Page "Signal generator" Paragraph 17

With the advent of digital communications systems, it is no longer possible to adequately test these systems with traditional analog signal generators.

This has led to the development of vector signal generators, also known as digital signal generators.

These signal generators are capable of generating digitally-modulated radio signals that may use any of a large number of digital modulation formats such as QAM, QPSK, FSK, BPSK, and OFDM.

In addition, since modern commercial digital communication systems are almost all based on well-defined industry standards, many vector signal generators can generate signals based on these standards.

Examples include GSM, W-CDMA ( UMTS ), CDMA2000, LTE, Wi-Fi ( IEEE 802. 11 ), and WiMAX ( IEEE 802. 16 ).

In contrast, military communication systems such as JTRS, which place a great deal of importance on robustness and information security, typically use very proprietary methods.

To test these types of communication systems, users will often create their own custom waveforms and download them into the vector signal generator to create the desired test signal.