JPH02308464A - Constant velocity controller for cassette tape - Google Patents

Abstract

PURPOSE:To perform the fast forward and rewind of a tape at constant speed in spite of the presence/absence of a control signal by calculating the rotating speed of a tape driving motor capable of setting tape speed at a constant value in the fast feed and the rewind from a residual value, and controlling the rotating speed of the motor. CONSTITUTION:A tape residual quantity arithmetic circuit 14 is comprised of a small scale microcomputer, and a take-up reel FG signal and a supply reel FG signal are inputted from pulse generators 12 and 13, respectively, and furthermore, the control signal and a capstan FG signal are inputted, then, the residual value of a cassette tape 1 is calculated. In other words, it is possible to calculate the frequency of a motor FG signal corresponding to the tape speed decided in advance at the position of the tape by computing the position of the tape sequentially by the circuit 14 at the time of fast forwarding and rewinding. Next, a motor rotating speed control circuit 16 controls the rotating speed of the motor 10 so as to go to the frequency of the motor FG signal from a circuit 11 at the frequency calculated at a circuit 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a constant speed control device for tape speed during fast forwarding and rewinding of a magnetic recording/reproducing device using a cassette tape.

[Prior Art] Fig. 5 is a block circuit diagram showing an example of a conventional cassette tape constant speed control device, in which (1) is a cassette tape, (
2) is a take-up reel, (3) is a supply reel, (4) is a magnetic tape, (5) is a CTL head, (6) is a CTL amplifier, [7] is a control circuit, (8) is a changeover switch, ( 9) is a motor drive circuit; (10) is a motor for driving magnetic tape fast forwarding and rewinding (hereinafter referred to as "motor"); (11) is a motor for driving magnetic tape fast forward and rewind;
) is a motor FG signal generation circuit.

Next, the operation will be explained.

The CTL head (5) picks up the control signal recorded on the magnetic tape (4) and sends it to the CTL amplifier (6).
After being amplified, the control signal is input to the control circuit (7) and multiplied by a predetermined multiple, and the control signal is input to the input terminal a of the changeover switch (8).

On the other hand, the input terminal of the changeover switch (8) is connected to the motor FG.
A motor FG signal having a frequency proportional to the rotational speed of the motor (10) is generated from a signal generation circuit (11) and is manually inputted. The control circuit (7) outputs a switching control signal to the changeover switch (8), and when a control signal is input from the CTL amplifier (6), a multiplied control signal input from the control circuit (7) is output. is selected, and when no control signal is input from the CTL amplifier (6), switching is made to select the motor FG signal input from the motor FG signal generation circuit (11).

The signal selected by the changeover switch (8) is input to the motor drive circuit (9), and controls the rotation speed of the capstan motor (lO) so that the frequencies of the input signal and the motor FG signal match.

During fast forwarding and rewinding of the tape, the magnetic tape (4) is driven by a drive system connected to the motor (10). At this time, the control signal recorded on the magnetic tape (4) is a signal with a frequency proportional to the running speed of the magnetic tape (4), so the motor (lO) is adjusted so that the frequency of this control signal is constant. By controlling the rotation speed, the magnetic tape (4) is fast forwarded or rewound at a constant speed. The tape speed at this time is determined by the frequency of the multiplied control signal output from the control circuit (7).

Further, when no control signal is recorded on the magnetic tape (4), the changeover switch (8) is switched to the input end side, and the rotation speed of the motor (10) is controlled by the FG flaw signal frequency. In this case, the take-up reel (2)
Since the rotational speed of the tape is controlled at a constant rotational speed, the tape speed depends on the winding radius of the tape wound around the hub of the take-up reel (2) and is not constant.

[Problems to be Solved by the Invention] Since the conventional constant speed control device for cassette tape is configured as described above, if no control signal is recorded on the magnetic tape, the speed of the motor is controlled by the motor FG signal. Since the magnetic tape is controlled, there is a problem in that it is not possible to control the constant speed of the magnetic tape.

This invention was made in order to solve the above-mentioned problems, and it is a constant speed cassette tape that allows fast forwarding and rewinding of the tape at a constant speed even if no control signal is recorded on the 6N tape. The purpose is to obtain a control device.

[Means for Solving the Problems] A constant speed control device for a cassette tape according to the present invention includes means for detecting the rotational speed of a supply reel and a take-up reel;
The remaining amount of tape is calculated sequentially from these detection signals and the data of the cassette tape, and the number of rotations of the motor required to feed the tape at a constant speed is calculated from this remaining amount value. The number of rotations of the motor that drives the tape is controlled so that the following is achieved.

[Function] The tape constant speed control device according to the present invention calculates the remaining amount of the tape that represents the tape position at that point in the constant speed running state during recording or playback, and then calculates the remaining amount value of the tape that represents the tape position at that time during fast forwarding or rewinding. The number of rotations of the tape drive motor corresponding to constant speed feeding is calculated from time to time, and the tape drive motor is controlled to the calculated number of rotations.

As a result, the fast forward and rewind speeds of the tape are always constant regardless of the presence or absence of the control signal.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, (12) and (13) are pulse generators, and the take-up reel (2) and the supply reel (2) are pulse generators, respectively.
3) The reel FG signal is connected to and rotates to generate a reel FG signal with a frequency proportional to the number of rotations. (14) is a tape remaining amount calculation circuit, (15) is a calculation circuit that calculates the rotation speed of the motor (10), and (16) is a control circuit that controls the rotation speed of the motor (10).

Next, the operation of this embodiment will be explained.

First, in order to know the type of cassette tape (1), that is, the total length of the tape, the thickness of the tape, the diameter of the hub, etc., first, the magnetic tape (4) is pressed onto a capstan (not shown) using a pinch roller. That is, the magnetic tape (4) is run in a state in which the tape speed can be determined by the frequency of the capstan FG signal.

