A high-speed digital-to-analog converter (DAC) measurement method acquires and quantizes an analog ramp output by the DAC corresponding to a digital ramp input to produce a quantized ramp, determines a start and end of the quantized ramp, obtains a difference between the quantized ramp and an ideal ramp to produce a quantized periodic signal (triangular or sinusoidal), determines a frequency for a qualified peak from an FFT of the quantized periodic signal, produces a mask filtered periodic signal from an iFFT around the qualified peak, and determines a sample window spanning a local maximum and minimum for each period of the quantized periodic signal. The ramp step levels are the averages of the samples within each sample window. From the step levels in DAC LSB's, resolution, monotonicity, differential lineary and integral linearity are determined for the DAC.