JPS63131362A - Tape speed control method - Google Patents

Abstract

PURPOSE:To make the tape speed constant independently of the size of tape by calculating the width of output pulse of both detectors when a tape is driven at a constant speed so as to convert the result into a tape length and using a tape speed proportional to the converted tape length as a setting voltage. CONSTITUTION:Detectors FG1, FG2 to detect the rotational speed of the tape supply reel 1 and take-up reel 2 are provided, and a tape speed voltage V1 is obtained from the square sum T1<2>+T2<2> calculated from two output data, rotational periods T1, T2 obtained from both the detectors FG1, FG2, the pulse width of the output of both the detectors FG1, FG2 is calculated when the tape is at a constant speed to convert the result into the length (l) of the tape. Then a tape speed setting voltage V2 proportional to the length (l) of the tape is obtained, both the tape speed voltages V1, V2 are compared and the voltage difference is fed to the drive motor. Thus, the tape speed is made constant independently of the tape size.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is particularly applicable to playback, recording, etc. in cheap recorders such as R-DAT (Rotary Digital Audio Tape, hereinafter abbreviated as R-DAT). A method of keeping the tape speed constant during high-speed running, which performs search operations such as detecting between tracks and cueing, which requires reading data from tapes that are sent at ten or hundreds of times faster than normal speed. Regarding.

(Prior art) Until now, no reliable method has been developed to keep this type of speed constant, and a simple method is to magnetically detect the natural frequency recorded on the Iopian track. There are two known methods for doing this, using this as a reference; (b) A method for bringing a roller into direct contact with the tape, detecting the rotational speed of the roller, which increases or decreases in proportion to the tape speed, and setting the value to a constant value from that value.

<Problems to be Solved by the Invention> However, in the case of using the above-mentioned means, the speed cannot be detected until after the natural frequency is recorded on the option track, so it is difficult or impossible to implement as a practical matter. .

In addition, when using the latter method, slipping phenomena are likely to occur during high-speed running due to the dimensional accuracy of the roller and tape during manufacture and their long-term stability, and the accuracy of the intended detection may be affected. The lack of stability makes it impossible to read the tape.

Means for Solving Problems> In view of the above-mentioned circumstances, it is an object of the present invention to provide a tape speed control method that can extremely accurately keep the tape speed constant during high-speed running.

In order to achieve the above object, a tape speed control method according to the present invention includes a detector (F to I L
(FG2) is installed, and both these detectors (FGIL (
FG2) to A: The two output data busy cycles (
The tape speed voltage (V1
), and calculate the pulse width of the output of both detectors (F = 1) v (FG2) when the tape is running at a constant speed, convert it to the tape length (1), and calculate the tape length (1). ), obtain a tape speed setting voltage (v2) proportional to t(Vz), compare both tape speed voltage values (V+)t(Vz), and apply the difference voltage to the drive motor to control the speed to a constant value. It is.

Effects> The present invention has the above-described configuration, and the rotational speed detectors (F
The rotation period (T) of the detection output from GI ), (FG2)
IL (T, 2) is calculated to calculate (T+'+722), and the tape speed voltage (V, ) is obtained from that value.

On the one hand, the rotational speed detector (FGI).

Calculate the pulse width of the output of (FG2) to determine the tape length (1)
is converted to obtain the tape speed setting voltage (v2) proportional to the tape (&).

Then, compare both tape speed voltages (V1) and (V2), and apply the difference voltage to the drive motor as a servo voltage (Vs) to keep the rotation speed of the drive motor constant. The tape speed can be controlled by

<Embodiment> The background of the tape speed control method according to the present invention having such a characteristic configuration is as follows.

This invention will be described with reference to the embodiments shown in FIGS. 1 to 4.

The relationship between the tape speed and the rotational speed of each reel is as follows.

In Fig. 3, D=maximum tape winding diameter, a: hub diameter, σ: tape thickness, V:
Tape running speed (constant), 1: Tape total length, dltd2
: Tape winding diameter, T, , T2: Reel rotation period on the supply side and take-up side. Then, the rotation period T is the length of one tape round πd divided by the speed V″C″, so Naro.

Next, the sum of the areas of the tape winding diameter cL-d2 is equal to the sum of the area of the hub (diameter a) and the area of the tape (σ By calculating the value and applying it to the motor as a servo voltage, the rotational speed of the motor can be kept constant and the speed of the tape can be kept constant.

