Abstract: A method was proposed to measure the gradient waveform on low-field MRI systems with a digital receiver. The principles underlying such a method were discussed in detail. A variable gain amplifier was used in the digital receiver to modulate the amplitude of RF signal according to the audio-frequency (AF) signal. The performance of the digital receiver was tested and evaluated. It was shown that fitting the gradient waveforms measured with the digital receiver could result in correct pre-emphasis parameters, as demonstrated by evidently reduced eddy currents.

Key words: MRI, eddy current, gradient waveform measurement, digital receiver