According to an output from a voltage-controlled oscillator, there are generated by a fractional divider a high-frequency division signal and a low-frequency division number. A phase comparison is conducted between the high-frequency division signal and a high-frequency reference signal by a phase comparator....http://www.google.com/patents/US5424687?utm_source=gb-gplus-sharePatent US5424687 - PLL frequency synthesizer and PLL frequency synthesizing method capable of obtaining high-speed lock-up and highly-reliable oscillation
