JPH0485745A - Video tape recorder - Google Patents

Abstract

PURPOSE:To shorten the operating time of a video tape recorder by feeding a tape at the highest speed from both FF and REW starting time points and sending the tape up to its end at the highest speed that does not cut the tape based on the reel diameter at a point near the end of the tape. CONSTITUTION:The S (supply) side reel revolution detecting pulse obtained from an S side reel 101 is supplied to a reel diameter calculation part 103 together with the T (take-up) side reel revolution detecting pulse obtained from a T side reel 102. Then the diameters of both reels 101 and 102 are calculated. The reel diameter data received from the part 103 are inputted to an optimum speed calculation part 104. At the part 104 a tape steady moving velocity Vt and a tape end velocity Ve are calculated. Both Vt and Ve are given to a reel disk driving motor revolution members calculation part 105 for the calculation of the number of revolution of the motor with which both Vt and Ve are obtained. Then this number of revolution is given to a motor driving voltage generation circuit 106 which generates the driving voltage in order to secure the relevant number of revolution. Then the driving voltage is applied to a motor 107 which drives the reels.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to video tape recorders (VTRs).

(b) Conventional a? $5 ~' Fast forward (FF) or rewind REW in TR
), it is preferable to set the tape speed as high as possible because the winding time can be shortened.

By the way, when the brake is applied to stop tape movement near the end of winding from the FF or REW state, the tape movement amount CA) during braking by this brake is as follows:
The faster the tape speed at the time the brake is applied, the more it increases. In particular, since the brake is applied by detecting the leader tape at the end of the tape, when the value of the movement amount (A,) exceeds the leader tape length, very high tension is applied to the tape.
Problems such as tape breaking occur.

Conventionally, fast forwarding or rewinding operations in ~'TR are performed by rotating the reel stand at a constant speed using a capstan motor, and therefore the tape speed increases gradually from the start of winding and reaches its maximum at the end of the tape. . As mentioned above, when the leader tape is detected, the brake is applied to the reel stand to reduce the tape speed and reduce the tape tension that occurs at the end of tape winding.
Although attempts are made to prevent tape breakage, etc., it is necessary to limit the tape speed at the time of applying the brake to a certain upper limit value in order to prevent tape breakage from occurring. In other words, conventionally, the reel stand was rotated at a constant rotational speed so that the tape speed would be the highest speed at which no tape breakage would occur when the brake was applied.

(c) Problems to be Solved by the Invention As mentioned above, in conventional VTRs, the tape speed reaches its maximum near the end of the tape, so the time required for FF and REW cannot be sufficiently shortened.

The present invention therefore seeks to overcome such drawbacks.

(d) Means for Solving the Problems In order to solve the above problems, the video tape recorder of the present invention includes: reel winding diameter detection means for constantly detecting the winding diameter of the reel of the tape force cent; and the reel winding diameter detection means. The apparatus includes a calculation means for calculating a reel rotation speed for transporting the tape at a constant high speed based on a detection output of the means, and a control means for controlling a reel drive motor based on the calculation means.

(E) Effect According to the Ifl configuration described above, the tape is transported at the maximum speed within the allowable range of ~'TR from the start of winding.

(f) Examples Examples of the present invention will now be described with reference to FIGS. 1 to 5.

FIG. 2 is a diagram for explaining changes in tape moving speed according to the present invention. As is clear from FIG. At the same time, the tape speed reaches the highest speed V, (hereinafter referred to as steady moving speed v) obtained by the VTR, and the tape is transported at this speed \・'1 until it reaches the point RD near the end of the tape. It has become so. Note that the tape speed Vl here is the maximum speed limited by the strength of the mechanism of the VTR, the maximum rotation speed of the motor, etc.

Then, when the tape is completely wound, the tape end speed is the maximum speed v at which the tape does not break, etc.
(hereinafter referred to as tape end speed \"2"). Therefore, according to the present invention, the time required for FF and REW of the tape can be reduced as a whole.

