OSD INSERT CIRCUIT

摘要

An On-Screen-Display (OSD) insert circuit includes: an OSD signal generation circuit for generation a switch signal and an analog addition image signal according to a first clock signal; an analog-digital converter for digital-converting the addition video signal generated by using a second clock signal as a sampling clock signal; a switch circuit for switching between the digital video signal and the digital-converted addition image signal by a switch signal when outputting them; and a control signal generation circuit for generating the second clock signal. The digital video signal is accompanied by a horizontal synchronous signal. The control signal generation circuit generates the horizontal synchronous signal and a signal having a predetermined phase difference including 0 so as to reset the first clock signal and generates the second clock signal so that the phase can be adjusted with respect to the horizontal synchronous signal. The OSD insert circuit can insert an analog addition video signal into a digital video signal without converting the digital video signal into an analog signal.