  We demonstrate Josephson junction based double-balanced mixer and phase
shifter circuits operating at 6-10 GHz, and integrate these components to
implement both a monolithic amplitude/phase vector modulator and a quadrature
mixer. The devices are actuated by flux signals, dissipate no power on chip,
exhibit input saturation powers in excess of 1 nW, and provide cryogenic
microwave modulation solutions for integrated control of superconducting
qubits.
