JPH06282970A - Tape position calculator - Google Patents

Abstract

(57) [Summary] [Purpose] To obtain an accurate tape position indication without a timer roller and without a capstan transfer condition. [Structure] Rotation detection pulses of motors 124 and 123 that drive a supply-side reel and a winding-side reel, respectively, are input to a detection processing unit 112, and are input to a control unit 110 as rotation direction and rotation speed information. The control section 110 calculates the current reel tape winding diameter information, and from this information, the amount of information corresponding to (tape control pulse / reel pulse 1) corresponding to the tape winding diameter or (tape control pulse / reel pulse). 1 pulse)
× 2 ⁿ Is determined, and a signal for displaying the tape position is calculated from the obtained information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape position calculating device used in a tape position display device for grasping and displaying a winding position of a tape in a video tape recorder.

[0002]

2. Description of the Related Art Household VTs are used as tape position display devices.
In R, a method of simply displaying the reel pulse by integrating or displaying a tape position by integrating and calculating control pulses is adopted.

However, in a simple integrated display of reel pulses, the tape advance amount per the same pulse differs depending on the reel winding diameter, and therefore the tape position corresponding to the tape advance condition during normal recording / reproducing cannot be known. Since the tape advance amount per pulse is constant in the display by control pulse integration / calculation, the accurate tape position can be displayed as long as the control pulse is recorded, but it does not work at all in the unrecorded part or the control pulse unreadable part. Disappear. Therefore, when fast-forwarding or rewinding, the display changes accurately according to the tape position up to the middle, but the display may suddenly stop changing and the display may change again. This makes it impossible to know if the tape position indication is correct.

In a commercial VTR, a time code is usually recorded on a tape in order to control and display the accurate tape position, and by reading this, the accurate tape position is displayed.

FIG. 5 shows a UNI in which a time code is recorded.
It is an explanatory view in the HI system, and a time code is recorded on the lower end of the tape and corresponds to a recording signal for one frame. A frame is a unit that makes up one screen
In the IHI system, one frame is one during the normal recording / playback time.
/ 30 seconds, and one frame consists of two fields. Then, one field is divided into six tracks and recorded. Therefore, one frame is divided into 12 tracks and recorded on the tape. The tape position display on a normal commercial VTR is "... hour ... minute ...
The format is "frame". When recording, the value at the start can be arbitrarily set by the operator, and thereafter, the correct tape position corresponding to the frame is added to the value at the start and recorded.

It has been described above that the VTR for business use normally displays the accurate tape position by reading the time code, but if the time code cannot be read, it is set to 1 for each control pulse. Display the frame by adding or subtracting it to the value displayed last time. When the time code becomes readable again, the time code is displayed with priority. The control pulse is a plus / minus pair of rectangular wave signals corresponding to a frame for maintaining the tape speed at a predetermined value during reproduction and controlling the recording track of the magnetic tape and the rotation phase of the rotating magnetic head drum, Accurate tape position display in frame units can be performed by counting the advance or delay of one frame in synchronization with this signal and adding or subtracting it to the value previously displayed.

As shown in FIG. 6, in the middle of the tape path from the supply reel to the take-up reel, a roller called a normal timer roller, which operates at a 1: 1 ratio with magnetic tape movement, is arranged. The rotary encoder converts the operation into a pulse signal, and this pulse signal complements the tape position display when both the normal time code and the control pulse signal become unreadable.

When both signals become unreadable, firstly, in the case of a non-recording tape, secondly, when the signal is erased or demagnetized for some reason, thirdly, the tape speed becomes very high. It may be too late to be read by the signal reproducing head. Especially when searching for a predetermined tape position for editing work,
As it approaches the target position, it is gradually decelerated and stopped at a predetermined position. However, the tape speed is very slow just before the stop and the signal reproducing head hardly reads the signal. Even in such a case, it is necessary to calculate an accurate tape position and calculate the difference from the target position to control the drive device in order to guarantee the high-precision tape position stop position required for a commercial VTR. Yes, it is important to supplement this tape position display.

The above-mentioned timer roller has an outer peripheral portion made of a material having a high coefficient of friction such as rubber, and the outer peripheral portion is in contact with the tape. When the tape is moved, the tape is moved with a slippage which is almost negligible. The pulse signal output from the rotary encoder is set to a predetermined number of pulses per frame, so the number of pulses is counted, and a pseudo control pulse signal is output for each predetermined pulse. A signal equivalent to the control pulse signal of can be obtained. In order to match the phase of the pseudo control pulse signal, the register for counting the output pulse of the rotary encoder is reset by the normal control pulse signal. In this way, by adopting the tape position by each signal in order of priority of the time code, the regular control signal, and the signal by the timer roller, it is possible to always realize an accurate tape position display in response to all cases. .

