IMAGE PROCESSOR FOR PROCESSING INPUT IMAGE SIGNAL BY OPERATING WITH FREQUENCY-SPREAD CLOCK AS REFERENCE

摘要

PURPOSE: To stably analyze the specifications of an input image signal in an image processor for processing the input image signal by operating with a frequency-spread clock as a reference. CONSTITUTION: A system clock generating part outputs the frequency spread clock as a system clock by changing an oscillation frequency. A synchronizing signal measuring part measures a synchronizing signal characteristic value containing at least a synchronizing signal period and a synchronizing signal period corresponding to the input image signal with a clock for measurement generated on the basis of the system clock as a reference. An image signal analyzing part decides that the specifications of the input image signal are changed when the measured synchronizing signal characteristic value is out of a prescribed range, decides that the specifications of the input image signal are not changed when that value is in the prescribed range, and analyzes the input image signal on the basis of the measured synchronizing signal characteristic value.