KR920002706Y1 - Reel pulse generating circuit of v.t.r. - Google Patents

Abstract

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Description

VTI's auxiliary reel pulse generator

1 is a block diagram of the present invention.

2 is an embodiment circuit diagram of the present invention.

3 is a voltage waveform diagram of FIG.

* Explanation of symbols for main parts of the drawings

2: amplification part 3: waveform shaping part

4 driving unit 5 auxiliary reel pulse generating unit

6: Abnormal display part 7: Logic circuit part

PI: Photointerrupter R1-R17: Resistance

Q1-Q6: transistors C1, C2: capacitors

D1, D2: Diodes AD1, AD2: And Gate

OR1, OR2: OR gate M / M: Unstable multivibrator

The present invention indicates an abnormal state of a reel pulse generator when a breakdown or failure of a reel pulse generator occurs in a VT or audio system, and generates an auxiliary reel pulse to assist the current operating mode to be performed to the end. It relates to a reel pulse generating circuit.

Conventionally, a magnet installed under the reel table is used to detect the presence or absence of rotation of the reel table, or a hall IC is used to generate a pulse according to the reel rotation to detect the normal operation of the reel rotation, or the reel table By installing a reflector and port interrupter at the bottom, the photo interrupter is 'on / off' according to the light reflected from the reflector, so that a reel pulse is generated to detect an operation state of reel rotation. If it did not occur, it was determined that the reel rotation was abnormal, invalidating the input of all function keys and 'off' the power to stop all operation.

However, when the reel is rotated by the reel motor in a normal state, the reel pulse is not generated due to a failure or failure of the photo interrupter and the reflector, which are the reel pulse generators, or the reel pulse is caused by foreign matter such as dust attached to the photo interrupter and the reflector. Even if it does not occur, there is a problem that all the functions such as recording, reservation recording or playback that is in operation is stopped so that the user is inconvenient.

In order to solve this problem, the present invention determines whether a reel pulse is output from a reel pulse generator, and if the reel pulse is not output, an error indicator of the reel pulse generator is turned on to indicate that an error has occurred in the reel pulse generator. Simultaneously with the zoom, the auxiliary reel pulse generated by driving the auxiliary reel pulse generator is applied to the microcomputer to finish the performance of the currently operating function.

Hereinafter will be described in detail by the accompanying drawings the configuration and effect of the present invention as follows.

As shown in FIG. 1, the present invention includes a reel pulse generator 1 for generating a reel pulse according to rotation of a reel, an amplifier 2 for amplifying an output signal of the reel pulse generator 1, and A waveform shaping section 3 for differentiating the output of the amplifying section 2 into a square wave, and a driving section for converting the output of the waveform shaping section 3 into a DC voltage to drive an auxiliary reel pulse generator. (4) and an auxiliary reel pulse generator (5) for generating an auxiliary reel pulse by the output of the driver (4), the output and the reel motor of the amplifier (2) and the auxiliary reel pulse generator (5). Logic circuit section for applying the reel pulse generated by the reel pulse generator (1) (5) by the logical combination of the rotation signal (RF) (RR) to the reel pulse input terminal (RP) of the conventional microcomputer (MC) 7) and an abnormality display section 6 which displays whether or not the reel pulse generator is abnormal by the outputs of the drive section 4 and the logic circuit section 5.

The effect of the present invention configured as described above is that the video tape is inserted into the VTI as shown in the embodiment of FIG. 2, and when the playback, recording, fast-forwarding or rewinding mode is performed, the reel pulse generator 1 When the reel pulse generated by 'on / off' the photointerrupter PI by the light reflected from the reflecting pin RE is normally output, the reel pulse generated by the reel pulse generator 1 is amplified. When applied to (2) and amplified, a pulse equal to the 3a degree is output, and this amplified pulse is a differential pulse equal to the 3b degree through a differential circuit composed of the capacitor (CI) and the resistor (R4) in the waveform shaping section (3). This differential pulse is shaped into a square wave by a waveform shaping circuit consisting of resistors R5-R9 and transistors Q2 and Q3 to produce pulses like the third c diagram.

When the square wave is applied to the base of the transistor Q4 through the bias resistor R10 after being leveled by the diode D2 and the capacitor C2 in the driving unit 4 as the 3d degree, the transistor Q4 is applied. As the collector output of the transistor Q4, which is the output of the driver 4, becomes 'low' level voltage, the power supply voltage VD applied to the unstable multivibrator M / M that is the auxiliary reel pulse generator 5 ), There is no oscillation output in the multivibrator (M / M).

