Aspects of this disclosure relate to reducing settling time of a sawtooth ramp signal in a phase-locked loop. Information from a loop filter of the phase-locked loop can be stored and used within the loop filter so as to improve the settling time of the sawtooth ramp signal. In certain embodiments, the settling time of a periodic sawtooth ramp signal can be reduced to less than one microsecond. An output frequency at the end of the sawtooth chirp can be brought back to an initial value without significantly modifying phase error in disclosed embodiments.