Vector signal generators

Vector signal generator 8PSK constellation

A vector signal generator is a device that contains:

a baseband vector I/Q signal generator producing arbitrary digital signals.
a passband vector signal generator that modulates IQ output to high frequencies.

Vector signal generator utilizes the so-called vector signal representation to synthesize virtually any bandwidth-limited signal.

How is a signal modulated in the vector signal generator?.

Vector signal generator applications

The main application for a vector signal generator is testing. Vector signal generator can synthesize a huge variety of signals and can be connected to any receiving circuit that is under test. A vector signal generator can help not only to ensure that the receiver being tested works correctly, but also to measure its parameters related to noise resistance. A good vector signal generator is also able to add controllable noise to the signal, helping to evaluate performance of the Forward Error Correction (FEC) decoders.

Vector signal generator parameters

One should pay attention to the following parameters when choosing a vector signal generator:

Passband frequency limit. This is simple: the higher is the maximum frequency, the higher is price.
Baseband spectrum width. This parameter is crucial to generate broadband signals.
Noise level of the vector signal generator. Additive and phase noise levels are to be considered. Good vector signal generator should have phase noise not bigger than -100 dBc/Hz.
Warranty and money-back. Vector signal generator is quite an expensive device, and one should ensure that he can return the vector signal generator to the seller if it doesn't suit for a necessary application. Usually a month moneyback guarantee is sufficient for a vector signal generator. As for warranty, many vector signal generator manufacturers provide 2 or more year warranty for free.