Idea of six-port vector-voltmeter with homodyne phase-sensitive detectors

A broadband six-port vector-voltmeter concept is presented. Homodyne detection with rectangular phase modulation is used in the measurement system. A mathematical model of the system, which takes into account all the imperfections of system components, is discussed in detail. The principles of the system calibration procedure are described, and the solutions for a six-port structure are given. The concept of homodyne detection with rectangular phase modulation, which is equivalent to double-sideband suppressed-carrier modulation, is presented. The combination of systematic error elimination with high dynamics offered by homodyne detection makes high-accuracy measurements possible