JPS6129477A - Automatic discriminating method of cassette tape - Google Patents

Abstract

PURPOSE:To discriminate types of tape C46, C60, or C90 by measuring a rotating period of a reel axle at the supply side and a rotating period of a reel axle at the rewind side by calculating the doubled shorter period to the doubled longer period, and comparing the sum with a preset winding diameter constant to check which is greater. CONSTITUTION:The signals detected by slit disks 1 and 2 and by photosensors 3 are supplied to pulse variation counters 5 and 6, and the rotating periods of reel axes are measured by the timer 7 at the supply reel side and by the timer 8 at the rewind reel side. The doubled shorter period and doubled longer period obtained from a comparison changeover device 10 are calculated together by an adder 12, and the calculated result is compared by a comparator 13 with the value preset by a generator 14 that generates a constant for each tape to discriminate the diameter of wound tape. Further, a changeover switch 15 is switched at the first tape thickness discrimination and at the time of second tape thickness discrimination and the difference of measured values is compared by a comparator 19 with the value preset by the tape constant generator 18. As a result of the comparison by the comparators 13 and 19, the tape can be discriminated that is of C46, C60, or C90.

Description

[Detailed Description of the Invention] [Field of Industrial Application] ' The present invention relates to a method for automatically identifying cassette tapes, and in particular C-46, C-, which indicates the recordable time of cassette tapes.
60 and C-90 and display the distinction with the cassette tape still attached to a cassette deck or cassette tape recorder, or display the recorded time and remaining time (recording time). possible remaining time)
This invention relates to an automatic cassette tape identification method that can be used to display cassette tapes.

[Prior art]

Commonly used cassette tapes are C-46 (46 minutes round trip), C-60 (60 minutes round trip), and C-90 (24 minutes round trip), depending on the length of the tape, that is, the recording time.
There are three types (90 minutes round trip).

These cassette tapes have different tape winding diameters and thicknesses.C-46 and C-60 have the same tape thickness, but the winding diameter (the winding diameter when the tape is completely wound around one hub) )
are different (C-60 has a larger winding diameter than C-46)
, C-60 and C-90 have approximately the same winding diameter but different tape thicknesses (C-90 is thinner).

Traditionally, the user has been able to determine the type of cassette tape by looking at the label attached to the cassette half.When displaying the recorded time and remaining amount on the tape recorder, I had to enter the information for this tape type.

This is because in order to calculate the recorded time and remaining time, information on the tape winding diameter and tape thickness on the winding side or supply side at that point is required, but the former is measured on the tape recorder side. Although it was possible to do so, the latter was difficult to measure, so it was determined based on input information about the type of tape.

Attempts have also been made to determine the type of tape based on its maximum winding diameter, but in that case the tape had to be completely wound onto one of the hubs before the winding diameter could be measured. .

[Problem that the invention seeks to solve]

This conventional method of determining cassette tapes based on their winding diameter not only takes time to wind the tape inside the cassette half onto one of the hubs, but also causes problems when the tape is wound halfway. There is a problem in that it is impossible to start recording or playback from the tape position where the tape is installed or has already been installed.

In addition, it can quickly distinguish between tape thicknesses and
It was not possible to completely distinguish between -46, C-60, and C-90.

This invention aims to solve these problems.

[Means for solving problems]

Therefore, the first invention is to detect whether the cassette tape is C-46 with a small diameter or a C-46 with a large diameter even if the tape is in the middle of winding or rewinding. This is a method that can automatically determine whether the tape is C-60 or C-90.The cassette tape is run at a constant speed and the reel shafts on the supply side and take-up side are rotated one or more revolutions, and the rotation period on the supply side is determined. and the rotation period on the winding side,
The sum of the shorter cycle and twice the longer synchronization is calculated, and depending on whether the value is larger than the preset winding diameter constant, the cassette tape is C-46 or C-46.
-60 or C-90.

In addition, the second clever invention makes it possible to completely distinguish between the three types of cassette tapes by making a distinction based on the difference in tape thickness in addition to the above discrimination. In addition to the determination method, the time required for the reel shaft on the supply side or take-up side to rotate by a preset number of revolutions is measured twice in succession, and the difference between the two measurements is determined by the thickness constant determined in advance. Depending on whether the cassette tape is large or not, it may be C-46 or C-60 or C-90.
The present invention is characterized in that it determines whether the cassette tape is C-46, C-60, or C-90 based on the results of these two determinations.

[For production]

First, the first invention will be explained.

