JPS6128305Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a tape time display device that calculates and displays the remaining amount of tape or running tape time by detecting the rotation period of the supply side (or take-up side) reel in a cassette tape recorder. It is.

Generally, in a device that detects the rotation period of the supply side (or take-up side) reel of a cassette tape and calculates and displays the remaining amount of tape or tape running time based on this detected rotation period, the condition for the calculation display is It is necessary to detect the rotation period of the reel while the tape is running at a constant speed (recording or playback speed).

However, in such a tape time display device, even if the tape is run at a constant speed to detect the rotation period in the initial state after the power is turned on or the reset button is pressed, the display does not appear for a certain period of time, and the operator is forced to There was a risk that this could be mistaken for a device malfunction. In other words, in the conventional device, when calculating and displaying the tape time, the detection data of the rotation period obtained for the first time in the initial state is canceled because it is the data obtained when the reel rotation fluctuation is large, and the data for the second reel rotation is canceled. The tape time is calculated and displayed based on the detection data of the rotation period obtained by . Therefore, from the start of constant speed running until the tape time is displayed, there is a certain waiting time corresponding to the sum of the time required for two rotations of the reel and the time required for calculation. For this reason, even if the vehicle is driven at a constant speed after the initial state, the display does not appear immediately, and there is a risk that the operator may mistake the device for failure.

The present invention has been developed to solve these problems. During rotation period detection and tape time calculation operations after the initial state, the numerical display segment of the tape time display is used to detect and calculate the rotation period. It is an object of the present invention to provide a tape time display device that can display a predetermined display indicating that the device is in operation and can notify an operator that the device is normal.

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

FIG. 1 is a diagram for explaining an arithmetic expression for calculating the remaining tape time T used in the embodiment of the present invention. In the same figure, supply side reel SR
Let r ₀ be the radius of the hub, d be the tape thickness, and r _s be the radius of the remaining tape, then the total length l of the tape wound on the supply reel SR can be expressed by equation (1).

l=π/d( _rs2 − _r02 )...(1) Therefore, if ^the tape runs at ^a constant speed _v0 (speed during playback and rewinding), the remaining time T is as follows:
It can be expressed by equation (2).

T=l/v ₀ =π/v ₀ d( _rs ² − r ₀ ² )...(2) In this case, the rotational speed Vs of the supply reel SR when the radius of the remaining tape is _rs is, It is expressed as Vs=v ₀ /2πr _s (3). Therefore, based on the above equations (2) and (3), the remaining amount time T can be expressed by the following equation (4).

T=v ₀ /4πd×(1/Vs) ² −π/v ₀ dr ² …
...(4) Here, d, r ₀ , and v ₀ are numerical values fixed in advance by the tape base and tape recorder, that is, constants. Therefore, these constants d, r ₀ , v ₀
If is given in advance, the remaining amount time T during constant speed running can be easily determined by detecting the rotational speed Vs of the supply reel.

On the other hand, during fast forwarding and rewinding, the tape does not run at a constant speed, so the rotational speed Vs
cannot be calculated using equation (3), and the remaining amount time T cannot be calculated using equation (4). Therefore, find it as follows.

In other words, after calculating the remaining amount time T using equation (4), fast forwarding or rewinding is performed, and the supply reel is n
Remaining time t when rotating (-n when rewinding)
Since the tape radius is ( _rs −nd), according to equation (2), t=π/v ₀ d{( _rs −nd) ² −r ₀ ² } =π/v ₀ d(r _s ² −2ndr _s +n ² d ² −r ₀ ² ) =πd/v ₀ n ² −2πr _s /v ₀ n+π/v ₀ d(
r _s ² −r ₀ ² ) =πd/v ₀ n ² −2πrs /v ₀ n+T ( ₅ ). Here, according to equation (3), 2πr _s /v ₀ =1/Vs, so by substituting this into equation (5), t=πd/v ₀ n ² -1/Vsn+T ...(6) Obtainable.

