A floating-point digital receiver for MRI.
A magnetic resonance imaging (MRI) system requires the highest possible signal fidelity and stability for clinical applications. Quadrature analog receivers have problems with channel matching, dc offset and analog-to-digital linearity. Fixed-point digital receivers (DRs) reduce all of these problems. We have demonstrated that a floating-point DR using large (order 124 to 512) FIR low-pass filters also overcomes these problems, automatically provides long word length and has low latency between signals. A preloaded table of finite impuls response (FIR) filter coefficients provides fast switching between one of 129 different one-stage and two-stage multrate FIR low-pass filters with bandwidths between 4 KHz and 125 KHz. This design has been implemented on a dual channel circuit board for a commercial MRI system.
Hoenninger
John C
JC
Toshiba America MRI, Inc, RIL Division, South San Francisco, CA 94080, USA. hoenning@mindspring.com
Crooks
Lawrence E
LE
Arakawa
Mitsuaki
M
D000465:Algorithms; D000703:Analog-Digital Conversion; D005583:Fourier Analysis; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods*; D011846:Radio Waves; D012815:Signal Processing, Computer-Assisted