[0010]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In, the timer roller is an important element for indicating the tape position. However, the timer roller has the drawback that it is very expensive as a component. In order to maintain a high coefficient of friction, it is necessary to process materials with no traps such as rubber and high mechanical precision to guarantee the required display accuracy of ± several seconds for a range of several hours over the entire tape length. It depends. Also, since the timer roller is in contact with the tape with high friction and is rotating, it has a great influence on the tape running. If the guide of the tape running system is slightly adjusted to adjust the tape running, the tape running will be improved. Since it changes slightly, it is necessary to readjust the tilt of the timer roller with respect to the tape running. That is, the tape running adjustment requires adjustment of various guides of the tape running system and the adjustment of the inclination of the timer roller with respect to the running of the tape, which requires a very long adjusting time.
There are two major reasons why the timer roller is not used in the home VTR, that is, the price is high and the adjustment is troublesome.

Further, as a requirement for recognizing the tape position, if the time code is recorded on the tape, its content may be identified and displayed. If the control pulse is recorded, the control pulse corresponds to the moving amount of the magnetic tape, so that it can be counted and converted into time to recognize the tape position. When there is a timer roller or when the magnetic tape is transported by the capstan, the timer roller rotation and the capstan rotation correspond to the moving amount of the magnetic tape, so the tape position is recognized by counting the number of rotations. it can.

However, in the case of fast-forwarding and rewinding in which the magnetic tape is phase-shifted from the supply reel to the take-up reel without passing through the capstan, in the case where neither the time code nor the control pulse is recorded, the tape is advanced. The corresponding tape position cannot be recognized.

Therefore, according to the present invention, an accurate tape position can be displayed without a timer roller and without a capstan transfer state. Therefore, the tape running adjustment can be easily performed, and an inexpensive tape position calculating device can be provided. The purpose is to provide.

[0014]

According to the present invention, there are provided a supply-side reel for supplying a tape, a winding-side reel for winding, and a drive source for driving the supply-side and winding-side reels, respectively. Reel driving means, pulse signal generating means for generating a pulse signal according to the rotation of each reel, forward / reverse determining means for determining whether the reel is rotating in the normal direction or not, and detection for detecting these signals. It has a processing section and a control section to which a signal from this detection processing section is inputted. The control section acquires the current reel tape winding diameter information and corresponds to the tape winding diameter from this information (tape control Information equivalent to (pulse / reel pulse 1) or (tape control pulse / reel pulse 1) × 2 ⁿ And means for determining the tape position from the information obtained by this means and obtaining a display signal. Further, in the present invention, when the control section calculates the tape position for display by using the amount of information corresponding to the (on-tape control pulse / one reel pulse), the previous data stored in the register is used. And a means for converting the result into a tape position signal.

[0015]

According to the above-mentioned means, the tape winding diameter can be dealt with by the tape winding diameter information and the forward / reverse information of the reel rotating direction (control pulse on tape / reel pulse 1
The tape position is calculated at the reel pulse timing using a considerable amount of information and converted into a display signal, which can be realized at low cost. In addition, the amount of information is added to or subtracted from the previous data stored in the register. At this time (tape control pulse / reel pulse 1
Information on the tape instead of (control pulse on tape / reel pulse 1) × 2 ⁿ By using the corresponding information to, ⁿ The above digits can be converted, which facilitates the calculation.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. This embodiment schematically shows a control and signal system in a high definition VTR (UNIHI system).

In the case of recording, the input video / audio signal is converted into a digital signal by the A / D converter 100 and temporarily stored in the memory 101. Here, one frame is read so as to be distributed to 12 tracks (generally called shuffling). The signal read from the memory 101 is converted into an analog signal by the D / A conversion unit 102, input into the image signal processing unit 103, converted into a recording signal, and supplied to the recording head unit 104.

In the case of reproduction, a recording signal is picked up by the reproducing head unit 105 from the magnetic tape, input to the image signal processing unit 103, and restored to a signal before recording. This reproduction signal is converted into a digital signal by the A / D conversion unit 106, temporarily stored in the memory 101, arranged in one frame so as to have the original arrangement, and read out, and the D / A
The conversion unit 107 converts the analog signal to an original video / audio signal. The control unit 110 controls the signal processing unit of each unit so that these series of operations proceed smoothly.

