A network analyzer is an instrument used to analyze the properties of electrical
networks, especially those properties associated with the reflection and transmission
of electrical signals known as scattering parameters (S-parameters). Network
analyzers are used mostly at high frequencies; operating frequencies can range
from 9 kHz to 110 GHz.
The two main categories of Network Analyzers are:
Scalar Network Analyzer (SNA) - Measures amplitude properties only
Vector Network Analyzer (VNA) - Measures both amplitude and phase properties
A VNA may also be called a gain-phase meter or an Automatic Network Analyzer.
An SNA is functionally identical to a spectrum analyzer in combination with
a tracking generator. As of 2007, VNAs are the most common type of network analyzers,
and so references to an unqualified 'network analyzer' most often mean a VNA.