Patent ID: 6140851
Filing Date: 2000-10-31
Classification: H03J,H03L

Abstract:
A PLL (Phase-Locked Loop) synthesizer comprising:a voltage controlled oscillator including an oscillating section for selectively oscillating with frequencies respectively lying in at least two different frequency bands by switching a connection of circuit elements of said oscillating section by a first switch, and an outputting section for tuning to a fundamental wave or a harmonic thereof contained in an output of said oscillating section by switching a connection of circuit elements of said outputting section by a second switch;a frequency divider for dividing with a preselected frequency division ratio a frequency of a signal to which said outputting section is tuned; anda phase comparator for comparing a phase of a signal output from said frequency divider and a phase of a reference signal to thereby output a control voltage indicative of a phase error;said oscillating section varying, in response to the control voltage output from said phase comparator, an oscillation frequency so as to converge said phase error substantially to zero.