FIG. 1 is a block diagram showing the concept of the present invention, in which the S-side reel rotation detection pulse obtained from the supply (8 examples) reel 101 and the T obtained from the take-up (T-side) reel 102 are shown.
The side wheel rotation detection pulse is supplied to the reel diameter calculation section 103, and the diameter of each reel is calculated. The reel diameter data output from the reel diameter calculation section 103 is input to the optimum speed calculation section 104, where a steady tape moving speed Vt and a tape end speed Ve, which will be described later, are calculated. V, j', from this maximum speed calculation unit 104
is given to the reel stand drive motor (capstan motor) rotation speed calculation unit 105, where 1. The motor rotation speed at which a tape speed of Vs is obtained is calculated. This number of rotations is then given to the motor drive voltage generation circuit 106, which generates the drive voltage necessary to obtain the number of rotations, and applies this drive voltage to the motor 107 that drives the reel. Next, Figure 2 shows a block diagram of the main parts of the \'TR that implements the present invention. To explain this operation, 1 is the supply (
8) Reel, 2 is a take-up (T (11, 11) reel, both reels are placed on each side, and the motor drive circuit (capstan motor drive or reel motor drive circuit, etc.) 15 drives the rotation. The supply and take-up reel stand (not shown) is equipped with S-side and T-side rotation detectors 3 and 4 for optically measuring the rotation speed, and detects the rotation of each reel. S-side and T-side full pulses nl+n are emitted depending on the number.

6.7 is S fl! from the S side and T side pulses and the reference clock obtained from the clock generation circuit 5. ,! S side and T side to calculate rotation periods T3 and T1 of I and T side wheels
This is a side 0 rotation period measurement circuit.

Specifically, this rotation period measuring circuit 6.7 counts the number of reference clocks included in one period of each wheel pulse, which is generated once per rotation of each wheel. The rotation periods T5 and T1 of each reel can be determined. Incidentally, the period of the reference black 7 is set to be sufficiently shorter than the period of the reel pulse.

The rotation period T of both reels measured in this way
,,T, are input to the arithmetic circuits 8.9, where they are each squared, and furthermore, the outputs of the arithmetic circuits 8, 9 are T, ,T%.
is supplied to the adder circuit 10.

]1, when the tape cassette is installed in the VTR, the FF
Or, at M''+7 where the REW operation is executed, there is a tape type discrimination circuit that discriminates the type of tape force cent and performs initial settings. The tape is transported at a running speed of 2, and the sum of the squares of the rotation periods T, , T, obtained at this time (T, ``+T, 2) is obtained from the adding circuit 10.

By the way, let the reel winding diameters of the S side and T side reels 1 and 2 be R8 and R1, and furthermore, the total winding amount of Q7 ", hub area"
+(tape area)] is C-π ・R%+π
・R8...$ holds, while R,=N', ・T,'2π, R,=~°.・Tl/2π
Therefore, C=VD'(T,'+T,')'4:r=-@
It is expressed as

Here, the tape warp winding amount C is the type of tape cassette (
T-60, T-90, T-120, etc.), and the tape type discrimination circuit 1 determines the total winding amount C for each type of tape force set I in advance in the internal memory. It is stored as data for use.

Therefore, if (T, '10T, 2) is calculated, the above 2゛(
Since the total winding amount C can be obtained from the formula, the tape type discrimination circuit 11 calculates the total winding amount C obtained from this formula (1) by comparing it with the value of C in the internal memory. matched C
The type of tape cassette inserted into the VTR is determined based on the value of
．． 2. “Supply to 3.

In this way, when the tape cassette is inserted into the VTR, the type of the tape cassette is first determined, and the total tape winding amount C is obtained.
When the FF or REW operation is started, the reel winding diameters R, , R, of the S-side and T-side reels at the time of opening of the FF or REW operation are calculated by the calculation circuit 1.2.13.

The arithmetic circuit 13 determines the tape type based on the number of rotations (number of reel pulses) of the reel 2 obtained from the T-side reel detection circuit 4 n the number of rotations (number of reel pulses) of the reel l obtained from the S-side reel detection circuit 3. The tape warp winding amount C is obtained from the circuit 11, and the following formula (2) is calculated to calculate the T-side thread diameter R1.

Further, the arithmetic circuit 12 measures the number of revolutions nl+s of the reel 2 obtained from the T-side reel detection circuit 4, and the reel detection circuit 3
The number of rotations 02 of the reel 1 obtained from 02 and the tape warp winding amount C from the tape type discrimination circuit 11 are obtained, and the following formula (2) is calculated to calculate the S-side reel diameter R1.

In the present invention, when FF is performed, the optimum speed calculation circuit 14 obtains the reel diameter data R5 of the T-side reel 2 supplied from the calculation circuit 3, and sets the FF speed to a constant maximum speed. ~', (V,: The amount of tape movement per second is determined by the following 0 formula, and the motor drive circuit 15 is controlled to achieve the rotation speed determined by the 0 formula. .

Further, when REW is performed, the optimum speed calculation circuit 14 obtains the reel diameter data R1 of the S-side reel 1 supplied from the calculation circuit 12, and determines that the REW speed is a constant maximum speed V.
.

As shown in FIG. 2, the tape speed is changed to RD (speed down point) near the end of the tape to switch from Vl to Vo as follows.

