KR900004467Y1 - Video signal selecting circuit for electronic view-finder - Google Patents

Abstract

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Description

Image signal selection circuit for electronic finder

1 is a circuit diagram of the present invention.

* Explanation of symbols for main parts of the drawings

1: Encoder output part 2: Buffer part

3: integrating circuit 4: regeneration mode detecting circuit

5: Camera and VHS type VCR output part 6: Broadcast VCR output part

7: control signal generator Q ₁ -Q ₁₄ : transistor

R ₁ -R ₃₄ : Resistor D ₁ : Diode

C ₁ -C ₅ : Capacitor

The present invention monitors the video signal of the video camera and the playback video signal of the VHS VCR and the playback video signal of the U-matic VCR according to the method and operation mode of the VCR connected to the camera. And a video signal selection circuit for an electronic finder.

In the past, since a video camera was used exclusively for a VHS-type VCR or a broadcast VCR, only one signal of the camera's own video signal and the VCR playback video signal was output to the electronic finder, so the switch was selected.

In other words, by receiving the control signal and switching the connection of the electronic switch, the camera video signal and the VCR playback video signal were selected and output to the electronic finder.

And when connecting a VHS VCR and a video camera, the video signal is transmitted to the input and output common lines, while in the U-matic VCR, a separate line is used to input and output the video signal. In order to connect and use a broadcast VCR to a video camera, it is necessary to select three video signals: a video signal of a video camera, a playback video signal of a VHS VCR, and a playback video signal of a broadcasting (U-matic) VCR.

However, in the conventional method, only two video signals can be selected, and when a signal line is connected in parallel, a VHS method and a broadcast (U-matic) VCR are connected to the video signal, which causes a malfunction. There was a problem.

In consideration of the above, the present invention selects three video signals according to the method and operation mode of the VCR connected to the camera so that they can be monitored by the electronic finder. It detects the component and selects the camera signal and playback video signal.When connected with a U-matic VCR, it creates a separate output unit that receives the playback video signal and outputs it to the electronic finder so that the camera signal and playback video signal can be selected. It is possible to connect and use two types of VCR, and to select three signals according to the operation status and output them to the electronic finder so that the performance and image quality of the video signal and the recorded video signal can be monitored. .

This will be described in detail with reference to the accompanying drawings.

The video signal of the encoder output unit ₁ passes through the buffer unit 2 composed of the bias resistors R ₁ -R ₃ and the transistor Q ₁ , and then the VHS through the capacitor C ₁ and the resistor R ₃₄ . It is connected to the video input / output terminal (E) of the method VCR and is output to the electronic finder output terminal (A) through the camera and the VHS method VCR output unit (5), but the video signal of the video input terminal (E) is a resistor (R ₂₇ ). And a regeneration mode sensing circuit 4 composed of transistors Q ₁₂ -Q ₁₄ operating simultaneously with the resistors R ₂₈ -R ₃₃ through an integrating circuit 3 composed of a capacitor C ₅ and a diode ( D ₁ ) and the transistor Q ₂ are controlled to control the driving.

And a transistor of the control signal generator 7 comprising transistors Q ₉ -Q ₁₁ and resistors R ₂₂ -R ₂₆ driven according to the input levels of the VCR selection stage C and the recording / playback adjusting stage D. FIG. The collector outputs of (Q ₁₀ ) and (Q ₁₁ ) control the transistors (Q ₄ ) (Q ₅ ) (Q ₆ ) (Q ₈ ) of the camera and the VHS type VCR output unit 5 and the broadcast VCR output unit 6. The playback video signal terminal B is connected to the base of the transistor Q ₇ of the broadcasting VCR output unit 6, and the electron finder output terminal A is connected from the collector side of the transistors Q ₅ and Q ₈ . ) Is configured to be connected.

At this time, the high level is applied to the VCR selection terminal C when the VHS VCR is connected, and the low level is applied when the VCR for broadcasting is connected, and the low level is applied when the recording signal is reproduced.

In the present invention configured as described above, when the camera is used in connection with the VHS VCR, the VCR selection terminal C is connected to the VHS VCR, so that the high level signal is transmitted to the transistor Q ₉ through the bias resistor R ₂₂ . applied to the base because the transistor (Q ₉₎ is "off" the transistor (Q ₁₀₎ and the transistor (Q ₁₀₎ regardless of the input signal of the adjusted recording and playback to be applied to the base terminal (D) "off" doemeurosseo transistor of Since the emitter current of Q ₁₀ does not flow, the transistor Q ₁₁ also becomes a "turn off" state.

Therefore connected to the collector side of the transistor (Q ₁₀₎ transistor (Q ₄₎ (Q ₅₎ the base has a low level is applied and the base of the transistor (Q ₁₁₎ transistor (Q ₆₎ (Q ₈₎ connected to the collector side of there of Transistor Q ₄ is " turned on " and transistor Q ₅ " Q ₆ "

Therefore, the broadcast VCR output unit 6 is not operated and only the camera and the VHS type VCR output unit 5 are operated so that the electron finder output terminal A is connected through the resistor R12 from the collector side of the transistor Q ₅ . The camera video signal or the video signal of the VHS type VCR is output.

On the other hand, the camera video signal of the encoder output unit 1 is connected through the VHS video signal of the video input / output terminal E through the buffer unit 2, the condenser C ₁ , and the resistor R ₃₄ . The VHS video signal applied from stage E is applied to the camera with a DC component of about 3-6V.

