If you are technically inclined, read the paper and don't let the equations put you off. Over and over again throughout this paper the author states the VCO runs like a free running ring oscillator in short time intervals and if I read it correctly, during these short intervals, the VCO can range by 20% in speed until the phase detector knocks the ring oscillator back down (or up). If this is an accurate interpretation I'm hopeful. Looking for EE confirmation tomorrow.