JPS60187956A - Magnetic tape device - Google Patents

Abstract

PURPOSE:To generate a tape end signal before a magnetic tape end and eliminate the need for a reflecting marker, etc., by detecting the counted value of a clock signal indicating the run length of a magnetic tape above a specific value and then generating the tape end signal. CONSTITUTION:When the magnetic tape 21 comes to its start position, a tape start position signal is inputted to a signal line 22 and a counter 23 is reset. The two-phase pulse signal of an optical tachometer 25 synchronizing with the rotational angle of a take-up motor 24 is inputted to a forward/backward run detector 28. A high-level forward run signal or a low-level backward run signal is inputted to the counter 23 through signal lines 29 and 30 and the counter 23 counts up or down; and its counted value is inputted to a comparator 32 and compared with the specific value inputted from a signal line 33 and when the counted value is larger, the tape terminal end signal is outputted from a signal line 34 to detect the terminal end before the tape terminal end.

Description

[Detailed Description of the Invention] (Technical Field) The present invention prevents deterioration of downstream data [! The present invention relates to a magnetic tape device that can generate a tape end signal without causing any interference.

(Prior Art) FIG. 1 is a diagram showing conventional tape end marks used for detecting the end of magnetic tape (EOT), in which 11 is a magnetic tape, 12 is a reflective marker, and 13 is a transparent tape. . In the case of FIG. 3A, a reflective marker 12 is pasted near the end of the magnetic tape 11. When the reflective marker 12 reaches the photodetector t and the detection light is reflected, the photodetector detects this and issues a tape end signal. , a transparent tape 13 is connected to the end of the magnetic tape 11. When the transparent tape 13 reaches the photodetector position and the detection light passes through it, the photodetector detects this and a tape end signal is issued.The former in the case of,
If the magnetic tape 11 is left wound for a long time, the thickness of the foul marker 12 is about 20pn+, so the -
The part of the magnetic tape 11 that is wound around the magnetic tape 11 undergoes permanent deformation (Technical Research Report MR83-17 of the Institute of Electronics and Communication Engineers). Therefore, there is a problem that a gap is created between the magnetic head and the magnetic head during reading, making it impossible to read the arc written in the part A. Furthermore, in the latter case, a step difference of about 20 prn occurs at the connection portion between the magnetic tape and the transparent tape, so there is the same drawback as described above.

(Object of the Invention) In view of the above-mentioned drawbacks, the present invention is designed to indicate the running length of a magnetic tape and detect when the count value of the 1 cock signal exceeds a predetermined value, and generate a tape end signal. It aims to provide a magnetic tape device.

(Structure of the Invention) In order to achieve the above object, a first invention provides a drive means for running a magnetic tape, a faith generation means for generating a signal synchronized with the rotation angle of the drive means, and a rotation angle based on the synchronization signal. detecting means for generating a signal indicating whether the magnetic tape is moving forward or backward; and detecting means for generating a clock signal indicating whether the magnetic tape is moving forward or backward;
It is characterized by comprising a counting means for reading one number, and a comparing means for comparing the counted value with a predetermined value and generating a tape end signal when the counted value is larger than the predetermined value. The second invention provides a rotating means rotated by a running magnetic tape, a signal generating means generating a signal synchronized with the rotation angle of the rotating means, and whether the magnetic tape is moving forward or backward based on the synchronizing signal. Detection means for generating a clock signal and a clock signal, a counting means for adding and subtracting the number of the clock signals based on the forward/backward signals; The present invention is characterized in that it has a comparison means for comparing the magnitude of the counted value with a predetermined value and generating a tape end signal when the counted value is larger than the predetermined value.

(Embodiment) FIG. 2 is a schematic diagram showing an embodiment of the apparatus of the present invention, in which 21 is a magnetic tape, 22.26.27.29.30
．． 31, 33 and 34 are signal lines, 23 is a forward/
The number of backward signals will be described later [addition of the number of backward signals by π1]
It is a counter that performs number/subtraction and is composed of the known up-daushika 1 kunta.

24 is a drive means for running the magnetic tape, ie, a winding motor; 25 is a signal generation means for generating a two-phase pulse signal (synchronization signal) synchronized with the rotation angle of the drive means, ie, a known two-phase output type. An optical tachometer 28 generates a signal indicating whether the magnetic tape is moving forward or backward based on the synchronization signal (forward: high level, backward 20-level) and a clock signal. A detector 32 compares the count value of the counter with a predetermined value, and when the t1 value is larger than the predetermined value, a detector 32 detects 7.
This is a comparator that generates a single termination signal.

