Application Note

Part 1 introduces the historical basis for power measurements, and provides definitions for average, peak, and complex modulations. This application note overviews various sensor technologies needed for the diversity of test signals. It describes the hierarchy of international power traceability, yielding comparison to national standards at worldwide national measurement institutes (NMIs) like the U.S. National Institute of Standards and Technology.

Part 2 presents all the viable sensor technologies required to exploit the wide range of unknown modulations and signals under test. It starts with explanations of the sensor technologies, and how they came to be to meet certain measurement needs. Sensor choices range from the venerable thermistor to the innovative thermocouple to more recent improvements in diode sensors. In particular, clever variations of diode combinations are presented, which achieve ultra-wide dynamic range and square-law detection for complex modulations.

Part 3 discusses the all-important theory and practice of expressing measurement uncertainty, mismatch considerations, signal flowgraphs, ISO 17025, and examples of typical calculations. Considerable detail is shown on
the ISO 17025, Guide for the Expression of Measurement Uncertainties, has become the international standard for determining operating specifications. Agilent has transitioned from ANSI/NCSL Z540-1-1994 to ISO 17025.

Part 4 overviews various instrumentation for measuring RF and microwave power, including spectrum analyzers, microwave receivers, network/spectrum analyzers, and the most accurate method, power sensors/meters. It begins with the unknown signal, of arbitrary modulation format, and draws application-oriented comparisons for selection of the best instrumentation technology and products. Most of the chapter is devoted to the most accurate method, power meters

Provides a useful EVM troubleshooting decision tree.

Error vector magnitude (EVM) measurements can provide a great deal of insight into the performance of digitally modulated signals. With proper use, EVM and related measurements can pinpoint exactly the type of degradations present in a signal and can even help identify their sources. This note reviews the basics of EVM measurements on the Agilent Technologies 89400 vector signal analyzers, and outlines a general procedure that may be used to methodically track down even the most obscure signal problems.

This application note from Agilent describes the challenges of measuring distortion products from your device under test. The challenges arise from the need to measure weak distortion product and harmonic signals in the presence of strong carrier signals, combined with the fact that the analog components in the test instrumentation produce their own unwanted distortion signals.

This application note, Measuring the Nonlinearities of RF Amplifiers Using Signal Generators and a Spectrum Analyzer, from Rohde-Schwarz covers the measurement of amplifier nonlinearities. It includes a very useful discussion of the relationship between harmonics and their intermodulation products. Particularly, the ratio between the second harmonic intercept point and IP2 is described. Several useful figures are supplied to aid understanding.

This PDF guide from Huber+Suhner is a comprehensive look at connector performance issues. Many popular RF connector types are also described.

Covers resolution bandwidth, cable losses, low level signals, dynamic range, internal distortion products, optimizing speed for transients, selecting display detectors, and time gating.
From Agilent (AN-1286-1)

Explanation and derivation of the VNA 12- and 8-term calibration error models. Presentation slides from a conference paper by Doug Rytting.