JPH0520737A - Tape traveling state detecting method for tape player - Google Patents

Abstract

PURPOSE:To immediately and surely detect a tape residual amt. and a tape traveling state, CONSTITUTION:Rotaion periods T1 and T2 are detected by detecting rotations of reel bases on the supply side and the take-up side respectively. For example, both rotation periods are detected, and their ratio alpha=(T2/T1) is obtained. When the diameter of a reel hub is denoted as (a), while the overall length of the tape as L and the thickness of the tape as sigma, the tape residual amt. L1 on the supply side can be calculated from these values and the above beta. Since this calculation is not related to the tape speed V, the tape residual amt. can be calculated by the same calculation at whatever double the speed value of the tape is required. Moreover, the tape residual amt. can immediately be calculated when a cassette pack is loaded and the tape is traveled by its fixed amt.

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 tape player such as DAT or a cassette type tape player, and more particularly to a method for detecting a tape running state by using a rotation cycle of a tape reel.

[0002]

2. Description of the Related Art In a rotary head type tape player such as a DAT or a cassette type tape player, as a detecting portion capable of detecting the running state of a tape, the rotating state of each reel stand on the supply side and the winding side is optically detected. There are a reel pulse detection unit for detecting, an FG detection unit for detecting the rotation speed of the capstan, and the like.

For example, as a method of detecting the remaining amount of tape, the number of rotations of the tape reel is detected based on the outputs from the both reel pulse detectors, and the thickness of the tape used and the like are transferred to the reel hub. The number of tape turns is calculated. Also, the running speed of the tape during recording and playback,
The rotation speed of the capstan feeding the tape can be recognized by detecting it from the FG detection unit.

[0004]

However, for example, in order to calculate the remaining tape amount by the reel pulse on the supply side and the winding side, it is necessary to know the total length and the thickness of the tape in advance. . Recording / playback, FF, R
When EW, high-speed search, etc. are repeated, it is necessary to judge the accumulation of reel pulse counts.
The control for calculating the remaining tape amount becomes complicated, and an error easily occurs due to the accumulation of counts.

The tape speed can be known from the rotational speed of the capstan as described above. However, if there is an abnormality in the tape running such as when the tape is cut, the capstan will rotate. Since the abnormality cannot be judged from the FG output because it continues, if the tape is still running at the predetermined speed, it will be erroneously recognized.

The present invention solves the above-mentioned problems of the prior art. It is possible to immediately and accurately detect the remaining tape amount regardless of the tape speed, and whether the tape running state is normal or abnormal. It is an object of the present invention to provide a tape traveling state detection method for a tape player, which can also make a judgment.

[0007]

The tape running state detecting method according to the present invention is a tape player provided with a rotation detector for detecting the rotation of each of the tape reels on the supply side and the winding side. The rotation cycle of the tape reel on the supply side obtained from the detection output from the container is T1.
Then, the rotation cycle of the tape reel on the take-up side is T2, the sum of the square of T1 and the square of T2 is calculated, and whether or not there is an abnormality in tape running is determined by whether or not this value is constant. It is characterized by judging,

Further, the ratio of both rotation cycles (α = T2 / T1) is determined, and by this α, the total length of the tape, the thickness of the tape, and the diameter of the reel hub around which the tape is wound, the tape remaining on the supply side is left. It is characterized by determining the quantity.

Further, in the second means, it is judged whether or not there is an abnormality in the tape running depending on whether or not the value of α is within a certain range or whether or not the value of α is abruptly changed. You can also do it.

[0010]

All the above means detect the tape running state based on the rotation cycle of the tape reels on the supply side and the winding side. First, set the rotation cycle of each tape reel to T1.
And T2, the sum of the square of T1 and the square of T2 is always a constant value when the tape is running at a predetermined speed. Therefore, by determining the rotation cycles T1 and T2 from the output from the reel pulse detection unit, calculating the sum of the squares, and monitoring the value, it is possible to determine whether the tape is running at a constant speed accurately or whether the tape is being cut. It is possible to detect whether or not it has occurred.

