Full and partial cycle counting apparatus and method

Apparatus for determining the number of cycles occurring in a frequency modulated signal during a sample period, including not only the number of full cycles but any portion of a cycle, by determining the number of whole cycles and adding to this a value obtained by counting the number of high frequency clock cycles occurring between the time of the last rising edge of a full cycle and the end of the sample period, and the number of high frequency clock cycles occurring from the last rising edge prior to the start of the sample period and the start of the sample period and the number of high frequency clock cycles in a whole cycle.