (Tp × sin θr / tan θr) (Equation 20).

At this time, the B1 head moves to the point B1srn (n)
And the head locus angle Srundeg at a certain search
The line segment moves at an angle of. Here, using the relationship obtained by the head locus angle Srundeg (Equation 16), a line segment at an arbitrary point B1srn (n) is expressed on the (Xt, Yt) axis on the tape pattern by Search Trace [Xt, n] = tan [−Srundeg × π / 180] × Xt + Yt−tan [−Srundeg × π / 180] × (B1srnXt (n)) (Equation 21)

Next, the position of the B1 head on the drum is determined. On the (Xt, Yt) axis, the point P is expressed as follows: Xp = Tp × cos [(90 × π / 180) −θ ₀ ] Yp = Tp × sin [(90 × π / 180) −θ ₀ ] 22) can be obtained as

The above-mentioned R point is similarly calculated as (Xt, Yt)
The on-axis, Xr = (π × D × cosθ 0/4) Yr = (- π × D × sinθ 0/4) can be obtained as (equation 23).

Therefore, the position Headposition of the B1 head on the drum is Headposition [Xt] = ((YpYr) / (Xp−Xr)) × Xt + (Xp × Yr−Xr × Yp) on the (Xt, Yt) axis. ) / (Xp−Xr) (Equation 24).

As described above, the B1 head obtained by (Equation 21) is a line segment passing through the point B1srn (n) and moving at an angle forming the head locus angle Srundeg at a certain search, and (Equation 24) (Equation 25) (Equation 2)
In (6), (Headxsub [N,
n], Headysub [N, n]). That is, Headxsub [N, n] = ((Xp × Yr−Xr × Yp) / (Xp−Xr) −B1srnYt−tan [−Srundeg [N] × π] / 180] × B1srnXt (n)) / (tan [−Srundeg [N] × π / 180] − ((Yp−Yr) / (Xp−Xr))) (Equation 25) and Headysub [N, n] = ((Yp−Yp) / (Xp−Xp) )) × Headxsub [n] + (Xp × Yp−Xp × Yp) / (Xp−Xp) (Formula 26)

FIG. 14 shows the B1 head position on the Xt axis on the tape format, which is the result of (Equation 25), as the horizontal axis search double speed N, and n is a parameter.

FIG. 15 shows the Y1 axis B1 head position on the tape format, which is the result of (Equation 26), and the horizontal axis search double speed N, and n is a parameter.

The above description is based on Xt and Yt on the tape format.
The position of the B1 head on the axis is obtained. next,
The position of the B1 head on the drum is determined.

As shown in FIG. 16, the Xt and Yt axes of the tape format and the Xd and Yd axes on the drum are rotated by a still angle θ ₀ . Therefore, Xd, Yd on the drum
In order to express by an axis, (Hxb [N, n], Hyb [N, n]) on the (Xd, Yd) axis in the following (Equation 27) and (Equation 28) from (Equation 25) (Equation 26) described above. ). Hxb [N, n] = ( Headxsub [N, n] + Hyb [N, n] × si n [-θ 0]) / cos [-θ 0] ( Equation 27) Hyb [N, n] = (Headysub [ n] × cos [−θ ₀ ] −Head xsub [N, n] × sin [−θ ₀ ]) / ((sin [−θ ₀ ]) ² + (cos [−θ ₀ ]) ² ) (Equation 28) FIG. 17 shows the position of the B1 head of the Xd axis on the drum, which is the result of (Equation 27), as the horizontal axis search speed, and shows n as a parameter. Also, FIG. 18 shows the position of the B1 head of the Yd axis on the drum, which is the result of (Equation 28), as the horizontal axis search speed, and n is a parameter.

The position of the B1 head on the drum is shown in FIG.
By obtaining Xd as shown in FIG. 1, Yd is uniquely determined, so that it can be indicated only by Xd on the drum.

As described above, according to the present invention, the arrangement of at least two heads in a rotary drum type magnetic recording / reproducing apparatus having a plurality of heads is determined as described above, thereby improving the subcode reproduction probability at the time of search. It is to let. Hereinafter, the configuration of the rotary head drum type magnetic recording / reproducing apparatus will be specifically described.

(Embodiment 1) FIG. 1 is a diagram showing one configuration example of a rotary head type magnetic recording / reproducing apparatus of the present invention.

