JPH0441435B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for automatically discriminating cassette tapes, and in particular, to automatically distinguishing between C-46, C-60, and C-90, which indicate the recordable time of a cassette tape. For example, the distinction can be displayed with the cassette tape still attached to a cassette deck or cassette tape recorder, or the recorded time and remaining time (remaining recording time) can be displayed. The present invention relates to an automatic cassette tape discrimination method that can be used for

[Prior art]

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

These cassette tapes have different tape winding diameters and heat.C-46 and C-60 have the same tape windings, 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), and C-60 and C-90 have approximately the same winding diameter but different tape heat (C-90 is thinner).

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

This is because in order to calculate the recorded time and remaining time, information on the tape winding diameter and tape heat on the take-up or supply side at that point is required, but the former is measured on the tape recorder side. Although possible, the latter was difficult to measure and was therefore 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 winding diameter must be measured after the tape has been completely wound onto one of the hubs. Nakatsuta.

[Problem that the invention seeks to solve]

This conventional method of determining cassette tapes based on the winding diameter has the problem that it takes time to wind up the tape in the cassette half onto one of the hubs. installed or already installed,
There is a problem in that it is not possible to start recording or playback from that tape position.

Furthermore, it was not possible to determine the difference in the heat of the tape in a short time and to completely distinguish between C-46, C-60, and C-90.

This invention aims to solve these problems.

[Means for solving problems]

Accordingly, the first invention provides that even if the tape is in the middle of winding or unwinding, the cassette tape can be changed to C-46 with a small winding diameter or C-46 with a large winding diameter in a short time while recording or playing back. -60 or C-
This is a method that can automatically determine whether the tape is 90. The 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 and the rotation period on the take-up side are detected. , calculate the sum of the shorter period and twice the longer period, and determine whether the cassette tape is C- 46, C-60 or C-90.

In addition to the above-mentioned discrimination, the second invention also performs discrimination based on the temperature of the tape, thereby making it possible to completely discriminate between the three types of cassette tapes. 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 from the preset thickness constant. Depending on whether or not the cassette tape is C-46 or C-60 or C-90
The present invention is characterized in that it is determined whether the cassette tape is C-46, C-60, or C-90 based on the results of these two determinations.

[Effect]

First, the first invention will be explained.

The tape of the cassette tape is run at a constant speed (tape running state during recording or playback), and the reel shaft, which rotates integrally with the hub that winds the tape on the supply side and the take-up side, is rotated at least one revolution (for example, two rotate)
If the rotation period on the supply side is Ta and the rotation period on the take-up side is Tb when 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 the larger of these periods is defined as TL,
When the smaller one is TS, S = TL + TS x 2 is used as the winding diameter variable, and the results obtained from the start to the end of winding of various tapes are shown in Figure 3.

As can be seen from Figure 3, the winding diameter variable S is always smaller for C-46, C-60, and C-90, no matter where the tape is located, and the value is the same. There is no reversal of the size relationship.

Therefore, the winding diameter constant Sk is the intermediate value between the value at the start of winding where the S value is the largest for C-46 and the value at the center position of the tape where the S value is the smallest for C-60.
The winding diameter variable S obtained by the above calculation is compared with the winding diameter constant Sk, and if S>Sk, it is C-60 or C-90, and if S<Sk, it is C-46.
It can be determined that

Note that if the number of revolutions of the reel shaft during period measurement is increased, the difference in the number of turns variable S will increase, making it easier to distinguish, but since the measurement time will become longer, approximately two revolutions is appropriate.

Next, in the second invention, in addition to the above discrimination, discrimination is also made based on the difference in the heat of the tape, so the time required for the reel shaft to rotate by a preset number of rotations (for example, 6 rotations) is determined. Continue with 2
Measure twice.

By the way, if the heat of the tape is b, the average winding radius of the tape at the first measurement is _r1 , the average winding radius of the tape at the second measurement is _r2 , and the number of rotations at each measurement is N. , d=|r ₂ −r ₁ |/N.

Therefore, the tape speed is υ, the time required for the first time is T ₁ and the time required for the second time is T ₂ according to the above measurement results.
Then, υT ₁ = 2πr ₁・N υT ₂ = 2πr ₂・N, so d=υ/2π|T ₂ −T ₁ |/N ² , where υ/2π and N ² are constants. Therefore, T ₁ and T ₂
The difference between |T ₂ −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
The thickness constant Dk is determined in advance by actual measurement or calculation for C-60 tape and C-90 tape, and the thickness constant Dk is set to the intermediate value between these values. The heat of the tape can be determined by comparing the value of D obtained by the above calculation with the thickness constant Dk.

