JPH0567391A - Recording or playback device - Google Patents

Abstract

(57) [Summary] [Purpose] The recording / reproducing apparatus continuously outputs and displays the calculated value of the remaining tape amount regardless of whether the tape running speed is high or low. [Structure] The rotation cycle of each reel of the recording or reproducing device,
And the rotation cycle that is inversely proportional to the running speed of the magnetic tape is CP.
Input to U. The average value of the rotation cycle of each reel is calculated (S21), and the remaining tape value is calculated based on the calculated average value (S22). If the tape speed is high (S23),
When the tape speed is low (S2), the time constant A filtering process is performed on the calculated tape remaining amount value (S2).
3) The time constant B is filtered for the calculated remaining tape value (S25), and the remaining tape value is updated. The updated remaining tape amount value is displayed and output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording or reproducing apparatus, and more particularly to a recording or reproducing apparatus which uses a tape-shaped recording medium and calculates the remaining tape amount.

[0002]

2. Description of the Related Art Conventionally, there is a video tape recorder as a recording or reproducing apparatus of this type, and the calculation of the remaining tape amount is performed as follows, for example. First, the cycle of the output signal of the reel frequency generator (hereinafter referred to as FG) according to the rotation of each reel on the supply side and the winding side during tape running is determined by the clock from the clock generator as a reference. Side cycle counter, and each measured cycle counter value is measured in a constant cycle by a central processing unit (hereinafter, CPU).
Called)) and averaged and then filtered, and the remaining tape value obtained by this processing was displayed on the display.

That is, as shown in FIG. 6, the cycle data fetched by the CPU is averaged in step 61 to eliminate data variations, and then in step 62, the tape remaining amount is calculated by the averaged cycle data. Calculate the value by the following formula.

[0004]

[Equation 1] However, Ts: average value of cycle of output signal of supply-side reel FG, Tt: average value of cycle of output signal of take-up reel FG, r: reel hub diameter, v: tape running speed, remaining tape amount obtained in step 62. The calculated value is
In step 63, the filtering process is performed by the filter processing circuit to update the remaining tape value, thereby removing the variation in the calculated value of the remaining tape amount, and the output is displayed. We are trying to prevent changes in the update timing.

[0005]

However, according to the above-mentioned conventional example, in the filtering process, the calculated value of the remaining tape amount is larger than the previous value in order to determine the remaining tape amount direction and to update the remaining tape value. Since it is updated when the large or small state continues for a predetermined time or more, it takes a certain time or more before the remaining amount value is updated, and as the variable range of the tape running speed expands as in recent years. The following problems occur.

(1) When the tape is running at a high speed, the time interval between changes in the actual remaining tape value is smaller than the update time of the remaining tape value due to the filtering process. It becomes discontinuous.

(2) When the tape is running at a low speed, the time interval for the change of the actual remaining tape amount is large, and the actual remaining tape value is near the threshold value for judging the direction of the remaining tape and the previous value. Becomes longer and the predetermined time for determining the update of the remaining tape value in the filtering process becomes relatively short, so that it is not possible to suppress variations in the remaining tape value to be output.

The present invention has been made in view of the above circumstances, and provides a recording or reproducing apparatus capable of continuously outputting and displaying the remaining tape value without variation, regardless of changes in the tape running speed. The purpose is to

[0009]

To achieve the above object, the recording or reproducing apparatus of the present invention comprises means for reading the rotation cycle data of the supply side reel and the winding side reel at a constant cycle when the tape is running, and the reading means. Means for calculating the remaining tape amount based on the sub-cycle data, means for filtering the calculated remaining tape value and updating the remaining tape value,
It is characterized in that it has means for displaying the updated tape remaining amount value and means for changing the time constant of the filtering processing according to the tape running speed.

[0010]

According to the present invention, the time constant of the filtering process of the tape remaining amount calculation value is changed according to the tape running speed, and the tape remaining amount value can be calculated stably and accurately regardless of the tape running speed.

