Low-noise amplifier structure

Abstract

The invention discloses a low-noise amplifier structure. The low-noise amplifier structure comprises a bandgap reference circuit (Bandgap), a digitally-controlled gain circuit (DCG), a signal amplification circuit (Amplifier) and a notch filter circuit (IRnotchfilter) with an adjustable image rejection frequency. An operating frequency signal Vop is amplified through antenna reception, an image signal Vim under image frequency is rejected, and an effective signal is further amplified by a capacitance and inductance resonant circuit (LCtank) to obtain an image rejection (IR) gain response from the reception to the output; through a digital control part, an input quiescent point is controlled so as to maximize the gain of an operating frequency point. The image signal is rejected, namely the gain of the image frequency im is reduced through a notch filter network, a load resonant frequency is higher than the image frequency so to enhance the rejection performance on an image frequency output signal and improve the performance of low-noise amplifier, and thus the overall performance of a superheterodyne radio frequency receiver designed in the future is improved.

Description

technical field [0001] The invention relates to a low noise amplifier circuit, in particular to a low noise amplifier structure. Background technique [0002] As the first module of the radio frequency receiver, the low noise amplifier is also the module with the highest operating frequency. It undertakes the purpose of amplifying the signal while introducing less noise, which has a decisive impact on the performance of the entire receiver. Since the signal received by the receiver is generally not large (-100 to -50dBm), and the working bandwidth of the whole system is wide, and the mixer noise in the receiver is very large (about 12dB), if it is directly connected to the back-end If a mixer is used, the noise amplitude will directly overwhelm the signal, so that the real information cannot be expressed. Therefore, it is necessary to amplify the signal while only adding a small amount of noise. This is the function of the low noise amplifier. [0003] The low noise amplifi...

AI Technical Summary

Problems solved by technology

At present, there are many ways to realize this filtering function, such as surface acoustic filter (SAW) or ceramic filter, but because these filters are all implemented off-chip, it greatly increases the difficulty of integration, so it is impossible to achieve single-chip system integration

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