In the figure, reference numerals 7 and 8 denote a pair of reel stands for holding and running the magnetic tape 9. Reel motors 10 and 11 for rotating and driving the reel bases 7 and 8 are directly connected, and rotation detection plates 12 and 13 are attached to the reel bases 7 and 8, respectively. Rotation detectors 14 and 15 are arranged close to the rotation detection plates 12 and 13, respectively. Each rotation detector 14, 1
5 outputs rotation information of the reel bases 7 and 8 to the tape running controller 18. At a position in contact with the magnetic tape 9, a speed detecting roller 16 that rotates with the running speed of the magnetic tape 9 is provided. The rotation speed is detected by a roller rotation detector 17, and the detection result is input to a tape running controller 18.

The tape running controller 19 controls the reel motor 10 and the tape motor 10 so that the tape running speed and the tape tension are adjusted to the respective modes according to external commands such as recording, reproducing, fast-forwarding, rewinding, and high-speed search. 11 and outputs a tape speed information signal indicating the current tape speed. Tape running controller 18
Are input to the reel motor drivers 23 and 24, converted into reel motor drive signals, and input to the reel motors 10 and 11.

The rotating drum 5 has four pairs of magnetic heads 1, 2, and 3, having positive and negative azimuth angles.
4 are mounted at 180 degree intervals. A drum motor 6 is directly connected to a rotating shaft of the rotating drum 5. The drum motor 6 drives the rotary drum 5 according to a command from a drum rotation controller 21 described later, and outputs a drum PG signal indicating the rotation phase of the rotary drum 5. This drum PG
The signal is input to the drum rotation controller 21 and the reproduction signal switching signal generator 36.

The drum rotation controller 21 also receives the tape speed information signal output from the tape running controller 18 and
The current rotation speed of the rotary drum 5 is detected from the frequency of the drum PG signal. In addition, a drum command signal is output to the drum drive motor 6 at a predetermined rotation speed during recording and reproduction, and as a target rotation speed in other modes so that the head-tape relative speed matches the recording speed. further,
A drum rotation speed information signal indicating the current rotation speed of the rotating drum is output.

The reproduction signal switching signal generator 36 is connected to the drum P
On the basis of the G signal, a reproduction signal switching signal whose state changes depending on which of the magnetic heads 1, 2, 3 and 4 is in contact with the magnetic tape 9 is output.

The reproduction signals from the magnetic heads 1 and 2 are amplified by the reproduction amplifier circuits 25 and 28 and then input to the signal switching circuit 35. The reproduction signals from the magnetic heads 3 and 4 are amplified by the reproduction amplifier circuits 27 and 26 and then input to the signal switching circuit 35. The signal switching circuit 35 reproduces the reproduction amplifier circuits 25, 26, 2 according to the reproduction signal switching signal.
A reproduced signal is selected and output from the outputs of 7, 28.
In this example, when the reproduction signal switching signal is at "H" level, the outputs of the reproduction amplifier circuits 25 and 28, that is, the magnetic heads 1 and 2 are output.
When the reproduction signal switching signal is at "L" level, the outputs of the reproduction amplifier circuits 27 and 26, that is, the reproduction signals from the magnetic heads 3 and 4, are selected and output.

The output of the signal switching circuit 35 is input to the waveform equalization circuits 29 and 30, respectively. Waveform equalization circuits 29, 30
After equalizing the waveform of the signal so as to match a predetermined reference, the peak of the signal is detected and a peak point detection pulse is output. The peak point detection pulse is output from the PLL circuit 3
1, 32. The output from the PLL circuits 31 and 32 is input to the subsequent data detection circuits 33 and 34.

The tape speed information signal and the drum speed information signal are input to the relative speed error detector 20. The relative speed error detector 20 calculates the current head / tape relative speed based on the tape speed signal and the drum rotation speed signal, detects an error from the recording time, and controls the rotation speed of the rotary drum 5.

The schematic configuration of the rotary head type magnetic recording / reproducing apparatus shown in FIG. 1 has been described above.
The arrangement of 3 and 4 will be described.

In the rotary head type magnetic recording / reproducing apparatus shown in FIG. 1, the heads 1 and 3 and the heads 2 and 4 have the same azimuth angle.
And the azimuth angle is different. And heads 1, 3
(And the heads 2 and 4) have the above-described positional relationship, that is, the amplitude period of the reproduction envelope from the head 1 (head 3) at a predetermined search speed and the head 2
The positional relationship is such that the phase difference between the amplitude periods of the reproduction envelope from (head 4) is 180 °.

