Lecture 1.1 Absolute Phase Noise Measurements

Absolute Phase Noise Measurement (Standard and LN)

Measuring phase noise in an important issue as the demand grows for higher performance RF instrumentation. In the next video, we will take a look at the basic components of Phase Noise, and compare measurement with a Spectrum Analyzer versus a Dedicated Phase Noise Measurement system.

The Model 7000 Series Phase Noise Test System is an all-in-one measurement system with a software interface (GUI) that allows some unique features:

Automatic DUT frequency search

Frequency counter and power meter

Adjustment of offset range, resolution, # of correlations and averages, show spurs, etc.

In the Statistics tab you will find jitter, Allen Deviation, etc.

The GUI to the instrument is show below:


Measurements above done with 1 cross-correlation

When using internal references, the Model 7300 LN mode improves phase noise test sensitivity especially in the offset range < 1 kHz. Regardless with internal / external references, multiple cross-correlation further improves the measurement sensitivity:

  • 10 correlations: ~ 5 dB better
  • 100 correlations: ~ 10 dB better
  • Limit: system noise floor

So how does a Phase Noise Tester actually make the measurements? The following video explains how the phase fluctuation is digitized and processed, and how a cross correlation engine strips system and reference noise for an accurate result. The GUI then provides additional post-processing support and tools to the user. ATE applications may bypass the software GUI to increase measurement speeds.