Simulation of DAC-based truncated sine excitation pulse generator

Abstract

A signal with high quality rectangular frequency spectrum is generated for MRI medical imaging applications. The center frequency of the signal is 4MHz and the bandwidth is 8KHz. This signal is generated by feeding Digital to Analog Converter (DAC) with repetitive truncated and modulated sinc function. Resolution and update rate of the required DAC is chosen theoretically and by simulations in MATLAB. Further simulations are carried out to optimize the truncating, which resulted in 800Hz transition bandwidth, -32.27dB pass-band ripple, -37.92dB stop-band ripple and 6.977MHz image signal gap by means of feeding a 15MSPS 14-bit DAC with 75,000 samples.