Frequency of an oscillating signal is temporarily adjusted to adjust frequency and/or phase of an output signal. For example, the frequency of the oscillating signal may be adjusted for a very short period of time to adjust the phase of the output signal. In addition, the frequency of the oscillating signal may be temporarily adjusted in a repeated manner to adjust the effective frequency of the output signal. In some aspects the frequency of the oscillating signal is adjusted by reconfiguration of reactive circuits associated with an oscillator circuit.