Patent ID: 7142614

Claim:
A signal generating circuit which is coupled to a local oscillator for generating a local oscillation signal having a predetermined frequency, the signal generating circuit comprising: a 90-degree divider for generating, from a first input signal having a predetermined frequency, an intermediate reference phase signal and an intermediate quadrature signal that is orthogonal in phase to the intermediate reference phase signal; a first mixer for generating a reference phase signal by mixing a second input signal having a predetermined frequency and the intermediate reference phase signal generated by the 90-degree divider; a second mixer for generating a quadrature signal by mixing a third input signal having a predetermined frequency and the intermediate quadrature signal generated by the 90-degree divider; a shifter for generating a shift signal by shifting a phase of the local oscillation signal generated by the local oscillator by a predetermined amount; and a divider for dividing the shift signal generated by the shifter into two signals being in-phase with each other, and outputting the two signals to the first and second mixers, respectively, wherein the 90-degree divider generates the intermediate reference phase signal and the intermediate quadrature signal by taking the local oscillation signal generated by the local oscillator as the first input signal, wherein the first mixer generates the reference phase signal by taking the shift signal supplied by the divider as the second input signal, and wherein the second mixer generates the quadrature signal by taking the shift signal supplied by the divider as the third input signal.