JPS6237455B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an automatic tape type detection device that automatically detects the type of tape in a tape recorder.

[Technical background of the invention] There are 18 types of cassette tape depending on the thickness.
There are three types: μ, 12μ, and 9μ, and five types depending on the total length: C-30, C-46, C-60, C-90, and C-120. Among these tapes, C-46 and C-60 tapes have a tape thickness of 18μ and differ only in length. On the other hand, 3 of C-60, C-90, and c-120
Different types of tapes have different thicknesses and total lengths, but the product of thickness and total length is a substantially constant value regardless of the tape type.

Therefore, if the tape thickness can be known from this tape relationship, at least C-60, C-
Three types of tapes, 90 and C-120, can be distinguished.

[Object of the Invention] The object of the present invention is to automatically determine the thickness of the tape and determine the type of tape, especially C-60, C-90, C-60,
An object of the present invention is to provide an extremely useful automatic tape type detection device capable of detecting three types of tapes: -120.

[Summary of the Invention] Now, if the rotation period of the tape reel is T and the tape reel winding diameter at that time is 2R, the following equation holds true.

2πR=V・T...(1) Here, V is the tape speed. In equation (1),
Considering minute changes in the period T and tape winding radius R, the following equation can be obtained.

2πdR=VdT...(2) Here, since the radius R decreases or increases by the tape thickness A every time the reel rotates, the times T ₁ and T ₂ required for each previous and subsequent rotation at a certain time are △ If T=|T ₁ −T ₂ |, equation (2) can be expressed as the following equation.

ΔT=2πA/V (3) Therefore, it can be seen that the tape thickness A can be determined using the tape speed V and the period difference ΔT between successive rotations. And as mentioned above, C-60, C-
Tape thickness A for 90 and C-120 tapes
Since the product A·L of the total tape length L and the total tape length L is approximately constant K, the total tape length L, that is, the tape type can be determined using this A.

Therefore, the tape type automatic detection device of the present invention has the following features:
a measuring means for measuring the time T required for one rotation of the tape reel; a first storage means for storing the time _T1 measured by the measuring means and required for one rotation of the reel immediately before a predetermined time; a second storage means for storing the time T ₂ required for one rotation of the reel immediately after a predetermined time; and storage contents T ₁ and T ₂ of the first and second storage means;
Using tape speed V and constant K, tape thickness A = |T ₁ − T ₂ |・V/2π ...(4) Tape total length L = K/A ...(5) Based on the formula It is characterized in that it includes a calculation means for calculating the total length L, and thereby it is possible to calculate the total length L, so that the tape type, especially C-60, C-90, and C-120, can be calculated.
It becomes possible to detect the type of tape.

[Embodiments of the invention] The present invention will be explained below with reference to the drawings.

1 and 3 are block diagrams showing one embodiment of the present invention, and FIG. 2 is a waveform diagram of the operation of each part of FIG. 1. A photocoupler 1 is provided to detect the rotation period of a take-up reel or a supply reel (not shown), respectively, and a rotating plate that rotates with the rotation of the reel stand is provided between the issuing and light receiving elements of the photocoupler 1. By forming a predetermined slit in this rotary plate, a pulse signal is generated at the output of the photocoupler in accordance with the rotational speed of the reel. This pulse signal is shaped and amplified by the waveform shaping circuit 2 to obtain an output signal a. In this example, as shown in FIG. 2a, the arrangement is such that four (n) pulse signals are obtained for each rotation of the reel. The pulse signal a is converted into a predetermined pulse signal b by an n-ary counter, in this example, a quaternary counter 3. Note that the quaternary counter 3 counts the pulse signal a after being reset by a reset pulse, which will be described later.When a pulse signal is input, it becomes a high level, and when it counts four pulse signals, it becomes a low level. It is.
This pulse signal b is input to the monostable multi 4. Assuming that this monostable multi 4 is triggered by the rising edge of the input pulse signal b, Fig. 2 c
As shown in the figure, one pulse is generated approximately at the beginning of one rotation of the reel. The output c of this monostable multi 4 becomes the clear input of the counter 5 at the next stage. On the other hand, an oscillation circuit 6 is provided which generates a pulse signal having a constant frequency, and its output serves as the clock input of the counter 5. The output of the counter 5 is an m-bit parallel digital output signal, and the parallel output is input to a latch circuit 7 as a first storage means for storing m bits in parallel. Furthermore, the parallel digital outputs of this latch circuit 7 are input to a latch circuit 8 as a second storage means.

Also, a detection circuit 9 for detecting one revolution of the reel.
is provided. That is, in this example, there are 5 (n+1)
It is detected that the pulse d is generated by the photocoupler 1, and a predetermined pulse d is generated as shown in FIG. 2d. In response to the falling timing of this pulse d, a reset pulse e shown in FIG. 2e is generated from the reset signal generating circuit 10 at the next stage. The quaternary counter 3 is reset by this reset pulse e, and a reading instruction for the latches 7 and 8 is issued at the timing of the rise of the output pulse d of the detection circuit 9.

