JPS6035753B2 - Tape position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape position detection device that automatically detects the current position of a tape in a tape radar.

A tape counter is used to display the tape position of a tape recorder, but since this is a special mechanical device, it is impossible to determine the exact tape position. Further, although it is difficult for a tape counter to display both the amount of tape running and the remaining amount of tape, there are many requests for such display. SUMMARY OF THE INVENTION An object of the present invention is to provide a tape position detection device that can accurately determine the current tape position and simultaneously determine the amount of tape travel and the remaining amount of tape.

Now, let Ts and Tt be the rotation periods of the supply reel and the take-up reel at arbitrary times, respectively, and let Δt be the tape running time from the time when both reels have the same tape winding diameter, then the following equation holds true.

rS2-Tze=k・△t...
...{1} Here, k is a constant determined by the tape speed, tape thickness, and tape length.

The formula {1} is expressed in the form of the difference of the squares of each period, but
If this is expressed as a difference between each period, it is transformed as shown in the following equation. T
s-Tt=k'(notn-Δt-nottn-Δt).・・・
．． ...'21 where k' and tn represent constants.

In the equation '2}, by setting Δt'/m=x and Ts-Tt=y, a glue equation can be obtained. y=k (No1-x-No10x)
...{31 In this formula [3}, k=k'nottn
For simplicity, if we draw a graph as 100/no2, the first
The result will be as shown in the figure.

As is clear from the figure, in the range of -0.7<x<0.7, the values of x and y have a linear proportional relationship, and it can be seen that they can correspond one to one. That is, by finding the difference y (Ts-Tt) between the rotation periods of both reels, it is possible to immediately obtain Δt (the tape running time from the time when the tape winding diameters of both reels are equal). Therefore, the tape position detection device of the present invention includes means for generating first and second rotation period signals corresponding to each rotation period of both reels, and means for generating first and second rotation period signals corresponding to each rotation period of both reels. It is characterized by comprising means for generating a difference signal corresponding to the difference in the rotation period of the reels, and a storage means for temporarily storing this difference signal at a predetermined timing, and the storage contents of the storage means are used as tape position information. It is something to do.

In a preferred embodiment, the first and second rotation period signals are pulse signals having pulses corresponding to the rotation periods of both reels, and the means for generating the difference signal is a reversible signal in which predetermined information is written in advance. Using a shift register,
The shift operation of the shift register is stopped during a period when both the first and second rotation period signals are generated, and the contents of the shift register are shifted in one direction during a period when only the first rotation period signal is generated; Furthermore, it is characterized in that control is performed to shift in the other direction during a period in which only the second rotation period signal is generated.

Here, the predetermined information to be preset for the shift register is set to 2.
As value information, the middle stage (middle bit stage) of the relevant register
For example, “1” information is stored in “1” information, and “0” information is stored in all other bit stages.
"Preset information is loaded, and the preset information in this register is calculated as the difference between the first and second pulses (
In other words, by shifting to the right or left according to the difference in rotation period of both IJ wheels, the position of the bit stage in the shift register of "1" information accurately indicates the current tape position.

Therefore, based on the bit stage where "1" information exists, the number of bits on the left side indicates the amount of tape travel, and the number of bits on the right side indicates the amount of tape, and these are displayed on a predetermined display device. This allows the amount of tape travel and remaining amount to be displayed at the same time.

Hereinafter, the present invention will be explained using the drawings.

FIG. 2a is a schematic block diagram showing an embodiment of the invention. In the figure, photocouplers la and lb are provided to detect the rotation periods of a take-up reel and a supply reel (not shown), respectively. A rotary plate that rotates with the rotation of the reel stand is provided between the light emitting and light receiving elements of each photocoupler la, lb, and predetermined slits are formed at equal intervals in each of the rotary plates. Pulse signals are generated at the la and lb outputs in accordance with the rotational speed of the reel stand. These pulse signals are shaped and multiplied by each waveform shaping circuit 2a, 2b and input to the next stage 1/n frequency divider 3a, 3b. The outputs A and B of each frequency divider 3a and 3b become one input of AND gates 4a and 4b, respectively, and the AND gate 4a
, 4b are respectively applied to shift control inputs S and S2 of a reversible shift register 5, and
Furthermore, it is applied to each clock input ck of JK type flip-flops (FF) 6a and 6b.

