A Joint Scheme of AGC and Gain/Phase Mismatch Compensation for QPSK DCR

This paper presents a simple gain/phase blind compensation algorithm with an automatic gain control (AGC) function for the adoption of the AGC function and compensation for gain/phase imbalances in quadrature phase shift keying (QPSK) direct conversion receivers (DCRs). The AGC function is interactively operated with the compensation algorithm for gain/phase imbalances. By detecting the gain sum and difference values between the I-channel and Q-channel, the combined AGC and gain imbalance compensation algorithm provides a simpler DCR architecture.

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