Patent ID: 8687968
Filing Date: 2014-04-01
Classification: H03H,H04B

Abstract:
1. A vector sum phase shifter comprising: a 90° phase shifter which generates, from an input signal, an in-phase signal and a quadrature signal 90° degrees out of phase with the in-phase signal; a first four-quadrant multiplier which changes an amplitude of the in-phase signal based on a first control signal on an in-phase signal side and outputs the in-phase signal; a second four-quadrant multiplier which changes an amplitude of the quadrature signal based on a second control signal on a quadrature signal side and outputs the quadrature signal; a combiner which combines the in-phase signal output from said first four-quadrant multiplier and the quadrature signal output from said second four-quadrant multiplier and outputs a combined signal; and a control circuit which outputs the first control signal and the second control signal, wherein said control circuit comprises: a voltage generator which generates a reference voltage; and a differential amplifier which outputs a difference signal between the reference voltage and an externally input control voltage as one of the first control signal and the second control signal, and when the control voltage is near the reference voltage, said differential amplifier performs an analog operation of converting the control voltage into one of the first control signal and the second control signal which is similar to one of a sine wave and a cosine wave.