JPS5933654A - Measuring method for length of non-recorded part of signal of magnetic tape - Google Patents

Abstract

PURPOSE:To measure and display the length of a magnetic tape where no signal is recorded, by switching a cue state to a review state at a prescribed time point with an indication for measurement of said length of the magnetic tape, then switching the review state to a pause state to display the length of the tape traveled for a period between two time points. CONSTITUTION:An indicating signal for detection of the length of a magnetic tape where no signal is recorded is supplied to a microcomputer 7 via a switch 15, and the main body 1 of a magnetic sound recording/reproducing device is switched to a cue active state to read the output signal of a level detector 4. The change is monitored for both the output signal of the detector 4 and a detecting signal E for magnetic tape leader part. The level comparator 4 delivers an L signal when a non-recorded part of signals, and the signal E goes to an H signal at the tape leader part. In this case, the computer 7 switches the main body 1 in a review state. At the same time, the magnetic tape is driven the adverse winding direction. Then the display value of a display device 8 increases in proportion to the traveled amount of the tape. The computer 7 stops the operation of the main body 1 when a change of the signal E is detected. In such a way, the length of the magnetic tape where no signal is recorded is measured and displayed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the length of a non-recorded portion of a magnetic tape signal in a magnetic recording and reproducing apparatus such as a magnetic recording and reproducing apparatus or an 11TL1 image signal recording and reproducing apparatus.

A conventional method for measuring the length of a non-recorded portion of a magnetic tape detects the rotation speed of at least one of the reel stand on the supply side or the IJ-roll stand on the take-up side of the magnetic tape, and detects the rotation speed of the reel when the rotation speed of the magnetic tape is detected. A magnetic tape whose running distance is calculated based on the total length of the magnetic tape in use, using the changes that occur while the tape is running at a constant speed (while running during playback or recording). The distance traveled is subtracted, and this subtraction result is divided by the speed at which the magnetic tape runs at a constant speed to convert it into a time length, and then the time is displayed on the display.However, when using the conventional method as described above, Is it magnetic?
The remaining amount of the magnetic tape is displayed in time, but if there is a non-signal recording part in the middle of the magnetic tape in the length direction, there is a drawback that the time length corresponding to the signal non-recording part cannot be measured and displayed. For this reason, when it is desired to record a new signal in the signal-free area, it is difficult to judge whether all of the desired signals can be recorded in the signal-free area.

The present invention has been made in view of the above, and an object of the present invention is to provide a magnetic tape signal non-recording portion length measuring method that eliminates the above-mentioned drawbacks and measures and displays the signal non-recording portion length of a magnetic tape.

According to the present ship, the purpose of this is to set the magnetic recording/reproducing device to a cue operating state by an instruction to measure the length of the non-recorded part of the magnetic tape, and to prevent the magnetic tape from producing no signal during the cue operating state due to changes in the playback output signal level. The cue operation state is switched to the review operation state at the first test time when either the change from the recording part to the signal recording part or the arrival of the magnetic tape to the blade side league part is detected, and the review operation is performed. During the state, due to a change in the playback signal level, the review is performed at the second point in time, whichever comes first: a change from a signal-free portion of the magnetic tape to a signal-recorded portion, or when the magnetic tape reaches a league portion on the other side. This is achieved by switching from the operating state to the stopped state and displaying a value corresponding to the amount of travel of the magnetic tape from the first time point to the second time point.

The present invention will be explained below using examples.

FIG. 1 is a block diagram showing an embodiment of the method of the present invention. An embodiment of the method of the present invention will be explained using a magnetic recording/reproducing device as an example.

The magnetic recording/playback device main body 1 includes a mechanism section 2, an amplifier 4-1 for amplifying the playback signal from the playback magnetic radar 3, and a level comparator 4 for detecting the output signal level of the amplifier 4-1.
-2, and rotation speed detectors 5 and 6 for detecting the rotation speed of the supply reel and the take-up reel, and a microcomputer 7.
The operating state of the microcomputer 7 is controlled by the state indicating switches 10 to 15 supplied to the microcomputer 7.

Further, the status indication switches 10-15 include a recording status indication switch 10, a reproduction status indication switch 11, a fast forward) reproduction status (herein referred to as cue operation status) indication switch 12, and a rewind reproduction status (herein referred to as cue operation status). 13.5 pause state indicating switch 14, signal non-recorded portion length detection indicating switch 15.