In other words, if D>Dk, the tape is thicker than 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 aforementioned determination based on the winding diameter variable, it is possible to determine whether the cassette tape is C-46, C-60, or C-90.

That is, if S<Sk then C-46, if D<Dk then C-90, if S>Sk and D>Dk then C-60
It is.

Note that the heat of the tape differs slightly depending on the type of tape such as normal tape, chrome tape, metal tape, etc., and the above-mentioned winding diameter variable S and the value D proportional to the tape thickness also differ, so compare them. It is desirable to change the values of the winding diameter constant Sk and the thickness constant Dk in accordance with 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 discriminating device showing an embodiment of the present invention. , C-90.

1 and 2 are slit discs that are fixed to the reel shaft (rotating shaft) on the tape recorder side, which is fitted into the hub on which the tape is wound inside the cassette case and rotates integrally. The output signals of photo sensors 3 and 4, in which a light emitting diode and a phototransistor are disposed facing each other, generate pulse changes due to the rotation of the slit disks 1 and 2, respectively.

In this example, 1 and 3 are the slit disk and photo sensor on the supply side, and 2 and 4 are the slit disk and photo sensor on the take-up side.

Note that a detection circuit, a waveform shaping circuit, etc. are required to detect the pulse signals from the photo sensors 3 and 4, but since these are well known, they are not shown and included in the photo sensors 3 and 4.

Reference numeral 5 denotes a pulse change counter on the supply side, and 6 a pulse change counter on the winding side, which count down a preset value based on changes in the rise and fall of the pulse signal from the photo sensor 3 or 4, respectively.

7 is a timer on the supply side, 8 is a timer on the winding 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, it is input to each. The measurement ends with the END signal.

9 is a control circuit that controls the operation of each of these circuits, and at the start of measurement, it resets the timer counters 7 and 8, and tells the pulse change counters 5 and 6 that the slit disks 1 and 2 are rotating at the number of revolutions required for measurement (this In the example, a numerical value corresponding to the number of pulse changes emitted to the photo sensors 3 and 4 is preset when the tape rotates by 2 rotations when determining the tape winding diameter and 6 rotations when determining the tape thickness.

Reference numeral 10 denotes a comparison switch which compares the data of timers 7 and 8 at the end of measurement and always outputs the larger data to output terminal A and the smaller data to output terminal B.

11 is 2 which doubles the larger data (period)
Multiplier, 12 is the smaller data (period) and 2
an adder 1 for adding the calculation result of the multiplier 11;
3 is a comparator that compares the added value S with the winding diameter constant Sk according to the type of tape (normal, chrome, metal) from the constant generator 14 for each tape. 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 9, which turns on the a side during the first measurement of tape thickness discrimination, and switches to the b side during the second measurement.

A data memory 16 stores the smaller data output from the output terminal B of the comparison/switcher 10 during the first measurement. 17 is a subtracter, which subtracts the smaller data from the first measurement stored in the data memory 16 from the smaller data from the second measurement, and calculates the difference (absolute value) D from the comparator. Output to 19.

The comparator 19 compares this difference D with the thickness constant Dk according to the tape type (normal, chrome, metal) from the tape-specific constant generator 18, and determines C-90, C-46, or C depending on the difference. -60.

These 15 to 19 constitute a circuit for determining the thickness of the tape.

20 is an AND circuit for determining C-60,
C-60 is determined by ANDing the C-60 or C-90 determination signal from the comparator 13 and the C-46 or C-60 determination signal from the comparator 19.
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, the functions of the control circuit 9 and the tape discrimination circuit based on the winding diameter and thickness from the comparison switch 10 to the comparator 19 in the embodiment shown in FIG. 1 are performed using a microcomputer. The operation will be explained with reference to FIGS. 4 and 5.

Figure 4 shows C-46 and C- depending on the tape winding diameter.
60 and C-90 is a flowchart showing the determination operation.

First, in step 1, an initial set is performed. That is, the timers 7 and 8 shown in FIG. 1 are reset, and the pulse change counters 5 and 6 are preset with numerical values corresponding to the number of pulse changes that occur during two rotations of the slit disks 1 and 2, respectively.

Then, in step 2, it is determined whether there is a change in the pulses from the photo sensors 3, 4, and if not, in step 3, timers 7, 8 measure time.