The tape remaining amount calculating circuit (14) is composed of a small-scale microcomputer, and a pulse generator (12)
A take-up reel FG signal and a supply reel FG signal are input from and (13), respectively, and a control signal and a capstan FG signal are input manually to determine the type of cassette tape (1) according to the flowchart in FIG. and the remaining amount value (indicating the position) of the tape.

That is, as shown in FIG. 2, in step (101) the number of pulses of the capstan FG per revolution of the supply reel (3) is counted, and then in step (102) the number of pulses of the capstan FG is counted per revolution of the supply reel (3). ), and then in step (103) the total amount of tape is calculated based on the number of pulses of the FG signal for both reels (2) and H). and then step (
In step 104), the hub diameter of the cassette (1) is determined.

Since a general VH5 type cassette tape has a hub diameter of 2ffI, it is possible to identify which type of cassette tape it is.

In step (105), based on the total amount of tape and the hub diameter, the cassette tape is T-120, T-90, T-60,
Next, in step (106), a remaining amount value is calculated from the amount of tape remaining on the supply reel (3) side.

Calculation of this remaining amount value is performed in the following procedure.

In FIG. 4, the tape winding radius on the supply reel side is Rs,
The tape winding radius on the take-up reel side is RT, the hub diameter is r,
Assuming that the tape thickness is t, the tape speed during recording and playback is Vo, and the length of the tape remaining on the supply reel is Ls, the remaining amount TR of the tape when running at the tape speed vO can be found as follows.

Once the type of cassette tape is determined, the relationship between the tape (remaining amount value) and the frequency of the motor FG signal to keep the tape speed constant during fast forwarding or rewinding is as shown in Figure 3. There is a certain relationship depending on the type of

That is, during fast forwarding or rewinding, by sequentially calculating the tape position (remaining amount value) by the tape remaining amount calculating circuit (14), the frequency of the motor FG signal corresponding to the predetermined tape speed at that tape position is determined. can be calculated.

For example, when the cassette tape type is B and the tape position is Tl, the frequency of the motor FG signal is set to Fl, and when the tape position is Tl, the frequency of the motor FG signal is set to F2. Just control it.

The frequency of the motor FG signal corresponding to this tape speed is:
In the motor rotation speed calculation circuit (15), it is calculated by the following calculation.

The tape winding radius Rs of the supply reel (3) is determined by the following equation.

Now, let the tape speed at the time of first return be V, and the time required for the supply reel (3) to rotate once at this point is T.
When s is assumed, substituting equation (1) into equation (2) gives the following equation.

Here, the reduction ratio of the drive shaft of the motor (lO) and the drive side reel (rewind reel) is set to 1/2, and the rotation shaft of the motor (10) is set to 1/2.
Assuming that the number of pulses of the motor FG signal per rotation is 720, the relationship between Ts and the frequency f of the motor FG signal is expressed by the following equation.

Substituting equation (4) into equation (3): ...(5) Therefore, the relationship between the tape position (remaining amount value) and the frequency f of the motor FG signal to be controlled is given by the following equation.

...(6) Next, the motor rotation speed control circuit (16) calculates the frequency of the motor FG signal input from the motor FG signal generation circuit (11), which is calculated by the motor rotation speed calculation circuit (15). The rotation speed of the motor (10) is controlled so that the frequency becomes fFG.

In this way, the tape speed when rewinding the tape can be controlled to a constant speed regardless of the presence or absence of the control signal.

The above operation has been explained using the case of rewinding as an example, but the operation during fast forwarding is also similar.

In addition, in the above embodiment, the operation for determining the type of cassette tape, that is, the total length and thickness of the tape, the hub diameter, etc., was explained, but if these values are known in advance, this determination operation can be performed. No longer needed.

[Effects of the Invention] As described above, according to the present invention, the remaining amount of the tape is calculated from the number of revolutions of the cassette reel and the data of the cassette tape, and fast forwarding or rewinding is performed from this remaining amount value. The number of revolutions of the tape drive motor is calculated so that the tape speed becomes a predetermined constant value, and the number of revolutions of the motor is controlled. Therefore, the tape can be fast-forwarded and rewound at a constant speed regardless of the presence or absence of a control signal. This has the advantage of providing a constant speed control device for cassette tapes that can perform the following functions.

[Brief explanation of drawings]

Fig. 1 is a block circuit diagram of an embodiment of the present invention, Fig. 2 is a flowchart of the remaining tape amount calculation circuit in this embodiment, and Fig. 3 shows the tape position and frequency of the motor FG signal when the tape speed is constant. Diagram showing the relationship between
The figure is a diagram for explaining a formula for calculating the remaining amount of tape, and FIG. 5 is a block circuit diagram of a conventional fast forward/first return constant speed control device. (1)...cassette tape, (2)...take-up reel, (3)...supply reel, (4)...magnetic tape,
(9)...Motor drive circuit, (10)...Motor for driving tape fast forward/rewind, (11)...Motor FG signal generation circuit, (12), (13)...Pulse Generator, (14)...Tape remaining amount calculation circuit, (1
5)...Motor rotation speed calculation circuit, (16)...Motor rotation speed control circuit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A means for detecting the number of revolutions of a take-up reel and a supply reel of a cassette tape, a means for calculating the remaining amount of tape based on these revolution number signals and data determined by the type of the cassette tape, means for calculating the number of rotations of a tape drive motor for fast forwarding or rewinding the tape at a predetermined constant speed from the amount; and means for controlling the number of rotations of the motor so as to achieve the calculated number of rotations; A constant speed control device for cassette tapes.