DOT CLOCK REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To automatically adjust a dot clock frequency of high precision by using the maximum value and the minimum value of the result of accumulating the absolute values of a difference between the sample values of an input signal. SOLUTION: A clear pulse is inputted in an accumulation circuit 24 to be cleared after a latch circuit 25 is latched and as the result, the accumulation result of each one vertical frequency is inputted to a maximum value detecting circuit 26, a minimum value detecting circuit 27 and a control circuit 28. The circuit 26 receives the output of the circuit 25 to detect the maximum value until then to store. The circuit 27 receives the output of the circuit 25 to detect the minimum value until then to store. The circuit 28 controls the phase of a dot clock by outputting a phase control signal to a PLL circuit 14 and controls the frequency of the dot clock by receiving the outputs of the circuit 26 and the circuit 27 and outputting a frequency control signal to the circuit 14.