A class-s rf transmitter for mri scanners

A Class-S RF transmitter for Magnetic Resonance Imaging (MRI) scanners comprising

• a Peak to Average Ratio Reduction (PARR) block having at least a first output and a second output where an analog input signal (X(n)) is split into sections in equal time intervals (t0), a distortion coefficient (k(m)) for each section is calculated by dividing the maximum signal value of each section into the maximum signal value of the analog input signal (X(n)), each section is divided into corresponding distortion coefficient (k(m)) and combined together to obtain a distorted signal (h(n)), where the distortion coefficients (k(m)) are transformed into a distortion function (k(n));
• a delta sigma modulation (DSM) block converting the distorted signal (h(n)), fed from the first output, into a digitally modulated distorted signal (h_dsm(n));
• a DSM based envelope modulator converting the multiplicative inverse of the distortion function (1/k(n)), fed from the second output, into a correction signal (z_dsm(n));
• a dynamic supply modulator converting the correction signal (z_dsm(n)) into a DC feeding signal (env(n));
• a Class-D RF power amplifier having at least a RF input and a DC input, the RF input of which the digitally modulated distorted signal (h_dsm(n)) is applied to and the DC input of which the feeding signal (env(n)) is applied to, amplifying the digitally modulated distorted signal (h_dsm(n)) and via correcting the amplified digitally modulated distorted signal (h_dsm(n)) with the feeding signal (env(n)) generating a digitally modulated signal (y(n)) with high signal to noise ratio (SNR) of the analog input signal (X(n)).