Multiple PLL high frequency receiver

摘要

A radio receiver includes a first PLL to provide a first local oscillator signal to convert an RF signal to an IF signal, and a second PLL to provide a second local oscillator signal to convert the IF signal to baseband. The first PLL operates at a higher frequency with optimized performance, but it has limited tuning ability. The second PLL operates at a lower frequency and has more tuning ability to compensate for the first PLL lack of it. The first PLL provides an inter-PLL control signal to the second PLL to influence the frequency at which the second PLL operates.