Network Analyzer

A network analyzer is an instrument used to analyze the properties of electrical networks, especially those properties associated with reflection and transmission of electrical signals known as s-parameters. Network analyzers are used mostly at high frequencies; a typical unit can make measurements from a few hundred kilohertz up to several gigahertz.

The two main categories of Network Analyzers are
Scalar network analyzer (SNA) - amplitude properties only
Vector network analyzer (VNA) - both amplitude and phase properties; also called gain-phase meter

VNAs are the most common type of Network Analyzer. References to a 'network analyzer' most often mean a VNA since an SNA is functionally identical to a spectrum analyzer in combination with a tracking generator.

A new category of Network Analyzers has also been developed for the measurement of non-linear microwave signals:
Large signal network analyzer (LSNA) - both amplitude and phase of the fundamental and harmonics are acquired
The microwave transition analyzer (MTA) was historically commercialized before the LSNA but was lacking some of the user-friendly calibration features now available with the LSNA.