JPH0668904B2 - Tape running time display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention detects the rotation cycle of a tape winding side reel,
The present invention relates to a tape running time display device which displays a tape running time by performing a predetermined calculation based on the detected value of the rotation cycle.

[Conventional technology]

The conventional tape running time display device calculates and displays the next tape running time and a new tape running time, for example, based on the pulse output of the reel every predetermined rotation of the take-up reel during constant speed running of the tape. A device that does this is generally used.

At the time of recording and reproducing, the cycle of the reel varies depending on the number of tape windings, but the variation range is about several seconds such as 6 seconds at the beginning of winding and 3 seconds at the end of winding. When the calculation is performed for each reel rotation of such a cycle, a new tape running time is calculated on the order of several seconds.

The tape running time calculated in this way is updated by displaying a calculation value every time a calculation is performed on the order of several seconds.

Therefore, the relationship between the elapsed time, the calculated value when the tape is running, and the display tape running time value is as shown in FIG.

In FIG. 5, assuming that the traveling time calculated at time t1 is c1, for example, the value is continuously displayed until time t2 as indicated by the one-dot chain line, or only the display is changed as indicated by the solid line. Next, if the tape running time calculated at time t2 is c2, the value is
It is displayed as a one-dot chain line or a solid line. After that, the tape running time is repeatedly displayed in the same manner as above. here,
For the times t1, t2, ... For example, the time for each reel rotation is used.

[Problems to be solved by the invention]

Since the conventional tape running time display device is configured as described above, variations in tape winding, such as when the tape is tightly wound and when it is loosely wound, and reel rotation such as wah and flatter. And a measurement error of the reel rotation period, which causes variations in the calculation results. Therefore, if the calculated result is displayed as it is, the displayed tape running time contains a large error, and the time display skips or returns every time the tape running time is displayed, and the tape running time display is not displayed. There is a problem that a continuous phenomenon occurs.

The present invention has been made to solve the above-mentioned problems, and it is possible to accurately confirm the instantaneous tape running time, and there are variations in tape winding and variations in reel rotation such as wow and flutter. Another object of the present invention is to provide a tape running time display device capable of displaying the tape running time accurately.

[Means for solving problems]

The tape running time display device according to the present invention comprises a winding-side reel rotation cycle detecting means for detecting the rotation cycle of the winding-side reel of the tape at predetermined intervals, and a rotation detected by the winding-side reel rotation detecting means. From the cycle fs, the reel pulse number P corresponding to the tape running time of the take-up reel is: P = (mv / 2лd) fs-mr / d v: Tape running speed d: Tape thickness r: Take-up reel hub diameter m: The reel pulse number calculating means outputs the reel pulse number calculating means for each predetermined period according to the pulse number per one rotation of the take-up reel, and the filter means receives the reel pulse number P from the reel pulse number calculating means. The reel pulse number P input for the Nth time by P
_IN (N), the output of the filter means at this time is P
_OUT (N), the number N of reel pulses input at the previous N-1 time is P _IN (N-1), and the output of the filter means at the previous N-1 time is P _OUT (N-1). At this time, P _OUT (N) = a · P _IN (N) + b · P _IN (N−1), where a, b, and c are the same as the reel pulse number calculation results up to the previous time according to a predetermined constant including 0. and a filter means for outputting a new reel pulse number P _OUT the correlated (N), said take-up reel tape running from the new reel pulse number P _OUT (N) above, which is the output of the filter means The feature is that the time T is calculated according to T = {(2лr / mv) + m} · P _OUT (N) + (л d / m ² v) · {P _OUT (N)} ² and the result is displayed. To do.

[Action]

According to the present invention, the value of the calculation result of the tape running time is not displayed as it is, but is displayed as an output by correlating with the calculation result of the tape running time up to the previous time. Even if there is a large error in the detection of the rotation cycle, it is possible to reduce the influence of the detection error and accurately display the tape running time.

Example of Invention

An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a case will be described in which the reel pulse number corresponding to the tape running time is calculated from the rotation cycle of the take-up reel and the tape running time is converted from the reel pulse number.

FIG. 1 is a block diagram showing a tape running time display device according to an embodiment of the present invention. In FIG. 1, (1) is a microcomputer for displaying reel pulses output by rotation of a take-up reel (3). Input the tape loading status such as whether the tape is loaded or ejected, the running status such as constant speed running or fast forward, the reference clock for reel rotation cycle measurement, is stored in advance as internal data, Alternatively, when the tape running time display command is input, the tape running time is displayed on the display (2), or when the tape running time cannot be measured, the corresponding display is performed.

