A multiplier-divider circuit for signal process according to the present invention comprises a digital-to-analog converter, a first counter, a second counter, an oscillation circuit, and a control-logic apparatus. The digital-to-analog converter generates an output signal of the multiplier-divider circuit in accordance with the value of an input signal and a first signal. The first counter generates the first signal in response to a clock signal and the duty cycle of the input signal. The second counter generates a second signal in response to the clock signal and the period of the input signal. The oscillation circuit generates the clock signal in accordance with a third signal. The control-logic apparatus generates the third signal in response to the second signal and a constant. The first signal is correlated to the duty cycle of the input signal. The second signal is correlated to the period of the input signal.