Fig. 14.
Comparison of dual slice MR images before (left) and after (right) the addition of the FOCF control system to a 63.9 MHz power amplifier at the 1.5 T MRI system. The linear and log plots compare mathematical (green) and RF loopback FFT waveform (red) with physical slice select projections (blue) for each acquisition. The artifacts created by the 3rd order intermodulation products of the RF power amplifier are substantially suppressed by the action of the loop.