In such a configuration, as shown in FIG.
In response to the first pulse of the signal a at _t1 , the counter is cleared by the output c of the monostable multi 4, and at the same time, the pulses of a constant frequency from the oscillation circuit 6 start counting up from zero. When the reel rotates once from time _t1 and the fifth pulse of the signal a is generated, a detection pulse is output from the output d of the detection circuit 9 in response to this. At the rising timing _t2 of this detection pulse d, the count contents of count 5 at time _t2 are written into the latch circuit 7 as a parallel digital signal. This content is the number of output pulses from the oscillation circuit 6 generated within _the time T 1 required for one rotation of the reel from time t ₁ to _{t 2} , as shown in Figure 2 f. This shows the required time T ₁ (Fig. 2 f).
This content continues to be stored until the detection pulse d is generated again from the detection circuit 9.

Falling timing of output pulse d of detection circuit 9
At _t3 , the reset signal e is generated from the reset signal generating circuit 10, and the quaternary counter 3 is reset to return to its initial state. At the generation timing _t4 of the pulse a, which arrives immediately after the time _t3 , the counter 5 starts counting up again from zero.
As described above, this operation is continued including the pulse a at time _t4 until time _t5 when the fifth pulse arrives. Then, at time _t5 , the memory content _T1 of the latch circuit 7 is transferred to the latch circuit 8 in synchronization with the rising timing of the detection pulse d of the detection circuit 9, and the new content _T2 of the counter 5 is transferred to the latch circuit 7. written. This content T ₂ is the number of count pulses between times t ₄ and _{t 5} , and in other words, it indicates the time T ₂ required for one revolution of the reel (FIG. 2 f).

These m-bit digital signals T ₁ and T ₂ are input to an arithmetic circuit 11 as shown in FIG.
On the other hand, data representing the tape speed stored in the memory circuit 12 in advance is input to the arithmetic circuit 11 . Using these input data, an operation is performed based on the above equation (4), that is, A=|T ₁ -T ₂ |·V/2π, and as a result, the tape thickness A is calculated. Furthermore, in this example, the above-mentioned C-60, C-90, C-120 from the memory circuit 12
An almost constant constant K (=A・L) for the tape
and using the above tape thickness A, L=K/
The configuration is such that the tape total length L is calculated using the formula A.

The calculated data obtained in this way is converted into a display drive signal by the decoder 13, and the tape type C
-60, C-90, C-120 display 1
Drive 4.

In addition, in the above example, for convenience of explanation,
Although the configuration is such that four pulses a are output for each rotation of the reel, the number of pulses is further increased and the second
It is clear that by reducing the waiting times _t2 to _t4 shown in the figure and making them negligible with respect to the time T required for one rotation, accurate calculation of the tape thickness becomes possible.

[Other Embodiments] In the above embodiments, a case is shown in which the means for measuring the time required for one revolution of the reel, the storage means for storing the measured value of the measuring means, etc. are realized as a hardware configuration, but a microcomputer may also be used. The computer can be controlled by so-called software using a control means such as the above, and constitute a part of the measuring means and the storage means. A schematic diagram in this case is shown in FIG.

In FIG. 4, parts equivalent to those in FIGS. 1 and 3 are indicated by the same reference numerals. That is, the oscillation circuit 6
A microcomputer 20 controls the clearing, count-up, and hold operations of the counter 5 using the output pulses of the photocoupler 1 as a clock input. /O port 21, output T ₁ of counter 5,
An I/O port 22 for inputting T ₂ and an I/O port 24 for supplying a control output signal from the CPU 23 to the counter 5 and the display 14 are provided. Furthermore
The CPU 23 includes a RAM (random access memory) 25 that temporarily stores the output of the counter 5 and the pulse signal a, and a ROM (read only memory) 26 that stores programs for controlling the computer, tape speed, etc. It is. ROM26
Appropriately design the program stored in
It is possible to perform the same operation as the embodiment shown in FIGS.

[Effects of the Invention] As detailed above, according to the present invention, the thickness is determined according to the type of tape, and furthermore, using this thickness, C-60, C
It becomes possible to automatically distinguish between -90 and C-120 tapes, making it an extremely useful device.

[Brief explanation of the drawing]

1 and 3 are block diagrams showing one embodiment of the present invention, FIG. 2 is a waveform diagram of each part of FIG. 1, and FIG. 4 is a schematic block diagram showing another embodiment of the present invention. . Explanation of the symbols of the main parts, 1...Photocoupler,
5... Counter, 7, 8... Latch circuit, 11...
...Arithmetic circuit, 20...Microcomputer, 2
3...CPU.

Claims (1)

[Scope of Claims] 1. Measuring means for measuring the time T required for one rotation of the tape reel; and a first memory for storing the time T ₁ required for one rotation of the reel immediately before a predetermined time, which is measured by the measuring means. means; second storage means for storing the time T ₂ required for one rotation of the reel immediately after the predetermined time measured by the measurement means; and storage contents T ₁ and T of the first and second storage means. ₂ , tape speed V, and constant K, calculating means for calculating the tape total length L based on the formula A=|T ₁ −T ₂ |・V/2π L=K/A; 1. An automatic tape type detection device comprising: a display device that displays a tape type based on data calculated by the means.