Therefore, if you memorize the rotational speed Vs and remaining amount time T during constant speed running immediately before starting fast forwarding or rewinding, and measure the rotation speed n of the reel after fast forwarding or rewinding, then (6 ) can be used to approximately sequentially determine the remaining tape time even during fast forwarding and rewinding.

FIG. 2 is a diagram for explaining an arithmetic expression for calculating the tape running time ts used in the embodiment of the present invention. In the same figure, the take-up reel DR
When the radius of the hub is r ₀ , the thickness of the tape is d, and the tape is wound n times on the take-up reel, the length l ₁ of the tape on the outer periphery can be expressed by equation (7).

l ₁ =2π(r ₀ +nd) ...(7) Therefore, the total length l of the magnetic tape when it is wound n times can be expressed by equation (8).

Here, since r ₀ >>d/2, equation (8) can be expressed as equation (9).

l=2πn(r ₀ + d/2n) ...(9) Then, when the tape is running at a constant speed v ₀ in the x direction, the running time from the start of winding to the current time t _s
can be expressed by equation (10).

t _s =l/v ₀ =2π/v ₀ n(r ₀ +d/2n)...(
10) In this equation (10), A=πd/v ₀ , B=2πr ₀ /
If v ₀ , this equation (10) can be expressed as equation (11).

t _s = An ² + Bn (11) Note that A is a value determined by the tape thickness d and tape speed v ₀ , and B is a value determined by the hub radius r ₀ and tape speed v ₀ . Incidentally, the rotation speed V _R of the take-up reel can be obtained by differentiating n in equation (10) with respect to t, and can be expressed by equation (12).

V _R =dn/dt=1/2An+B...(11) In this case, the rotational speed of the take-up reel immediately after resetting the counter that counts the number of turns n of the take-up reel is expressed as V _R and V _RR . Then, the thickness of the tape is extremely thin, about 18 μ or less, the radius r ₀ of the hub is about 11 mm, and the number of turns n is 1, so 2An<<B.

Therefore, from equation (11), B immediately after reset
_R can be calculated using the following formula.

B _R = 1/V _RR ... (13) Also, A _R after reset is calculated from equation (11) as A _R = 1/2n (1/V _R - B _R )... (14) be able to.

Therefore, first, we perform a reset process at the start, and then use the values B _R and A _R obtained from equations (13) and (14) after the reset, and the value n of the counter that counts the number of turns n after the reset. te, no.
By performing the calculation shown in equation (11), the running time is
_s required. Furthermore, even if the tape is reset in the middle of the tape, the running time from the reset position can be displayed.

FIG. 3 is a block diagram showing one embodiment of the present invention. In the figure, SR is the supply side reel and DR is the take-up side reel, and these reels SR and
Rotating disks a and b are attached to the rotating shaft of the DR, and the rotation of these rotating disks a and b is detected by sensors (magnetic sensor or photoelectric sensor, etc.) Sa and Sb. , Sb to reel SR,
A pulse signal corresponding to the rotation period of the DR is extracted. It should be noted that the switch _SW1 selects which of the pulse signals obtained from the sensors Sa and Sb is used to calculate the tape time (remaining amount or running). Next, 10 calculates the tape time using the above-mentioned arithmetic formula, and if the operations are not performed in accordance with the predetermined order of operations, the tape time is calculated using the numerical display segment of the tape time display. This is an arithmetic control unit that executes control to instruct constant speed driving or display an error display, and includes an arithmetic unit CPU and memories RAM and ROM.

Next, 11 is a display driver, and 12 is a display device for displaying tape time. SW ₂ is a remaining amount mode switch for instructing the remaining amount time as the tape time to be displayed on the display 12, SW ₃ is a running mode switch for instructing the running time as the tape time to be displayed on the display 12, and SW ₄ is the remaining amount mode switch for instructing the remaining amount time as the tape time to be displayed on the display 12. Type (C
-30, C60, C90); SW ₅ is a reset switch for returning the entire device to its initial state; SW ₆ is for displaying the remaining amount of time during fast forwarding and rewinding; (6) in the expression
This is a storage instruction switch for storing Vs and T in memory RAM.

