JPS59140661A - Controller for tape traveling speed - Google Patents

Abstract

PURPOSE:To shorten a quick traverse time or rewind time by measuring the tape up to its middle position although any type of tape is loaded and traversed quickly or rewound, and driving the tape at a high speed. CONSTITUTION:When a signal showing the quick traverse or rewind is supplied, a command to set the tape traveling speed at a low level is sent to a reel driving circuit 42 when the tape is traveling toward its end from its middle part and a command to set the tape traveling speed at a high level when the tape is traveling toward the middle part from the end respectively by the signals sent from a tape traveling direction discriminating circuit 34 and a comparator 33. Then a tape traveled amount detecting circuit 39 is reset to start setection for the tape traveled amount. In case a tape is driven fast from its initiation to the termination, the tape traveling speed is set at a high level to detect the tape traveled amount from its initiation to the middle part. This detected amount is recorded to a memory 40. Then the tape traveled amount is detected again. When this detected amount is equal to the value of the memory 40, the tape traveling speed is set at a low level.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides fast forwarding and rewinding nine times in a shorter time in a magnetic tape recording and reproducing device such as a video tape recorder (hereinafter referred to as VTR). The present invention relates to a tape running speed control device that can perform the following steps.

Conventional configuration and its problems V? When trying to record or play a tape using R etc.
If the tape position is not where you want to record or play,
The tape is fast-forwarded or rewound to the desired tape position, but during this time the user just has to wait, and during that time he often misses the scene he wants to record. The shorter the time for forwarding and rewinding, the better. Also,
If you want to record a tape from the beginning to the end and then play it again from the beginning, you have to rewind from the end to the beginning, and the shorter the time, the better.

To shorten tape fast forwarding 92 rewinding time, the tape running speed at that time can be made faster, but if it is too fast, even if the end of the tape is detected and a stop command is sent, there will be no electricity. detection delay.

Due to the delay in actually applying the brakes after the stop command is output, the tape does not stop immediately, and the tape and reel stick together to the root, causing abnormal tension to be applied to the tape, and sometimes the tape breaks from the root. It is also said that it will be done. To avoid this, most conventional VTRs perform fast forwarding and rewinding at a speed that prevents the tape from penetrating all the way when the end of the tape is detected and stopped. It takes a lot of time to fast forward a long tape from the beginning to the end, or to rewind it from the end to the beginning. In order to shorten this fast forward 9 rewinding time, fast forward 2 rewinding is performed near the end of the tape at a speed that prevents the tape from reaching its roots when the end of the tape is detected and stopped. When the tape is not nearby, it is essential to control the tape running speed by fast forwarding and rewinding nine times at high speed. Conventionally,
The following two methods have been considered for this tape running speed control method.

The first method is to run the tape at high speed when it is moving from the beginning to the center, and at a slower speed when it is moving from the center to the beginning and end. In other words, when fast-forwarding from the start to the end as shown in Figure 1, the tape is fast-forwarded from the start to the middle to shorten the running time, and after passing the middle, the speed is reduced and the tape reaches its base at the end. This is a control system that prevents the machine from penetrating too far. An example of the configuration of this system is shown in FIG.

Supply of cassette tape 1-/L/2 and take-up reel 3
Rotation detectors 6 and 7 are installed on the reel drive shafts 4 and 6, respectively.
is located. This rotation detector 6゜7 detects marks etc. provided on the reel drive shaft 4.6 magnetically, photoelectrically or mechanically with detection elements 8 and 9, and outputs pulses with a frequency corresponding to the rotation speed. When there is only one mark, the rotation detectors 6 and 7 output one pulse when each reel rotates once.

The rotation detection pulses outputted from the rotation detectors 6, 7 are sent to the counters 1, 0, . Sent to 11.

