Low-noise amplifier circuit

Abstract

The invention discloses a low-noise amplifier circuit. The low-noise amplifier circuit comprises an input coupling network, a first amplifier element, a first biasing unit, a second amplifier element and a second biasing unit, wherein a front-end circuit and the rear-end first amplifier element are connected by the input coupling network; the first amplifier element is connected with the input coupling network and used for amplifying an input signal; the first biasing unit is connected with the first amplifier element, and used for controlling a quiescent operating point of the first amplifier element in a linear amplifying zone; the second amplifier element is connected with the first amplifier element and used for amplifying an output signal of the first amplifier element; the second biasing unit is connected with the second amplifier element, and used for controlling a quiescent operating point of the second amplifier element in the linear amplifying zone. According to the technical scheme, a high-input impedance wideband and low-noise amplifier is adopted, the wideband amplifier realizes pre-amplifying decoupling through high-input impedance, provides a wider frequency band, provides a low noise coefficient, and supports the application of multi-nuclear magnetic resonance imaging; the design complexity is reduced, the circuit is convenient to debug, and element materials are saved.

Description

technical field [0001] The invention belongs to the field of radio frequency signal receiving integrated circuit design, and in particular relates to a low-noise amplifier circuit. Background technique [0002] In the field of medical imaging, magnetic resonance imaging is a non-invasive imaging technique that can show good soft tissue contrast. The technical principle is to superimpose the radio frequency signal under the condition of an externally strengthened magnetic field to make the nuclei in the target area resonate and send out a radio frequency signal of a certain intensity, and then the receiving coil receives the radio frequency signal, and the signal is amplified by the amplifier on the receiving link. It is transmitted to a spectrometer for subsequent further signal processing, and finally converted into an image that can be used by doctors to diagnose lesions. [0003] In existing magnetic resonance imaging (MRI) systems, the gyromagnetic ratio (that is, the p...

AI Technical Summary

Problems solved by technology

It is difficult for existing technology low input impedance LNAs to cover such a wide frequency band and provide low noise figure

[0006] Therefore, in reality, corresponding to multiple atomic imaging, the current method is to use multiple low-noise amplifiers corresponding to different frequencies, which makes the circuit design more complicated, is not conducive to the debugging of the circuit, and causes a waste of components.

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