Display device performing clock modulation and method of operating the display device

A method of operating a display device, the method comprising:

• receiving image data at an input frame frequency;
• randomly selecting a modulation frequency within a modulation frequency selection range, a reference modulation frequency being within the modulation frequency selection range;
• generating a modulated clock signal by modulating an input clock signal with the randomly selected modulation frequency;
• determining an output start timing of the image data based on the input frame frequency;
• initiating, at the output start timing, output of the image data in synchronization with the modulated clock signal;
• and
• displaying an image based on the outputted image data.

A display device comprising:

• a display panel comprising a plurality of pixels;
• a gate driver configured to provide gate signals to the plurality of pixels;
• a data driver configured to provide data signals to the plurality of pixels;
• and
• a timing controller configured to receive image data at an input frame frequency and to control the gate driver and the data driver, the timing controller comprising:
• a clock modulation block configured to generate a modulated clock signal by modulating an input clock signal according to a modulation frequency;
• and
• a frequency randomizer configured to randomly select an output frame frequency or the modulation frequency and to adjust an output timing of the image data based on the randomly selected output frame frequency or the modulated clock signal modulated according to the randomly selected modulation frequency.