SIGNAL-PROCESSING IN TRANSCEIVERS FOR NUCLEAR-MAGNETIC-RESONANCE AND IMAGING

The relationships between signal processing schemes and expected perfo rmances of several types of NMR transceiver are discussed to show how emerging digital technologies may be used in future systems. We identi fy a transceiver architecture where accuracy of the analog signal proc essing functions is not critical, and top performances are obtained th rough real-time digital signal processing. Our receiver, comprising an oversampling analog-to-digital converter scheme, achieves a dynamic r ange of 12 bits at bandwidths above 1 MHz, and a dynamic range in exce ss of 16 bits at bandwidths < 15 kHz. We give an outline of specificat ions and hardware design issues of the main parts of this transceiver and demonstrate experimentally the superior performances of our receiv er.