On the other hand, as the output voltage of the driving unit 4 becomes 'low' level, the output of the AND gate AD3 in the abnormality display unit 6 also becomes 'low' level, so that the transistor Q6 is 'off' so that The abnormality indicator light emitting diode LD1 is maintained in an 'off' state.

In addition, the 'low' level voltage output of the driver 4 is applied to one side pressure of the AND gate AD2 in the logic circuit 7 and at the same time through the bias resistors R12 and R13 to the base of the transistor Q5. As the transistor Q5 is 'off', the resistor R17 is applied to the other input of the AND gate AD1 to which an amplified reel pulse, which is an output of the amplifier 2, is applied to one input. B voltage through is applied. Accordingly, the output of the AND gate AD2 becomes a 'low' level voltage, and the output of the AND gate AD1 outputs an amplified reel pulse signal to the input of the OR gate OR1 as shown in FIG. 3h. Since each is applied, the output of the OR gate OR1 becomes the same amplified reel pulse signal as that of the AND gate AD1 and is applied to the reel pulse input terminal RP of the microcomputer MC.

Accordingly, the microcomputer MC determines that the reel is in a normal state and continues the current execution mode.

In addition, when the reel pulse is not generated by the foreign matter such as the defect or dust of the photo interrupter PI or the reflector RE in the reel pulse generator 1, the amplifying unit 2 and the waveform shaping unit 3 ), The transistor Q4 in the driver 4 is 'off' so that the B voltage through the resistor Q18 becomes the power supply voltage VD of the unstable multivibrator M / M as shown in FIG. This multivibrator (M / M) is operated so that a square wave pulse set to several tens of HZ is applied to one input of the AND gate AD2 in the logic circuit portion 7 as shown in FIG. 3F. On the other hand, the B voltage, which is the output of the driving unit 4, is a high-level reel motor forward rotation signal RF or reverse rotation signal RR having a 'high' level at one input via the abnormality display unit 6 resistors R14 and R15. Is applied to the other input of the AND gate AD3, and the output of the AND gate AD3 becomes a 'high' level voltage, and thus the transistor Q6 to which the 'high' level voltage is applied to the base is The conductive light emitting diode LD of the reel pulse generator is turned on.

The voltage B, which is the output of the driver 4, is applied to the other input of the AND gate AD2 in the logic circuit 7, so that the 'high' level voltage is applied to two of the three inputs of the AND gate D2. Since an auxiliary reel pulse, which is an output of the auxiliary reel pulse generator 5, is applied to the other input, an auxiliary reel pulse signal is output from this AND gate AD2 as shown in FIG. The output signal of the AND gate AD1 that is 'level' is applied to the other input of the OR gate OR1 to which it is applied.

Therefore, as shown in FIG. 3i, the ore gate OR1 outputs an auxiliary reel pulse almost identical to the reel pulse, and is applied to the reel pulse input terminal RP of the microcomputer MC. It is determined that the rotation is in a steady state and continues to perform the current mode.

In this way, the present invention lights up the light emitting diode for displaying the abnormality of the reel pulse generator even when the reel pulse generator is not generated due to a defect of the reel pulse generator or the adhesion of foreign matter such as dust, and the auxiliary reel pulse generator drives the auxiliary reel. Generates a pulse and applies it to the reel pulse input terminal of the microcomputer to generate auxiliary reel pulses such as playback or recording currently in operation. In addition, it has the effect of notifying that an abnormality has occurred in the reel pulse generator.

Claims (1)

In response to the output signal of the conventional reel pulse generator 1 which generates a reel pulse in accordance with the rotation of the reel, the amplifier 2 differentiates the output signal from the amplifier 2 and amplifies the output of the amplifier 2 into a square wave. The waveform shaping section 3 to be shaped, the driving section 4 for converting the output of the waveform shaping section 3 into a DC voltage to drive the auxiliary reel pulse generator, and the auxiliary reel by the output of the driving section 4. The reel is generated by a logical combination of an auxiliary reel pulse generator 5 for generating a pulse, an output of the amplifier 2 and an auxiliary reel pulse generator 5, and a reel motor rotation signal RF RR. Logic circuit section 7 for applying the reel pulse generated by pulse generators 1 and 5 to the reel pulse input terminal RP of the conventional microcomputer MC, and the driving section 4 and the logic circuit section 5. Auxiliary display unit (6) for indicating whether or not the reel pulse generator is abnormal by the output of Pulse generating circuit.