Vector Signal Generators (VSG) vs Vector Signal Analyzers (VSA)

2 min read

This article explores the differences between Vector Signal Generators (VSG) and Vector Signal Analyzers (VSA), crucial tools in modern wireless communication system testing.

Due to advent of complex modulation schemes (QPSK, 16QAM, 64QAM), multiple antenna and multi-carrier systems (OFDM, OFDMA) in modern wireless communication systems (Mobile WiMAX, WLAN, LTE, LTE-Advanced); it has become essential to analyze the waveforms generated by them. This has pioneered the development of vector signal generation and analysis.

There are two types of Vector Signal Generator and Analyzer.

Offline Version: This is essentially a software application that generates In-phase and Quadrature (IQ) data. This data is typically in text files, formatted as floating-point, fixed-point, or integer values. This version operates without any radio frequency (RF) components. Offline VSGs and VSAs are particularly useful in the initial stages of development before integrating with RF hardware.
Online Version: This version combines both baseband and RF components. It produces real-time modulated signals based on the complex vector data dictated by the respective wireless standards.

Difference between Vector Signal Generators (VSG), Vector Signal Analyzers (VSA)

VSG (Vector Signal Generator)	VSA (Vector Signal Analyzer)
It is the short form of Vector Signal Generator.	It is the short form of VEctor Signal Analyzer.
It is used to generate complex IQ vector or modulated IQ vector at respective RF carrier frequency.	It is used to analyze complex IQ vector or modulated IQ vector at respective RF carrier frequency.
It is used to test receiver functionality of DUT(Device Under Test) with or without RF.	It is used to test transmitter functionality of DUT(Device Under Test) with or without RF.
Hardware version of VSG consists of Waveform Generator and RF Up Converter.	Hardware version of VSA consists of RF Down Converter and Digitizer.
Input to VSG is binary data and Output is complex IQ vector in offline baseband version.	Input to VSA is complex IQ vector and output is binary data in offline baseband version.
Typical measurements include transmit power, power spectrum, spectral flatness, CCDF, Constellation diagram etc.	Typical measurements include EVM, channel response etc.

Leading Manufacturers of VSGs and VSAs

Here are some of the leading test and measurement companies and their respective models for Vector Signal Generators and Analyzers: