An apparatus for measuring intervals of time, which requires only a simple counter circuit (15) and delay circuit (17), through which electrical pulses travel. The counter circuit (15) counts pulses during the time interval. During each count of the counter circuit (15), the delay circuit (17) tracks the position of the pulse. The output of the two circuits are a counter word and a vernier word, such that the counter word may be multiplied by the period of each pulse, and the product added to the vernier word, to obtain the time interval measurement. The apparatus may also be used for frequency measurement.
Walter L. Lockhart; Benjamin M. Piepgrass