US 5,347,222 AGranted

Signal/noise ratio optimization tuning system

AssigneeKabushiki Kaisha Toshiba

InventorsTimothy R. Fox, Richard J. Faehnrich

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Abstract

A signal/noise ratio optimization tuning system, which can be used for tuning receiver antennas in Magnetic Resonance Imaging receiver systems, has a switch-controlled noise source means that is weakly coupled to the receiver antenna. The switch-controlled noise source switches a noise source between higher and lower power states at a predetermined frequency. A noise power meter means, which is synchronized to the switch-controlled noise source means, measures outputs of the receiver antenna. The noise power meter means measures the outputs of the receiver antenna when the noise source is switched between higher and lower power states and computes a ratio of the receiver antenna output with the noise source in the higher power state to the receiver antenna output with the noise source in the lower power state to obtain a noise power ratio. The tuning adjustment means is varied to maximize this noise power ratio.

Claims13

Dependent claims

A signal/noise ratio optimization tuning system for tuning a receiver antenna circuit and amplifier comprising:

a switch-controlled noise source means weakly coupled to the receiver antenna circuit during tuning operations for switching a noise source between higher and lower power states at a predetermined frequency;
a noise power meter means synchronized to the switch-controlled noise source means for measuring outputs of the amplifier, wherein the noise power meter means measures the outputs of the amplifier when the noise source is switched between higher and lower power states and computes a ratio of the amplifier output with the noise source in the higher power state to the amplifier output with the noise source in the lower power state;
and
tuning adjustment means for tuning the receiver antenna circuit and amplifier to maximize the ratio of amplifier outputs with the noise source in the higher and lower power states by making an adjustment to the receiver antenna circuit.

1 more element

Dependencies are inferred from the claim text.