LOW NOISE BLOCK (LNB) DOWN CONVERSION CHIP CIRCUIT AND CHIP, LNB DOWN CONVERSION CIRCUIT AND METHOD

摘要

The present invention disclosed a type of LNB frequency down conversion integrated circuit. The present invention frequency-down-converts the RF signal with the Quadrature local oscillation signal (LO) and Quadrature Mixer. Then the 90 degree phase-shifting of the quadrature intermediate frequency (IF) signal after mixed is done by the use of passive Polyphase filter. The present invention further disclosed a LNB frequency down conversion chip, a LNB frequency down circuit adopting the LNB frequency down conversion chip circuit and a method of LBN frequency down. The invention ensures the elimination of the mirror image signal and the realization of the mirror image suppression function.