By the way, although the arithmetic control section 10 has a microcomputer type hardware configuration, the arithmetic section
A tape time meter and revolution counter are provided using the CPU's working register. The memory ROM stores programs corresponding to flowcharts as shown in FIGS. 4 to 6 in order to execute predetermined arithmetic and control operations.
Constants necessary for tape time calculation processing (hub diameter r ₀ ,
tape thickness d, tape speed _v0, etc.) are stored.

The operation of the tape time display device of the embodiment shown in FIG. 3 will be explained below using the flowcharts shown in FIGS. 4 to 6.

FIG. 4 shows a main program for executing arithmetic and control operations, and after power is turned on, the entire device is initialized by operating the reset switch _SW5 or by an initialization signal synchronized with power-on. After this, the main program shown in FIG. 4 is first executed. That is, step 1 in FIG.
At 00, whether the mode is the remaining amount mode or the running mode is determined based on the output signals of the switches SW ₂ and SW ₃ . As a result, if the remaining amount mode is to display the remaining amount time, the process advances to step 101, a remaining amount time routine, and a program for displaying the remaining amount time is executed. On the other hand, if the driving mode is to display the driving time, the process proceeds to step 102, the driving time routine.
Execute the program to display running time. After this, proceed to step 103 and turn on the reset switch.
Determine whether SW ₅ is on. If reset switch SW ₅ is on, proceed to the next step 10.
4, reset the tape time meter. Thereafter, in step 105, the memory instruction switch is activated.
Determine whether SW ₆ is on or not, and turn on the corresponding switch SW _6.
is on, the contents of the tape timer (T in equation (6)) and the most recently detected rotational speed Vs are stored in the memory RAM in the next step 106.
to be memorized. When such processing is completed, the process returns to step 100 and the same processing is repeated thereafter.

FIG. 5 shows steps 101 and 1 in FIG.
This is a flowchart showing in detail the common parts of the remaining amount time routine and running time routine of 02. In the figure, when processing first proceeds to the remaining amount time routine or running time routine, in step 200, the character "PLAY" is displayed using the numeric display segment of the display 12. In other words, an instruction is given to the operator to perform constant speed playback or recording. In this case, the characters "PLAY" can be displayed as shown in FIG. 7 by utilizing the numeric display segments of the display 12.

Next, in step 201, it is determined whether the playback or recording button has been pressed according to the character display of "PLAY". If the fast forward or rewind button is suddenly pressed without pressing the play or record button, step 202
This is determined in the next step 203.
The ``PLAY'' character display will blink, indicating an error message indicating an operational error. This error display will not be canceled until reset switch SW ₅ is operated, and after operating reset switch SW ₅ , the process returns from step 204 to step 220 again.
You will be prompted to redo the operation. In addition, the error display not only flashes all the letters "PLAY" but also displays the letters P, L, A, and
Since there are various methods such as displaying Y individually one by one, it is sufficient to apply the method that is easiest for the operator to understand.

On the other hand, if the operator performs the correct operation according to the word "PLAY" displayed in step 200, that is, if the operator presses the record or play button,
In step 205, the character "-" is displayed on display 1.
Display on 2. That is, a display indicating that the process has now shifted to detecting the rotation period of the reel and calculating the tape time is displayed. Thereafter, the rotation period (speed) of the reel is detected as shown in steps 206-209. in this case,
Each time a rotation pulse is input, the "-" display is sequentially shifted to the right as shown in FIGS. 8a to 8d. This allows the operator to know that the reel rotation period detection process is being executed correctly. The rotation period is detected in this manner, and when the process is completed, the process proceeds to the next step 210, where the tape time is calculated using the above-mentioned arithmetic expression. Then, in the next step 211, the calculated tape time is displayed on the display 12. If reset switch SW ₅ is operated at this stage, Step 2
12 returns to step 200, the word "PLAY" is again displayed on the display 12, and the contents of the tape timer are reset. If the reset switch _SW5 is not operated, the program returns from step 212 to step 210 and calculates the tape time for each reel rotation period.