One reel shaft rotates integrally with the hub on which the cassette tape is wound at a constant speed (tape running state during recording or playback) and the tape is wound on the supply side and take-up side.
If the rotation period on the supply side is Ta and the rotation period on the take-up side is Tb when the tape is rotated more than 2 times (for example, 2 rotations), then the tape changes from the state where it is completely wound around the hub on the supply side to the hub on the take-up side. As it is wound up, it changes as shown in FIG. The rotation period in this case refers to the time required for every predetermined number of rotations, for example, two rotations.

These rotation periods Ta and Tb are values proportional to the winding diameters of the tape on the supply side and take-up side at the tape position at the time of measurement, and when the larger one of these periods is TL and the smaller one is TS, S :TL+TSX2 is used as the winding diameter variable, and the results obtained from the beginning of winding to the end of winding of various tapes are as shown in FIG.

As can be seen from Fig. 3, this winding diameter variable S is C-46
Among C-60 and C-90, C-46 is always smaller no matter where the tape is located, and the values will never be the same or the magnitude relationship will never be reversed.

Therefore, the winding diameter constant Sk is set to an intermediate value between the value at the start of winding where the S value is the largest in C-46 and the value at the tape center position where the S value is the smallest in C-60. However, by comparing the winding diameter variable S obtained by the above calculation with the winding diameter constant Sk, it is possible to determine that if SO8k, it is C-60 or C-90, and if S<Sk, it is C-46. can.

It should be noted that if the number of revolutions of the reel shaft is increased during this cycle measurement, the difference in the number of turns per turn variable S will increase, making the discrimination easier, but since the measurement time will become longer, it is appropriate to make the number of revolutions about two revolutions.

Next, in the second invention, in addition to the above discrimination, discrimination is also made based on the difference in tape thickness, so the time required for the reel shaft to rotate a preset number of rotations (for example, 6 rotations) is determined. Measure twice in succession.

By the way, if the thickness of the tape is d, the average winding radius of the tape at the first measurement is rl, the average winding radius of the tape at the second measurement is r2 + the number of rotations at each measurement is N, then
d=1r2rtl/N.

Therefore, if the tape speed is υ, the time required for the first time is T1, and the time required for the second time is T2 according to the above measurement results,
Since t+T1 =2tcr1 °NυT2=2πr2・N, d=7. l'r2 T11/N', where υ/2π and N2 are constants, so T1
The difference between T2 and T2, 1T2-T□1, is a value proportional to the thickness of the tape.

Therefore, let this be D, and the value of this D is C-46 and C
-60 tape and C-90 tape in advance by actual measurement or calculation, and set the thickness constant Dk to the intermediate value between these values. By comparing the value of Dk with its thickness constant Dk, the thickness of the tape can be determined.

That is, if DADk, it can be determined that the tape is thick C-46 or C-60, and if D<Dk, it can be determined that the tape is thin C-90.

In this case, it is possible to complete the measurement and make the determination more quickly by measuring the rotation time of the reel shaft with the shorter rotation period among the reel shafts on the supply side and the take-up side.

By combining this determination with the determination based on the winding diameter variable described above, it is possible to determine whether the cassette tape is C-46,
It is possible to determine whether it is C-60 or C-90.

That is, if it is 5O5k, it is C-60, if D<D, it is C-90, and if S>Sk and DADk, it is C-60.

In addition, the thickness of the tape may vary depending on the type of tape such as normal tape, chrome tape, metal tape, etc.
Since the values proportional to the above-mentioned winding diameter variable S and tape thickness are different, the winding diameter constant Sk and thickness constant Dk are compared.
It is desirable to change the value of , depending on the selection of these tape types (selected by a select lever or the like).

〔Example〕

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram of a cassette tape type discrimination device showing an embodiment of the present invention, which discriminates the tape winding diameter and tape thickness.
, C-90.

1 and 2 are slit disks fixed to the reel shaft (rotating shaft) on the tape recorder side, which are fitted into the hub on which the tape is wound inside the cassette case and rotated integrally.
The output signals of the photosensors 3 and 4, in which a light emitting diode and a phototransistor are arranged facing each other with their outer peripheries in between, are
Pulse changes are generated by the rotation of the slit disks 1 and 2, respectively.

In this example, 1 and 3 are the slit disks and photosensors on the supply side, and 2 and 4 are the slit disks and photosensors on the take-up side.

Note that a detection circuit, a waveform shaping circuit, etc. are required to detect the pulse signal from this photosensor 3.4, but since these are well known, they are omitted from illustration and included in the photosensor 6.4. .

5 is a pulse change counter on the supply side, and 6 is a pulse change counter on the winding side, which counts down a preset value based on changes in the rise and fall of the pulse signal from the photosensor 3 or 4, respectively.

7 is the timer on the supply side, and 8 is the timer on the take-up side.