More specifically, the maximum search speed of the present rotary head type magnetic recording / reproducing apparatus is determined, and the interval between heads 1 and 2 and the interval between heads 3 and 4 are set to the maximum search speed Nmax.
Head 1 (head 3) and head 2 (head 4)
When the relative position of the head 1 (head 3) is the origin, the drum axis is the Y axis, and the outer periphery of the drum is the X axis,
The position of (head 4) is obtained from (Equation 27) and (Equation 28), and (Hxb [Nmax, n], Hyb [Nma
x, n]).

In the fixing method, the individual heads may be mounted at predetermined positions, or the heads 1 and 2 and the heads 3 and 4 may be positioned so that their relative positions with respect to the head mounting reference plane have a predetermined relationship. It may be a method in which a pair head is attached and this is attached to a drum.

In the above specific example, the arrangement of each head is determined on the basis of the maximum search speed. This is to improve the reproduction probability of the subcode when the search speed increases. By doing so, it is possible to solve the problem that the number of subcodes accessible by the head decreases with a high search speed.

Hereinafter, the arrangement of the heads in this embodiment will be described with reference to a specific example of FIG. FIG.
FIG. 7 is a diagram showing a relationship between Xd on the drum and a search speed obtained by the above relational expression. Here, assuming that the maximum search speed is, for example, -100 times, the phase of the amplitude cycle of the reproduction envelope of the head 2 (head 4) is the head 1 (head 3).
In order for the phase of the amplitude cycle of the reproduction envelope to be substantially opposite to that of FIG.
In the case of n = −40, by setting Xd to about 4.8 mm, the reproduction envelopes of the respective heads at the time of the -100 × search become opposite phases, and the head 1 (head 3) and the head 2
It can be seen that the subcode area can be reproduced with either of the heads (head 4).

(Embodiment 2) FIG. 19 is a diagram showing a configuration of a rotary head type magnetic recording / reproducing apparatus according to Embodiment 2 of the present invention. In this figure, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The difference between the rotary head type magnetic recording / reproducing apparatus shown in FIG. 19 and that shown in FIG.
And head interval control mechanisms 37 and 38. The head interval controller 22 controls the tape speed detecting means 18.
Is calculated based on the calculated tape speed at the time of search, and the head spacing control mechanisms 37 and 38 are controlled so that the head spacing corresponding to the search speed is obtained. The interval between 1 and 2 (heads 3 and 4) is moved. Specifically, the intervals between the heads 1 and 2 (heads 3 and 4) are moved so that the reproduction envelopes of the heads 1 and 2 (heads 3 and 4) have opposite phases (180 ° phase difference). As a result, as described above, it is possible to improve the probability of reproducing the subcode area with either head 1 or head 2 (head 3 or head 4).

Hereinafter, the head interval controller 22 and the head interval control mechanisms 37 and 38 according to the present embodiment will be described.

FIG. 20 is a diagram for explaining the arrangement of the heads 1, 2, 3, and 4. FIG. 20A is a view of the state in which the heads 1 and 2 and the heads 3 and 4 are mounted close to each other, as viewed from above the drum. FIG. 20B is a diagram showing the positional relationship between the head 1 and the head 2 (and the head 3 and the head 4).
Here, the heads 1 and 3 are set to the origin O. in this case,
When the heads 1 and 3 and the heads 2 and 4 are arranged so that a normal recording / reproducing operation can be performed, the heads 2 and 4 are positioned on the line segment PR in the same manner as described with reference to FIG. I have to do it. Therefore, when the heads 1 and 3 are fixed,
Head interval controller 22 and head interval control mechanisms 37 and 38
Must move the heads 2 and 4 on the line segment PR in FIG.

The head interval control mechanisms 37 and 38 can be constituted, for example, as shown in FIG. here,
The head spacing is adjusted by the laminated piezoelectric actuators 37-1 and 38-1. FIG. 21A is a diagram showing the arrangement of the multilayer piezoelectric actuators 37-1 and 38-1 as viewed from above the drum, and FIG.
FIG. 21B is a diagram showing 7-1 and 38-1 in association with FIG.

Multilayer piezoelectric actuators 37-1, 38-
1 moves the head 2 (head 4) to a predetermined position on the line segment PR under the control of the head interval controller 22. Here, the laminated piezoelectric actuators 37-1 and 38-1 are provided so as to move the head 2 (head 4) about the center of the drum as the center of rotation. The P point side is fixed, and the other end of the head 2 (head 4) is fixed. ) Is attached. According to such a configuration, the multilayer piezoelectric actuator 37-
The head 2 (head 4) can be moved on the line segment PR by controlling the voltage applied to the heads 1 and 37-2.

