A method includes generating a reference clock using a crystal oscillator; generating a first clock based on the reference clock using a clock multiplier unit, in which a frequency of the first clock is higher than a frequency of the reference clock by a clock multiplier factor; generating a second lock based on the first clock using a frequency multiplying circuit in accordance with a frequency multiplying signal, in which a frequency of the second clock is higher than the frequency of the first clock by a factor that is equal to either five fourths or three halves, depending on whether the frequency multiplying signal is in a first state or in a second state; dividing down the second clock by a factor of two to generate a first LO (local oscillator) signal; dividing down the first LO signal by a factor of two to generate a second LO signal.