Patent ID: 8212938
Filing Date: 2012-07-03
Classification: H04N

Abstract:
1. A sync signal acquisition device for generating a composite sync signal according to an analog image signal containing sync pulses, comprising: a transistor having a terminal coupled to a predetermined voltage and another terminal designated as a first input node; a resistor having one terminal coupled to the first input node and another terminal coupled to a fixed voltage; a clamper having an output terminal designated as a second input node; an analog multiplexer for receiving voltages of the first input node and the second input node and outputting one of them via an output terminal of the analog multiplexer according to a mode selecting signal; and a comparator for comparing the output voltage of the output terminal of the analog multiplexer with a comparing voltage to generate the composite sync signal; wherein the analog multiplexer outputs the voltage of the first input node at start-up.