A single chip RF communication system and method is provided including a transmitter and a receiver. The RF communication system in accordance with the present invention can include an antenna that receives/transmits RF signals, a PLL that generates multi-phase clock signals having a frequency different from a carrier frequency and a reference signal having the carrier frequency, a demodulation-mixer that mixes the received RF signals with the multi-phase clock signals having the frequency different from the carrier frequency to output signals having a frequency reduced relative to the carrier frequency, two stage amplification that amplifies a selected channel signal to a required dynamic level, and an A/D converting unit for converting the RF signals from the mixing unit into digital signals. The two stage amplification can provide the selected channel signal with sufficient gain, even when an adjacent channel signal is output by the demodulation mixer with greater amplitude or power.