The invention discloses a line-field synchronous signal separation shaping circuit, which adopts an analog decoding circuit and cooperates with the line-field synchronous signal shaping circuit to realize the analog decoding of a video signal by an LCD TV, solves the problem of shaping the line-field synchronous signal in analog decoding, not only ensures the image quality of the LCD TV, but also greatly reduces the production cost, which is beneficial to the wide popularization of the LCD TV. In addition, its simple circuit design makes it widely used in analog decoding flat panel display devices, which has high practical value.

The liquid crystal displays a line synchronization signal (HS) and a field synchronization signal (VS).

In liquid crystal display, the function of line synchronization signal (HS) is to select the effective line signal interval on the liquid crystal panel, and the function of field synchronization signal (VS) is to select the effective field signal interval on the liquid crystal panel. The effective video signal interval on the LCD panel can be selected by the simultaneous action of the line synchronization signal and the field synchronization signal.

It should be noted that the synchronization signal used in LCD is a two-level signal without blanking signal, while the synchronization signal in CRT display color TV is a three-level signal with blanking signal. This is because LCD processes digital signals, and digital signals can only have two levels, high level 1 and low level 0.

In the circuit, the line synchronization signal is usually represented by HS or HSYNC, and the field synchronization signal is usually represented by VS or VSYNC.