A high level (10B voltage) is always applied to both the J and K inputs of the JK type FFs 6a and 6b, and each output Q serves as the other input of the AND gates 4a and 4b, respectively.

The outputs C and D of these AND gates 4a and 4b are further applied to an OR gate 7 for detecting during pulses,
This OR gate output E becomes the trigger input of the monostable multi 8, and the output of the monostable multi 8 also becomes the trigger input of the monostable multi 9 in the next stage. The output G of this monostable multi-9
serves as each clear input CL of the 1/n frequency dividers 3a, 3b and FFs 6a, 6b. Furthermore, a latch circuit 10 for storing parallel digital signals of the shift register is provided,
The write command timing of this latch circuit 10 is the output F of the monostable multi-channel 8.

Then, the output of the latch circuit 10 is used to select a desired display 11.
The configuration is such that the display is driven. Now, as shown in FIG. 2b, the operation mode of the reversible shift register 5 is such that left/right shift, shift operation stop, and preset command are performed depending on the combination of the respective levels of the control inputs S and S2. "L" means low level,
"H" indicates a high level control signal.

The shift operation speed of the shift register 5 is determined by a shift pulse from a shift pulse generator 12. Third
The figure shows operating waveforms of each part in one operation mode of the circuit shown in FIG. 2a, and parts equivalent to those in FIG. 2a are indicated by the same reference numerals.

In FIG. 3, the rotation period Tt of the take-up reel is shorter than the cycle opening s of the supply reel, and the output signal of the photocoupler la is generated earlier than an arbitrary time (i.e., in the example of the take-up reel). (when the pulse occurs quickly), and for each rotation of each reel, n
It is assumed that pulses are generated from the output of each photocoupler la, lb. Therefore, the output A of the 1/n frequency divider 3a
becomes a high level at the pulse generation timing t on the take-up reel side that continues for a long time, maintains a high level from t to a half period of one cycle Tt, and becomes a low level during the latter half period. Similarly, the output B of the frequency divider 3b becomes a high level at a time ratio of 2 after time t, maintains a high level for a period of half of one cycle Ts from L to t4, and then becomes a low level. During periods t to t, both FFs 6a and 6b are in the reset state, each output Q is both at high level, and other inputs A and B of the AND gate are both at low level, so each gate output C and D is at a low level. is at a low level.

This low level output is applied to the control inputs S and S2 of the shift register 5, respectively, and at this time, the shift register 5 can be preset loaded with a parallel digital signal IN. The signal at this time is assumed to be information such that only the middle bit of the register is set to "1" and the others are set to "0". Since the two inputs of the AND gate 4a are both at a high level between times t and t3, the output C is also at a high level, and the output D of the AND gate 4b is also at a high level during a time period from 2 to t4. It has become.

At time scale 3, the output C of the AND gate 4a transitions to a low level, and at the same time the state of the FF 6a is reversed, its output Q changes to a low level, and this state is maintained until the next clear input CL goes to a high level. Ru. Therefore, frequency divider 3a
Even if the output A of the AND gate 4a becomes high level from then on,
The output C of does not become high level. Therefore, during the period L to t4, that is, during the period Ts/2, which is approximately half the rotation period Ts of the slower reel rotation, the AND gates 4a and 4 are activated, respectively.
One pulse each having pulses (Tt/2, Ts/2) corresponding to the rotation period of both reels is generated at the outputs C and D of b. Since the shift operation of the shift register 5 is controlled by these output pulses C and D,
As shown by the mark in FIG. 3, a shift is made to the right in periods t2 to t2, a shift is stopped in periods t3 to t3, and a left shift is made in periods 3 to 4.

It is clear that this shows the difference in force between the left shift and right shift periods s-Tt.
The state in which information is loaded is shifted to the left in this column with respect to the period difference Ts-Tt, and therefore is shifted closer to the tape start position than to the middle position of the tape. This shifted information is stored in the latch circuit 10.

For this purpose, an OR gate 7 for detecting during a pulse is used, and the next stage monostable multi is triggered at the end (rising edge) of the long pulse D during the pulse, and the latch circuit 10 is activated at the timing of the rising edge (t5) of the output F. Make a write command. The monostable multi 9 is triggered by the rise of this write command signal F,
At the timing of the rising edge (t6) of the output G, frequency dividers 3a, 3b and FF6 are used to detect the tape position again.
This clears a and 6b. Here, if the tape thickness or tape length is different, proper display can be achieved by changing the oscillation frequency of the shift pulse that determines the shift operation speed of the shift register.

