Mirror image inhibiting frequency mixer in chip of RF signal transceiver

Abstract

The invention provides a mirror image inhibiting frequency mixer in a chip of an RF signal transceiver, and aims at solving the problems that a mirror image inhibition effect of a traditional mirror image inhibiting frequency mixer is not satisfied and gain loss is generated by the whole circuit. The mirror image inhibiting frequency mixer comprises a buffer unit, a frequency mixer core unit, a passive multi-phase filter, a summation circuit and a bias circuit; the buffer unit separates the frequency mixer core unit from a pre-stage frequency halving circuit; a double-balance orthogonal frequency mixing structure in the input end of the mixer core unit realizes a down-conversion function for input signals, and provides four paths of orthogonal differential signals for the post-stage passive multi-phase filter; the passive multi-phase filter realizes narrowband inhibition of mirror image interference signals; the summation circuit controls a gain compensation result of the buffer unit,the frequency mixer core unit, the passive multi-phase filter and the bias circuit via a two-bit binary digital control signal; and the bias circuit provides a variable tail current for the buffer unit, and a corresponding bias voltage for transconductance and switching levels in the frequency mixer core unit. Thus, a good mirror image inhibition effect can be realized.

Description

technical field [0001] The invention relates to an image suppression mixer used in a radio frequency signal transceiver chip, and is especially suitable for a monolithic integrated radio frequency chip applied in a global positioning system receiver. Background technique [0002] The difficulty of eliminating image interference signals has always been a difficult problem for RF signal receiver chip designers. The function of the image rejection mixer in the chip is to convert the RF input signal received by the receiver into an analog IF signal through down-conversion. And in the conversion process, the suppression of the image interference signal is realized. [0003] The image suppression structures commonly used in engineering mainly include filter image suppression structure, multiple frequency conversion image suppression structure, Hartely image suppression structure, Weaver image suppression structure and so on. The filter-type image rejection mixer is a relatively s...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem that the image rejection effect of the traditional image rejection mixer is not ideal and it is not compatible with other related indicators, the present invention provides an image rejection mixer in a radio frequency signal transceiver chip. On the basis of suppression, it can provide high conversion gain, good noise figure, linearity and layout area

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