Abstract

SONORA MENGANA, Alexander. Design of digital modulators using FPGA for magnetic resonance scanners. uct [online]. 2005, vol.9, n.35, pp.151-154. ISSN 1316-4821.

This paper presents the methodology for the design of digital modulators for magnetic resonance equipment using Field Programmable Gate Arrays (FPGA). After selecting the system sampling frequency, synthesizer and mixer are designed, the family of FPGA to be used and finally the digital-analog converter are chosen. The method is applied to the design of a modulator for Giroimag scanners using two XC4003e-pc84 FPGA of Xilinx. The synthesizer has a precision over 0.1 Hz, a maximum output frequency of 4MHz and a maximum level of spur of 60dB below the fundamental component, the mixer carries out the modulation of the carrier with a gaussian pulse of 8 bits with a maximum sampling frequency of 5.12MHz. The modulator obtained by this method is electrically simpler than an analogical one of same characteristics. The proposed method allows to carry out in a simple way designs of digital modulators for magnetic resonance equipment.

Keywords : Digital Modulator; FPGA; Magnetic Resonance; Pulse Modulator.