Further, the rotation periods T1 and T2 of the tape reel are obtained from the respective reel pulses, and the ratio α = T2 / T1.
Based on the above, the remaining tape amount can be known by calculating the total tape length and the tape thickness. The calculation of the remaining tape amount does not depend on the tape speed. Therefore, no matter what value the tape running speed is, the remaining tape amount can be immediately detected by knowing the ratio α of the tape reel cycle at that time. Further, it is possible to judge whether or not there is an abnormality in the tape running state based on whether or not the value of α is within a predetermined range or whether the value of α is abruptly changed.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic structure of a rotary head type tape player for DAT and a circuit block. Reference numeral 1 is a cassette pack. In the cassette pack 1, a reel hub 2 on the supply side and a reel hub 3 on the winding side are rotatably accommodated, and the magnetic tape 10 includes both reel hubs 2.
And 3 are wound. When the cassette pack 1 is loaded, one reel hub 2 is connected to the supply reel stand 4
The reel hub 3 on the take-up side
Is installed in.

As shown in FIG. 2, a disc 4a is provided on the supply side reel base 4 so as to rotate integrally with the disc 4a. Reflective surfaces and non-reflective surfaces are alternately formed on the disc 4a in the direction of rotation to form a chassis. An optical detector 6 facing the disk 4a is provided on the fixed part such as. When the reel stand 4 rotates, the reflective surface and the non-reflective surface of the disk 4a alternate with each other by the optical detector 6
And the reel pulse is output by the optical detector 6. Similarly, the reel table 5 on the winding side is also provided with a similar disk, and the rotation thereof causes the optical detector 7 to output a reel pulse.

Reference numeral 8 is a rotary head device, and magnetic heads 9a and 9b are mounted on a rotary drum of the rotary head device 8. The magnetic tape 10 in the cassette pack 1 is pulled out by the loading post 11 and wound around the rotary head device 8. In the case of DAT, the diameter of the rotary head device 8 is 30 mm and the winding angle of the tape 10 is 90 mm.
It is degree.

In the recording / reproducing operation, the magnetic tape 10 is pressed against the capstan 12 by the pinch roller 13, and the magnetic tape 10 is rotated by the rotation speed of the capstan 12.
Are driven at a constant speed V. In the case of DAT, the standard running speed V of the magnetic tape 10 is 8.15 mm / sec.
Is.

Outputs from the optical detectors 6 and 7 provided facing the disks of the reel stands 4 and 5 are detected and amplified by the pulse detectors 15a and 15b, and the waveform shaping unit is further provided. The waveform is shaped by 16a and 16b and input to the data processing unit 17. The data processing unit 17 is mainly composed of a CPU and performs various calculations based on a preset program.

Next, the various arithmetic processes will be described in order. (Confirmation of tape running state) First, the rotation cycle of the reel is measured from the reel pulse detected by the optical detectors 6 and 7 shown in FIG. 1, the rotation cycle of the supply-side reel stand 4 is T1, and the winding-side reel is The rotation cycle of the table 5 is T2. At this time, the diameter of the outermost peripheral outer surface of the tape wound on the supply-side reel hub 2 is d1, and the diameter of the outermost peripheral outer surface of the tape wound on the winding-side reel hub 3 is d2. If the speed is V,

[0018]

[Equation 1] T1 = πd1 / V, T2 = πd2 / V

Next, assuming that the total length of the tape is L and the thickness of the tape is σ, and there is no slack in the winding of the tape,

[0020]

[Equation 2] π (d1 / 2) ² + π (d2 / 2) ² = 2π (a /
2) ² + σ · L

[0021] Here, a is the diameter of each of the reel hubs 2 and 3. In the above mathematical expression 2, the left side is the sum of the areas in the plan views of both reel rotating parts, and the right side is the sum of the areas in the plan views of the two reel hubs 2 and 3 and the area (cross-sectional area) in the plan view of the wound tape. And both are naturally equal.

