the adaptive frequency control apparatus includes : a frequency downstreamer for converting the frequency of the radio frequency signal to a frequency of a defined band according to a reference signal ; a frequency error measurer for measuring a frequency error between a frequency of the output signal of the frequency downstreamer and a defined frequency ; a loop filter for filtering the frequency error output from the frequency error measurer based on a plurality of operational parameters , the operational parameters being changeable ; a differential amplifier for generating a control signal for a voltage control based on the output signal of the loop filter ; and a voltage - controlled oscillator for changing the frequency of the reference signal according to the control signal of the differential amplifier .