FIG. 22 shows a head spacing control mechanism 37, 38.
Is a diagram showing another example. Here, the head gap is adjusted by the voice coil motors 37-2 and 38-2. FIG. 22A shows the voice coil motors 37-2, 38-.
FIG. 22 (b) is a view of the arrangement of No. 2 viewed from above the drum.
FIG. 21 is a diagram showing the movement locus of the head in association with FIG.

Voice coil motors 37-2, 38-2
Is controlled by the head interval controller 22 to move the head 2 (head 4) to a predetermined position on the line segment PR. Here, the rotation center of the movement of the head 2 (head 4) is set at the center of the drum. The head spacing control mechanisms 37-2 and 38-2 using voice coil motors are mechanisms used for head control such as HD (hard disk). The head 2 (head 4) is attached to the tip of the movable part of the voice coil motors 37-2 and 38-2. Then, the head 2 (head 4) is moved on the line segment PR by applying a predetermined current to the voice coil motors 37-2 and 38-2.

Hereinafter, the arrangement of the heads in the present embodiment will be described with reference to a specific example of FIG. FIG.
FIG. 7 is a diagram showing a relationship between Xd on the drum and a search speed obtained by the above relational expression. In this embodiment, when the speed at the time of search is varied, the head 1 (head 3) at the time of search is changed.
Are varied so that the phase of the amplitude cycle of the reproduction envelope of the head 2 and the phase of the amplitude cycle of the reproduction envelope of the head 2 (head 4) are always at opposite positions.
Assuming that the operating range of the head 2 (head 4) on the drum is within the thick line in FIG. 24, that is, 5 mm to 10 mm, the B1 head is located at the position of 10 mm, that is, Xd1-1 in the low-speed search (near -20-fold search). By doing so, the reproduction envelopes of the respective heads have opposite phases.

Since the search speed becomes faster, n = −
If the position of the head 2 (head 4) is set along the line 20, the search speed is about -50 times (in this case, X in the figure)
Up to d1-2), an opposite phase between the heads can be realized. However, if the search speed is further increased, the line of n = -20 exceeds the movable range of the head 2 (head 4) (below 5 mm). Therefore, next, the head position is set using the line of n = -40, that is, the head position is determined using the point Xd2-1 in the figure. Further, if the search speed is further increased, the head position can be set by moving the head position along the line of n = -40 toward Xd2-2. Thereafter, as the search speed increases, the value of Xd in FIG.
The value of Xd can be found by changing to a line with a different value of n so as to be 10 mm to 10 mm. With this setting, it is possible to reproduce the subcode area with either the head 1 (head 3) or the head 2 (head 4).

As described above, according to the present invention, by setting the head interval specially, it is possible to improve the probability that the subcode can be reproduced during the search. In the first and second embodiments, the distance between two heads having different azimuth angles is adjusted. However, the distance between two heads having the same azimuth angle may be adjusted. However, it is desirable to adjust the interval between two heads having different azimuth angles because the head can be arranged at a position where normal recording and reproduction can be performed.

[0117]

According to the present invention, the first head and the first head are controlled so that the phase difference between the amplitude period of the reproduction envelope of the first head and the amplitude period of the reproduction envelope of the second head at the time of search falls within a predetermined range. Arrange two heads. This allows
It is possible to improve the reproduction probability of the subcode (head information and the like) at the time of search.

The above-mentioned phase difference is set to 180 °. As a result, even if the search speed changes, the reproduction probability can be maintained to some extent.

Further, if the maximum search speed is used as a reference, the reproduction probability of the subcode can be improved under the condition that the reproduction of the subcode is most difficult.

Furthermore, if the head position is made variable, the probability that the subcode can be reproduced by either the first head or the second head can be improved regardless of the change in the search speed.

If the head position is set to a position where normal recording and reproduction can be performed, both recording and reproduction and search can be realized by the same head.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of a rotary head type magnetic recording / reproducing apparatus according to the present invention.

FIG. 2 is a diagram showing a head trajectory, a reproduction envelope, and a cycle thereof during a search.

FIG. 3 is a diagram showing a control signal area (sub code area) such as a head at the time of searching for HD specifications determined by the “HD Digital VCR Council”.

FIG. 4 is a diagram for explaining that a subcode area cannot be reproduced during a search.

FIG. 5 is a diagram illustrating an example in which a subcode area can be reproduced during a search.

FIG. 6 is a diagram showing a relationship between a subcode area to be reproduced and a reproducible time width at the time of an N-times search.

FIG. 7 is a diagram showing, by phase, whether or not data in a subcode area can be reproduced during a search.

FIG. 8 is a diagram illustrating a phase relationship between an A head and a B head.

