KR910004657Y1 - Analog/ttl signal automatic distinction circuit for monitor - Google Patents

Abstract

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Description

Analog / Tield Signal Automatic Identification Circuit of Monitor

1 is a circuit diagram of an embodiment of the present invention.

2 is a voltage waveform diagram of FIG.

* Explanation of symbols for main parts of the drawings

1: buffer part 2: pulse generator

3: drive unit 4: output unit

R ₁ -R ₈ : Resistor Q ₁ -Q ₂ : Transistor

C ₁ -C ₃ : Condenser MM ₁ : Monostable Oscillator

RY: Relay

The present invention is a combined monitor connected to a computer that outputs an analog signal and a computer that outputs a TiTel signal, to automatically determine whether the input signal is an analog signal or a TITEL signal to switch and select the analog TiTel driving circuit of the monitor. It relates to an analog / TI signal automatic discrimination circuit.

In the conventional combined monitor, it is inconvenient to operate the selection switch manually because the mechanical selection switch attached to the monitor is switched manually by recognizing whether it is a computer that outputs an analog signal or a computer that outputs a TI signal. If the input signal and the selector switch do not match, not only the image of the screen collapses, but also the mechanical cost increases due to the use of the mechanical selector switch.

In order to solve this problem, this paper suggests that the ground signal is input from the computer where the analog signal is output to the connection terminal of the computer and the monitor (pin 8 on the IBM combined computer), and the horizontal synchronous signal is input from the computer where the TTI signal is output. By increasing the duty cycle of the horizontal synchronous signal input from the computer where the TTI signal is output, and smoothing the extended pulse, the relay is operated to automatically operate the analog signal driving circuit and the TTI signal driving circuit in the monitor. It is designed to switch.

Hereinafter will be described in detail the configuration and effect of the present proposal.

The horizontal synchronous signal or the ground signal output from the computer is input from the connection terminal CN ₁ and applied to the buffer unit 1, and the stabilized signal, which is the output of the buffer unit 1, is applied to the pulse generator 2. A pulse signal having a large duty cycle output from the pulse generator 2 is applied to the driver 3, and the output of the driver 3 is applied to the output unit 4 so as to be connected to the monitor terminal CN _2. Analog / TiTel signal input to) is configured to be applied to the analog TiTel driving circuit of a normal monitor.

In the above configuration, the buffer unit 1 is a horizontal synchronization signal or ground signal input to the monitor terminal CN ₁ of the collector via the coupling capacitor (C ₁ ) and the bias resistor (R ₁ ) (R ₂ ) Is applied to the base of the transistor TR ₁ connected to the B power supply via the resistor R ₃ , and the emitter output of this transistor TR _{1 to} which the emitter resistor R ₄ is connected is supplied to the pulse generator 2. The pulse generator 2 is applied to the clock terminal CK of the monostable oscillator MM ₁ , and to the pulse width determining terminal PC ₁ (PC ₂ ). The output Q of this monostable oscillator MM ₁ , to which the pulse width determining resistor R ₈ and the capacitor C ₃ are connected, is connected to the driving unit 3, and the driving unit 3 is a pulse generating unit. The output of (2) is applied to the base of the transistor TR ₂ via the bias resistor R ₇ and the smoothing capacitor C ₂ , the emitter resistor R ₆ is connected to the emitter, and the output resistor ( R ₅₎ Connected and the collector output resistor (R ₅₎ are each attached with the collector output of the transistor (TR ₂₎ is connected to be applied to the output unit 4, an output section 4 connected to the ground side output of the drive unit 3 One relay RY is applied to the other side of the coil, and the fixed contact points a and b are connected to the movable contact c of the relay RY, respectively connected to the analog drive circuit ADC and the TTI drive circuit TDC. The analog / TI signal input through the connection terminal CN ₂ is connected to be applied.