In addition, in order to make the explanation easier, this example shows cases where one instruction switch is provided for each function, but if the same instruction switch is pressed multiple times, multiple instruction switches may It is also possible to make the same function as when pressing other instruction switches by pressing the switch, and it goes without saying that the number of instruction switches can be made smaller than the number of instruction operations. be. The microcomputer 7 detects the pressed recording state indicating switch 10. Playback status instruction switch 11, cue operation status instruction switch J
2. Read the output signal of the review operation state instruction switch 13 or the pause state instruction switch 14, and control the magnetic recording/reproducing apparatus main body 1 to the state specified by the pressed state instruction switch. Also, microcomputer 7
Inputs the output signals of the rotation speed detectors 5 and 6 (7)2, calculates the odometer of the magnetic tape, and performs 11th addition or subtraction corresponding to the running direction of the magnetic tape. In addition to converting the traveling distance of the magnetic tape into time, a display 13 consisting of a 7-segment discharge display tube
to be displayed.

In equation (1), T11 is the rotation speed of the supply side reel stand detected by the rotation speed detector 5, n2 is the rotation speed of the take-up side reel stand detected by the rotation speed detector 6, and R
is the square root of the sum of the squares of the radii of the take-up and supply reels, and is the radius of the magnetic tape when the entire amount of the magnetic tape is wound onto one reel, assuming the heb radius is 0. It is. Here, although the magnetic tape radius R-& is included in equation (1), the cassette magnetic radius f
C-60, 0-90.

In C-120, C-45 large hubs, etc., the radius R is approximately constant within a predetermined error range regardless of the type of magnetic tape, and can be regarded as a constant. Therefore, the running distance of the magnetic tape can be calculated within a predetermined error range using equation (1). In addition, when the magnetic tape is in the recording state, playback state, or cue state according to the instructions of the recording instruction switch 10, playback instruction switch 11, and cue operation state instruction switch 12, the amount of magnetic tape travel is added and displayed. In the review state as instructed by the state indication switch 13, the running distance of the magnetic tape is subtracted and displayed.

When the signal-free portion length detection switch 15 is pressed, the output signal of the signal-free portion length detection switch 15 is supplied to the microcomputer 7, and the operation shown in the flowchart of FIG. 2 is performed. That is, when the output signal of the signal unrecorded portion length detection switch 15 is supplied, the magnetic recording and reproducing device 6 main body 1 is switched to the cue operation state, and the output signal of the level detector 4 is read and the change in the sheep and the magnetic recording and reproducing device main body 1 are detected. All changes in the magnetic thesor reader section detection signal E output from the sensor are monitored. b Temporarily born magnetic head 3
The level comparator 4 outputs a high potential output signal when detecting a signal recording portion, and outputs a low potential output signal when detecting a signal non-recording portion. It is assumed that the output signal becomes high in the reader section.

Therefore, after switching to the queue operation state by detecting the output signal of the unrecorded portion length detection switch 15, the output signal of the level detector 4 that generated the high potential output signal or the reader section detection signal is transferred to the microcomputer 7. is detected, and at the time of detection, the magnetic recording/reproducing device main body 1 is switched to the review operation state, and at the same time, the output signal to the display 8 is set to zero, and the display value of the display 8 is set to zero, and in this case, During the review operation state, the magnetic tape running display is set to the addition mode, that is, the review operation state instruction switch 13
Set to the opposite mode to the subtraction mode during the review operation state according to the instruction.

During the review operation state from the time when it is detected that the output signal of the level detector 4 or the league part detection signal E changes to a high potential output signal, the magnetic tape does not run in the rewinding direction. During this review operation state, whether or not the output signal of the level detector 4 changes from a low potential output signal to a high potential output signal, and whether the other league part detection signal changes from a low potential output signal to a high potential signal is determined. to monitor. During the rewinding of the magnetic tape during the review operation state, the magnetic tape running amount is added and the display 8
The displayed value increases in proportion to the amount of magnetic tape travel. On the other hand, while the magnetic tape is running in the rewinding direction in this review operation state, the microcomputer 7 detects the output signal of the level detector 4 that first generated the high potential output signal or the other reader section detection signal. At this time, the magnetic recording/reproducing device main body 1'ff: switches to the stopped state. Therefore, the magnetic tape stops running, and at this point the display value on the display 8 stops increasing. Therefore, the displayed value on the display 8 at this time indicates the length of the signal-free portion. FIG. 3 is a diagram showing the above state, and FIG. 3 (,) shows the state of the magnetic tape 16, and the shaded area A shows the signal recording part.
A non-hatched area B indicates a signal-free area, and C1 and C2 indicate boundaries between the signal-recorded area and the signal-free area.

