Patent ID: 6037978
Filing Date: 2000-03-14
Classification: H04N

Abstract:
A sync signal self-test device of a computer system utilizing a computer and a monitor, wherein said device comprises:a pre-amplifier for pre-amplifying red, green, and blue video signals from said computer;a microprocessor for measuring frequencies of horizontal and vertical sync signals received from said computer;on-screen display means for outputting red, green and blue on-screen display signals in synchronization with control signals from said microprocessor;said microprocessor for generating said control signals when said frequencies of said horizontal and vertical sync signals received from said computer are outside a frequency range of said monitor;said microprocessor for generating self-generated horizontal and vertical sync signals when said frequencies of said horizontal and vertical sync signals received from said computer are outside said frequency range of said monitor;said microprocessor for generating horizontal and vertical sync signals corresponding to said horizontal and vertical sync signals received from said computer, when said frequencies of said horizontal and vertical sync signals received from said computer are within said frequency range of said monitor;a buffer for temporarily storing said red, green and blue on-screen display signals output from said on-screen display means;mixing means for providing a mixed output by mixing outputs from said pre-amplifier and said buffer; anda main amplifier for amplifying said mixed output for display on said monitor.