LINC imbalance correction using baseband preconditioning

An open loop means of correcting the imbalances in a linear amplification using nonlinear components (LINC) transmitter is presented it is shown that all amplitude, phase and quadrature errors can be compensated for by preconditioning the baseband modulation signals and making one DC adjustment in the transmitter the six necessary compensation coefficients can be determined by a simple set of relative RF power measurements. Using an automatic tuning procedure, a one watt VHF LINC transmitter was able to meet the FCC emissions mask with 6.25 kHz /spl pi//4 QPSK modulation.