a voltage controlled oscillator runs at full speed to generate an output frequency dependent on temperature and process variation . first and second clock signals are generated from the oscillator signal , while third and fourth clock signals are developed in response to an input clock signal . the number of clock signals occurring during a first state of the third clock signal are counted for providing a plurality of output signals also indicative of the temperature and process variation . the plurality of output signals compensate an input signal for the temperature and process variation for providing an output signal .