Abstract: A touchscreen display device include a display device and a touch sensor. The display device is configured to output image data during a display operation of the touchscreen display device. The touch sensor configured to perform touch sensing using a step-and-wait sensing scheme, wherein performing touch sensing includes: generating a driving waveform during the display operation of the touchscreen display device, wherein the driving waveform is a quadrature trapezoidal waveform, a triangular waveform, or a harmonic reject waveform; obtaining resulting signals based on the generated driving waveform; and determining presence and/or movement of an input object in a sensing region of the touchscreen display device based on the obtained resulting signals.