KR0136094B1 - Method for sensing starting point and ending point in cassette tape - Google Patents

Abstract

No content

Description

How to detect start and end points of cassette tapes

1 is a circuit diagram for explaining the method of the present invention.

2 is a flow chart of the method of the present invention.

3, signal waveforms for explaining the method of the present invention.

4 is a start and end point detecting circuit diagram of a cassette tape according to a conventional constant current driving method.

b is a start and end point detection circuit diagram of a cassette tape by a conventional pulse driving method.

* Description of the symbols for the main parts of the drawings *

I: Microcomputer R _1- R ₃ : Register Q ₁ : Light receiving transistor

TR ₁ : Transistor LED ₁ : Light Emitting Diode

Detailed description of the invention

The present invention relates to a method for detecting the start and end points of a cassette tape. In particular, a predetermined program is inputted to a microcomputer in a cassette tape recorder to prevent malfunction of external light and noise having a regular period so that the start and end points of the tape can be accurately determined. A method for detecting the start and end points of a cassette tape which can be detected.

In the conventional cassette tape recorder, the tape start and end point detection circuits can be largely divided into two types as shown in a and b of FIG. The latter is a constant current system as shown in FIG. 4A, and the latter is a pulse system as shown in FIG. 4B composed of a light emitting unit using a pulse driving method and a light receiving unit using an amplifier.

First, in the case of the former, the current i _F flowing through the light emitting diode LED _{1 as} shown in FIG. (V _LED1 forward voltage drop) As a constant amount of current flows i _F , the light emitting diode (LED ₁ ) is always kept on. At this time, since the start and end points of the cassette tape are transparent, the light passes through The light receiving transistor Q ₁ is turned on.

Therefore, the voltage induced across the emitter resistor R _E of the light receiving transistor Q ₁ becomes i × R _E. At this time, the microcomputer 31 detects the voltage through the input terminal I ₁ and detects the voltage with the cassette tape. You will recognize the start and end points. However, since such a configuration requires the use of a transistor composed of a Darlington circuit to increase the sensitivity of the light receiving transistor Q ₁ , the production cost of the product is increased and a separate light shielding device is required for external light.

That is, the light-receiving transistor (Q ₁₎ is easily conducts the light-receiving transistor which operates even in so flowing a predetermined current (i) a microcomputer 31, noise or the like (Q ₁₎ in accordance with the sensitivity of the use of the preferred light-receiving transistor (Q ₁₎ As it can be easily misunderstood due to the characteristics of the light emitting transistor (Q ₁ ) and the emitter resistor (R _E ), the use range is limited, especially since a constant current flows to the light emitting diode (LED ₁ ) for a long time use. There is a problem such that deterioration of the device is caused to shorten the life of the device.

를 갖는 펄스가 인가되므로 순간적(통상 듀리 동안)으로 온이 되는데, 이때 이는 듀리가 짧으므로 발광다이오드(LED₂)에 큰 영향을 주지않기 위해 발광다이오드(LED₂)에 흐르는 전류(i_F)는 최대에 가깝게 흘려주게 된다.In the latter case, as shown in b of FIG. 4, the duty ratio is constant at a constant period T at the base of the transistor TR ₁ controlled by the pulse generated by the microcomputer 41.

So it has a pulse momentarily there is turned ON (while the normal dyuri), where it therefore dew Riga short light-emitting diode current (i _F) flowing through the light-emitting diode (LED ₂₎ not to have a significant impact on (LED ₂₎ is Shed close to the maximum.

이 인가되므로 비교기(42)의 출력은 반전 입력단자에 인가되는 전압(V_0N)이 기준전압(V_R)보다 작을 경우에만 '로우'상태로 나타나게 되고, 마이컴(41)은 이 '로우'신호에 의해 카세트 테이프의 시작점 및 종단점을 인식할 수가 있게 된다.Therefore, the light receiving transistor Q ₂ is turned on only during the course of the driving pulse so that a predetermined voltage is applied to the inverting input terminal (-) of the comparator 42.

Since the output of the comparator 42 is applied to the 'low' state only when the voltage V _0N applied to the inverting input terminal is smaller than the reference voltage V _R , the microcomputer 41 receives the 'low' signal. This makes it possible to recognize the start point and the end point of the cassette tape.