The ACE head 111 is a magnetic head for recording and reproducing time code and control pulse signal. In the case of recording, the time code and control pulse signal are recorded in synchronization with the frame of the image signal. In the case of reproduction, the reproduced signal is processed by the detection processing unit 112 and transmitted to the control unit 110. The reproduced time code is basically used for recognizing and displaying the tape position, and the control pulse is basically used for speed control and phase control of the capstan motor in the case of reproduction.

The drum motor 121 is provided with a frequency pulse generator (FG) and a phase pulse generator (PG), and the FG pulse and PG pulse are input to the detection processing unit 112. The FG pulse information and PG pulse information processed here are transmitted to the control unit 110. The FG pulse information is used to keep the speed of the rotary magnetic head constant, and the PG pulse information is used to control the rotation phase of the rotary magnetic head and the timing control of each recording / reproduction of the rotary magnetic head.

The capstan motor 122 is a means for transporting the magnetic tape at a constant speed, and is provided with a frequency pulse generator (FG) and a phase pulse generator (PG). FG pulse and PG pulse are detected. It is input to the unit 112. The FG pulse information and PG pulse information processed here are transmitted to the control unit 110. here,
The FG pulse information is used to keep the speed of the capstan motor constant, and the PG pulse information is used to control the rotation phase of the rotary magnetic head and the rotation phase of the capstan motor with respect to the control pulse of the magnetic tape.

The supply reel motor 124 and the take-up reel motor 123 are devices for winding the magnetic tape on and off the reel and feeding it from the reel. To be done. Each of the supply reel motor and take-up reel motor has a frequency pulse generator (FG).
Is provided, and the FG pulse by this is composed of two signals of A phase and B phase, and the rotation speed and rotation direction of the reel motor can be detected. Further, this FG uses an MR element and can detect rotation at high speed and low speed without being influenced by the rotation speed of the reel.

In the case of fast-forwarding or rewinding in which the magnetic tape is transferred from the supply reel to the take-up reel without passing through the capstan, the FG signals of both motors are processed and calculated to control the transfer speed to a predetermined value. It is also possible to recognize the rotation direction.
The control unit 110 has a tape position calculation function and provides a tape position display signal to the tape position display unit 125.

When a new cassette tape is inserted, the pinch roller is pressed and the specifications of the cassette are checked in the capstan transport mode. An example of the calculation formula for that is shown below. In the formula, f1p and f2p are the rotation frequency of each reel, np is the rotation speed ratio, r1 and r2 are the tape winding radii, and v (x1) is the tape transport speed. The relationship with the reel is shown in FIG. There is.

[0025]

[Equation 1]

[0026]

[Equation 2]

[0027]

[Equation 3]

[0028]

[Equation 4]

The present reel winding radius is calculated from the formulas (2) and (3) or a modified formula thereof, and the tape thickness is calculated from the formula (8) or (9) or a modified formula thereof, and there is no capstan described later. The reference amount of tape speed control in the case of the tape transfer can be obtained from the expression (5) or a modified expression thereof.

In the case of tape transfer without a capstan,
By using the equation (14), the equation (18), or a modified version thereof, it is possible to control at a predetermined speed only with pulse information from the reel. Further, the actual transfer speed can be monitored by the formula (18), the formula (19), or a modified form thereof. The reel winding radius can be obtained from the equation (16), the equation (17) or a modified equation thereof. In this system, the servo circuit of the control unit 110 described with reference to FIG.

The servo circuit processes various signals in order to perform recording / reproduction and other mode operations, and controls the rotation / phase of drum, capstan and reel motors, recording / reproducing head switching timing, and signal switching timing. It is a circuit for controlling the etc. In addition, in order to simplify the calculation of the reel winding radius and the actual transfer speed (monitor) described above in relation to the calculation processing capacity of the central processing unit (CPU), the reel winding radius is calculated in mm. unit,
The actual transfer speed (monitor) is calculated by the integer part.

Now, regarding tape position detection, (16)
From the formula (17) or a modified form thereof, the reel winding radius is calculated as fine as possible to the right of the decimal point, and the tape thickness is obtained from the formula (8) or (9) or a modified form of the tape. It can also be converted to position (time). However, since the tape is wound loosely or tightly depending on the tension, there is a variation in the amount even with the same reel winding radius, and there is a limit in the CPU capacity to calculate the calculation itself down to the decimal point. , Not realistic. So this system
It is a method that can calculate a more realistic and accurate tape position.

