Method and apparatus for reducing input impedance of a preamplifier

摘要

A feedback circuit is provided for reducing the input impedance of a preamplifier circuit, such as for use with a sensing coil in an imaging system. The feedback circuit permits adjustment of the input impedance by balancing inductive and capacitive components of a feedback control circuit. The imaginary component of the input impedance may be adjusted independently of the real component, to provide a substantially zero input impedance, while allowing adjustment of the stability of the system. The circuitry may function in conjunction with a reactance matching circuit to reduce cross-talk in multiple sensing coil arrangements.