FIG. 3(b) is a state diagram showing the state of the magnetic recording and reproducing device ff2- during measurement and display of the length of the unrecorded portion of the signal, and as described above, in the cue operating state, the output signal of the level detector 4 is high. The fact that the potential output signal has changed to the low potential output signal and the league part detection signal is I'fj>*,' (
Since the microcomputer 7 does not detect the change from the fl output signal to the low potential output signal, the instruction by the signal non-recording portion length measurement instruction switch 15 is applied to any signal in the signal recording portion A of the magnetic chip 7'16. It may be performed at time S2 or at any time S1 within the signal-free portion B. Further, FIG. 3(c) shows the output signal level and comparison level of the comparator 4-1, the solid line shows the output signal level of the amplifier 41, and the one-dot chain line shows the comparison level Lf of the level comparator 4-2. .

In addition, if there is no signal recording part A following the signal non-recording part B, the boundary C1 in FIG. become.

As explained above, according to this embodiment, the time corresponding to the length of the no-signal recording section is displayed on the display 8, and it is possible to record all of the content newly desired to be recorded in the no-signal recording section using this displayed value. You can easily judge whether or not.

In addition, the magnetic tape running length is calculated by detecting the rotation speed J+n2 of the supply side reel stand and the take-up side reel stand with the rotation speed detectors 5 and 6, and performing inverse calculation using equation (1). Illustrated as an example. However, as in the conventional case, the rotation speed of the supply side reel stand or the rotation speed of the take-up side reel stand is detected, and the magnetic tape is The amount of tape travel may also be calculated. In the latter case, a problem arises in that a highly accurate time measurement function is required in order to accurately detect the amount of tape travel.

Next, another embodiment of the method of the present invention will be described. In one embodiment, when the magnetic recording and reproducing apparatus main body 1 is switched to the review operating state and the stopped state, the inertia of the magnetic tape drive system causes There are cases where the magnetic tape runs excessively, but this is an example of how to accurately measure and display the length of the non-signal recording portion of the magnetic tape, taking this into account.

FIG. 4 is a flowchart showing another embodiment of the method of the present invention, and FIG. 5 is a diagram for explaining another embodiment of the method of the present invention.

While the signal non-recorded portion length detecting switch 15 is busy with the suppression operation, measurement of the signal non-recorded portion length is started through the steps shown in FIG.

When the output of the signal unrecorded portion length detection switch 15 is supplied, the magnetic recording/reproducing apparatus main body 1 is switched to the cue operation state,
Changes in the output signal of the level detector 4 and the magnetic tape reader section detection signal E are monitored.

By switching to this cue operating state, the magnetic tape runs in fast forward mode. Next, the output signal of the level detector 4 which generated the high potential output signal first or the league section detection signal E
is detected, and at the time of this detection, the magnetic recording/reproducing apparatus main body 1 is brought to a halt state. This time point is 02 time point shown in FIG. After switching to the stop state, the magnetic recording/reproducing apparatus main body 1 is switched to the review operation state after a predetermined period of time. During this review operation state, it is detected whether the output signal of the level detector 4 or the league portion detection signal E changes from a high potential output signal to a low potential output signal. When it is detected that the output signal of the level detector 4 or the league part detection signal has changed from a high potential signal to a low potential signal, the output signal to the display 8 is set to zero, and the value displayed on the display 8 is changed to zero. zero, and set the magnetic tape running display to addition mode. As mentioned above, this addition mode is the opposite mode to that in the review operation state as instructed by the review operation state instruction switch 13.

Therefore, even if the magnetic tape 16 continues to run for a while due to the inertia of its drive system from the time point 02 in FIG. Since the display on the display 8 is set to zero at the point C2 in FIG.

Further, although the stopped state is temporarily set before switching to the review operating state, it is also possible to omit this stopped state and switch from the cue operating state to the review operating state.

In FIG. 5(b), Fl indicates a period during which the magnetic tape 16 is overrunning. C in Figure 5 (,)
During the rewinding of the magnetic tape during the review operation state from time point 2 onwards, the amount of magnetic tape travel is added, and the value displayed on the display 8 increases in proportion to the amount of travel of the magnetic tape. During this review operation state, the output signal of the level detector 4 that generated the high potential output signal first or the other reader detection signal is detected, and when this detection is performed, the magnetic recording/playback device main body 1
Switch to stopped state. At the same time as this switching to the stopped state, the magnetic tape running display is switched to the subtraction mode. Then, the state is switched to the playback state via the stop state.

In this state, it is detected that the magnetic tape running amount has changed by a predetermined amount, and the magnetic recording/reproducing apparatus main body 1 is switched to a stopped state or a bowed state.

