HA7000 Series Phase Noise Analyzers


Holzworth Phase Noise analyzers offer a valuable External LO Mode feature. The External LO Mode function allows the user to connect two non-coherent frequency sources to the system to generate the test system LO frequencies. This feature is advantageous for testing DUTs that have a considerably better phase noise performance level than the internal, synthesized LO sources of the phase noise analyzer.


All of the Holzworth HA7000 Series Phase Noise Analyzers offer External LO Mode capability. The HA7062B offers 3 different modes, one being External LO Mode. The HA7402A operates only in External LO Mode.

WHITE PAPER: ..Quickly Evaluate High Performance Oscillators - April 2012

This white paper addresses the topic of External LO Mode using the original (revision A) HA7000 Series Phase Noise Analyzers. Although some minor aspects of the system have been modified, the overall configuration and procedures for running External LO Mode remain unchanged.




The most common application for External LO Mode is the measurement of high performance crystal oscillators. High performance reference sources (oscillators) typically have a 10dB to 20dB phase noise performance level than what a high performance synthesizer can deliver at the same frequency output.


Holzworth phase noise analyzers have the ability to quickly reduce the noise floor level with each cross correlation, ultimately to accurately settle at the true performance level of the DUT. However, even with Holzworth's unique high speed phase noise analyzers, correlations consume time. To speed up these measurements for both manufacturing and R&D application, the External LO Mode enables measurements of the best oscillators within seconds, versus minutes or even hours.