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

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

When the measurement is completed, in step 6, the measurement time Ta of the supply side timer 7 (corresponds to the period of two rotations of the supply side hub) and the measurement time Tb of the winding side timer 8 (corresponds to the period of two rotations of the winding side hub) ), compare the size of
If Ta>Tb, proceed to step 7 and S=Tb+
The calculation Ta×2 is performed, and if Ta<Tb, the calculation S=Ta+Tb×2 is performed in step 8, and the process proceeds to step 9.

That is, in steps 7 and 8, the calculation of [shorter cycle + twice the longer cycle] is performed.

In step 9, this calculated value S is determined as the winding diameter constant according to the type of tape (normal, chrome, metal).
Determine whether or not it is larger than Sk. If it is larger, output a discrimination signal of C-60 or C-90 in step 10, and if not, output a discrimination signal of C-46 in step 11 and end the discrimination operation. .

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

In this routine as well, first, an initial set is performed in step 1. That is, the timers 7 and 8 in FIG. 1 are reset, and the pulse change counters 5 and 6 are reset.
A numerical value corresponding to the number of pulse changes occurring while each of the slit disks 1 and 2 rotates six times is preset.

Then, in step 2, it is determined whether there is a pulse change from the photo sensors 3, 4, and if not, in step 3, time measurement processing is performed using timers 7, 8.

If there is a pulse change, proceed to step 4 and count down the pulse change counter 5 or 6, and in step 5 one measurement is completed (when the count values of both pulse change counters 5 and 6 have both reached "0") It is determined whether or not the time is the end of the measurement), and steps 3, 2, 4, and 5 are repeated until the end of the measurement.

In this case as well, steps 2, 3, and 4 include photo sensors on the supply side and take-up side, pulse change counters,
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 and calculates the shorter value of the measurement times of timers 7 and 8. The time required for the first six rotations is stored in the memory as _T1 .

Then, use switch 8 to perform an initial set similar to step 1, repeat steps 2 to 5, and perform a second measurement.

When the second measurement is completed, the process proceeds from step 6 to step 9, where the shorter value of the measured times of timer counters 7 and 8 during this second measurement is set to 2.
As the time required for the 6th rotation T ₂ , step 7
Difference from the first time required T ₁ memorized in D=｜T ₂
−T ₁ | is calculated.

Then, in step 10, it is determined whether or not this calculation result is larger than the thickness constant Dk according to the type of tape (normal, chrome, metal). If it is not larger, a discrimination signal of C-90 is output in step 12 and the discrimination operation is completed.

〔Effect of the invention〕

As explained above, the automatic cassette tape discrimination method according to the first invention detects differences in the tape winding diameter in a short time even if the tape is in the middle of winding and recording or playback is started from there. The length can be determined by That is, it can be determined whether the cassette tape is C-46, C-60 or C-90.

The automatic cassette tape discrimination method according to the second invention also allows
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, and the type of cassette tape.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an automatic cassette tape discriminating device showing an embodiment of the present invention, and FIGS. 2 and 3 show a supply side and a winding side for explaining the discriminating method according to the first invention. FIG. 4 is a flowchart showing the discrimination operation based on the winding diameter when the present invention is implemented using a microcomputer. FIG. 5 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...2x arithmetic unit, 12...Adder, 13
... Comparator, 14, 18 ... Constant generator for each tape, 15 ... Changeover switch, 16 ... Data memory, 17 ... Subtractor, 19 ... Comparator.

Claims (1)

[Claims] 1. Running the tape of a cassette tape at a constant speed and rotating 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,
The sum of the shorter period and twice the longer period is calculated, and depending on whether the value is larger than the preset winding diameter constant, the cassette tape is
1. A method for automatically discriminating cassette tapes, characterized by discriminating whether the tape is -46, C-60 or C-90. 2. Claim 1, wherein the winding diameter constant is changed depending on the type of tape such as normal tape, chrome tape, metal tape, etc.
Automatic identification method for cassette tapes as described in section. 3 Run the tape of the cassette tape at a constant speed and 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,
The sum of the shorter period and twice the longer period is calculated, and depending on whether the value is larger than the preset winding diameter constant, the cassette tape is
-46, C-60 or C-90, and the time required for the reel shaft on the supply side or take-up side to rotate by the preset number of revolutions is determined continuously.
It is determined whether the cassette tape is C-46, C-60, or C-90 depending on whether the difference between the two measurements is larger than a preset thickness constant. 1. An automatic method for discriminating a cassette tape, which comprises discriminating whether the cassette tape is C-46, C-60 or C-90 based on the discrimination result. 4. The automatic cassette tape discrimination method according to claim 3, characterized in that the winding diameter constant and the thickness constant are changed depending on the type of tape such as normal tape, chrome tape, metal tape, etc.