ADDITIVE MEASUREMENTS

HA7000B Series Phase Noise Analyzers

Phase noise measurements fall under two categories: absolute and residual (additive). Where absolute phase noise measurements are typical of oscillators and and other frequency sources, residual phase noise measurements are more specific to measuring the phase noise contribution of an individual component or subsystem.

 

Setting up a test system for additive phase noise requires some traditional microwave plumbing, but the challenge is in the proper calibration of the test system so as to not introduce measurement errors.

 

Holzworth's HA7000B Series Phase Noise Analyzers address the issues of setting proper system quadrature and calibration so that the results are accurate. The accuracy of the user's test results are NIST traceable via an ANSI z540 calibration.

 

When using an HA7000B Series analyze for additive phase noise measurements, the user must select a test system frequency source with good phase noise, as well as a 3 way power divider with good port-port isolation. The necessary additional hardware is dependent on whether the user wants complete automation over quadrature and calibration at a specific frequency or broadband test capability using the Quadrature Monitor feedback tool with automated calibration.

 

FIXED FREQUENCY TESTS

Full Automation of System Quadrature and Calibration

Holzworth's HX5100 Series Electronic Phase Shifters are z540 calibrated and sold in matched pairs. As per the block diagram, the user supplies a frequency source (oscillator, etc.) and a power divider to create 3 signal paths. The HX5100 units are installed on each LO input path and the 3rd path is dedicated to the DUT. In this fully automated test setup, the output DAC voltage control for each LO is used by the analyzer to independently control each phase shifter. HANDS OFF! ...the analyzer then uses the phase shifters to set system quadrature and calibrate the test system. z540 traceable data acquisition will begin per the user settings.

   

BROADBAND TESTS

Using Quadrature Monitor with Automated Calibration

Accurate broadband additive test setups can be configured by using Holzworth's HX5200 Series Time Delay Standard. This delay standard is also z540 calibrated to maintain NIST traceable data. The block diagram for this test setup shows a user supplied frequency source, power divider and mechanical (or electronic) phase shifters. In this configuration, the system quadrature is set via the user supplied phase shifters. The HA7000B Series GUI features a useful Quadrature Monitor tool, which provides visual feedback to the user for setting optimal system quadrature. Once quadrature has been achieved, the calibration process is then fully automated as the analyzer references the calibrated time delay prior to acquiring data.

ARTICLE: ..Automated Additive Phase Noise Measurements - MW Journal - April 2013

This article outlines the ability of the HA7000B Series Phase Noise Analyzers to make automated residual phase noise measurements that are NIST traceable. Ease of use, measurement speed, reliability and accuracy are the primary design aspects for Holzworth phase noise analysis products.

 
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