That is, in the case of FF, the reel diameter R1 of the S-side reel is calculated by the calculation circuit 12, and the reel diameter data R1 is supplied to the comparison circuit 16.

As shown in FIG. 2, the tape type discrimination circuit 1 has speed down point data Rh [(Rh) = (hub diameter RH of various tapes) + (predetermined tape Long Rh-RH)]
is stored in the internal memory, and this data R9 is input as the other data to the comparison circuit 16.

Then, when the data Rh from the tape type discrimination circuit 11 and the data R1 from the arithmetic circuit 12 match, the comparator circuit 16 outputs data from the arithmetic circuit 13 to the optimum speed arithmetic circuit 14 based on a command from the comparator circuit. Obtain the reel diameter data R1 of the T-side wheel 2, calculate the reel rotation speed at which the FF speed becomes a constant speed N゛8 using the following formula (①), and use the formula [Motor drive circuit]
Control 5.

Further, in the case of REW, the reel diameter R1 of the T-side reel is calculated by the calculation circuit 2, and the reel diameter data R1 is supplied to the comparison circuit 16.

Then, when the data R5 from the tape type discrimination circuit 11 and the data R1 from the arithmetic circuit 13 match, the comparator circuit 16 supplies the optimal speed arithmetic circuit 14 from the arithmetic circuit 12 based on a command from the comparator circuit. Obtain the reel diameter data R1 of the S side reel 1, and set the FF speed to a constant speed V,
Find the reel rotation speed such that
The motor drive circuit 15 is controlled to achieve the rotation speed determined by the formula.

FIG. 4 is a block diagram showing another embodiment of the configuration within the broken line frame A' in FIG. 2, that is, the tape type discrimination circuit system.

When the configuration shown in Fig. 4 is adopted, first, the tape is fed at a constant speed of A mm/sec for 8 seconds, and
S side and T side from reel rotation detection circuit 3.4 S side and T side from reel rotation detection circuits 3 and 4 Pulse number data C and D (In other words, C and D indicate the number of rotations of the reel. ).

Then, the S-side reel diameter calculation circuit 16 uses the data C to calculate the S-side reel diameter according to the following equation.

Further, the T-side thread diameter calculation circuit 17 uses the data D,
Find the lower reel diameter according to the following formula.

Then, these reel diameter data R,,R, are input to the tape type discrimination circuit]l, which performs calculations based on the formula ↓, calculates the tape warp winding amount C, and calculates the tape warp winding amount C in advance. Compare the tape warp view data C of the tape type stored in the memory, and calculate the corresponding 'v' from the matched value of C.
' Operates to determine the type of tape force mounted on the TR.

In Figure 2, the tape speed is set to \' at RB a little before the end of the tape, because even tapes of the same type have variations in tape length, so the tape speed is set a little earlier to absorb the variations. This is to bring it to a safe terminal velocity.

In addition, in Fig. 2, the part surrounded by the - dotted chain line frame is 1
Needless to say, it can be constructed using a Chisoff microcomputer.

As described above, according to this embodiment, the tape is transported at the maximum speed allowed by the VTR from the start of FF, R, and EW, and tape breaks occur near the end of the tape based on the reel diameter. By transporting the tape to the final end at a maximum speed that is as low as possible, the time required for FF, FF, and REXv can be shortened as much as possible as shown in FIG.

(g) Effects of the Invention As described above, according to the present invention, the time required for FF, REw can be shortened as much as possible.

[Brief explanation of drawings]

Fig. 1 is a block diagram for explaining the basic configuration of the present invention, Fig. 2 is a block diagram of the main part of a video tape recorder implementing the invention, and Fig. 3 is a block diagram for explaining the operation of the main part. 4 is a block diagram of main parts of another embodiment of a video tape recorder embodying the present invention, and FIG. 5 is a diagram showing speed down points. (3)...S side reel rotation detection circuit, (4)...T
Side wheel rotation detection circuit, (6)...S side rotation period measurement circuit, (7)・Tll! 1ll period measurement circuit, (8)
(9)...Arithmetic circuit, (1])...Tape type discrimination circuit, (12) (13)...Arithmetic circuit, (14)...
...Optimum speed calculation circuit, (15)...Motor drive circuit. Figure 4 t Hitsuko”Or cost, +6

Claims (1)

[Claims] (1) Reel winding diameter detection means that constantly detects the winding diameter of the reel of the tape cassette, and based on the detection output of the reel winding diameter detection means, calculating the reel rotation speed for transporting the tape at a constant high speed. A videotape recorder comprising: a calculation means for calculating the calculation means; and a control means for controlling a reel drive motor based on the output of the calculation means.