One embodiment of a clock synthesis apparatus can include a clock generator that can provide two or more clock waveforms. One clock waveform from the clock generator can be selected to be an output clock in accordance with an error signal determined by a difference between a level of data in a buffer and a predetermined threshold. The output clock can also be a timing reference waveform for data removed from the buffer. In another embodiment, the error signal can be determined periodically. In yet another embodiment, the output clock domain can be different from the input clock domain of the buffer.