Patent ID: 8351881

Claim:
An addition circuit comprising: a first multiplier multiplying a first high-frequency input signal, which is input to the first multiplier, by a first reference signal which is input to the first multiplier, and outputting a first direct-current output signal; a second multiplier multiplying the first high-frequency input signal, which is input to the second multiplier, by a second reference signal which is input to the second multiplier and which has a phase advanced by 90° with respect to the first reference signal, and outputting a second direct-current output signal; a third multiplier multiplying a second high-frequency input signal, which is input to the third multiplier, by the first reference signal which is input to the third multiplier, and outputting a third direct-current output signal; a fourth multiplier multiplying the second high-frequency input signal by the second reference signal, which are input to the fourth multiplier, and outputting a fourth direct-current output signal; a first adder adding the first direct-current output signal and the third direct-current output signal, which are input to the first adder, and outputting a fifth direct-current output signal; a second adder adding the second direct-current output signal and the fourth direct-current output signal, which are input to the second adder, and outputting a sixth direct-current output signal; a fifth multiplier multiplying the fifth direct-current output signal by the first reference signal, which are input to the fifth multiplier, and outputting a first high-frequency output signal; a sixth multiplier multiplying the sixth direct-current output signal by the second reference signal, which are input to the sixth multiplier, and outputting a second high-frequency output signal; and an output terminal connected to the fifth multiplier and the sixth multiplier and outputting a third high-frequency output signal resulting from adding the first high-frequency output signal and the second high-frequency output signal.