Voltage controlled oscillators with reduced incidental frequency modulation and use in phase locking oscillators

Abstract

A phase locking oscillator ( or ) and a radio frequency oscillator ( or ) achieve reduced incidental frequency modulation. A frequency-deviation sensitivity is reduced by a divider ( or ) that reduces a frequency-control voltage, thereby decreasing voltage spikes and other electrical noise, and thereby reducing incidental frequency modulation. In embodiments having an AC voltage divider ( ), the frequency-control voltage is reduced when a frequency thereof is above a predetermined roll-off frequency. Below the roll-off frequency, the voltage dividing function ceases, and full deviation sensitivity of the radio frequency oscillator ( or ) is restored, whereby a capture range of the phase locking oscillator ( or ) and a maximum frequency range of the radio frequency oscillator ( or ) are restored. Some of the phase locking oscillators ( or ) and some embodiments of the radio frequency oscillators ( or ) include means ( or ) for proportionally combining a supplementary voltage with the reduced frequency-control voltage. Proportionally combining is used in some of the phase locking oscillators ( or ) to increase a speed of phase locking. In other embodiments of the phase locking oscillator ( or ), proportional combining is used to maintain the capture range. In the phase locking oscillator ( ), proportional combining is used to maintain the capture range and to increase the speed of phase locking.