FIG. 9 is a diagram showing a reproduction state of a subcode area when the head width is 1.5 times the track pitch.

FIG. 10 is a diagram showing another phase relationship between the A head and the B head.

FIG. 11 is a diagram illustrating mounting of a head on a drum using HD-D / VTR specifications and recommended values.

FIG. 12 is a diagram showing mounting positions of A and B heads on a drum on a track pattern.

FIG. 13 is a diagram illustrating a relationship between a head trajectory at the time of a search and mounting phases of A and B heads.

FIG. 14 is a diagram showing the position of the X1 axis B1 head on the tape format as the horizontal axis search double speed N, and n as a parameter.

FIG. 15 is a diagram showing a B1 head position on the Yt axis on the tape format as a horizontal axis search double speed N, and n as a parameter.

FIG. 16 is a diagram showing a relationship between Xt and Yt axes on a tape format and Xd and Yd axes on a drum.

FIG. 17 is a diagram showing the B1 head position on the Xd axis on the tape format as the horizontal axis search double speed N, and n as a parameter.

FIG. 18 is a diagram showing a B1 head position on the Yd axis on a tape format as a horizontal axis search double speed N and n as a parameter.

FIG. 19 is a diagram showing a configuration of a rotary head type magnetic recording / reproducing apparatus according to a second embodiment.

FIG. 20 is a diagram illustrating a mounting position of a head.

FIG. 21 is a diagram illustrating an example of a head-to-head control mechanism.

FIG. 22 is a diagram illustrating another example of the head-to-head control mechanism.

FIG. 23 is a diagram illustrating a method of setting a head position according to the first embodiment.

FIG. 24 is a diagram illustrating a method of setting a head position according to the second embodiment.

FIG. 25 is a diagram showing a search double speed N and a drum peripheral speed Vh when using HD-D / VTR specifications and recommended values.

FIG. 26 shows a search double speed and a search head run angle when the HD-D / VTR specification and recommended values are used: Srund
FIG. 9 is a diagram illustrating a relationship of eg [N].

[Explanation of symbols]

1, 2, 3, 4 Magnetic head 5 Rotating drum 9 Magnetic tape 22 Head spacing controller 37, 38 Head spacing control mechanism Amplitude period of playback envelope during Bperi search Btime playbackable time width of playback envelope during Btime search SUBtime playback Subcode time width to be

Claims (6)

[Claims] 1. A rotating head type magnetic recording / reproducing apparatus having at least two or more heads including a first head and a second head, wherein a reproduction envelope has an amplitude period of Bperi, and a reproducible time width during a search. Is set to Btime, and the time width of the subcode area recorded on the tape to be searched is set to SUBti.
and DETp = (Btime−SUBtime) × 2π / B
When “peri”, the first head and the second head perform DETp ≦ X ≦ 2π when the phase difference X of the amplitude period of the reproduction envelope from the first head and the second head at the time of search is DETp is π or less. A rotating head type magnetic recording / reproducing apparatus, wherein the magnetic head is arranged so as to satisfy 2π-DETp ≦ X ≦ DETp when DETp is greater than π. 2. A rotating head type magnetic recording / reproducing apparatus having at least two or more heads including a first head and a second head, wherein the first head and the second head are the first head and the second head during a search. A rotary head type magnetic recording / reproducing apparatus, wherein a phase difference of an amplitude cycle of a reproduction envelope from the second head is arranged to be substantially π. 3. The rotary head type magnetic recording / reproducing apparatus according to claim 1, wherein a phase difference X between amplitude periods of reproduction envelopes from the first head and the second head during a search at a maximum search speed.
Is set so as to satisfy DETp ≦ X ≦ 2π-DETp when DETp is equal to or less than π, and to satisfy 2π−DETp ≦ X ≦ DETp when DETp is greater than π. Playback device. 4. The rotary head type magnetic recording / reproducing apparatus according to claim 2, wherein the phase difference between the amplitude periods of the reproduction envelopes from the first head and the second head during the search at the maximum search speed is substantially π. A rotary head type magnetic recording / reproducing apparatus characterized by being arranged as follows. 5. The rotary head type magnetic recording / reproducing apparatus according to claim 1, wherein a variable means for varying a search speed, and an interval between the first head and the second head is changed according to the search speed. A rotating head type magnetic recording / reproducing apparatus, comprising: 6. The rotary head type magnetic recording / reproducing apparatus according to claim 1, wherein the first head and the second head are arranged at positions where a normal recording / reproducing operation is possible. A rotary head type magnetic recording / reproducing apparatus characterized by the above-mentioned.