JPH04143988A - Recording time measuring method for cassette tape - Google Patents

Abstract

PURPOSE:To automatically measure recording time with simple constitution and without performing a complicated arithmetic operation by discriminating a hub diameter by finding the corresponding value of a hub diameter data storage part based on the rotating count value of a reel. CONSTITUTION:When a tape end is detected by a tape and detecting part 35, a rotation count part 31 is reset by a zero-reset part 32. Thence, a magnetic tape 23 is rewound, and also, a rotating pulse from a rotation detecting part 27 in accordance with the rotation of a take-up reel 22 is counted by a counter 31, and a count value N' when the tape 23 arrives at the end is stored, and also, the counter 31 is reset. Program searching for recording is performed in such state, and the pulse of the detecting part 27 is counted by the counter part 31, and the hub diameter is discriminated by comparing the count value when the program searching is completed with the storage content of the hub diameter data storage part 38. Thereby, the recording time in accordance with a storage value N stored in a recording time data storage part 39 is found corresponding to the hub diameter, and the recording time of cassette tapes with different hub diameters can be automatically measured with simple constitution and without performing the complicated arithmetic operation.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a recording time measuring method for automatically calculating the recording time of a cassette tape in a cassette tape recorder.

Conventional Technology Conventionally, there was no system for automatically calculating the recording time of a cassette tape in a cassette tape recorder.
A cassette tape running time calculation method as shown in FIGS. 7 to 7 was used. The method will be explained below.

That is, as shown in Fig. 4, when the radius of the knob is R8 and the thickness of the tape is 61, when it is wound n times on the take-up reel, the magnetic tape runs in the X direction at a constant speed v0. If so, the running time t from the beginning of the winding to the present can be expressed by the formula 411.

t=An2+Bn・・・・・・・・・・・・
... (11Here, A=πd/Vo, B=2πRo/
In actual cassette tapes, the apparent thickness d has a large error due to the precision of the magnetic tape, uneven winding, etc. Since this error differs depending on the cassette tape, it is necessary to correct it for each cassette tape. Therefore, if n is differentiated by t in equation (1), then the rotational speed VR of the take-up reel immediately after resetting the counter that counts the number of turns n of the take-up reel is V
Assuming RR, the thickness d of the tape is extremely thin, approximately 18 μm or less, the radius Ro of the hub is approximately 11 mm, and the number of turns n is 1, so that 2An<<B.

Therefore, from the equation (2), the value BR of the constant B immediately after reset can be determined by the following equation.

Further, the value AR of the constant A after reset can be obtained from equation (2) as follows.

Therefore, when you want to find the running time of the tape, perform a reset process, find BR from equation (3), use the value of the counter that counts the number of turns n after reset to find AR from equation (4), and then calculate AR from equation (4). The travel time can be determined by performing the calculation shown in the formula. Further, even when the tape is reset in the middle of the tape, the running time from the reset position can be determined.

FIG. 5 is a block diagram showing a conventional example of determining the running time of a cassette tape based on the above-mentioned information.

In the figure, 1 is a supply reel, 2 is a take-up reel, 3 is a magnetic tape, 4a and 4b are guides, 5 is a cassette tape, 6 is a reel rotation axis on the take-up side, and 7 is this reel rotation axis 6. This is a rotation detection unit consisting of a rotating body 8 attached to a rotating body 8 and a detection element 9 that magnetically, optically, or mechanically detects a mark on the rotating body 8 and outputs a rotation detection pulse, and the period of this rotation detection pulse is It is directly proportional to the rotation period of the take-up reel 2. 10 is a rotation speed detection unit that detects the rotation speed by inputting this rotation detection pulse;
Reference numeral 11 denotes a rotation count unit that counts the rotation pulses of the winding reel 2 of the cassette tape, 12 a zero reset unit that resets the rotation count unit 11 to zero when setting the cassette tape 5 or during the magnetic tape 3, and 13 ( 2) A running time calculation unit that calculates the running time from the time of reset processing to the present by substituting AR and BR obtained by equations (3) and (4) into the equations; 14 is a unit that reverses one direction of the current tape running; 15 is a tape end detection unit that detects the end of the cassette tape and notifies it to the tape run reversal control unit; 16 is a tape end detection unit that sends the tape to a recordable position on the magnetic tape to avoid the leader tape portion; This is a cue control section.

