Biomedical Engineering Reference
In-Depth Information
Fig. 8.4 NMR RF transceiver architectures for ( a ) the palm system and ( b ) the 1-chip system
(From Ref. [ 3 ])
Fig. 8.4 a or b) is activated by operating switches S3 through S11 in the configuration
that is opposite to their configuration during the excitation phase. In this reception
phase of NMR, the excited protons electromagnetically interact with the coil,
inducing an AC voltage signal with the NMR frequency, ! 0 , across the coil. This
NMR signal, whose peak-to-peak voltage is on the order of 100 nV and bandwidth is
about 1 kHz, is amplified and frequency down-converted by the heterodyne receiver.
The intermediate frequency (IF) for the receiver is set at 3 kHz, which is high
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