Phasemeter output waveform resolution
Phasemeter output appears to have phase drift
Written by Paul Cracknell
Updated at January 26th, 2026
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Moku:Go
Moku:Go General Moku:Go Arbitrary Waveform Generator Moku:Go Data Logger Moku:Go Digital Filter Box Moku:Go FIR Filter Builder Moku:Go Frequency Response Analyzer Moku:Go Logic Analyzer & Pattern Generator Moku:Go Oscilloscope & Voltmeter Moku:Go PID Controller Moku:Go Spectrum Analyzer Moku:Go Waveform Generator Moku:Go Power Supplies Moku:Go Lock-in Amplifier Moku:Go Time & Frequency Analyzer Moku:Go Laser Lock Box Moku:Go Phasemeter
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Moku:Lab
Moku:Lab General Moku:Lab Arbitrary Waveform Generator Moku:Lab Data Logger Moku:Lab Digital Filter Box Moku:Lab FIR Filter Builder Moku:Lab Frequency Response Analyzer Moku:Lab Laser Lock Box Moku:Lab Lock-in Amplifier Moku:Lab Oscilloscope Moku:Lab Phasemeter Moku:Lab PID Controller Moku:Lab Spectrum Analyzer Moku:Lab Time & Frequency Analyzer Moku:Lab Waveform Generator Moku:Lab Logic Analyzer/Pattern Generator
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Moku:Pro
Moku:Pro General Moku:Pro Arbitrary Waveform Generator Moku:Pro Data Logger Moku:Pro Frequency Response Analyzer Moku:Pro Oscilloscope Moku:Pro PID Controller Moku:Pro Spectrum Analyzer Moku:Pro Waveform Generator Moku:Pro Lock-in Amplifier Moku:Pro Laser Lock Box Moku:Pro Digital Filter Box Moku:Pro FIR Filter Builder Moku:Pro Phasemeter Moku:Pro Multi-instrument Mode Moku:Pro Logic Analyzer/Pattern Generator Moku:Pro Time & Frequency Analyzer
- Python API
- MATLAB API
- Arbitrary Waveform Generator
- Data Logger
- Digital Filter Box
- FIR Filter Builder
- Frequency Response Analyzer
- Laser Lock Box
- Lock-in Amplifier
- Oscilloscope
- Phasemeter
- PID Controller
- Spectrum Analyzer
- Time & Frequency Analyzer
- Waveform Generator
- Logic Analyzer & Pattern Generator
- Multi Instrument Mode
- Moku Cloud Compile
- Moku general
- LabVIEW
- mokucli
The Moku Phasemeter instrument features an on-board waveform generator. This waveform is generated by a NCO ('numerically controlled oscillator') with an internal reference of 10 MHz. Over a long period, it is possible to observe a steady slow phase drift when comparing this output waveform with another signal.
The NCO has a finite precision on the frequency, determined by the number of bits involved and the DAC involved in the generation of the waveform. This fundamental frequency resolution can be computed by the equation:
Using N = 48 bits for the reference NCO, this gives an output waveform with a resolution of 3.6 μHz for Moku:Lab, 0.4 μHz for Moku:Go, and 4.4 μHz for Moku:Pro, and 17.8 μHz Moku:Delta.