A DAC/ADC system for generating reference clocks for DAC/ADC by a look-up table method. The DAC/ADC system includes a sampling signal generator, a DAC, and an ADC. The sampling signal generator generates first and second sampling signals according to first and second reference clocks by a look-up table method, respectively. The DAC receives a digital input signal and converts it into an analog output signal according to the first sampling signal. The ADC receives an analog input signal and converts it into a digital output signal according to the second sampling signal.