JPS5857651A - Tape recorder - Google Patents

Abstract

PURPOSE:To ensure the stable travelling of a tape, by controlling a motor driving current after comparing the reference voltage with the value which is obtained by multiplying the value obtained by amplifying the motor driving current by the value obtained by giving an F/V conversion to the frequency of a speed generator which is proportional to the speed of a motor. CONSTITUTION:A motor 1 is driven by a voltage driving circuit 2. A speed generator 4 produces a pulse signal of a frequency proportional to the speed of revolution of the motor 1. This pulse signal undergoes an F/V conversion 5, and the rotational frequency omega of the motor 1 is obtained in the form of the DC voltage. The voltage proportional to a current I of the motor 1 is produced at a resistance 3 and then amplified to obtain alphaI+beta(alpha, beta: constants). The value v obtained by multiplying omega by (alphaI+beta) through a multiplying circuit 7 is fed to a comparator 8. The comparator 8 controls a current driving circuit 2 so as to get the value approximate to the reference tape travelling speed v0. As a result, the tape travelling speed is kept at a constant level, and a non-recorded part of a tape is detected accurately regardless of the size of the winding diameter of the tape.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a reel drive motor.

Conventionally, in this type of apparatus, the rotation speed of the reel drive motor was controlled to be constant during tape fast forwarding. For this reason, the running speed of the tape is different between the beginning and the end of the tape winding, and the playback time of the unrecorded part is also different, so there is a drawback that it is difficult to detect the unrecorded part during fast forwarding.

An object of the present invention is to eliminate the above drawbacks by controlling the current flowing through the reel drive motor so that the tape running speed is constant.

If the winding diameter of the tape wound on the take-up reel is R1 and the winding diameter of the tape wound on the sending reel is R2, then the torque of the drive motor of the take-up reel is inversely proportional to R1 and proportional to R2. Also, if C is a constant, R12+
There is a relationship R22=C, and the electric current flowing through the motor is proportional to the torque. Obey or obtain, from this R1=
c/I-Hi row] "〒]-(α is a constant ℃α=1/(C'3
is obtained.

The tape running speed (2) is given by (2) = ωR1, where Q) is the rotational speed of the winding reel drive motor, and from the above result, it becomes v-0ω/1/(α-work)2+1. Here C1
In order to simplify the damping structure, C,/v(α-work)2+1 is linearly approximated, and when α-work+μ is taken, V-ω(α-work+β) is obtained. However, α and β are constants C.

From this result, we can see that the change in can flow ≦ On the other hand, if we control the magnetic pressure applied to the motor and change ω appropriately, the tape speed If
V can be kept constant.

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

(1) is a motor for driving the take-up reel; (2) is a motor for driving the take-up reel;
) is the voltage applied to the motor (1), and (3) is the resistor for detecting the current flowing to the voltage drive circuit (2). (41 is the rotation speed of the motor (1). A speed generator (5) generates a pulse signal with a frequency f which is proportional to the speed generator (4). /V
Conversion circuit, (6) is a width circuit to increase the voltage of resistor +31, (7) outputs the product of the output of F/v conversion circuit +51 and width expansion circuit (6). At the conclusion of the T-comme (81), the output of the multiplication circuit (7) and the reference input are compared, and the difference approaches zero.

The speed generator (2) generates a pulse signal proportional to the rotational speed of the motor (11) and has a frequency of f, and is connected to the II'' force conversion circuit (
5) outputs a DC voltage proportional to the frequency (-), and the human power of the multiplier circuit (7) is controlled by the motor (11's rotation speed ω).
is obtained as DC Iu pressure. In addition, a voltage proportional to the current ■ of the motor (11) is generated in the resistor +31, and if this voltage is appropriately amplified by the circuit width t61, a DC voltage of α×β is applied to the input of the multiplier circuit (7). is obtained.Multiplication circuit (7)
multiplies the above two manual forces ω and α-work+β, and outputs the result V to the comparison circuit J (81).

Comparison cycle 181 controls the voltage applied to the motor (1st) through the commercial drive circuit (2) so that it approaches the reference tape running speed vo.The above operation keeps the tape running speed fairly constant. I'm floored by the speed vo.

As described above, according to the present invention, the running speed of the tape can always be kept constant, and the playback time of a certain unrecorded part is detected as a constant value regardless of the tape winding diameter. becomes oral Noh.

[Brief explanation of the drawing]

The figure is a configuration diagram showing an embodiment of the present invention. In the figure, (11 is a motor, (2) is a voltage drive circuit,
(3) is a resistor, (4) is a speed generator, (5) is a v/v conversion circuit, I[]) is an amplification circuit: valley, (7) is a multiplication circuit, (
8) is the comparison time 1 bath. Agent Shin Kuzuno −

Claims (1)

[Claims] A motor for driving the reel, a drive circuit for driving the voltage applied to the motor, a single speed generator interlocked with the motor, and a DC voltage proportional to the frequency of the output signal of the speed generator. an F/V conversion circuit for detecting the current flowing through the motor; a resistor connected in series to the motor for detecting the current flowing through the motor; an amplification circuit for amplifying the voltage applied to the resistor; A multiplier circuit for outputting the product of the outputs of the amplification circuit, and a multiplier circuit for outputting the product of the outputs of the amplification circuit, and a multiplier circuit that compares the multiplier circuit output with a reference input, and outputs the multiplier circuit via the drive circuit so that the difference becomes zero. The voltage applied to the motor is a
1. A tape recorder comprising a circuit that performs l[I.