Device for extracting synchronizing signal and relevant method thereof

Abstract

The invention relates to a device for extracting a synchronizing signal, which comprises a signal receiving end, a threshold voltage adjuster, a truncated circuit and a signal output end, wherein the signal receiving end is used for receiving a composite video signal; the threshold voltage adjuster is coupled with the signal receiving end and used for adjusting a threshold voltage as ((C1V1 / (C1+C2))+((C2V2 / (C1+C2))) according to a first characteristic electrical level and a second characteristic electrical level of the composite video signal, V1 is the first characteristic electrical level, V2 is the second characteristic electrical level; the truncated circuit is coupled with the signal receiving end and the threshold voltage adjuster and used for extracting one synchronizing signal in the composite video signal according to a presetting threshold voltage when the circuit is initialized, and initializing the device for extracting the synchronizing signal, and after the circuit is initialized, truncating the composite video signal according to the threshold voltage generated by the threshold voltage adjuster and extracting the synchronizing signal in the composite video signal; and the signal output end is coupled with the truncated circuit and used for outputting the extracted synchronizing signal.

Description

technical field [0001] The present invention relates to a synchronous signal extracting device and a related method thereof, in particular to a synchronous signal extracting device and a related method for correctly extracting a synchronous signal by dynamically adjusting the threshold voltage of a truncation circuit. Background technique [0002] Generally speaking, the monitor must process and display the received video signal correctly according to the synchronous signal. In some video transmission interfaces, a synchronization signal can be carried on a certain video signal for transmission. For example, when the input signal of the display is an RGB signal, the synchronization signal can be carried in the G signal representing green; and when the input signal of the display is a YPbPr signal, the synchronization signal can be carried in the Y signal representing brightness. The above-mentioned green signal including the synchronous signal can be called as SOG (Sync on ...

AI Technical Summary

Problems solved by technology

like Figure 4 As shown, the synchronous signal extracted by the known truncation circuit 20 will generate a glitch signal (Glitch) due to the noise extracted, which will also cause the display screen to shake

[0006] In short, since the video processing chip of the known display extracts the synchronous signal according to a fixed threshold voltage, when the DC level of the composite video signal changes or excessive noise is mixed in, it is easy to extract the wrong synchronous signal and cause Shaking the display screen

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