A radio frequency front-end circuit with continuously adjustable gain

Abstract

The invention discloses a radio frequency front end circuit with continuously adjustable gain. The radio frequency front end circuit comprises an auxiliary circuit, a low noise amplifier, a DC blocking capacitor, a frequency mixer and a DC power supply, wherein the auxiliary circuit converts an input radio frequency signal into a differential voltage signal, the differential voltage signal is input into the low noise amplifier, the low noise amplifier converts the voltage signal into a current signal and converts the current signal into the voltage signal again at an output terminal, the voltage signal output by the low noise amplifier is input into the frequency mixer by virtue of the DC blocking capacitor to be subjected to frequency conversion, and an intermediate frequency signal after the frequency conversion is input into a backward stage circuit; and the DC power supply provides a DC bias voltage for a switching tube in the frequency mixer. By adjusting the bias voltage of the frequency mixer, the duty ratio of a passive frequency mixer is controlled, so that continuous and variable gain of the circuit is realized; and a capacitance value of an intermediate frequency filter capacitor array is configured, and a function that multiple intermediate frequency bandwidths can be selected is realized, so that needs of various communication standards can be met.

Description

technical field [0001] The invention belongs to the field of multi-mode and multi-standard receivers, in particular to a radio frequency front-end circuit with continuously adjustable gain. Background technique [0002] With the continuous increase of multi-mode and multi-standard communication carrier frequency bands, the complexity and cost of narrow-band multi-mode receivers have also increased greatly. The development and evolution of narrow-band multi-mode structures is not sustainable, while the receiver The receiver has the characteristics of wide carrier frequency range, large signal dynamic range, wide range of channel bandwidth variation, and complex interference signals, making it the development trend of multi-mode and multi-standard receivers. [0003] At present, the method of changing the gain of multi-mode and multi-standard receivers used in the prior art is mostly to change the parameter characteristics of the circuit through digital coding control. This me...

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Problems solved by technology

[0003] At present, the method of changing the gain of multi-mode and multi-standard receivers used in the prior art is mostly to change the parameter characteristics of the circuit through digital coding control. This method has discontinuous parameter changes and complicated control methods, which greatly affects the multi-mode Effects of using multi-standard receivers

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