Further, a reference clock is sent from the control circuit 13 to the counters 10 and 11. The period of this reference clock is sufficiently shorter than the period of the rotation detection pulse. Counters 10 and 11 count the number of reference clocks included in one cycle of the input rotation detection pulse. Therefore, the number of reference clocks counted by the counter 10111 is a value proportional to the rotation period of each reel. The comparator 12 determines whether the values of the counters 10 and 11 are large or small, and sends the results to the control circuit 13. When the control circuit 13 receives a signal indicating the fast forward 9 rewind mode from the mechanism control circuit 15 that controls the mechanism of each motor in the VTR, the comparator 1
According to the signal from 2, a high speed command or a low speed command is output to the reel drive circuit 14 to control the running speed of the tape. That is, mechanism control circuit 1
When a signal indicating fast forward mode is received from 5, comparator 12
The period of the signal from I)-/L/2 is the winding signal /L
If the signal indicates that the cycle is larger than /3, a command to increase the speed is issued.
If the signal indicates that the cycle is greater than 20, a command to reduce the speed is sent to the reel drive circuit 14.

During rewinding, the speed is controlled to be high if the cycle of the take-up reel is greater than the cycle of the supply reel, and to be controlled to be slow if the cycle of the supply reel is greater than the cycle of the take-up reel. In this method, the length of the tape that can be run at high speed is only half of the total length of the tape at the maximum, and it is better to perform fast forwarding and rewinding in the shortest possible time, so it cannot be said to be the best method.

The second method is to know the tape running position by calculating the remaining time of the tape, and if it is not near the end of the tape, fast forward and rewind two times at high speed, and when it is near the end, it returns to normal speed. This is a method to do so. However, there are two types of cassette tapes for VTRs, one with a thick hub and one with a thin hub, and even those with the same hub diameter have various tape lengths, so there is a huge variety of cassette tapes. Therefore, in order to calculate the remaining amount of tape, very complicated calculations are required, such as distinguishing between the many types of cassette tapes, and correcting for variations in tape thickness to obtain accurate tape remaining time. Must. In addition, various patents have been issued for methods for calculating the remaining time of a tape, but most of these can only be calculated when the tape is running at a constant speed, and do not require fast forwarding or rewinding. Since the tape running speed during rewinding changes depending on the reel diameter, it is very difficult to determine the remaining amount of tape during fast forwarding and rewinding. Furthermore, even if this were possible, the configuration would be extremely complicated and expensive.

OBJECTS OF THE INVENTION The present invention eliminates these conventional drawbacks and provides a tape running speed control system that is simple in construction and capable of shortening the fast forwarding and rewinding times.

Structure of the Invention The tape running speed control device of the present invention comprises rotation detecting means provided on the supply reel and take-up V, and a tape running direction determining circuit that forms a signal regarding the tape running direction from the output of the rotation detecting means. a winding diameter ratio determining circuit for forming a signal regarding the winding diameter ratio between the supply reel and the take-up reel from the output of the rotation detecting means; a tape movement amount detection circuit for detecting the amount of tape movement; Equipped with a tape running speed control circuit that can be switched in stages, when the tape is fast forwarded or rewound, the tape moves towards the center based on the signals from the tape running and direction determining circuit and the signal from the winding diameter ratio determining circuit. If so, the tape is run at high speed, and from the start of fast forwarding or rewinding until the tape position is in the middle, the winding diameter ratio discrimination circuit detects the ratio of the winding diameter of the supply reel and the winding diameter of the take-up reel. The amount of movement of the tape until it outputs a signal indicating that the values have become equal, or until the winding diameter ratio discrimination circuit outputs a signal indicating that the magnitude relationship of the winding diameter ratio has changed from when fast forwarding or rewinding started. When the tape position is past the center, the tape is moved at high speed until the tape length is the same as the tape length that was moved from the start of fast forwarding or rewinding until the tape position is in the middle, or a tape length that is slightly shorter is moved. After that, run the tape at normal speed, and no matter what type of tape is inserted and fast-forwarded or rewound, measure the length of the tape to the middle and double the length. The tape is run at high speed, reducing fast-forwarding and rewinding time.