As a result, the efficiency of the light emitting diode (LED ₂ ) is good and there is no need to use a light receiving transistor composed of a Darlington circuit as described above. However, the circuit is complicated and the light receiving transistor is similar to a normal pulse for noise having a regular period. Since Q ₂ is driven, there is a problem that the reliability of the product is lowered.

The present invention has been proposed to solve such a conventional problem, and the external noise is achieved by using a predetermined program by inverting a data signal by a short duration by inputting a predetermined program into the microcomputer without using a comparator in the conventional pulse driving method. The starting point and end point detection method of the cassette tape, which can not only prevent malfunctions but also reduce the production cost of the product, will be described in detail as follows.

을 레지스터(R₂)에 기억시키고, 이어서 수광 트랜지스터(Q₁)의 콜렉터가 연결된 상기 마이컴(I)의 입력단자(I₁)에 소정 펄스가 입력되고 있는가를 계속 검출하여 소정 신호가 입력되면 이 신호를 레지스터(R₃)에 기억시킨후 2주기(2T)의 데이타를 입력받아 레지스터(R₂,R₃)내에 기억된 데이터가 동일한가를 검출하여 같지않으면 최초 과정으로 돌아가고, 같으면 센서 인식모드로 전환하고 종료하는 과정으로 이루어짐을 특징으로 하는 것으로, 여기서 미설명 부호 R_B,R_F,R은 저항이고, TR₁은 트랜지스터이다.As shown in Figs. 1 and 2, the method of the present invention stores the digital pulse signal output from the output terminal O ₁ of the microcomputer I in the register R ₁ and then the contents of the register R ₁ . Reversed

Is stored in a register (R ₂ ), and then a signal is continuously inputted by detecting whether a predetermined pulse is input to the input terminal (I ₁ ) of the microcomputer (I) to which the collector of the light receiving transistor (Q ₁ ) is connected. Is stored in register (R ₃ ), and data from two cycles (2T) is inputted to detect whether the data stored in registers (R ₂ , R ₃ ) are the same. And it is characterized in that it consists of a process of terminating, wherein reference numeral R _B , R _F , R is a resistor, TR ₁ is a transistor.

The operation and effect of the method of the present invention made as described above will be described with reference to a and b in FIGS. 1 to 3.

First, assuming that the output terminal O ₁ of the microcomputer I outputs a signal such as a in FIG. 3, that is, random data that is discontinuously and continuously changed, the transistor TR _{1 is} connected to a in FIG. Since the LED is turned on only in the 'high' period, the light emitting diode LED ₁ is repeatedly performed on and off like the transistor TR ₁ .

Therefore, the light of the light emitting diode LED ₁ is transmitted only at the start or end of the tape, and the light receiving transistor Q ₁ is turned on and off. In this case, the collector of the light receiving transistor Q ₁ is driven as shown in FIG. A waveform such as b in FIG. 3, which is identical to the inverted pulse, appears.

Accordingly, in the microcomputer I, the inverted signal (value stored in the register R ₂ ) and the input terminal I ₁ of the signal initially output through the output terminal O ₁ are inputted through the register R _3. If the two signal data are the same, it is recognized as the start and end point, and if it is not the same, the next control operation is performed. The starting and ending points can be detected accurately.

As described above, according to the method of the present invention, the pulse receiving method is used to increase the efficiency of the light emitting part, but the light receiving part is not only simple to reduce the production cost of the product but also to use the data signal due to the short duration. By inverting again and detecting the starting point and the ending point by mutual comparison, it is possible to prevent the malfunction of the external noise signal and improve the reliability of the product.

Claims (1)

Was that which stores the digital pulse signal to be output from the output terminal (O ₁₎ of the microcomputer (I) in a register (R _1), then stored in a register (R _1), and then, inverting the contents of the register (R ₁₎ Contents

Is stored in a register (R ₂ ), and then a signal is continuously inputted by detecting whether a predetermined pulse is input to the input terminal (I ₁ ) of the microcomputer (I) to which the collector of the light receiving transistor (Q ₁ ) is connected. Is stored in register (R ₃ ), input data of 2 cycles (2T) is detected and the data stored in register (R ₂ , R ₃ ) is the same. Starting and ending point detection method of the cassette tape, characterized in that consisting of a process of ending.

Images