Patent ID: 7589576

Claim:
A phase shifter, comprising: a first multiplier unit receiving an input signal and a first digital control signal that specifies a phase shift quantity for the input signal and outputting a first output signal obtained by multiplying the input signal with a first multiplication value calculated by the first multiplier unit based upon the first digital control signal, wherein the first multiplier unit includes: an operational amplifier; an input resistor having a predetermined input resistance value; and a feedback resistor at which a specific feedback resistance value is selected based upon the first digital control signal, the first multiplier unit calculating the first multiplication value by calculating a ratio of the feedback resistance value relative to the input resistance value based upon the first digital control signal; a second multiplier unit receiving an orthogonal input signal having a phase perpendicular to a phase of the input signal and a second digital control signal that specifies the phase shift quantity, and outputting a second output signal obtained by multiplying the orthogonal input signal with a second multiplication value calculated by the second multiplier unit based upon the second digital control signal; and an adder/subtractor unit that executes addition or subtraction by using the first output signal and the second output signal based upon a third digital control signal corresponding to the phase shift quantity.