[The sparkle noise abatement in RF excitation signal of LMW-400 MRI system]

We found a sparkle noise in the Radio-Frequency excitation signal of LMW-400 MRI system manufactured by Guangdong Weida Medical Apparatus (Group) Corporation. This sparkle noise appeared just following the RF pulse and had a maximum level of about 40% of maximum RF pulse level. Furthermore, since this sparkle noise existed during the read-out gradient period, it must be eliminated in order to reduce image artifacts. Tests on the Modulation Board showed that this noise was inherent due to abrupt rising edges of two control. signals. Simple integrating circuits had been applied to those two signals and the sparkle noise could be eliminated successfully by the modification.