First, when the air tube 21 is attached and reaches the tape starting position, a tape starting signal is input to the signal line 22, and the counter 23 is reset to 1. The tape start signal may be generated in a conventional manner. When the magnetic tape 21 is wound or rewound for reloading or reading, two-phase pulse signals from the optical meter 25 synchronized with the rotation angle of the winding motor 24 are transmitted to the signal line 26 and the signal line 8. 2
7 and is input to the forward/reverse detector 2B. The forward/backward detector 28 detects whether the magnetic tape 21Q is moving forward or backward, and in the case of winding, a high-level forward signal is sent via the signal line 29, and a ``1'' signal is sent via the signal line 30. , d is input to the counter 23. Counter 23
enters addition counting mode, and the number of clock signals is added or subtracted. On the other hand, in the case of rewinding, a low-level backward signal is inputted to the signal FA29, the digitizer 23 enters the decrement δ1 number mode, and the number of clock signals is decremented by h1. The count value of the counter 23 is sent to the comparator 32 via the signal line 31.
The comparator 32 compares the h1 value with a predetermined value input from the signal line 33, and outputs a tape end signal to the signal line 34 if the counted value is greater than or equal to the predetermined value. do. The predetermined value is the count value of the counter 23 from the beginning of the magnetic tape (BOT) to just before the end where permanent deformation occurs.
This was measured in advance.

There are various ways to give this value, such as giving it as a fixed value, or automatically selecting one from a plurality of numbers according to the length of the magnetic tape.

FIG. 3 is a configuration diagram of another embodiment of the present invention, in which 41 is a magnetic tape, 42 is a rotating mechanism rotated by the running magnetic tape 41, and 43 is a rotation mechanism synchronized with the rotation angle of the rotating mechanism 42. An optical tachometer that generates a signal.
The other configurations are the same as those of the previous embodiment.

According to this embodiment, the rotation mechanism 42 rotates as the magnetic tape 41 runs, and the optical tachometer 43 outputs two-phase pulse signals in synchronization with the rotation angle. Other operations are similar to those in the previous embodiment.

In another embodiment of the present invention, the winding motor shown in FIG. 2 may be replaced with a delivery motor.

In addition, in the case of a cab's tongue drive type magnetic tape device,
The rotation mechanism 42 in FIG. 3 may be replaced with a capstan motor.

(Effects of the Invention) According to the magnetic tape device of the present invention as described above, it is detected that the H1 value of the signal indicating the running length of the magnetic tape has exceeded a predetermined value of 1fff. , it is possible to generate an end-of-tape (FOT) signal before the end of the C1 magnetic tape, causing permanent deformation and preventing the end of the tape (such as a reflective marker, etc.) from being permanently deformed. ), which has the advantage of improving the long-term reliability of written data.

[Brief explanation of drawings]

The drawings are provided to explain the present invention, and include FIGS. 1(a) and (b).
) is an explanatory diagram showing a conventional tape end mark, FIG. 2 is a schematic diagram showing one embodiment of the apparatus of the present invention, and FIG. 3 is a schematic diagram showing another embodiment of the apparatus of the present invention. 11.21.41...Magnetic tape, 12...Reflective marker, 13...Transparent tape, 23...n1 number counter, 2
4... Winding motor, 25. 43... Opteinoy) Retachometer, 33... Comparator, 42... 1 rotation, Patent applicant Nippon Telegraph and Telephone Public Net 1 Agent Patent attorney Yoshitaka Figure 1 (a) (b) Figure 2

Claims (2)

[Claims] (1) A drive means for running the I&magnetic tape, a signal generation means for generating a signal synchronized with the rotation angle of the drive means,
detection means for generating a clock signal and a signal indicating whether the magnetic tape is moving forward or backward based on the synchronization signal; and counting/subtracting the number of clock signals based on the forward/backward signal. A magnetic tape characterized in that it has a subcount means, and a comparison means that compares the counted value with a predetermined value and generates a tape end signal when the counted value is larger than the predetermined value. Device. (2) Rotating means rotated by the running magnetic tape, signal generating means generating a signal synchronized with the rotation angle of the rotating means, and indicating whether the magnetic tape is moving forward or backward based on the synchronizing signal. Detection means for generating a clock signal; count means for adding/subtracting the number of clock signals based on the forward/reverse signal;
and compares the scale value with the predetermined value and the it
1. A magnetic tape device, comprising comparison means for generating a tape end signal when the numerical value is greater than a predetermined value.