DESCRIPTION OF EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a block diagram showing a schematic configuration of an embodiment of the present invention. In FIG. 3, the reel drive shaft 2 of the supply-tV22 and winding-1v23 of the cassette tape 21 is shown.
Rotation detectors 26 and 27 are arranged at 4.25, respectively, and detection elements 28.30, which have the same configuration as the conventional example described above and generate one pulse when each reel rotates once, are attached.

Using the rotation pulses generated by the rotation detectors 26 and 27, the counters 31 and 32 count the rotation pulses using a reference clock whose period is sufficiently shorter than that of the rotation pulses generated by the reference clock generator 43 as described above. The respective rotation periods of the supply Lee /I/22 and the winding IJ-/V23 are input to the comparator 33, and a signal indicating the magnitude relationship of the cycles, that is, the magnitude relationship of the two winding diameters, is sent to the comparator 33. 33 is 1”21 strong. In this embodiment, the counters 31, 32 are used to measure the period of each reel, and the comparator 33 outputs the magnitude relationship. Alternatively, the rotation detector 26. Any circuit configuration may be used as long as it can output the magnitude relationship between the winding diameters of the two reels based on the signal from 27. The tape running direction determining circuit 34 determines the running direction of the tape according to signals from two detecting elements 28 and 29 attached to the supply reel 22 that generate rotational pulses with different phase angles. .

In this method, for example, when the rotation pulse from the detection element 28 rises, the level of the rotation pulse of the detection element 29 is High.
It can be determined depending on whether it is a gh level or a low level. In this embodiment, the amount of tape movement is detected as follows.

The rotating body 46 is crimped to the bonnet 36 with the tape 44 in between, and is attached to rotate as the tape runs. A rotation detector 37 is attached to the rotation shaft 45 of the rotating body 46. This rotation detector 3
Reference numeral 7 has the same configuration as the rotation detectors 26 and 27 described above, and generates one PALNU rotation pulse when the rotating body 46 rotates once. By counting the rotation pulses from the rotation detector 37 with the reference clock output from the reference clock generator 43 by the counter 38, the rotation speed of the rotating body 460, that is, the running speed of the tape 44 can be detected.

The tape movement amount detection circuit 39 detects the running speed of the tape 44 sent from the counter 38 and the reference clock generator 43.
The amount of tape movement is detected by integrating the time created from the reference clock sent from the controller. The tape running speed control circuit 36 receives signals from a mechanism control circuit 41 that controls the mode, mode, etc. of the system.
When a signal indicating that the tape has started to advance or rewind is sent, it is determined by the signal from the tape running direction determining circuit 34 and the signal from the comparator 33 that if the tape is moving from the center to the edge, the tape is A command to reduce the tape running speed to the reel drive circuit 42 is sent to the reel v drive circuit 42, and a command to increase the tape running speed to the reel drive circuit 42 if the tape is moving towards the center, resetting the tape movement amount detection circuit 39. Start detecting the amount of tape movement. When the signal from the comparator 33 becomes a signal indicating that the winding diameters of both reels have become equal or a signal indicating that the magnitude relationship between the winding diameters of both reels has been reversed, the tape movement amount at that time is detected. The tape movement amount detected by the circuit 39 is stored in the memory 40, and the tape movement amount detection circuit 39 is reset again to start detecting the tape movement amount. After that, the tape movement amount detection circuit 3
When the tape movement amount detected in step 9 becomes the same value as the tape movement portion stored in memo jJ40, a command is sent to the reel drive circuit 42 to reduce the tape running speed.