Figure tJS1 shows the schematic configuration of the main part of R-DAT, and (1
) is the supply reel of the tape (T), (2) is the take-up reel, (3) is the drum, and (4) is the capstan,
A detector (FGI) for magnetically or optically detecting the reeling speed of each reel (1) and (2) is provided on each reel (1) and (2).
(Fe2) is provided. These detectors (FGI
)t (Fe2) to detect the tape speed.

FIG. 2 is a block diagram of an embodiment of the tape speed detection servo circuit (FIG. 4) of the speed control method of the present invention, and in FIG. 2, detection "5 (Fil: 1).

Among the outputs of (Fe2), periodic data in particular are processed by two integrating circuits (S+), (S+°), (S2) and (
A double integrating circuit (S, +
S,'), (S2+S2"), and the output is applied to the next stage AC-DC converter (^DC) to convert the AC signal to a DC signal, resulting in (T,") and (T2' )
The values of are added by the adder (1,), the output is taken out as the speed detection value (V,), and the comparator (
C).

On the other hand, the outputs of the detector (FGI) and (Fe2) are led to the microprocessor (MP) through a separate circuit, and the set tape is rotated at a constant speed (v=constant) for a certain period of time, and the pulse width of the output is is calculated, and from the result, the tape size (or 议!) is detected, stored, and the tape speed setting voltage (
v2) and input the output to the comparator (C).

The tape speed voltages (V1) and (V2) are compared in the humpator (C), and the difference voltage is output from the comparator (C) as a servo voltage.

When this servo voltage (Vs) is applied to the drive motor, the rotation of the motor becomes constant, and the tape speed can always be kept constant regardless of the tape size during high-speed running.

Although the embodiments considered to be representative of the present invention have been described above, the present invention is not necessarily limited to the structures of these embodiments. It can be implemented with appropriate modification within the scope of achieving the purpose and having the effects described below.

<Effects of the Invention> In the method of the present invention, the tape is rotated at a constant speed,
At that time, the width of the output pulses of both detectors is calculated, the tape length is converted, and a tape speed value proportional to the converted tape length can be obtained as the set voltage. , the speed of the tape can always be controlled constant for any size tape.

In addition, since the tape speed is detected by calculating the detection data of the rotational speed of both the supply side and the first roll/layer side, the conventional method described above is different from the one described above. Compared to the case of the mouth, there is no need for preliminary operations such as recording the natural frequency for detection, making it very easy and convenient to carry out. There is no error caused by the dimensional accuracy of the component parts, and the square value (T, , "+T2'
), the desired tape speed can be detected extremely accurately and stably over a long period of time. Wait, R-
When using the method of the present invention, such as when searching for DAT at high speed,
As described above, based on the accurate tape speed addition calculation component obtained by the present invention, the error value obtained from the comparison result with the set speed is fed back as a servo voltage to adjust the tape speed to the set speed. Because of this control, the degree of control to keep the tape speed constant regardless of the tape size becomes extremely high.

[Brief explanation of the drawing]

Figure 1 is a schematic #j completed diagram of the main parts of R-DAT, Figure 2 is a block diagram showing the configuration of this activation, and Figure fjIJ3 is a model diagram showing the relationship between tape supply and take-up reels and tape. , FIG. 4 is a circuit diagram of an embodiment of the present invention. (1) is the supply side reel, (2) is the take-up side reel, (FG
I) is the supply side detector, (F(:2) is the winding side detector, (
T+) is the supply side rotation period, (T2) is the take-up side rotation period,
(V,) is the tape speed voltage, and (■2) is the set tape speed voltage. /'-

Claims (1)

[Claims] Detectors (FG1) and (FG2) detect the rotational speed of each of the tape supply reel (1) and take-up reel (2).
), and the two output data rotation periods (T_1) and (T_
The sum of each square calculated by the operation of 2) (T_1^2
The tape speed voltage (V_1) is obtained from the value of +T_2^2), and on the other hand, when the tape is running at a constant speed, both the detectors (
Calculate the pulse width of the outputs of FG1) and (FG2), convert it to tape length (l), obtain tape speed setting voltage (V_2) proportional to tape length (l), and calculate both tape speed voltage values. A tape speed control method characterized by controlling the speed to be constant by comparing (V_1) and (V_2) and applying the difference voltage to a drive motor.