[0011]

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

FIG. 1 is a block diagram showing a video tape recorder as a recording or reproducing apparatus according to an embodiment of the present invention. In the figure, 1 is a magnetic recording tape, 2 and 3 are supply-side and take-up-side reels, and an output signal having a frequency corresponding to the rotation of the reel is generated on each reel when the tape is being fed or rewound while the tape is running. FG (not shown)
Is built in. Reference numeral 4 denotes a timer roller having a built-in FG (not shown) that rotates with the running of the tape and generates an output signal of a frequency proportional to the tape speed. Reference numeral 5 counts the cycle of the output signal of each FG of the timer roller and the reel. A clock generator 6 for generating a reference clock for counting the pulse interval of the output signal of the FG of the timer roller by the reference clock from the clock generator 5 and measuring the cycle of the output signal of the FG of the timer roller. A roller cycle counter, 7 is a supply side cycle counter that counts the pulse interval of the FG output signal of the supply reel by the reference clock and measures the cycle of the FG output signal of the supply reel, and 8 is an FG of the winding reel. FG of the winding side reel by counting the pulse interval of the output signal of the
Is a winding-side cycle counter that measures the cycle of the output signal of. 9 is a supply side cycle counter 7 and a winding side cycle counter 8
It is a CPU that calculates the remaining tape amount value by using each cycle data from and the tape running speed from the cycle data from the timer roller cycle counter 6. Reference numeral 10 is a display for displaying the calculated tape remaining amount value and the tape running speed from the CPU 9.

In the above structure, first, reproduction, fast forward,
During running of the magnetic recording tape 1 for rewinding or the like, the cycle of the FG output signal of each reel generated from the reel rotating with the tape running is supplied using the reference clock output from the clock generator 5. It is measured by the side cycle counter 7 and the winding side cycle counter 8. The cycle counter value of the output signal of the FG of each reel measured by the supply side cycle counter 7 and the winding side cycle counter 8 is fetched by the CPU 9 at a constant cycle. Further, the cycle of the output signal generated from the FG of the timer roller 4 rotating with the running of the tape 1 is measured by the timer roller cycle counter 6 using the reference clock output from the clock generator 5, and the obtained cycle counter is obtained. The value is also fetched by the CPU 9.

The CPU 9 calculates the tape remaining amount by using the cycle data of the taken FG output signal of each reel, calculates the tape running speed from the cycle data of the FG output signal of the timer roller 4, and calculates the calculated tape residual quantity. The quantity value and the tape running speed are displayed on the display unit 10.

The details of the tape remaining amount calculation will be described with reference to the flowchart of FIG.

First, in step S21, the CPU 9
The period data of the output signals of the FGs of the supply-side and take-up-side reels, which have been taken in by, are averaged. In step S22, the remaining tape value is calculated by the following equation using the averaged data.

[0017]

[Equation 2] However, Ts: average value of cycle of output signal of supply-side reel FG, Tt: average value of cycle of output signal of take-up reel FG, v: tape running speed, r: reel hub diameter Variation may occur due to measurement error of the FG output signal. For example, 1 minute 01 seconds, 59 seconds while the actual remaining tape amount is 1 minute 00 seconds.
There is a phenomenon in which the seconds and the calculated value vary, and there is a fluctuation in the update timing of the remaining tape value, for example, hunting occurs when the remaining tape display value is updated from 1 minute 01 seconds to 1 minute 02 seconds. is there. In order to eliminate such a defect, the calculated tape remaining amount value is filtered (steps S23 to S25).

In the conventional filtering process, the minimum time (update time) Tmin from one data update to the next data update, which is determined by the time constant of the filter processing circuit, is set to a fixed value. .. In the apparatus of this embodiment, this minimum time Tmin is variably set according to the tape running speed. In this embodiment, as a parameter for determining the minimum time, as will be described later in the processing of FIGS. 3 and 4, the threshold value α ₁ of the count value C ₁ for determining the remaining tape direction and the remaining tape value The threshold value α ₂ of the count value C ₂ for determining the update is variably set. α ₁ and α ₂ form the time constant of this filtering process. When it is determined in step S23 that the tape traveling speed obtained from the cycle of the output signal of the timer controller FG is high, the tape is switched to the shorter time constant A of the minimum time Tmin (step S24), and the tape traveling speed is low. If it is determined that there is, the time constant B is switched to a longer time constant Tmin (step S25), and the filtering process is executed.

3 and 4 show flowcharts of the filtering process.

Process 1 shown in FIG. 3 is a routine for determining the tape remaining amount direction, and process 2 shown in FIG. 4 is a routine for determining the update of the tape remaining amount value. Each of the processes 1 and 2 is executed in synchronization with a clock generated at a constant cycle.