Here, time C1 in FIG. 5(b) is the time when the output signal of the level detector 4 or other reader detection signal changes from a low potential output signal to a high potential output signal during the review operation state, and this time At this point, the magnetic recording/reproducing apparatus main body 1 is switched from a stopped state to a reproducing state, but the magnetic tape overruns for a period F2 due to the inertia of the drive device.

Therefore, by setting the aforementioned predetermined amount of the magnetic tape running amount to be equal to the sum of the running amount due to overrun of the magnetic tape and the unrecorded portion length necessary for cueing, the magnetic tape running amount can be set. At the end of measuring the length of the unrecorded signal portion, the display 8 will be displaying the length of the unrecorded signal portion, which is obtained by subtracting the unrecorded portion necessary for cueing.

Further, in other embodiments of the method of the present invention, even if the measurement start instruction by the signal non-recorded portion length measurement instruction switch 15 is performed at any time S in the signal recorded portion A, it is possible to It may be performed at time S.

According to another embodiment of the method of the present invention, the length of the signal-free portion of the magnetic tape can be measured without being affected by excessive running due to the inertia of the magnetic tape drive system.

As explained above, according to the method of the present invention, even when the No. ♂ unrecorded portion of the magnetic tape in a magnetic recording/reproducing device is located between the signal recording portions, the signal unrecorded portion extends all the way to the end of the magnetic tape. Even if the magnetic tape is read, the length of the non-signal recording portion of the magnetic tape can be measured.

In addition, the magnetic tape used is C-(io, C-90, C
- Even if the total length is different, such as 120, there is no need to specify in advance the type of magnetic tape used depending on the length, since the method does not subtract the length of the signal recording portion from the total length of the magnetic tape. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the method of the present invention. FIG. 2 is a flowchart showing one embodiment of the method of the present invention. 3(a), (b) and (c) are diagrams showing the recording state of a magnetic tape, diagrams showing the operating modes of the main body of the magnetic recording/reproducing apparatus, and the input of the level detector, which are used to explain one embodiment of the method of the present invention. FIG. 4 is a flowchart showing another embodiment of the method of the present invention. FIGS. 5(a) and 5(b) are diagrams showing the recording state of a magnetic tape and the operation mode of the main body of the magnetic recording/reproducing apparatus to explain another embodiment of the method of the present invention. l... Magnetic recording and playback device main body, 2... Mechanism section, 3.
... Reproducing magnetic head, 4... Level detector, 5 and 6... Rotation speed detector, 7... Microcomputer, 8... Display device. Patent applicant Trio Co., Ltd. Representative Patent attorney Nobuo Sunako Figure 1 Figure 2 Figure 3 Figure Ca+ Figure 5

Claims (2)

[Claims] (1) In a magnetic recording/reproducing device, a cue operation state is set by an instruction to measure the length of a signal-free portion of the magnetic tape, and a signal is recorded from a signal-free portion of the magnetic tape according to a change in the reproduction signal level during the cue operation state. The first one detects either the change to the magnetic tape part or the arrival of the magnetic tape to the leader part.
At the point in time, the cue operation state is switched to the review operation state, and during the review operation state, due to a change in the playback signal level, the magnetic tape changes from a signal-free area to a signal-recording area, and the magnetic tape reaches the leader section on the other side. Switching from the review operation state to a stop state at a second point in time when any of the above is detected first, and displaying a value corresponding to the traveling distance of the magnetic tape from the first point in time to the second point in time. A method for measuring the length of a non-recorded portion of a magnetic tape signal, characterized by: (2) In a magnetic recording/reproducing device, the signal non-recording portion length measurement instruction sets the cue operation state, and during the cue operation state, the change in the playback signal level causes the magnetic tape to change from the signal non-recording portion to the signal recording portion. The first one that detects either the change or the arrival of the magnetic tape to the leader section first.
At the point in time, the cue operating state is switched to the review operating state, and during the review operating state, due to a change in the playback signal level, the signal recording portion of the p magnetic tape changes to the signal non-recording portion, or the number of leader portions of the magnetic tape changes. Detecting the end of the second point in time, and then detecting a change in the playback signal level during the review operation, causing the magnetic tape to change from a signal-free area to a signal-recorded area and reach the leader section on the other side of the magnetic tape. The magnetic tape is switched to a stopped or paused state at a third point in time when one of the above is detected first, and a value corresponding to the amount of travel of the magnetic tape from the second point in time to the third point in time is displayed. A method for measuring the length of the unrecorded portion of a magnetic tape signal.