PREAMPLIFIER AND PROTECTION CIRCUIT FOR AN ULTRASOUND CATHETER

摘要

An ultrasound catheter (5) is disclosed wherein a rotatable transducer (10) couples to the input of a preamplifier (22). Protection circuits (25) at the input and output of the preamplifier protect the preamplifier from the transducer excitation signal. The preamplifier couples to the distal end of a transmission line (15). In an alternate embodiment, at least one switch (70) responds to the presence of the transducer excitation signal by coupling the transducer excitation signal to the rotatable transducer and protecting the preamplifier from the transducer excitation signal. The at least one switch responds to the absence of the transducer excitation signal by coupling a received signal produced by the rotatable transducer to the input of the preamplifier. The at least one switch further responds to the absence of the transducer excitation signal by coupling the output of the preamplifier to the distal end of the transmission line.