With the above configuration, the running time of the magnetic tape could be determined by the method shown in the flowchart of FIG.

That is, in step 1, when a cassette tape is set, the count value of the revolution count section 11 is set to zero by the zero reset section 12. In step 2, when the take-up reel 2 rotates and the magnetic tape 3 is supplied, the reel rotation shaft 6 rotates and the rotating body 8 also rotates, and the rotation detector 7 outputs a rotation detection pulse proportional to the rotation period. will be output, so enter this. In step 3, the rotation speed VR of the take-up reel is detected by the rotation speed detection section 10 based on the rotation detection pulse input in step 2. In step 4, it is determined whether or not the rotation of the rotating body 8 is the -th time after the reset. If it is the -time, the process moves to step 5, and if it is the second or more rotation, the process moves to step 7. In step 5, the running time calculation section 1
3 is the rotation speed VRR determined by the rotation speed detection unit 10 based on the first rotation detection pulse of the take-up reel 2.
B'R is determined from equation (3) and stored. In step 6, the rotation count section 11 sets the count value n to 1. In step 7, every time the rotation counting section 11 counts the pulse signal output from the rotation detector 7, - is added to the count value n. In step 8, the rotational speed V detected by the running time calculation section 13 or the rotational speed detection section 10 at that time.

, the count value n of the revolution counting section 11, and the value BR obtained and stored in step 5, the calculation shown in equation (4) is performed to obtain AR. In step 9, the running time calculating section 13 performs the calculation shown in (2) based on the thus obtained values AR, BR, and n, and calculates the running time t of the magnetic tape. In step 10, the tape end detecting section 15 determines whether the magnetic tape has reached the end. If the end has been reached, the process is terminated; if the end has not been reached, the process returns to step 2 and the calculation of the running time t is repeated.

Next, a method of determining the recording time of a cassette tape using the conventional method as described above will be explained. In FIG. 7, in step 21, it is determined whether the function of detecting the recording time of the cassette tape has been selected. If it has been selected, the process moves to step 22; if it has not been selected, the process is temporarily terminated. In step 22, the take-up reel 2 is driven to rapidly feed the tape. In step 23, the tape end detecting section 15 determines whether the end of the tape has been reached. If the end has been reached, the process moves to step 23; if not, the process returns to step 22 to continue fast-forwarding the tape. In step 24, the count value of the rotation count section 11 is set to zero by the zero reset section 12, and the running time t of the tape is determined by the method shown in FIG. 6 while rewinding the tape. In step 25, the tape end detection section 1
5, it is determined whether the tape has been completely wound and the end has been reached. If the end has been reached, the process moves to step 26; if the end has not been reached, the process returns to step 24 and the tape is continued to be rewound. Perform calculations. In step 26, the recording time of the cassette tape is determined by subtracting the leader tape time from the running time t when the tape is completely wound. In step 27, the beginning of the magnetic tape is found in preparation for starting recording.

SUMMARY OF THE INVENTION Since the development of CD players, it has been common practice to record signals recorded on optical discs onto cassette tapes. At this time, trunk editing calculations are usually performed in order to record the audio without interruption at the end of side A or side B of the cassette tape. There are already CD players that automatically perform this editing operation by inputting the recording time of a cassette tape. Furthermore, there is a cassette tape that can automatically detect this recording time and output the tape with that recording time to a C'D player.
A recorder is required. Therefore, the running time calculation method was used, which is the conventional automatic recording time detection method described above.

However, as long as the recording time displayed on a commercially available tape is simply detected using the flow shown in FIG. 7, it can be realized without the complicated configuration required for conventional running time calculations. SUMMARY OF THE INVENTION An object of the present invention is to provide a method of automatically detecting the recordable time of a cassette tape by performing simple calculations with a simpler configuration than conventional methods.

Means for Solving the Problems In order to achieve the above object, the present invention provides: 1 a rotation detecting section that outputs a rotation detection pulse of a winding side reel or a supply side reel of a cassette tape; and a rotation counting section that counts the rotation pulses. , a tape running reversal control section that reverses the running direction of the cassette tape, a tape end detection section that detects the end of the cassette tape and sends a signal to the tape running reversal control section, and a rotation count when the end of the cassette tape is detected. a zero reset section that resets the magnetic tape to zero, a cue control section that feeds the magnetic tape to a recordable position, a hub diameter data storage section that stores multiple types of hub diameter data determined in advance, and a cassette tape recording section. A recording time data storage unit stores range data of rotation count values corresponding to time, and a count value of the rotation count unit and recording time data storage unit stores the count value of the rotation count unit when the cassette tape is run from the start end to the end end. and a recording time calculation section that calculates the recording time of the cassette tape by comparing the values, and stores the value counted by the revolution count section and the hub diameter data storage section while the cueing control section is performing cueing. The feature is that the hub diameter is determined by comparing it with data.

