Abstract: A method and associated apparatus for accurately determining the frequency of signals in the Gigahertz range. The signal is gated and applied to a conventional prescaler, producing an output signal whose frequency is a whole number fraction of the input. The frequency of the prescaler output is counted and the count stored. The output of the prescaler initiates the application of clocking pulses to the prescaler sufficient in number to complete the count of the prescaler. The number of pulses required is counted and combined with the stored count of the prescaler to produce an accurate measure of the frequency of the signal.