Moku:Lab’s Phasemeter measures phase of up to two input signals with better than 6 µradian precision from 1 kHz up to 200 MHz. Based on a digitally implemented phase-locked loop architecture, Moku:Lab’s phasemeter provides exceptional dynamic range, zero dead-time and measurement precision that exceeds the performance of conventional lock-in amplifiers and frequency counters.
Yes! When both input channels are enabled, a Delta channel with the difference between Channel 1 and Channel 2 automatically appears. You can also plot the Delta channel alongside Channel 1 and 2 in the Timeseries and Spectral Analysis plots by selecting the Δ icon (color-coded orange).
The Power Spectral Density (PSD) and the Amplitude Spectral Density (ASD) in the iPad phasemeter are calculated using Welch’s method of overlapping periodograms, with a 50% overlap and a Hanning window. The number of points is either 512, 1048 or 2048 depending on the sampling rate chosen.
A Python based example can be found here.