Marta Gaia Zanchi1, John Mark Pauly1, Greig Cameron Scott1
1Electrical Engineering, Stanford University, Stanford, CA, USA
We present a Cartesian feedback system based on complex baseband loop driver amplifiers to control the radiofrequency signal generated by MRI power amplifiers. By shifting the control baseband frequencies far away from DC, our system eliminates the quadrature excitation ghosts and unmodulated LO leakagecaused by baseband mismatches and DC offsetsthat can affect power amplifier control systems based on the classic Cartesian feedback method.