PLL circuit which can be modulated by a modulation signal comprising a DC component

: Heuberger, A.; Wallrapp, L.; Seitzer, D.

Abstract
A PLL circuit which can be modulated by a modulation circuit comprising a DC component has a voltage- controlled main oscillator, a loop divider, a phase comparator and a loop filter. The comparison frequency signal for the phase comparator is derived from the modulation signal by a first compensation filter which is followed by a voltage-controlled reference oscillator and a reference divider. The voltage- controlled main oscillator is controlled by the modulation signal via a second compensation filter followed by a data lowpass filter.