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. Author manuscript; available in PMC: 2008 Mar 21.
Published in final edited form as: J Acoust Soc Am. 2000 Oct;108(4):1683–1696. doi: 10.1121/1.1310190

FIG. 4.

FIG. 4

Relationship between gradient coil noise and imaging pulse sequence (1.5 T). (A) Acoustic noise waveform from Fig. 2(A). Gray shading indicates when various gradients were on: (1) a brief “chemical saturation” gradient; (2) two slice-select gradients; and (3) readout and phase encode gradients. (B) Time course of the 1-kHz (thick solid curve), 2-kHz (thin solid curve and circles), and 700-Hz components (dashed curve) of the waveform in (A). Levels were computed from spectra of waveform segments obtained from a 10-ms rectangular window moved along the waveform in (A) at 5-ms intervals. Each data point in (B) corresponds to the center of the appropriate 10-ms window. Gray shading indicates gradient activity as in (A).