Therefore, since the video signal reproduced from the VHS VCR is loaded on the DC component of 3-6V, the signal passes through the integrating circuit 3 so that only the DC component remains, and the DC component of the integrating circuit 3 is a bias resistor. (R ₂₈₎ has a power supply (VCC given by the the associated transistor (Q ₁₂₎ "turn-on" the coupled transistors (Q ₁₃₎ to a "turned on" by the main meurosseo transistor (Q ₁₃₎ a resistance (R ₃₁₎ connected to the collector side A high level control signal of the same level as the voltage is generated.

This high level control signal is applied to the emitter of transistor Q ₁ through diode D ₁ so that the base-emitter of transistor Q ₁ is reverse biased so that the video signal generated by the camera is blocked and the video is blocked. The video signal applied from the input / output terminal E is applied to the electron finder output terminal A through the resistor R ₄ and the DC coupling capacitor C ₂ and the " turned on " transistor Q ₃ and Q ₄ . The camera's electronic finder can monitor the playback video signal of the VHS VCR.

At this time, the regeneration mode sensing circuit 4 is "turned on" of the transistor Q ₁₃ and the transistor Q ₁₄ is also "turned on" so that the transistor Q ₂ having a base connected to the collector side of the transistor Q ₁₄ is "turned off". By doing so, the VCR playback signal is output to the electronic finder as it is 1VP-P.

However, when the video signal of the camera is output through the buffer unit 2, only the DC signal coupled to the video input / output terminal E is coupled to the DC by the capacitor C ₁ and detects the integrating circuit 3 and the playback mode. By being applied to the circuit 4, the transistors Q ₁₂ -Q ₁₄ are all " turned off " so that the diode D ₁ is in the " open " state, and the collector side of the transistor Q ₁₄ is at a high level so that the transistor Q ₂ ) Will "turn on".

Accordingly, the video signal of the camera output to the emitter side of the transistor Q ₁ is divided by the resistors R ₅ and R ₅ , and then the transistors Q ₃ and Q ₄ of the camera and the VHS type VCR output unit 5. By being applied to the electronic finder output terminal (A) through the electronic finder it is possible to monitor the video signal of the camera.

At this time, when the transistor Q ₂ is "on", the video signal of the camera is divided by the resistor R ₄ (R ₅ ) and then output to the electron finder output terminal A. When the transistor Q ₂ is "off", The video signal of the VCR is output to the electronic finder output terminal A as it is 1VP-P.

On the other hand, when the camera is used in conjunction with a broadcast (U-matic type) VCR, a low level signal is applied to the VCR selector (C), and the recording / playback control stage (D) uses the camera's own video signal and the VCR according to the input signal. The playback video signal from is selected and output to the electronic finder.

That is, since the high level is applied to the reproduction video signal stage B when the reproduction video signal of the broadcast VCR is input to the base of the transistor Q ₇ and applied to the reproduction reproduction control stage D, the high level is applied. The transistors Q ₁₀ and Q ₁₁ of (7) are " turned off " so that the transistor Q ₄ of the camera and the VHS-type VCR output unit 5 is " turned on " and the transistors Q ₅ and Q ₆ are turned off. The video signal of the camera which is "turned off" and applied through the buffer unit 2 is applied to the electron finder output terminal A through the camera and the VHS VCR output unit 5 so that the electronic finder monitors the video signal of the camera. You can do it.

However, when you want to verify the contents of a recorded tape recording reproducing adjustment stage (D) to the transistor (Q ₁₀₎ (Q ₁₁₎ of a given control signal generator 7 by applying a low level "turned on" by broadcasting VCR output The reproduction video signal of the broadcast VCR, in which the transistor Q ₆ of the section 6 is " turned on " and the transistors Q ₄ and Q ₈ are " turned off ", is applied to the base side of the transistor Q ₇ . After Q ₇ ) (Q ₆ ) is applied to the electronic finder output (A) it is possible to monitor the video signal of the broadcast VCR.

That is, the video signal of the video camera and the playback video signals of the VHS type VCR and the broadcast (U-matic type) VCR can be selected and monitored by the electronic finder.

The present invention can be used to select one of several signals and can be useful in surveillance camera system when selecting the necessary signal when observing signals output from multiple cameras with one monitor. .

As described above, the present invention allows three signals of the video signal of the camera, the video signal of the VHS-type VCR, and the video signal of the U-matic VCR to be selected according to the method and operation mode of the VCR connected to the camera. By allowing the finder to monitor, the effect is to be compatible regardless of the type of VCR used.

Claims (1)

The camera video signal through the buffer unit 2 and the VHS video signal of the video input / output terminal E are composed of a camera (Q ₃ -Q ₅ ) and a resistor (R ₆ -R ₁₁ ) and a VHS type VCR output unit ( 5) through the broadcast VCR output section 6 composed of transistors Q ₆ -Q ₈ and resistors R ₁₃ -R ₂₁ and the video signal of the playback video signal stage B and the electron finder output stage A). Control signal generator 7 comprising transistors (Q ₉ -Q ₁₁ ) and resistors (R ₂₂ -R ₂₆ ) as input signals from the VCR selection stage (C) and the recording / playback adjustment stage (D). after the control over the camera and VHS system output unit 5 and the broadcast selecting give configure the operation of the VCR output portion 6, and is an integration circuit VHS method video signal of the video output stage (E) (3) transistor (Q ₁₂ - Q ₁₄₎ and a resistor (R ₂₈ -R ₃₃₎ to and controlling the driving of the diode (D ₁₎ and the transistor (Q ₂₎ through a play modal sensing circuit 4 is configured As the video signal and the VHS method video signal from the camera system the camera and VHS VCR output section 5, an optional electronic finder image signal selection circuit of the output to be configured through.