At this time, if we fast-forward from the beginning of the tape to the end, we are moving toward the middle of the tape, so we increase the tape running speed to detect the amount of tape movement from the beginning to the middle of the tape, and store that value in memory. 4o, the tape movement amount is detected again, and when the value becomes equal to the value in memory 4o, the tape running speed is reduced to a low speed, but when the tape reaches the end of the tape when trying to reduce the speed. can be,
Also, even if the speed is set to normal, the tape may be attached to the base and abnormal tension may be applied to the tape, causing the tape to break. Therefore, after passing the middle of the tape, it is better to set the tape running speed to the normal speed when the value of the tape movement amount detection circuit 39 becomes a value slightly smaller than the value of the memory 1740. In addition, in this embodiment, the signal for determining the running direction of the tenip is supplied! It is obtained from the detection element 28.29 that generates two rotational pulses with different phase angles attached to the winding reel /L/23.
It is also possible to attach two detection elements to the side and generate the signals from the two detection elements. Alternatively, the tape running speed control circuit 36 receives from the mechanism control circuit 41 a signal indicating that the fast forward mode has been set;9 a signal indicating that the rewinding mode has been set; and if the tape running direction is determined from the signal, the detection element 29.
The tape running direction determining circuit 34 can be removed.

Furthermore, if the configuration is such that the tape running speed is constant regardless of the reel diameter, the rotating body 46. Pos 1362 rotation detector 37. The counter 38 can be removed, and the tape movement amount detection circuit 39 only needs to count the reference clock sent from the reference clock generator 43.

Effects of the Invention As explained above, in the present invention, since the hub diameters of both /L/ are the same for any type of tape, the tape length from the start position of fast forwarding or rewinding to the center of the tape is the same as the center of the tape. Since the length of the tape from past 2 to the beginning and end is just as short, measure the length of the tape from the start position of fast forward 2 to the middle, run the tape nearly twice that length at high speed, and then run it at normal speed. By doing this, it is possible to stop immediately at the end. In this way, the tape length can be nearly twice as fast as the conventional method.

It is possible to rewind, and the time required for fast forwarding and rewinding, which is the time spent simply waiting, can be greatly reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the tape running position and tape running speed in a conventional tape speed control device, and FIG. 2 is a block diagram showing a schematic configuration of the conventional tape speed control device.
FIG. 3 is a block diagram showing a schematic configuration of an embodiment of a tape speed control device according to the present invention. 1.21...cassette tape, 2,22...
...Supply J supply reel, 3.23...Take-up reel, 4,5゜24.25...Reel drive shaft, 8,
9,28°29930...Detection element, 617?
261 27137...Rotation detector, 10
,11,31.32゜38... Counter, 12
．． 33. Old... Comparator, 13... Control circuit, 1
4,42...Reel drive circuit, 15.41...
...Mechanism control circuit, 34...
・Tape running direction determination circuit, 36...Tape running speed control circuit, 46...Rotating body, 36. Old.
・Bonuto, 39... Tape movement amount detection circuit, 4
o...Memory, 43...Reference clock generator, 44...Tape, 46...Rotary axis. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 3 Figure 3

Claims (2)

[Claims] (1) Supply reel and take-up -) Rotation detection means for generating a PALNU with a period corresponding to a rotation period of 1μ of the glue provided on each V, and a signal regarding the tape running direction from the output of the rotation detection means. a tape running direction determining circuit to form, a winding diameter ratio determining circuit to form a signal regarding the winding diameter ratio of the supply reel and take-up reel from the output of the rotation detecting means; and a tape movement amount to detect the tape movement amount. It is equipped with a detection circuit and a tape running speed control circuit that can change the running speed of the tape in stages, and when the tape is fast-forwarded or rewound, a signal from the tape running direction determining circuit and a signal from the winding diameter ratio determining circuit are provided. The tape running speed control device is characterized in that the tape moving amount is calculated by the tape moving amount detection circuit according to the signal, and the tape running speed is set stepwise by the tape running speed control circuit according to the result. (2) The tape running speed control bag M according to claim 1, wherein a signal related to the tape running direction is generated from a mechanism controller yoM that instructs all tape running directions.