Fundamental to various devices and systems, oscillators are components that produce repetitive, oscillating signals, such as sinusoidal waves.
Some oscillators generate a fixed output where the waveform’s amplitude and frequency remain constant, while others are variable with the ability to adjust the amplitude and change/tune the signal frequency as required, within the limits of the design. Although types and use-cases vary widely, a critical performance benchmark among oscillators is the quality of the output frequency.
All oscillators deviate from ideal, theoretical behavior where the output is completely pure at the intended frequency. Actual behavior will produce various levels of phase noise, which are random fluctuations in the phase or frequency of the signal. Phase noise analysis determines the severity of frequency instability, with low levels indicating a purer signal and higher quality oscillator.
This blog post reviews how to make a phase noise measurement of a 100 MHz oven-controlled crystal oscillator (OCXO) using the Holzworth HA7062D Real-Time Phase Noise Analyzer.