When d1 and d2 are deleted from the above equations 1 and 2 and arranged, the following equation 3 is obtained.

[0023]

[Formula 3] T1 ² + T2 ² = (2π / V ² ) · (πa ² + 2 · σ · L)

According to this equation 3, since the diameter a of the reel hub, the thickness σ of the tape and the length L are constant, the right side of the tape always has a constant value when the tape running speed V is determined. Therefore, if the speed V is determined, (T1 ² + T2 ² ) is always a constant value.

Therefore, in the data processing section 17,
It is the sum of the squares of the rotation cycles of both reel stands (T1 ² + T2 ² ).
Is calculated and whether or not this is a constant value can be monitored to determine whether or not the magnetic tape 10 is running at a constant speed. If there is a significant change in the speed V due to the running load of the magnetic tape being too large, or if a tape cut occurs, the calculation result of the above (T1 ² + T2 ² ) will change. You can determine that there is a problem running the tape.

Next, in a high speed search operation, the tape runs at a speed (n times) of the normal speed (8.15 mm / sec). Therefore, by substituting (n · V) for V in the equation 3, the equation 3 becomes the following equation 4.

[0027]

## EQU4 ## n ² (T1 ² + T2 ² ) = (2π / V ² )  (πa ²
+2 ・ σ ・ L)

From this equation, when the tape is running at n-times speed, the value obtained by multiplying (T1 ² + T2 ² ) by the square of n is constant. Therefore, in the data processing unit 17, n ² (T1
² + T2 ²⁾ calculates the tape running state by this value to monitor whether the constant can determine whether stable.

(Determination of Tape Type) In the above Expressions 3 and 4, the diameter (a) of the reel hub is a constant as described above.
Therefore, if the tape running speed V or (n · V) is known, T1 and T2 in FIG. 1 are measured, and the sum of the squares thereof (T1 ² + T2 ² ) is calculated, it is (σ · L), that is, the thickness of the tape. The type of length can be determined.

FIG. 3 is a diagram based on the above equation 4, where the horizontal axis represents the tape length (L) and the vertical axis represents n ² (T1
² + T2 ² ) and the tape thickness σ is shown as a parameter. FIG. 3 shows the case where V = 8.15 mm / sec and the tape thickness σ is 13 μm and 9 μm. Normally, the thickness σ of the magnetic tape can be detected by the identification hole formed in the cassette pack. Therefore, if the thickness σ is known by this detection, the velocity V and the speed number n can be known, and (T1 ² +
By measuring T2 ² ) the tape length can be determined.

As is clear from the diagram of FIG. 3, if the tape thickness σ is different, the slope of the line is different. Therefore, when a certain tape is loaded, the tape is run by changing the value of the double speed number n, T1 and T2 at that time are detected, and n ² (T1 ² +
If the calculation of T2 ² ) is performed, it is possible to determine the tape thickness σ based on that value, and it is also possible to obtain the tape length.

(Determination of tape double speed number) When the above equation 4 is modified, the following equation 5 is obtained.

[0033]

[Expression 5] n ² = {1 / (T1 ² + T2 ² )} · (2π / V ² ).
・ (Πa ² +2 ・ σ ・ L)

This is because when the thickness σ and the length L of the tape are known, T1 and T2 are measured, (T1 ² + T2 ² ) is calculated, and the operation of the above-mentioned equation 5 is performed to determine the double speed number n. It means that it can be calculated immediately.

For example, when the magnetic tape is fed at a predetermined speed by the rotation of the capstan 12, the tape running speed can be known by detecting the rotation speed of the capstan 12 by FG output or the like. However, tape feeding by the capstan 12 is generally 16 times faster (n =
16) is the limit. Therefore, at higher speeds, remove the pinch roller 13 from the capstan 12,
With the tape in a free state, the tape is run by rotating the reel stand 4 or 5. In this case, the tape running speed may not be known. Therefore, if the data processing unit 17 performs the calculation of the above equation 5, the double speed number n can be calculated.

