Timing controller, data processing method using the same and display apparatus having the same

A timing controller includes a receiver and a clock generator connected to output terminals of the receiver. The clock generator receives an external clock signal through the receiver and periodically modulates a frequency of the external clock signal to generate a modulation clock signal that is used to process a plurality of pixel data. The clock generator controls a delay time of the modulation clock signal based on a modulation rate of the frequency of the modulation clock signal. According to the timing controller, circuit blocks connected to output terminals of the clock generator are operated by the modulation clock signal. Thus, the circuit blocks operated by the delayed modulation clock signal may be prevented from malfunction due to electromagnetic interference.