Gradient-impulse-response-function (GIRF) measurement is a well-established method for MRI gradient-system characterization. Typical GIRF input-functions are triangles or chirps. For triangles, measurements have to be performed with different pulse lengths to get a continuous frequency spectrum due to blind spots in the spectrum, requiring long scan times. In contrast, the spectrum of the chirp waveform covers a large frequency range without blind spots. However, at low frequencies the chirp fails due to a diverging intensity in its spectrum. We interleaved both waveforms and obtained a continuous gradient modulation transfer function (GMTF) spectrum down to low frequencies in short measurement time.
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