The microcomputer (1) is composed of a computing unit, a RAM, a ROM, and the like. In the RAM, the flag FL indicating the end of reel pulse measurement, the reel pulse number before passing through the filter calculated from the reel rotation cycle fs P _IN (N), the number of reel pulses after passing through the filter P _OUT (N), the number of reel pulses P at the time of the previous calculation for use in the calculation of the filter
P _IN (N- for storing _IN (N), P _OUT (N)
1), P _OUT (N-1), the number of reel pulses after passing the fill
Each data area of the tape running time T converted from P _OUT (N) is provided, and the ROM stores a program for executing the processing shown in the flowchart of FIG.

Next, the operation of the above configuration will be described based on the flowchart of FIG.

When the system is reset, the program starts at process step (10) and then cycles through the process steps (20) to (70).

In step (10), the RAM is cleared and the input / output is set in the initial setting process.

In step (20), the rotation cycle of the take-up reel is always detected, and the reel pulse numbers _IN (N) and P _OUT (N) are moved up and down according to the rotation of the reel. If step (21), pulse by pulse
P _IN (N) and P _OUT (N) are counted down, and when the reel is rotating normally, P _IN (N) and P _OUT (N) are counted up for each pulse in step (22). .

Step (30) detects that the tape has been taken out and sets the flag FL to "0". At this time, the reel pulse number P _OUT (N) is not the correct reel pulse number. Means

Step (40) is the number of reel pulses P during constant speed running.
_{This is} for calculating _OUT (N), and it is judged whether or not the take-up reel has made one revolution in step (41) during constant speed running, and if it has not made one revolution, proceed to the next step (50). Transition. If the reel makes one revolution during constant speed traveling, the cycle fs of one revolution is obtained in step (42), and the previous calculation result P is calculated in step (43).
_IN (N) P _OUT (N) respectively as P _IN (N-1) and P
_{Evacuate to OUT} (N-1) and in step (44),
From the rotation cycle fs obtained in step (42), P _IN (N) of the current calculation result is calculated by P _IN (N) = A · fs−B (1) Here, A and B are constants calculated from the tape thickness d, the reel hub diameter r, the tape running speed v, the reel pulse number m per reel rotation, and the like, where A = mv / 2лd and B = mr / d. is there.

At this time, if the flag FL is "0", the current calculation is the first calculation of the reel pulse number P _OUT (N), and the current reel pulse number P _OUT (N) is the correct reel pulse number. Therefore, the reel pulse number P _IN (N) obtained in step (44) is directly set to P _OUT (N) in step (45), and at the same time, the flag FL is set to "1". On the other hand, if the flag FL is "1", step (4
Reel pulse number P _IN (N), P _IN (N-1), P _OUT (N-1) obtained in step (43) and step (44) by 6)
Digital filter calculation using _POUT (N) = _a.PIN (N) + _b.PIN (N-1) + _C.POUT (N-1) (2) The reel pulse after passing through the filter Calculate the number P _OUT (N). Here, a, b, and c are constants, but desired filter characteristics can be obtained by selecting them appropriately. Note that a =
If 1, b = c = 0, then P _OUT (N) = P _IN (N),
This is the same as when there is no filter, and the tape running time is calculated as in the conventional case. A block diagram of the filter configuration for performing the above calculation is shown in FIG.

In FIG. 2, (4), (5), and (6) are constant multipliers, (7) is an adder, (8) and (9) are delay units, and (10).
Is the input terminal of the reel pulse number P _IN (N) before passing the filter, (11) is the reel pulse number P after passing the filter
_OUT (N) output terminal.

In step (50), the tape running time T is calculated from the reel pulse number P _OUT (N), and when FL = 1, in step (51) T = C · P _OUT (N) + D · {P _OUT (N N)} ² ………
Calculated according to (3). Here, C and D are constants calculated by tape thickness d, reel hub diameter r, tape running speed v, number of pulses per reel rotation m, etc., and C = 2лr + 2лd / mv · D = лd / Vm ² . .

Step (60) displays the tape running time on the display (2) when the tape running time display command is input. When the flag FL is "1", the tape running time obtained in step (51) is displayed. T is displayed in step (61) and the flag is displayed.
When FL is "0", a display indicating that the tape running time cannot be measured is displayed in step (62).

In step (70), processing other than tape running time calculation and display, which is performed by the microcomputer (1), such as reception of key input, is performed.

Therefore, if the constant speed running is continued, the steps (40), (41), (42), (43), and
(44), the number of reels pulse has passed through the digital filter P _OUT (N) is calculated, as continued constant speed running, the calculation accuracy of the reel pulse number P _OUT (N) is improved by a filter effect by (46). That is, the reel pulse number P
_{Since OUT} (N) is calculated while always correlating with past data as can be seen from the above equation (2), the rotation cycle fs of the take-up reel obtained in step (42) causes a measurement error. Even if included, the reel pulse number P _OUT (N) is not affected by the above measurement error.

