Editing Signal generator (section)

==== Vector signal generator ====
[[File:E4438C ESG Vector Signal Generator.jpg|right|400px|thumb|A vector signal generator]]
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 the vector signal generator, which is also known as a digital signal generator. 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]], [[Frequency-shift keying|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]], [[WCDMA|W-CDMA (UMTS)]], [[CDMA2000]], [[Long Term Evolution|LTE]], [[WiFi|Wi-Fi (IEEE 802.11)]], and [[WiMAX|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.