A delta-sigma modulator includes a loop filter, a quantizer configured to change an analog output signal into a digital signal, and a digital-to-analog converter configured to receive the digital signal and including a first capacitor and a second capacitor. In a first sampling period, the first capacitor is discharged, and at the same time, the second capacitor is charged with a reference voltage. In a second sampling period, the digital signal includes noise caused by a clock jitter, the first capacitor is charged with a reference voltage, and the second capacitor is discharged and generates a charge corresponding to the noise. In a next first sampling period, the first capacitor is discharged, and at the same time, the second capacitor generates a noise current corresponding to the noise using the charge and is charged with a reference voltage.