(Identification of Tape Position) Next, a method of knowing the current tape position, that is, the remaining tape amount of one reel hub from the periods T1 and T2 of the reel base will be described. Assuming that the length of the tape wound on the reel hub 2 on the supply side is L1 and the length of the tape wound on the reel hub 3 on the take-up side is L2, the area of each reel portion in the plan view is calculated.

[0037]

[Formula 6] σ · L1 = π {(d1 / 2) ² − (a / 2) ² } σ · L2 = π {(d2 / 2) ² − (a / 2) ² }

[0038] Next, from the tape speed, period and tape diameter,

[0039]

[Equation 7] π ・ d1 = V ・ T1 π ・ d2 = V ・ T2

It is The above equations 6 and 7 and further (L = L
From 1 + L2)

[0041]

## EQU8 ## L1 = {T1 ² / (T1 ² + T2 ² )} {L + (πa ²
/ 2σ)}-(πa ² / 4σ)

It becomes When α = (T2 / T1) is set here, the following Expression 9 is derived.

[0043]

Equation 9] L1 = {1 / (1 + α 2)} {L + (πa 2/2
σ)}-(πa ² / 4σ)

It becomes Similarly,

[0045]

## EQU10 ## L2 = {α ² / (1 + α ² )} {L + (πa ² /
2σ)}-(πa ² / 4σ)

It is If the tape length L and the thickness σ are known from the above formula 9, the ratio α of rotation cycles of both tape reels α = (T2 / T1) is measured and calculated to wind the tape on the supply reel hub 2. Remaining tape amount L
You can know one.

In FIG. 4, the horizontal axis represents the value of α, and the vertical axis represents the length (tape remaining amount) L1 of the tape wound around the supply reel hub. The length L and thickness σ of various tapes are parameters. Is shown by a diagram. As is clear from this figure, if the cassette pack is loaded, tape feeding is started, and the cycle ratio α of both reels is measured, the remaining tape amount L1
You can know. In addition, since the tape speed V is not related in the equations 9 and 10, the tape remaining amount can be obtained from the same mathematical expression regardless of the double speed state of the tape speed.

As described in the above section (discrimination of tape type), the tape running speed V or (n · V) is known, T1 and T2 are measured, and the sum of squares thereof (T1 ² + T) is calculated.
If 2 ² ) is obtained, it is possible to determine (σ · L), that is, the type of tape thickness and length from Equation 3 or Equation 4 (σ can be detected by the type hole of the cassette pack). Therefore, when the cassette pack is loaded, the tape is run and the tape length L is obtained from the calculation of the equations 3 or 4, and the calculation is performed by the equation 9 based on this L and the tape thickness σ. The remaining tape amount L1 can be calculated.

Next, in Equation 9, the relationship between the remaining tape amount L1 and the cycle ratio α is obtained, and this is represented in a diagram as shown in FIG. As can be seen from this figure, while the remaining tape amount wound on the supply reel hub 2 changes from L to 0,
α changes between constant values α1 and α2. Moreover, the value of α gradually changes when the remaining tape amount decreases. Therefore, the value of α is monitored by the data processing unit 17, and α is α1
If the value is out of the range from to α2, it can be determined that the tape breakage or the like occurs. Further, it is possible to determine that the tape running state is abnormal even when α changes rapidly.

(Abnormality of Tape Loading) In FIG. 1, the tape path length stretched between both reel hubs 2 and 3 when the tape is not loaded is La, and the path length of the magnetic tape after loading is Lb.
Then (see FIG. 1), the length ΔL of the tape pulled out from the cassette pack during tape loading is ΔL
= Lb-La. Therefore, for example, the winding-side reel base 5 is fixed, the supply-side reel base 4 is allowed to rotate, and the magnetic tape is pulled out from the supply-side reel hub 2. Assuming that the number of pulses output from the optical detector 6 at the time of tape loading is N, the relationship between N and ΔL is given by the following formula 11.

