Apparatus and method for clock frequency estimation with delayed measurements

An apparatus, comprising:

• a clock signal input to receive N time measurements, a time measurement of the N time measurements to denote a respective time of a respective portion of a given cycle of a clock signal, the clock signal to include a frequency or period to be estimated over the N time measurements;
• a sampling circuit to:
• upon reception of a first time measurement on the clock signal input, generate a first sampled window from the clock signal input, the first sampled window based upon the first time measurement and a first previous time measurement, the first previous time measurement a time measurement which was received m time measurements earlier than the first time measurement, wherein m is greater than one;
• and
• upon reception of a second time measurement on the clock signal input, generate a second sampled window from the clock signal input, the second sampled window based upon the second time measurement and a second previous time measurement, the second previous time measurement a time measurement which was received m time measurements earlier than the second time measurement, wherein the second time measurement is subsequent to the first time measurement;
• and
• an estimation circuit to estimate the frequency or period of the clock signal based upon the first sampled window and the second sampled window.