Abstract: The present invention provides a frequency selective circuit. The frequency selection circuit comprises a voltage-controlled oscillator, a frequency divider, a frequency selective unit and a register group, the voltage-controlled oscillator is used to output a frequency corresponding to the frequency adjustment window; the frequency divider is used to divide the clock frequency output by the voltage-controlled oscillator, and to feed back the resulting low frequency to the frequency selection unit; the frequency selective unit is used to compare a reference frequency with the resulting low frequency output by the frequency divider, and to provide the frequency adjustment window which is configured based on the frequency search window to the voltage-controlled oscillator. The register group is used to output the frequency search window which is provided to the frequency selective unit.