A novel type-based vector modulator self-calibration technique

In this paper, we present a patent-pending type-based technique to compensate for gain/phase imbalances and DC offsets in vector modulators. Its underlining principle is that, given a modulation scheme and pulse-shaping and/or channel filter, the modulated signal has a unique statistical distribution, and any impairment in the vector modulator distorts its output statistical distribution. The difference between the ideal and the output statistics contains the impairment information, and is used to derive calibration coefficients. Computer simulations have shown that the type-based technique can effectively compensate for the gain/phase imbalances and DC offsets in vector modulators, and significantly improves the performance.