CIRCUIT FOR RECEIVING RADIO FREQUENCY SIGNALS OF DUAL BAND RECEIVER

摘要

PURPOSE: A circuit for receiving RF(Radio Frequency) signals of a dual band receiver is provided to enable the receiving of dual band signals while using only one VCO(Voltage Controlled Oscillator), so as to simply configure the dual band receiver. CONSTITUTION: A VCO(100) includes an impedance matching circuit in an output end thereof for setting the output power levels of reference frequency signals oscillated as local oscillating frequency signals corresponding to the first frequency band and the second harmonic signal components thereof to be similar each other. The first BPF(Band Pass Filter)(102) passes only the reference frequency signals. The second BPF(104) passes only the second harmonic signals. The first mixer(106) mixes RF signals of the first frequency band and the reference frequency signals passing the first BPF(102), to generate IF(Intermediate Frequency) signals. The second mixer(108) mixes RF signals of the second frequency band with the second harmonic component signals passing the second BPF(104), to generate signals that are fixed number times the as much as IF signals. And a frequency division circuit(110) divides output signals of the second mixer(108) to generate the IF signals.