Integrated Four-Channel Signal Acquisition System for MRI

This paper introduces an integrated four-channel signal acquisition system used in low-field MRI. The system is based on FPGA, DSP and Power PC. In this paper, a design of a compact and flexible signal acquisition system was presented. Sample the multi-channel magnetic resonance signals at a high speed simultaneously and demodulate them directly. A digital down conversion (DDC) chip (AD6636) demodulate and decimate four-channel signals. DSP as a controller completes the configuration of AD6636. Power PC reads out the I/Q data, either four channels at one time,or just only one channel which is concerned. Signal sampling frequency is up to 100 MSPS, as is known to all that the higher sampling frequency, the better SNR. The system can apply to magnetic field of 1 T. Experiments show that four channels work well, and filter parameters can be changed effortless. It is optimized for compact, with high sampling rate, and rich flexible filter design. And it provides a high-performance signal acquisition design for the development of magnetic resonance imaging spectrometer.