In the present invention configured as described above, when an analog signal is output from the computer, the ground potential is input to the connection terminal CN ₁ and applied to the buffer unit 1, so that the transistor TR ₁ in the buffer unit ₁ is " Off ", whereby the output of the buffer unit 1 is at the" low "level, and this" low "level output is applied to the clock terminal CK of the monostable oscillator MM _{1 in the} pulse generator 2. The monostable oscillator MM ₁ outputs the output terminal Q at a pulse width set by the pulse width determining resistor R ₈ and the capacitor C ₃ whenever a positive pulse is input to the clock terminal CK. Since the square waves are output one by one, when the "low" level is applied to the clock terminal CK, the monostable oscillator MM ₁ does not operate, and the "low" level is output from the output terminal Q. A transistor (TR _2), the output unit 4 via the B ⁺ supply, the output resistance (R ₅₎ thus being "off", in the "low" level signal is applied from the drive unit 3 drive unit 3 When the current flows through the coil of the relay RY, the movable contact c is switched from the fixed contact a to the fixed contact b. Therefore, the analog signal input to the connection terminal CN ₂ is applied to the normal analog driving circuit ADC through the contacts c and b of the relay RY.

On the other hand, when the TTI signal is output from the computer, a horizontal synchronization signal is input to the connection terminal N ₁ and applied to the buffer unit 1, and the horizontal synchronization signal applied to the buffer unit 1 is coupled to the coupling capacitor ( C ₁₎ and a bias resistor (R ₁₎ (the transistor (TR ₁₎ driven as R ₂₎ is applied to the base of the transistor (TR ₁₎ via an emitter output of the 2a horizontal synchronizing signal and the same waveform as help The stable pulse signal is output and applied to the pulse generator 2. The positive polarity pulse signal is in the monostable oscillator (MM ₁₎ clock terminal monostable oscillator (MM _1), the output (Q) each time it is applied, one at (CK) of in a pulse-generating unit (2) resistance (R ₈₎ And square wave signals having a pulse width set by the condenser C ₃ , are output one by one to become the same signal as that of the second diagram. When a large square wave signal having a duty cycle is generated and applied to the driving unit 3 in this manner, the pulse signal is smoothed by the resistor R ₇ and the condenser C _{2 in the} driving unit 3. the signal of the transistor (TR ₂₎ in the there is thereby conducting the transistor (TR ₂₎ is applied to the base transistor (TR ₂₎ the emitter resistor (R ₆₎ and the resistance value output resistance (R ₅₎ of the connected to the emitter of the The emitter output of transistor TR ₂ is set to be much smaller than the resistance value so that a "low" level voltage close to ground potential is output. When this " low " level voltage output from the drive unit 3 is applied to the relay RY coil in the output unit 4, the relay RY does not operate so that the movable contact c is fixed at the fixed contact b. By returning to the initial ecology of the contact point (a), the Ti-Tel signal input to the connection terminal (CN ₂ ) is applied to the normal Ti-Tel driving circuit (TDC) through the contact (c) (a) of the relay (RY).

As described above, the present invention uses horizontal synchronization signals or ground signals to be input to one connection terminal CN ₁ according to the output signal method of the computer, and when the TTI signal is output from the computer, the connection terminal CN ₁ is inputted. By converting the horizontal synchronous signal into a pulse signal with a large duty cycle, the relay RY is turned on and off according to the pulse signal so that the analog / tiel driving circuit is automatically switched according to the analog / tiel signal output from the computer. It is easy to use because there is no need to operate the mechanical selection switch manually, and it is possible to prevent the collapse of the screen that occurs when the selection switch is switched, and the cost of the product is reduced because there is no need to use the mechanical switch. It is a useful design with the advantages such as.

Claims (2)

A buffer unit 1 for stabilizing a horizontal synchronizing signal or a ground signal input through the monitor terminal CN ₁ , and a square wave signal having a large duty cycle when the output of the buffer unit 1 is a positive pulse. The pulse generator 2 to be made to be made, the output of this pulse generator 2 is smoothed, and the drive part 3 which is switched-controlled by this smoothing voltage, and the analog input to the monitor by the output of this drive part 3 is made. Or an output unit (4) for selectively applying a TTI signal to a conventional analog or TDC drive circuit (ADC) (TDC). The automatic discrimination circuit according to claim 1, characterized in that the pulse generator (2) consists of a monostable oscillator (MM ₁ ).