Calibration of vector modulators using a scalar detector

A method of calibrating a vector modulator having an input RF source connected to an input power divider providing two outputs, each connected to an adjustable phase shifter, the output of each adjustable phase shifter is independently connected to a mixer, one of the mixers is connected to an in-phase (I) signal path and the other mixer is connected to a quadrature (Q) signal path, the outputs from the mixers are connected to a power combiner, the power combiner produces an output RF signal having an amplitude, the method of calibrating requiring only the measuring of the amplitude of the output RF signal with a scalar detector connected to the RF output signal, the method comprising the following steps:

• (a) minimizing quadrature phase error;
• (b) minimizing carrier leakage;
• (c) balancing amplitudes of I and Q modulated signals;
• (d) balancing the amplitudes of quadrature calibration signals comprising:
• a positive quadrature DC reference signal (Qc+);
• a negative quadrature DC reference signal (Qc-);
• a positive in-phase DC reference signal (Ic+);
• a negative in-phase DC reference signal (Ic-);
• and
• (e) repeating steps (a) through (d) until no further changes are observed.