Each clock pulse generator and a timer counter that counts the clock pulses are used to measure the elapsed time after being reset, and when the count value reaches "0" from the pulse change counter 5 or 6, the input is made respectively. EN to do
The measurement is ended by the D signal.

is a control circuit that controls the operation of each of these circuits,
At the start of measurement, the timer counter 7.8 is reset, and the pulse change counters 5 and 6 indicate the number of rotations of the slit disks 1 and 2 necessary for measurement (in this example, 2 rotations when determining the tape winding diameter, and 2 rotations when determining the tape thickness). A numerical value corresponding to the number of pulse changes emitted to the photosensor 3.4 when the photo sensor 3.4 rotates by 6 rotations is preset.

10 is a comparison switch that compares the data of timers 7 and 8 at the end of measurement and always sends the larger data to output terminal A.
Output the smaller data to output terminal B.

11 is a doubling operator that doubles the larger data (period); 12 is an adder that adds the smaller data (period) and the calculation result of the doubling operator 11;

13 is a comparator that compares the added value S with the winding diameter constant Sac according to the type of tape (normal, chrome, metal) from the constant generator 14 for each tape.
46 and C-60 or C-90.

These 11 to 14 constitute a circuit for determining the winding diameter of the tape.

On the other hand, 15 is a changeover switch controlled by the control circuit S, and when measuring the tape thickness for the first time, a
The side is turned on, and during the second □ measurement, it switches to the b' side.

A data memory 16 stores the smaller data output from the output terminal B of the comparison/switching device 10 during the first measurement. 17 is a subtracter which calculates 1 stored in the data memory 16 from the same smaller data from the second measurement.
The smaller data from the second measurement is subtracted and the difference (absolute value) D is output to the comparator 19.

The comparator 1 compares this difference with the thickness constant Dk corresponding to the tape type (normal, chrome, metalla) from the tape-specific constant generator 18, and calculates the difference between C-90 and C-46. or C-60.

The 15th to 1st days of 2' constitute a circuit for determining the thickness of the tape.

20 is an AND circuit for determining C-60, which outputs the C-60 or C-90 determination signal from comparator 13 and
C-60 is determined by performing an AND with the C-46 or C-60 determination signal depending on the date. In this way, C-46, C-60° and C-90 can be completely distinguished.

Note that the tape-specific constant generators 14 and 18 generate constants according to the type of tape selected by the select lever (or knob, etc.) of normal tape, chrome tape, and metal tape.

Next, a microcomputer is used to perform the functions of the control circuit S and the tape discrimination circuit based on the winding diameter and thickness from the comparator 10 to the comparator 1 in the embodiment shown in FIG. The operation will be explained with reference to FIGS. 4 and 5.

Figure 4 shows C-46 and C-60 depending on the tape winding diameter.
It is a flowchart which shows the discrimination|determination operation of C-9,0.

First, in step 1, initial setting is performed.

That is, the timer 7.8 in FIG. 1 is reset, and the pulse change counters 5, 6 are preset with numerical values corresponding to the number of pulse changes occurring during two rotations of the slit disks 1, 2, respectively.

Then, in step 2, it is determined whether or not there is a pulse change from the photosensor 6.4, and if not, in step 3, time is measured by the timer 7.8.

If there is a pulse change, proceed to step 4, count down the pulse change counter 5 or 6, and then proceed to step 5.
Determine whether or not the measurement is completed (measurement is completed when the count values of both pulse change counters 5 and 6 both become "0"), and repeat steps 3, 2, and 4.5 until the measurement is completed. It's repeating.

Note that steps 2, 3, and 4 are performed separately for the photo sensors, pulse change counters, and timers on the supply side and winding side, but are shown together for convenience.

When the measurement is completed, in step 6, the measurement time T'a of the supply side timer 7 (corresponding to the period of two rotations of the supply side hub) and the measurement time Tb of the winding side timer 8 (corresponding to the period of two rotations of the winding side hub) are calculated. If Ta>”rb, proceed to step 7 and calculate 5=Tb+TaX2; if Ta<T'b, proceed to step 8 and calculate S=Ta + T-b X 2 After performing the calculation, proceed to step 9.

That is, in step 7.8, the calculation of [shorter cycle + twice the longer cycle] is performed.

In step 9, it is determined whether this calculated value S is larger than the winding diameter constant Sk corresponding to the type of tape (normal, chrome, metal), and if it is larger, in step 10 the C knee 60
．． A determination signal of C-90 is output, and if it is not larger, a determination signal of C-46 is output in step 11 and the determination operation is completed.

Figure 5 shows C-46, C-60 and C depending on the thickness of the tape.
It is a flowchart which shows the determination operation of -90.