Effect With the above configuration, when the function to detect the recording time of a cassette tape is selected, the tape is fast-forwarded and the entire tape is wound on the take-up reel, and then the tape is rewound and the The number of revolutions of the side reel is counted and the number of revolutions when the tape is wound from end to end is determined.

Next, the tape is run at a constant speed to find the beginning of the tape, and the count value of the number of revolutions of the take-up reel at this time is compared with the value stored in the hub diameter data storage unit to determine the hub diameter. Make a determination. Compare the data in the recording time data storage unit corresponding to this nop diameter with the rotational speed obtained earlier when winding the tape from end to end to determine which recording time range it falls within. You can find the recording time of the tape.

EXAMPLES Below, examples of the present invention will be explained with reference to the drawings.

FIG. 2 is a graph showing the relationship between the number of rotations N of the take-up reel when the tape is wound from end to end and the recording time displayed on a commercially available cassette tape. From this graph, if the rotation speed N of the take-up reel can be detected,
You can also find the recording time of a cassette tape. However, if the rotational speed N is in the range a-b in FIG. 2, for example, it is impossible to determine whether the cassette tape is capable of recording 40 minutes or 46 minutes. This is because the hub diameter of cassette tapes is not the same, and as shown in FIG. 2, the graph for a thick hub is a thick line, and the graph for a thin hub is a thin line. Therefore, in order to determine the recording time of a cassette tape using FIG. 2, it is necessary to determine the hub diameter. Therefore, a method for determining the hub diameter will be described. From the end of the tape ~ constant speed V.

And t. When the tape is run for a period of time, from equation (1), V
oto=2yrn (Ro+dn/2) ・==・f
5). If n is small enough, the second term on the right side of equation (5) can be ignored, so n=Voto/2πRO・・・・・・・・・・・・ (
6), and by running the tape at a constant speed for an appropriate time to and detecting the number of revolutions n of the take-up reel at that time, different values n can be obtained for different hub diameters Ro.

Therefore, as the range data of the rotation speed count value corresponding to the recording time of various cassette tapes, values corresponding to a and b in Fig. 2, and as several types of hub diameter data, n of equation (6)
By memorizing the value corresponding to , the recording time of the cassette tape can be determined.

In FIG. 1, 21 is a supply reel, 22 is a take-up reel, 23 is a magnetic tape, 24a and 24b are guides, 25 is a cassette tape, 26 is a reel rotating shaft on the take-up side, and 27 to 29 are conventional examples. Rotation detection unit 1 with the same function
31.32 is a rotating body and a detection element, and 31.32 also has a rotation count section, a zero reset section, and 3.32 which have the same functions as the conventional example.
4 to 36 are also a tape running/reversing control section, a tape end detection section, and a cueing control section which have the same functions as those of the conventional example. 38
39 is a hub diameter data storage unit that stores several types of hub diameter data determined in advance to determine the hub diameter; 39 is a recording time data storage unit that stores range data of rotational speed count values corresponding to recording times of various cassette tapes; A storage unit 37 calculates the recording time of the cassette tape by comparing the count value of the rotation count unit 31 when the cassette tape is run from end to end with the value stored in the recording time data storage unit 39. This is a recording time calculation section.

Regarding the embodiment of the present invention configured as described above, the third
The operation will be explained using the flowchart shown in the figure.