[0051]

[Equation 11] ΔL = (N / N0) · π · D

However, N0 is the number of pulses output from the optical detector 6 during one rotation of the reel hub 2, and D is the tape winding outer diameter of the reel on the pulling side at that time. As an actual operation, the cassette pack 1 is loaded and fast-forwarded for a short time, and when the tape on the reel hub 2 on the supply side runs out, the tape is pulled out from only the reel hub 3 on the take-up side to perform tape loading. At this time, D is the outer diameter of the tape wound on the winding reel hub.
On the contrary, after the cassette pack is loaded, the tape is rewound for a short time, and when the tape on the reel hub 3 on the winding side is exhausted, the tape is pulled out from only the reel hub 2 on the supply side.
At this time, D is the outer diameter of the tape wound around the reel hub on the supply side.

If the tape is wound on both reel hubs and the tape position is not known, the reel is rotated for a short time and α =
T2 / T1 is calculated, and the remaining tape amount L1 or L2 on either reel is calculated by the formula 9 or the formula 10, and the outer diameter of the tape winding on the pull-out side at the time of tape loading is calculated to obtain D by this. It is possible.

Then, N is counted at the time of tape loading, the calculation is made by the equation 11, and whether or not ΔL has become the length necessary for the predetermined loading is known based on N, so that whether or not the tape is reliably loaded is determined. You can judge. The remaining tape amount is not necessarily limited to the rotary head type tape player, and can be calculated in the same manner for a normal cassette tape.

[0055]

According to the first aspect of the invention, the running state of the tape can be confirmed by monitoring the sum of the squares of the rotation cycles of the supply-side tape reel and the winding-side tape reel. You can check whether the vehicle is running stably.

According to the second aspect of the invention, the remaining tape amount can be immediately known by obtaining the period ratio α of both tape reels. Further, since the remaining tape amount can be immediately obtained regardless of the tape speed, the remaining tape amount can be immediately known by the same calculation regardless of the speed of the magnetic tape running.

According to the third aspect of the present invention, it is possible to determine whether or not the tape running is stable depending on whether or not the period ratio α is within a certain range.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a tape running state and a detection controller of a rotary head type tape player,

FIG. 2 is a plan view showing the structure of a rotation detection unit in the reel stand,

FIG. 3 is a diagram showing the relationship between the sum of squares of the rotation cycle of the reel stand and the tape length;

FIG. 4 is a diagram showing the relationship between the reel cycle ratio and the remaining tape amount,

FIG. 5 is a diagram showing the relationship between the remaining tape amount and the cycle ratio,

[Explanation of symbols]

1 cassette pack 2 Supply side reel hub 3 Take-up reel hub 4 Supply side reel stand 5 Take-up reel stand 6,7 Optical detector 8 rotating head devices 10 magnetic tape 15a, 15b Pulse detector 16a, 16b waveform shaping section 17 Data processing unit

Claims (3)

[Claims] 1. A tape player provided with a rotation detector for detecting the rotation of each of the supply-side and the winding-side tape reels, wherein the supply-side tape reel obtained from the detection output from the rotation detector. The rotation cycle of T1 is T1, and the rotation cycle of the tape reel on the winding side is T2.
A method of detecting a tape running state of a tape player, which comprises calculating the sum of the square of T1 and the square of T2, and judging whether or not there is an abnormality in the tape running depending on whether this value is constant. . 2. A tape player provided with a rotation detector for detecting the rotation of each of the tape reels on the supply side and the winding side, wherein the tape reels on the supply side obtained from the detection output from the rotation detector. The rotation cycle of T1 is T1, and the rotation cycle of the tape reel on the winding side is T2.
Calculate the ratio of both rotation cycles (α = T2 / T1), and calculate the remaining tape amount on the supply side from this α, the total tape length, the tape thickness, and the diameter of the reel hub around which the tape is wound. A method for detecting a tape running state of a tape player, which is a feature. 3. The tape according to claim 2, wherein it is determined whether or not there is any abnormality in the tape running depending on whether or not the value of α is within a certain range or whether or not the value of α is abruptly changed. A method for detecting the tape running state of a player.