In this routine as well, initial setting is first performed in step l. That is, the timer 7.8 in FIG. 1 is reset, and the pulse change counters 5, 6 are preset with numerical values corresponding to the number of pulse changes that occur during six rotations of the slit disks 1, 2, respectively.

Then, in step 2, it is determined whether or not there is a pulse change from the photosensors 5, 4, and if not, in step 3, time measurement processing is performed using the timer 7.8.

If there is a pulse change, proceed to step 4, count down the pulse change counter 5 or 6, and then proceed to step 5.
(The measurement ends when the count values of both pulse change counters 5 and 6 reach 0.)
Steps 3, 2, 4.
5 is repeated.

In this case, steps 2 and 3.4 are photo sensors and pulse change counters on the supply side and winding side.

and timer will be described separately, but are shown together for convenience.

When one measurement is completed, it is determined in step 6 whether it is the first or second measurement, but since it is the first measurement, the process proceeds to step 7, where the shorter value of the time measured by timer 7.8 is determined. The time required for the first six rotations is stored in the memory as T1.

Then, in step 8, the same initial setting as in step 1 is performed, steps 2 to 5 are repeated, and a second measurement is performed.

When the second measurement is completed, proceed from step 6 to step 9, and set the shorter value of the timer count and 8 measurement times for this second measurement as the time required for the second 6 rotations, T2. The difference D=lT2Ttl from the first required time TI stored in step 7 is calculated.

Then, in step IO, this calculation result is determined by the tape type (
It is determined whether the thickness constant Dk is greater than the thickness constant Dk corresponding to normal, chrome, metal), and if it is larger, C- is determined in step 11.
46 and C-60 are output, and if it is not larger, a C'-90 determination signal is output in step 12 and the determination operation is completed.

〔Effect of the invention〕

As explained above, the automatic cassette tape discrimination method according to the first invention involves tape winding.

Even if recording or playback is started from an intermediate position, the length can be determined based on the difference in tape winding diameter in a short time. In other words, the cassette tape is C-
46, C-60, or C-90.

The automatic cassette tape discrimination method according to the second invention can be used regardless of the position of the tape.

The length can be determined based on the difference in tape winding diameter and thickness in a short time. That is, it can be determined whether the cassette tape is C-46, C-60, or C-90.

Therefore, even without inputting such data, the tape recorder can display the recorded time and remaining amount of time, as well as display the distinction between cassette tapes.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an automatic cassette tape discriminating device showing one embodiment of the present invention, and FIGS. 2 and 3 are supply side and take-up sides for explaining the discriminating method according to the first invention. FIG. 4 is a flowchart showing the determination operation based on the winding diameter when the present invention is implemented using a microcomputer; The figure is a flowchart showing the discrimination operation based on the thickness of the tape. 1.2...Slit disk 3,4...Photo sensor 5.6...Pulse change counter 7.8...Timer 9...Control circuit 10...
・Comparison switch 11... Double arithmetic unit 12... Adder 13... Comparator 14.18... Constant generator for each tape 15... Selector switch 16... Data memory 1
7...Subtractor 1 day...Comparator Figure 2 Tape position - 4 Tape position → Figure 4

Claims (1)

[Claims] 1. The tape of a cassette tape is run at a constant speed, the reel shafts on the supply side and take-up side are rotated one or more revolutions, and the rotation period on the supply side and the rotation period on the take-up side are measured. Calculate the sum of the shorter cycle and twice the longer synchronization, and depending on whether the sum is greater than the preset winding diameter constant, the cassette tape is C-46 or C-46. 60 or C-90
1. An automatic cassette tape discrimination method characterized by discriminating cassette tapes. 2 The above winding diameter constant is determined by normal tape, chrome tape,
2. The automatic cassette tape discrimination method according to claim 1, wherein the method is changed according to the selection of the type of tape such as metal tape. 3 Run the cassette tape at a constant speed, rotate the reel shafts on the supply side and take-up side one revolution or more, measure the rotation period on the supply side and the rotation period on the take-up side, and calculate the shorter period and the rotation period on the take-up side. The cassette tape is determined to be C-46, C-60, or C-90 by calculating the sum of twice the longer synchronization value and determining whether the value is larger than the preset winding diameter constant.
At the same time, the time required for the reel shaft on the supply side or take-up side to rotate by a preset number of revolutions is measured twice in succession, and the difference between the two measurements is determined as the preset thickness constant. determining whether the cassette tape is C-46, C-60, or C-90 depending on whether the tape is larger than the
Based on these discrimination results, the cassette tape is C-46.
, C-60, or C-90. 4. The automatic cassette tape discrimination method according to claim 3, characterized in that the winding diameter constant and the thickness constant are changed according to the selection of the type of tape such as normal tape, chrome tape, metal tape, etc.