Polarity synchronization method and apparatus for video signals in a computer system

A video signal processor for automatically detecting and selectively converting polarity of a synchronization portion of input video signals depending upon the display resolution of a display unit, said processor comprising:

• a buffer unit receiving a synchronization portion of input video signals and a synchronization blanking signal and storing the synchronization portion of the input video signals when the synchronization blanking signal is asserted;
• signal detection unit coupled to said buffer unit to receive and automatically determine polarity of the synchronization portions of the input video signals;
• and
• selection unit coupled to said detection unit for decoding and converting the polarity of the synchronization portion of input video signals to generate a plurality of output signals with a synchronized polarity when the synchronization blanking signal is deasserted.

In a computer system having a video circuit card for processing video signals, said video circuit card including a video circuit decoder for automatically synchronizing the polarity of a plurality of output video signals corresponding to a plurality of input video signals received in said computer system, said video circuit decoder comprising:

• a storage unit for temporarily storing a synchronization portion of the input video signals in response to an asserted synchronization blanking signal;
• a selection unit, coupled to said storage unit, for determining polarity of the synchronization portion of the input video signals;
• and
• a synchronization unit for decoding and synchronizing polarity of the synchronization portion of the video signals, said synchronization unit generating a plurality of synchronized polarity output video signals when the synchronization blanking signal is deasserted.