Various aspects of the disclosure are directed to methods and apparatuses involving providing a clock signal. As consistent with one or more embodiments herein, a sawtooth waveform signal is generated in a manner that facilitates low power operation. In some implementations, the sawtooth waveform signal is generated using an oscillator that operates without necessarily employing R-C circuits and/or without rail-to-rail voltage supply, such as via a nonlinear oscillator. The sawtooth waveform signal is used to generate a trapezoidal waveform signal, and a clock signal is generated using the trapeziodal waveform signal.