Abstract: A tachometer for generating a digital output signal representing velocity which is a stepped approximation to a 1/t velocity versus time curve where t is the time required to travel a fixed distance. High resolution is obtained by dividing the 1/t curve into octaves and an approximate straight line portion. A nonlinear counter counts a predetermined number of pulses during each octave as the time of the counting interval for succeeding octaves is doubled. Therefore, the counter total and the number of octaves completed after time t represents velocity. After completing eight octaves, the nonlinear counter counts at a predetermined frequency to generate a straight line approximation of the 1/t curve as it approaches zero velocity. The digital output can be converted to analog form by a digital-to-analog converter and operational amplifiers having an amplification factor determined by the number of octaves completed.