KR940012835A - Input signal automatic switching circuit - Google Patents

Abstract

The present invention relates to an input signal automatic circuit for automatically switching in accordance with an input signal so that a signal is displayed on the image display apparatus capable of displaying one or more video signals without error.

This circuit is provided in an image system having an image display device; First and second input terminals 5 and 15 for inputting a first video signal (binary code) and a second video signal (D-Sub), and a first synchronous signal (binary code) and a second synchronous signal ( D-Sub) to detect the presence or absence of the third and fourth input terminals 25 and 35 and the synchronization signal input to the third and fourth input terminals 25 and 35 to output a control signal. 90), a synchronization signal switching unit 60 which selects a synchronization signal input to the third input terminal (or fourth input terminal) by the output control signal of the signal detection unit 90 and outputs it to the image display device; The image signal switched by the output control signal of the signal detection unit 90 and input to the first input terminal (or the second input terminal) is output to the image display apparatus in synchronization with the output synchronization signal of the synchronization signal switching unit 60. The video signal switching unit 100 is characterized in that the automatic switching according to the input signal.

Description

Input signal automatic switching circuit

As this is a public information case, the full text was not included.

2 is an input signal automatic switching circuit diagram according to the present invention;

3 is a circuit diagram showing an embodiment according to FIG.

Claims (8)

First and second input terminals 5 and 15 for inputting a first video signal (binary code) and a second video signal (D-Sub), and a first synchronous signal (binary code) and a second synchronous signal ( D-Sub) to detect the presence or absence of the third and fourth input terminals (25,35) and the synchronization signal input to the third and fourth input terminals (25,35) and to detect a signal for outputting a control signal. Means 90 and a synchronous signal switching means for selecting a synchronous signal input to the third input terminal (or fourth input terminal) according to the output control signal of the signal detection unit 90 and outputting the selected synchronous signal to the image display apparatus (60) And an image signal which is switched by the output control signal of the signal detection unit 90 and input to the first input terminal (or the second input terminal) in synchronization with the output synchronization signal of the synchronization signal switching means 60. And an image signal switching means (100) for outputting to a display device. 2. The signal detecting means (90) according to claim 1, wherein said signal detecting means (90) comprises: a first synchronous signal detecting means (50) for detecting the presence or absence of a first synchronous signal input to the third input terminal (25), and a fourth input terminal; The second synchronous signal detecting means 51 for detecting the presence or absence of the second synchronous signal inputted to the 35, and the video signal switching means in accordance with the output of the first and second synchronous signal detecting means 50, 51; And a signal switching control means (80) for controlling the (100) and the synchronization signal switching means (60). The method of claim 2, wherein the first and second synchronous signal detecting means (50, 51) comprises a multivibrator (10, 11) for outputting a pulse signal for a predetermined time by a predetermined time constant when a synchronization signal is applied. Input signal automatic switching circuit. The second synchronous signal according to claim 2, wherein the signal switching control means (80) detects whether or not a synchronous signal is input while generating a pulse signal from the first and second synchronous signal detection means (50, 51). Signal switching control means (80) for controlling the video signal switching means (100) and the synchronous signal switching means (60) in accordance with the detection means (51) and the outputs of the first and second synchronous signal detection means (50, 51). Input signal automatic switching circuit comprising a. 3. The signal switching control means (80) is a high or low signal for determining whether or not a synchronization signal is input while generating a pulse signal from the first and second synchronization signal detection means (50, 51). And an integrating branch (R16, C7 R23, C10) for outputting a low logic control signal. 5. The first synchronization signal and the first image according to claim 4, wherein the signal switching control means (80) is configured to output a signal by simultaneously inputting a synchronization signal to the first and second synchronization signal detection means (50, 51). Input signal automatic switching circuit, characterized in that for outputting a control signal for signal selection. 2. The video signal switching means (100) according to claim 1, wherein the video signal switching means (100) comprises: a first buffer (40) which switches the video signal input to the first input terminal (5) by an output signal of the signal detection means (90); And a second buffer (41) for switching the video signal input to the second input terminal (15) by the output control signal of the signal detecting means (90). The method of claim 6, wherein the image signal switching means (100) is adjusted so that the output control signal of the signal detection means 90 applied to the first buffer 40 and the second buffer 40 are mutually opposite And an image signal switching control means (70). ※ Note: The disclosure is based on the initial application.