A generator waveform is measured using one or more techniques that reduce the computing resources for measuring the generator waveform and the time required for measuring the generator waveform. One example includes a template matching technique that iteratively selects templates to estimate the phase offset of the generator waveform. One example includes a root mean squared value calculated from less than sample time period that is less than one half of a cycle of the generator waveform. A generator controller calculates a command or parameter for the generator based on the estimated phase offset or the root mean squared value.