| 摘要 |
A radio frequency (RF) tuner includes a programmable tracking filter bank receiving an RF input and outputting a filtered RF signal. A mixer stage receives the filtered RF signal and outputs a first quadrature component of the filtered RF signal and a second quadrature component of the filtered RF signal. Two variable gain amplifiers receive the first and second quadrature components and output amplitude-controlled I and Q components of the filtered RF signal. In one embodiment, the programmable tracking filter bank includes a plurality of tank circuits each connected to the RF input through an impedance. Each tank circuit include an inductor and a capacitor connected in parallel thereby forming an LC network, and a plurality of switched capacitors in parallel with the LC network and switched in and out of the tank circuit by programmable switches. In another embodiment, the programmable tracking filter bank includes a plurality of peaked low-pass circuits each connected to the RF input through an impedance. Each peaked low-pass circuit includes a capacitor connected to ground, and a plurality of switched capacitors in parallel with the capacitor and switched in and out of the peaked low-pass circuit by programmable switches.
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