In addition, when the rotation period Ts of the supply reel is shorter than the rotation period Tt of the take-up reel in the same machine, the shift operation of the shift register 5 is controlled, and the right shift operation period becomes longer and the position is closer to the end of the tape than the middle position of the tape. This will indicate that the tape has come towards you.

FIG. 4 shows an example of a display for displaying the output of the latch circuit 10, in which the number of segment elements (light emitting diodes, etc.) 11 corresponds to the number of bits of the shift register 5.
It can be seen that by arranging 0's and lighting each element according to the contents of the shift register 5, the tape position can be displayed, and the amount of tape travel and the remaining amount of tape can be visually checked at the same time.

In addition, in the above embodiment, the pulse generating means having a pulse corresponding to the rotation period of each reel, the means for detecting the end of the longer pulse among the pulses, the display device, etc. are limited to these configurations. Various modifications are possible.

FIG. 5 is a diagram showing another embodiment of the present invention, and is a schematic block diagram in which the circuit shown in FIG. 2 and its operation are performed using a microprocessor, for example, the microcomputer 100.

Equivalent parts in both figures are indicated by the same symbols.
Pulses generated by the rotation of both reels are both input to the CPU 102 via the 1/0 port 101 and processed. C
In the PUI 02, signals corresponding to the rotation periods of both reels are obtained based on these pulse signals by a predetermined program, and in response to these signals, a left/right shift command signal for the shift register 5 is sent from the 1/0 boat 103. ，
A stop command signal, a preset command signal, etc. are generated.
The information (state) written in advance is shifted left and right in response to these command signals, and information indicating the difference ΔT between the rotation periods of both reels is held in the shift register. This held content is stored in the CPU again at a predetermined timing, and is sent to the display device 11 via the 1/0 boat 104.
It is obvious that the tape position can be displayed by displaying the following.

It is also possible to configure this shift register 5 and shift pulse generator 12 so that they fit inside the CPU.

As described above, according to the tape position detection device of the present invention, it is possible to accurately detect the tape position with a simple configuration, the amount of tape traveling and the remaining amount can be detected at the same time, and furthermore, the tape position detection device of the present invention can detect the tape position accurately with a simple configuration, can simultaneously detect the amount of tape traveling and the remaining amount, and can also perform preset loading to the shift register. This has the advantage that the tape position can be displayed accurately no matter when.

[Brief explanation of the drawing]

FIG. 1 is a graph explaining the principle of the present invention, FIG. 2 a is a diagram showing an embodiment of the present invention, FIG. 2 b is a diagram explaining the operation mode of the shift register, and FIG. FIG. 4 is a diagram showing an example of a display device, and FIG. 5 is a block diagram showing another embodiment of the present invention. Explanation of the symbols of the main parts, 1...Photocoupler,
3... Frequency divider, 4... AND gate, 5.
...Shift register, 10...Latch circuit,
12...Shift pulse generator, 100...
...Microcomputer. Figure 4 Ticket/Figure Figure 3 Figure N Baseball number 5 Figure

Claims (1)

[Scope of Claims] 1. Means for generating first and second rotation period signals corresponding to the respective rotation periods of the take-up reel and the supply reel, and means for generating the first and second rotation period signals using the first and second rotation period signals, respectively. means for generating a difference signal corresponding to the difference in rotation period between the take-up reel and the supply reel; a storage means for storing the difference signal at a predetermined timing; and a display for displaying the stored contents of the storage means as tape position information. the first and second rotation period signals are signals having pulse widths corresponding to respective rotation periods of the take-up reel and the supply reel, and generate the difference signal. The means for doing so has a reversible shift register in which predetermined information is written in advance, and stops the shifting operation of the shift register during a period in which both the first and second rotation period signals are generated, and During a period when only the rotation period signal is generated, the contents of the shift register are shifted in one direction, and during a period when only the second rotation period signal is generated, the contents of the shift register are shifted in the other direction. A tape position detection device comprising: 2. The predetermined information is composed of binary information, and one of the binary information signals is written in an intermediate stage of the shift register, and the other one of the binary information signals is written in the remaining stages. A tape position detection device according to claim 1.