In FIG. 3, steps 1 to 3 are the same as steps 21 to 23 in the conventional example, so their explanation will be omitted. In step 4, the count value of the revolution count section 31 is set to zero by the zero reset section 32. In step 5, the tape is rewound, and the pulse signal output from the rotation detector 27 is counted by the rotation counting section 31. In step 6, the tape end detection unit 35 determines whether the end of the tape has been reached. If the end has been reached, the process moves to step 7; if the end has not been reached, step 5 is performed.
Return to and continue counting the number of rotations of the take-up reel. In step 7, the count value of the rotation count section 31 is set to zero by the zero reset section 32, and the rotation number count value is stored as N. In step 8, the beginning of the magnetic tape is searched in preparation for starting recording, and the rotation count section 31 counts the pulse signals output from the rotation detector 27. In step 9, it is determined whether or not the beginning of the magnetic tape for running the tape at a constant speed for a certain period of time has been completed. If it has been completed, the process moves to step 10; if it has not been completed, the process returns to step 8 and the reel is moved to the winding side. Continue counting the number of revolutions. In step 10, the recording time calculation unit 37 compares the rotation count value at the end of cueing with the value stored in the hub diameter data storage unit 38 to determine the hub diameter, and corresponds to this hub diameter. Compare the data group stored in the recording time data storage section 39 with the rotational speed count value N stored in step 7, and
It is determined whether N is within the range and the recording time corresponding to N is determined.

In this way, according to this embodiment, even if the cassette tape is installed in the cassette tape recorder without being completely wound, the number of revolutions N of the winding reel 22 from one end of the tape to the other can be detected. Furthermore, the count value n of the number of revolutions of the take-up reel 22 at the time of starting the magnetic tape is determined, and the count value n is compared with the data stored in the hub diameter data storage section 38. The hub diameter is determined by determining whether the value is within the hub diameter range. Then, the rotation speed count value N is compared with the record corresponding to the hub diameter and the data group stored in the past time data storage unit 39, and it is determined whether the rotation speed count value N is within the range between N and the recording time corresponding to N. I can do what I want.

In this embodiment, the recording time is determined by counting the number of revolutions of the take-up reel, but it is also possible to similarly determine the recording time by counting the number of revolutions of the supply reel.

Effects of the Invention As described above, according to the present invention, the count value of the rotation count section when the cassette tape is run from the start end to the end end is compared with the value stored in the recording time data storage section. and a recording time calculation section that calculates the recording time of the recording time, and compares the value counted by the rotation count section with the data stored in the hub diameter data storage section while the cueing control section is cuing up. By determining the hub diameter by determining whether the count value is within the hub diameter range of the hub diameter data stored in the hub diameter data storage unit, the rotation speed detection unit is not necessary. It has a very simple configuration and does not require very complicated calculations.
You can automatically determine the recording time of a cassette tape.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a method for measuring the recording time of a cassette tape according to an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the number of revolutions N and the recording time displayed on a commercially available cassette tape. Fig. 3 is a flowchart for calculating the recording time of a cassette tape using the same device, Fig. 4 is a plan view showing the relationship between the magnetic tape and the take-up reel, and Fig. 5 is a conventional method for measuring the recording time of a cassette tape. The block diagram, FIGS. 6 and 7 are flowcharts of measurement by a conventional cassette tape recording time measurement method. 21... Supply side reel, 22... Winding side reel, 23... Magnetic tape, 25...
...Cassette tape, 27...Rotation detection section,
29...Detection element, 31...Rotation counting section, 32...Zero reset section, 34...
... Tape travel reversal control section, 35 ... Tape end detection section, 36 ... Cue control section, 37 ...
. . . Recording time calculation section, 38 . . . Hub diameter data storage section, 39 . . . Recording time data storage section. Name of agent: Patent attorney Yoshiaki Ogata and 2 others 1g 8
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Claims (1)

[Claims] a rotation detection unit that outputs rotation pulses of a take-up reel or a supply reel of a cassette tape; a rotation count unit that counts the rotation pulses; a tape running reversal control unit that reverses the running direction of the cassette tape; a tape end detection section that detects the end of the tape and sends a signal to the tape running/reversing control section; a zero reset section that resets the rotation count section to zero when the end of the cassette tape is detected; A cueing control section for sending the tape to a recordable position, a hub diameter data storage section for recording a plurality of types of hub diameter data determined in advance, and a hub diameter data storage section for storing range data of rotational speed count values corresponding to the recording time of the cassette tape. The recording time data storage unit compares the count value of the rotation count unit when the cassette tape is run from the start end to the end with the value stored in the recording time data storage unit, and determines the speed of the cassette tape. a recording time calculation unit that calculates a recording time, and compares the value counted by the rotation count unit and the data stored in the hub diameter data storage unit while the cue control unit performs cueing. A method for measuring recording time of a cassette tape, characterized in that the hub diameter is determined by