Therefore, the tape running time T calculated in step (51) based on the reel pulse number P _OUT (N) is also
The displayed tape running time is highly accurate without being affected by the above measurement error.

The relationship between the elapsed time and the tape running time calculated without passing through the filter and the tape running time display value after passing through the filter is as shown in FIG. This figure shows 1 when a = b = c = 1/3 in the equation (2).
This is an example, and the conventional calculated tape running time C1, C
2 shows the calculated tape running times d1, d2, ... improved by passing the filter and the display.

In the above embodiment, the configuration of the digital filter is described as P _OUT (N) = a · P _IN (N) + b · P _IN (N−1) + c · P _OUT (N−1). as long even resulting properties, the digital filter may be any configuration, for example, P _iN
If a high-order digital filter using (N-2), P _IN (N-3) ... Is used, although the RAM and ROM have a large capacity, a more accurate tape running time display can be realized.

In the above embodiment, the reel pulse number P _OUT (N) is calculated from the detected rotation cycle fs of the winding side reel, and the tape running time T is obtained from the reel pulse number P _OUT (N). , But is not limited to this. That is, the tape running time T is directly calculated from the detected rotation cycle fs,
Even if the digital tape processing is performed on the calculated tape running time T, the same effect as that of the above embodiment can be obtained.

〔The invention's effect〕

As described above, according to the present invention, the calculation result of the tape running time is not displayed as it is, but the calculation result of the tape running time up to the previous time and the calculation result of the current tape running time are correlated. Since a new output value is calculated and the new output value is displayed, even if there is a large error in detecting the rotation cycle due to variations in tape winding or uneven rotation of the reel due to wow, flutter, etc. It is possible to eliminate the discontinuity phenomenon due to the influence of an error and to display the tape running time with extremely high accuracy.

In particular, the concept of the reel pulse number P is introduced so that the tape running time can be calculated not only during playback / recording operations where the tape running speed is constant, but also during fast forward and rewind where the tape running speed is not constant, P = (mv / 2лd) · fs- (mr / d) where, v is the tape running speed, d is the tape thickness, r is the reel hub radius, and m is the number of pulses per reel rotation, and these are known values. Then, from the reel pulse number P to the tape running time T
Is calculated according to T = {(2лd / mv) + m} · P _OUT (N) + (л d / m ² · v) · {P _OUT (N)} ² , once P is calculated, Even when fast-forwarding or rewinding, the tape running time can be accurately displayed by counting P up / down each time the rotation reel pulse is detected.

Also, if fast-forwarding and rewinding are continued for a long time, the new P cannot be calculated, and the display accuracy of the tape running time gradually deteriorates. Even in this case, however, the reproducing / recording operation is next performed in the present invention. When a new P is calculated as a result, each time the P is calculated, the new P is gradually approached and the tape is accurately displayed, so that a natural tape running time display can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of a tape transit time display device according to an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of a digital filter, and FIG. 3 is a flowchart of processing programmed in the microcomputer shown in FIG. FIG. 4 is a diagram showing the relationship between the elapsed time, the calculated tape running time and the display tape running time according to the present invention, and FIG. 5 shows the elapsed time, the calculated tape running time and the display tape running time in the conventional tape running time display device. It is a figure which shows a relationship. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A winding-side reel rotation cycle detecting means for detecting a rotation cycle of a winding-side reel of a tape at predetermined intervals, and a winding cycle fs detected by the winding-side reel rotation cycle detecting means. The reel pulse number P corresponding to the tape running time of the side reel is: P = (mv / 2лd) fs-mr / d v: tape running speed d: tape thickness r: take-up reel hub diameter m: take-up reel 1 revolution Reel pulse number calculation means for calculating and outputting for each predetermined period in accordance with the number of pulses for each, and filter means for inputting the reel pulse number P from the reel pulse number calculation means, which is the Nth time input. P of the reel pulse number P
_IN (N), the output of the filter means at this time is P
_OUT (N), the number N of reel pulses input at the previous N-1 time is P _IN (N-1), and the output of the filter means at the previous N-1 time is P _OUT (N-1). When P _OUT (N) = a · P _IN (N) + b · P _IN (N-1) + c · P _OUT (N-1) where a, b, and c are in accordance with a predetermined constant including 0 A new reel pulse number P _OUT (N) that is correlated with the reel pulse number calculation result up to the above, and the new reel pulse number P that is the output of the filter means. Running time T from _OUT (N) to the reel tape on the winding side
Is calculated according to T = {(2лr / mv) + m} · P _OUT (N) + (л d / m ² v) · {P _OUT (N)} ² and the result is displayed. Driving time display device.