An image sensor, image processing system including the same, and an operating method of the same

According to an embodiment of the present invention, an image sensor includes: a photo gate controller which generates a plurality of demodulation signals corresponding to a plurality of rows of a pixel array; and a photo gate driver which controls phases of a plurality of the demodulation signals according to a source clock signal, removes a PVT noise, and applies the demodulation signals, of which the phase is controlled, to the pixel array. According to an embodiment of the present invention, the image sensor matches the phase of photo gate control signals based on a reference clock signal so as to increase the quality of a depth image.