Phase Noise Measurement

What is Phase Noise?

Phase Noise is a measure of the spectral purity of a signal in an oscillator system. It quantifies the short-term random variation of the frequency of the signal, and is a product of thermal noise and low frequency flicker noise injected into the oscillator. Most RF systems require an overall integrated phase noise specification to be met, as phase noise can corrupt both the upconverted and downconverted signal paths. For digital systems, the integrated phase noise can be converted and expressed as phase jitter.

OEwaves has developed a powerful system for automated phase noise measurement of ultra-high performance oscillators based on microwave photonic techniques. The phase noise measurement system is fast and fully automated, and yields the spectral density of the phase noise of an oscillator at any operating frequency in the 1 to 40 GHz range. The basic system operates in the range of 6-12 GHz. This homodyne-based system is unique in its ability to measure oscillator phase noise in a wide frequency band without the need for a second reference oscillator, a down-converter, or locking circuitry, as required in the conventional heterodyne systems on the market. The OEwaves’ Phase Noise Measurement System, known as PHENOM, has an exceptionally low noise floor, allowing measurement of the noise of highest performance oscillators, as shown with dotted blue line in the Graph below. The noise floor can be further improved by increasing the number of averages in the cross correlation scheme. The performance of the system shown in the figure has been calibrated through a comparison with measurements at NIST.  A lower cost version of the system without cross correlation is also available, with performance shown in the green curve in the Graph.  Both systems, with and without cross correlation, can also be configured to measure AM noise and residual phase noise for two-port devices such as RF amplifiers.

Automated Cross-Correlation Homodyne Phase Noise Measurement System

OEwaves' Phase Noise Measurement System and associated technical data are subject to the controls of the International Traffic In Arms Regulations (ITAR). Export, re-export or transfer of these items by any means to a foreign person or entity, whether in the US or abroad, without US State Department authorization, is prohibited and may result in substantial penalties.