That is, a pair of reels on the supply side / winding side for winding the tape, and a reel drive means including a drive source,
Pulse generation means for generating a pulse signal according to reel rotation, forward / backward determination means for determining forward / backward of the reel rotation direction, a detection processing section for detecting these signals, and current reel tape winding diameter information. , (Control pulse / reel pulse 1) or (control pulse / reel pulse 1) corresponding to the tape winding diameter x 2 ⁿ And the control section (having one or more registers for calculating the tape position) for calculating the tape position from these signals are necessary conditions. FIG. 2 conceptually shows a configuration for that purpose. Tape position calculation processing control unit 20
To 0, reel pulse, reel forward / reverse direction, and reel winding diameter information are input. The current reel tape winding diameter information may be obtained from other circuits, or the reel frequency signal (FG
It may be calculated by the control unit from the signal).

In this system, an amount corresponding to the tape winding diameter (on-tape control pulse / one reel pulse) is added to or subtracted from the register for calculating the tape position at the timing of the reel pulse. The value in this register is converted to tape position.

That is, the tape position calculation processing control unit 200
Corresponds to the tape winding diameter (control pulse / one reel pulse) at an amount corresponding to the reel pulse through the gate circuit 201 and the first register 202.
Add or subtract processing instruction to the contents of. Whether to add or subtract is determined by reel forward / reverse direction information. The contents of the first register 202 are the contents of the conversion / display control unit 203.
At, the tape position is converted and sent to the display unit. When there is an ^n- digit change (0 ← → 1) in the first register 202, the change is input to the tape position calculation processing control unit 200. Then, the tape position calculation processing control unit 200
A pseudo control pulse is output and the first register 20
Reset 2. Tape position calculation processing control unit 200
Also resets the first register 202 when a normal control pulse is input.

As a result, the amount of data corresponding to the tape winding diameter, which corresponds to (control pulse / reel pulse), is added to the content of the first register 202 according to the forward / reverse direction of rotation of the reel. Alternatively, the result is subtracted, and the result is converted into a tape position by the conversion / display control unit 203 and sent to the display unit. In addition, the value of the first register 202 is reset at the timing of the regular control pulse signal, and ⁿ A pulse is generated in response to a digit change (0 ← → 1) and can be used as a pseudo control pulse signal when the regular control pulse signal is lost on the way.

In the above embodiment, the amount equivalent to (control pulse / reel pulse) is calculated, but the tape amount per reel pulse is stored in a table in advance and read out. The contents of the register may be added or subtracted.

FIG. 3 shows still another embodiment. The same parts as those in FIG. 2 are designated by the same reference numerals. In the above description, the amount of (one control pulse on tape / reel pulse) is used to adjust the contents of the first register 202, but here, (control pulse on tape / reel pulse). (1 piece) instead of the equivalent amount (control pulse / reel pulse 1 piece) x 2 ⁿ Is used, ⁿ It is only necessary to convert more than one digit, which facilitates calculation. For this reason, the amount calculated in advance from the database 210 (control pulse / reel pulse 1 using the reel winding diameter information at the reel pulse timing).
X) ⁿ May be selected to add or subtract to the contents of the first register 202.

That is, the first register 202 has its ^nm
A pulse is generated in response to a digit change (0 ← → 1), and this pulse is input to the tape position calculation processing control unit 200. Tape position calculation processing unit 200
Is ^nm When a pulse whose digit changes (0 ← → 1) is detected, this pulse is added to or subtracted from the contents of the second register 204. Whether to add or subtract is determined by reel forward / reverse direction information.

Here, the change (0 ← → 1) of the ^m digit of the second register 204 is detected by the tape position calculation processing control unit 200. ^When there is a change of ^m digits, the tape position calculation processing control unit 200 outputs a pseudo control pulse. The second register 204 is reset by the pseudo control pulse and the regular control pulse. The regular control pulse is output through the tape position calculation processing control unit 200.

In this way, the first register 202
From the contents of the, you can recognize the absolute position of the tape, the second
Even if the regular control pulse disappears from the change of the ^m digit of the register 204, the pseudo control pulse can be obtained.

FIG. 4 shows a UNIHI cassette with one reel 3 rounds.
60 pulses, tape winding diameter divided by 1mm
Average (control pulse / 1 reel pulse) ×
Twoⁿ When using, the display table for the theoretical tape position
It is a graph of the display error of the position. Practically little problem
It turns out that there is no level.