In the process 1 of FIG. 3, first, in step S31, the remaining tape amount value L obtained by the present remaining tape amount calculation is compared with the previously updated remaining tape amount value L ₁ . L> For L _1, increments the count value C ₁ of the remaining amount direction determination counter (step S32), the count value C ₁ in comparison with the remaining tape direction determination threshold alpha ₁ at step S33, C ₁ ≧ alpha If ₁ , set the counter C ₁ to α
_1, to set the remaining tape direction dir 1 (step S3
4). On the other hand, if C ₁ <α ₁ , the processing is immediately terminated. If L <L ₁ at step S31, the counter C ₁ is decremented (step S35), and C at step S36.
_{If 1} ≤ -α ₁ , set counter C ₁ to -α ₁ , tape remaining amount direction di
The r is set to -1 (step S37), immediately terminated C _1> -α ₁ if treatment. Further, in step S31, L =
Also in the case of L ₁ , the processing is immediately terminated.

FIG. 5 shows a state transition and the count value C ₁ and the remaining tape direction dir remaining capacity direction determination counter in process 1.

Next, in the process 2 of FIG. 4, the remaining tape amount value L obtained by the present calculation is compared with the last remaining tape amount value L ₁ (step S41), and L> L ₁ for, dir = 1 if (step S42), increments the count value C ₂ of the tape remaining amount update determination counter (step S43), compares the count value C ₂ and the update time set threshold alpha ₂ (step S44 ), When C ₂ ≧ α ₂ , the counter C ₂ is reset to 0 and the tape remaining amount value L ₁
= L is updated (step S45). D in step S42
If ir ≠ 1 or C ₂ <α _{2 in} step S44, the process ends immediately. If L <L _{1 in} step S41, dir
If −1 (step S46), the count value C ₂ is decremented (step S47), and when C ₂ ≦ −α ₂ (step S48), the count value C ₂ is reset to 0, and the tape remaining amount value is reached. Update to L ₁ = L (step S 4
5). In step S46, dir ≠ -1 or step S48
If C ₂ > −α ₂ , the process ends immediately. Also, if L = L ₁ in step S41, the process is immediately terminated.

[0024] In the above embodiment, when the threshold time constant alpha ₁ constituting the constant A, the threshold alpha ₁ constituting a time constant B and alpha _2, is made smaller than alpha _2, and faster updating of remaining tape, It can handle high tape running speeds.

By the calculation and processing of FIGS. 2 to 4 described above, the optimum tape remaining amount value can be output and displayed according to the tape running speed.

In the above embodiment, an example in which the thresholds α ₁ and α ₂ are switched in two steps when the tape running speed is high and low, respectively, has been described. However, the present invention is not limited to this. The threshold value may be continuously changed according to the change.

Further, only _{one of} the thresholds α ₁ and α ₂ may be switched or changed.

Further, the recording or reproducing apparatus is not limited to the video tape recorder, but any apparatus such as an audio tape recorder which uses a tape as a recording medium may be used.

[0029]

As described above, according to the recording or reproducing apparatus of the present invention, the time constant of the circuit for filtering the remaining tape value is switched in accordance with the tape running speed, so that any tape speed can be obtained. Also, it is possible to eliminate variations and discontinuities in the output data of the tape remaining amount caused by running the tape, and output and display the appropriate tape remaining amount.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a flow chart showing a tape remaining amount calculation method of the embodiment of FIG.

FIG. 3 is a flowchart showing the processing of a tape remaining amount direction determination routine in the tape remaining amount calculation of FIG.

FIG. 4 is a flowchart showing the processing of a tape remaining amount update determination routine.

5 is a state transition diagram in the process of FIG.

FIG. 6 is a flowchart showing a conventional tape remaining amount calculation method.

[Explanation of symbols]

 1 magnetic recording tape 2 supply side reel 3 winding side reel 4 timer roller 5 reference clock generator 6 timer roller cycle measurement counter 7 supply side cycle measurement counter 8 winding side cycle measurement counter 9 central processing unit (CPU) 10 indicator

Claims (1)

[Claims] 1. A means for reading rotation cycle data of a supply-side reel and a winding-side reel at a constant cycle when the tape is running, a means for calculating a tape remaining quantity based on the read cycle data, and the calculated tape remaining quantity. A means for filtering the value to update the remaining tape remaining value, a means for displaying the updated remaining tape value, and a means for changing the time constant of the filtering processing according to the tape running speed. Characteristic recording or reproducing device.