HIGH-SENSITIVITY RECEIVER FRONT-END CIRCUIT HAVING IMPEDANCE MAPPING FUNCTION

摘要

The present invention belongs to the technical field of wireless communication and specifically relates to a high-sensitivity receiver radio frequency front-end circuit having an impedance mapping function. The circuit according to the present invention comprises: a linearity compensation circuit, a low-noise trans-conductance amplifier circuit, an active negative feedback circuit, a divider circuit, a passive mixer circuit, an in-phase trans-impedance amplifier and an orthogonal trans-impedance amplifier. By using the impedance mapping function of a passive mixer, the present circuit maps impedance having a low-pass characteristic at a low-frequency site to a radio frequency end by using a local frequency as the center; and the output end of the low-noise trans-conductance amplifier equivalently forms a band pass filter having a high-frequency high-quality factor. The low-noise trans-conductance amplifier provides gains at a first level of a receiver, so that noises of the post-stage circuit may be suppressed effectively, thus contributing to the sensitivity of the whole link being improved. Moreover, by using the active negative feedback of the low-noise trans-conductance amplifier, impedance is mapped to the input end and an out-of-band blocking signal is suppressed by using impedance matching of the input end, so that the anti-interference capability of a receiver may be enhanced, and the dynamic range of the entire front end may be increased.