In the above description of the prior art, a commercial VTR normally displays the accurate tape position by reading the time code, and if the time code cannot be read, one frame is displayed for each control pulse. It was added that the value displayed last time is added or subtracted, and when the time code becomes readable again, the time code is displayed with priority. Also, especially when searching for a predetermined tape position for editing work etc., it gradually slows down as it approaches the target position, and when the tape speed is very slow just before the stop and the control signal can hardly be read by the playback head, the timer roller is used. Count the output pulses,
It has been described that the time code is interpolated by outputting the pseudo control pulse signal at every predetermined pulse.

On the other hand, in this embodiment, the pseudo control pulse signal can be obtained without the timer roller, and a, time code, b, regular control signal c, and pseudo control pulse signal are given in order of priority. By adopting the tape position based on the signal, it is possible to realize an accurate tape position display in all cases.

[0045]

As described above, according to the present invention, the tape position can be calculated only by the information of the rotation and the rotation direction of the reel, and the tape position can be equal to or more than that when the conventional timer roller is used. Since it is possible to detect and recognize the position and does not use a timer roller, it is possible to realize tape position detection at a low cost, and there is no timer roller that greatly affects tape running,
The tape running adjustment can be greatly simplified, and it is effective to obtain a tape running system with little damage to the magnetic tape.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a concept of a main part of the present invention.

FIG. 3 is a diagram showing another concept of the essential part of the present invention.

FIG. 4 is a diagram showing an example of a tape display error of a VTR to which the present invention is applied.

FIG. 5 is an explanatory diagram showing calculation elements when calculating a tape winding diameter.

FIG. 6 is a tape pattern diagram of an UNHI system of a high definition VTR.

FIG. 7 is a diagram showing a tape running path of the VTR.

[Explanation of symbols]

100, 106 ... A / D converter, 101 ... Memory, 10
2, 107 ... D / A converter, 110 ... control unit,
111 ... ACE head, 112 ... Detection processing unit, 121 ...
Drum motor, 122 ... Capstan motor, 123 ...
Take-up reel, 124 ... Supply reel, 125
… Tape position indicator.

Claims (5)

[Claims] 1. A supply-side reel for supplying a tape and a winding-side reel for winding, a reel driving means including drive sources for respectively driving the supply-side and winding-side reels, and each reel. A pulse signal generating means for generating a pulse signal according to the rotation, a forward / reverse determining means for determining the forward / reverse of each reel rotation direction, a detection processing section for detecting each of these signals, and the detection processing. And a control unit to which a signal of a part is input. The control unit acquires the current reel tape winding diameter information and corresponds to the tape winding diameter from this information (on-tape control pulse / reel pulse one). Of information equivalent to (or control pulse on tape / 1 reel pulse) x 2 ⁿ A tape position calculating device comprising: a means for determining information corresponding to the above, and means for calculating a tape position from the information obtained by this means to obtain a display signal. 2. When the control section calculates the tape position for display using the amount of information corresponding to the (on-tape control pulse / one reel pulse), the previous data stored in the register 2. The tape position calculation device according to claim 1, further comprising means for adding or subtracting the information of the amount according to the discrimination result of the forward / reverse discrimination means, and converting the result into a tape position signal. 3. The means for selecting the information corresponding to the (on-tape control pulse / reel pulse) from a table in which the control section acquires the current reel tape winding diameter information, There is provided a means for adding or subtracting information corresponding to the above (one control pulse on tape / one reel pulse) to the contents of the register according to the discrimination result of the forward / reverse discrimination means, and converting the result to a tape position signal. The tape position calculation device according to claim 1, wherein 4. The control unit detects a bit change of n digits of the register and generates a pseudo control pulse,
The tape position calculation device according to claim 1, further comprising means for resetting the first register. 5. The control unit acquires the current reel tape winding diameter information from the (on-tape control pulse / one reel pulse) × 2 ⁿ Means for selecting information corresponding to the above from a table stored in advance, and (on-tape control pulse / one reel pulse) × 2 ⁿ Means for adding or subtracting to the contents of the first register the information corresponding to the above, according to the discrimination result of the forward / reverse discriminating means, and converting the result of ⁿ digits or more into a tape position signal; of ^(nm) to detect the bit change digit, said means for adding or subtracting "1" in response to forward and reverse discrimination result, the bit change in the ^m-digit of the second register to the contents of the second register Is detected and a pseudo control pulse is generated, and the second
2. The tape position calculating device according to claim 1, further comprising means for resetting the register of FIG.