A phase-locked loop, PLL, comprising: an oscillator configured to generate an output signal ( s out) at an output of the PLL responsive to a reference signal ( s R) input to the PLL, the oscillator including a primary control input and a separate auxiliary control input, a detector configured to compare the reference signal ( s R) to a feedback signal ( s F) to generate one or more PLL control signals, the feedback signal being derived by a feedback loop of the PLL from the output signal; and a phase control system configured to control a phase of the output signal to achieve a desired phase shift (Δ φ) at the output of the PLL, the phase control system comprising: a modulation circuit operatively coupled to the oscillator and configured to execute open loop phase control of the PLL by: generating a phase modulation signal ( S mod) comprising one or more pulses having a total area based on the desired phase shift; and applying the phase modulation signal to the auxiliary control input to change the phase of the output of the PLL to achieve the desired phase shift; and a phase skew circuit configured to execute closed loop phase control of the PLL to maintain the phase of the output of the PLL at the desired phase shift by setting a time relationship between the reference signal and the feedback signal based on the desired phase shift. an oscillator configured to generate an output signal ( s out) at an output of the PLL responsive to a reference signal ( s R) input to the PLL, the oscillator including a primary control input and a separate auxiliary control input, a detector configured to compare the reference signal ( s R) to a feedback signal ( s F) to generate one or more PLL control signals, the feedback signal being derived by a feedback loop of the PLL from the output signal; and a phase control system configured to control a phase of the output signal to achieve a desired phase shift (Δ φ) at the output of the PLL, the phase control system comprising: a modulation circuit operatively coupled to the oscillator and configured to execute open loop phase control of the PLL by: generating a phase modulation signal ( S mod) comprising one or more pulses having a total area based on the desired phase shift; and applying the phase modulation signal to the auxiliary control input to change the phase of the output of the PLL to achieve the desired phase shift; and a phase skew circuit configured to execute closed loop phase control of the PLL to maintain the phase of the output of the PLL at the desired phase shift by setting a time relationship between the reference signal and the feedback signal based on the desired phase shift. a modulation circuit operatively coupled to the oscillator and configured to execute open loop phase control of the PLL by: generating a phase modulation signal ( S mod) comprising one or more pulses having a total area based on the desired phase shift; and applying the phase modulation signal to the auxiliary control input to change the phase of the output of the PLL to achieve the desired phase shift; and generating a phase modulation signal ( S mod) comprising one or more pulses having a total area based on the desired phase shift; and applying the phase modulation signal to the auxiliary control input to change the phase of the output of the PLL to achieve the desired phase shift; and a phase skew circuit configured to execute closed loop phase control of the PLL to maintain the phase of the output of the PLL at the desired phase shift by setting a time relationship between the reference signal and the feedback signal based on the desired phase shift.