FIG. 6 is a flowchart showing details of the tape time calculation routine in step 210 of FIG. In the same figure, when moving to the tape time calculation routine, it is first determined in step 300 whether or not a rotation pulse has been input, and in the next step 301, a rotation counter that stores the number of rotations n for each rotation of the reel is checked. Update content. At this time, the record or play button is pressed,
If one rotation has been completed, the process proceeds to the next step 306 based on the judgments in steps 302 and 305, and the calculation formula for constant speed running (Equation (4) or Equation (11)) is used.
(expression) is executed. In this case, the remaining amount mode switch
If SW ₂ is in the ON state, the remaining tape time is calculated by the above-mentioned equation (4). Further, if the running mode switch SW ₃ is in the ON state, the tape running time is calculated by the above-mentioned equation (11). When the tape time calculation is completed in this way, the content "n" of the revolution counter is reset in the next step 307, and then the display 12 is reset in step 308.
Display the colons continuously. Then, proceed to step 211 in FIG. 5, display the tape time,
Thereafter, while the recording or playback button is pressed, the tape time is calculated for each rotation of the reel. Thereafter, when the recording or playback button is turned off to stop tape running, the program stops at step 300 in FIG. 6, and the tape time display continues to stop changing. However, if memory instruction switch SW ₆ is pressed here,
An interrupt program (not shown) causes the program execution to jump from step 300 in FIG. 6 to step 105 in FIG. Stored in memory RAM. After this, the program returns to steps 200 and 205 in FIG. 5 because the device is not in its initial state.
The process returns to step 300 in FIG. 6 without going through the process. In this state, when the fast forward or rewind button is pressed, the process proceeds to step 303 based on the determination made in step 302 in FIG. 6, where the fast forward/rewind calculation formula is executed. When this calculation is completed, in step 304, the colon on the display 12 is blinked to notify that the display 12 is currently displaying the tape time based on the approximate calculation.

As explained above, the present invention is designed to display that the detection/calculation operation is in progress from the detection of the reel rotation period to the calculation display. Therefore, even if the vehicle is driven at a constant speed, the display will not appear for a certain period of time, and it can be confirmed that the device is operating normally.

In addition, in the embodiment, a "-" display is used to notify that the detection/calculation operation is in progress, but if it is distinguished from the "PLAY" display and the error display, it can be easily displayed in other display formats. It is.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining the tape time calculation formula used in the present invention, FIG. 3 is a block diagram showing an embodiment of a tape time display device to which the present invention is applied, and FIGS. FIG. 6 is a flowchart showing an example of a program used in the tape time display device of FIG. 3, FIG. 7 is a diagram showing an example of a constant speed running instruction display, and FIGS. 8 to 9 are a flowchart showing an example of a program used in the tape time display device of FIG. FIG. 4 is a diagram illustrating an example of a display inside and an example of an error display. 10... Arithmetic control unit, 11... Display driver, 12... Display unit, SW ₁ ... Sensor changeover switch, SW ₂ ... Remaining amount mode switch, SW ₃ ... Traveling mode switch, SW ₄ ... Tape selection switch,
SW ₅ : Reset switch, SW ₆ : Memory instruction switch, SR: Supply side reel, DR: Take-up side reel.

Claims (1)

[Scope of Claim for Utility Model Registration] A tape time display device that detects the rotation period of a supply reel or take-up reel of a cassette tape recorder and calculates and displays the remaining tape time or tape running time, and displays the calculation result. A display device that detects the rotation period and calculates the remaining tape time or tape running time, and also performs the calculation from the detection of the rotation period during the first constant speed tape run after initializing the tape time display. and a calculation control section that displays a predetermined display indicating that a detection/calculation operation is in progress using the numerical display segment of the display until the end of the tape time display.