Terminology » What is RF Vector Signal Generator and Analyzer

What is RF Vector Signal Generator and Analyzer

rf vector signal generator vector signal analyzer vsg vsa

An RF Vector Signal Generator and Analyzer are essential tools used in wireless communication testing and RF system development. A vector signal generator (VSG) creates complex modulated RF signals, while a vector signal analyzer (VSA) measures and analyzes signal quality, modulation accuracy and performance. Understanding their key differences helps engineers select the right instrument for RF testing, validation and troubleshooting.

What is Vector Signal Generator?

It is basically a Vector Signal Generator which generates baseband IQ vectors for various modulated signals as per wireless standards viz. WLAN, WiMAX, Zigbee, GSM, CDMA, LTE and more. It is available in various flavors, in different ways as per user need. Following are well known deliverables provided by Test and Measurement Companies such as Agilent, National Instruments, R&S, Anritsu, Litepoint and more.

Offline VSG Application: It generates IQ vector in various formats (floating point, fixed point and more). Can be saved in a file and the same can be played on realtime RF instrument or can be loaded to any VSA (Vector Signal Analyzer) application in offline mode manually.
RF VSG: It generates modulated RF vector so that it can be used to cross check realtime DUT’s Receiver’s performance/functionality. Most of the RF VSGs provides facility to load external IQ file to be played and will in turn generates modulated RF signal.

What is Vector Signal Analyzer?

It is basically vector Signal Analyzer which analyzes baseband IQ vector of various modulated signals as per wireless standards viz. WLAN, WiMAX, Zigbee, GSM, CDMA, LTE and more. It is available in various flavors i.e. in different ways as per user need. Following are well known deliverables provided by Test and Measurement Companies such as Agilent, National Instruments, R&S, Anritsu, Litepoint and more.

Offline VSA Application: It analyzes IQ vector in various file formats (floating point, fixed point and more). Decoded data can be saved in a file and compared with standard expected data.
RF VSA: It generates analyzes RF vector so that it can be used to cross check realtime DUT’s Transmitter’s performance/functionality.

Difference between Vector Signal Generator and Analyzer

The following table highlights the key differences and roles of VSGs and VSAs in RF and wireless communication systems.

Feature	RF Vector Signal Generator (VSG)	Vector Signal Analyzer (VSA)
Purpose	Generates RF signals with specific characteristics for testing.	Analyzes and demodulates RF signals to measure their properties.
Functionality	Used to create test signals for RF systems.	Used to capture and analyze signals for troubleshooting and validation.
Input/Output	Takes digital/analog input to produce RF signals as output.	Captures RF signals as input and provides analysis as output.
Key Components	Modulators, synthesizers, DACs, and waveform memory.	ADCs, mixers, filters, and digital signal processors (DSP).
Primary Use Cases	Device testing, calibration, and simulation of real-world conditions.	Signal integrity testing, spectrum analysis, and demodulation.
Frequency Range	Covers a wide frequency range depending on the model.	Also operates over a wide frequency range, typically matching VSG.
Output Type	RF signals with modulated and unmodulated options.	Measurement data, including frequency, power, and modulation accuracy.
Software Integration	Often includes signal creation software for custom waveforms.	Comes with signal analysis software for detailed measurements.
Example Applications	Testing RF receivers, amplifiers, and transceivers.	Debugging and verifying RF transmitter performance.
Complexity	Simpler in terms of operation; focused on signal generation.	More complex due to signal analysis and diagnostic capabilities.
Cost	Generally less expensive compared to VSA.	Usually more expensive due to advanced analysis capabilities.

Popular RF VSG and VSA Vendors/manufacturers

Company	RF VSG model	RF VSA model
National Instruments- www.ni.com/	NI RFSG Models available: PXI-5670, NI PXI-5671, NI PXIe-5672, NI PXIe-5673	NI RFSA Models available: PXI-5660, PXI-5661
Agilent Technologies-www.home.agilent.com/	N5182A MXG vector signal generator, M9381A PXIe Vector Signal Generator	M9392A PXI Vector Signal Analyzer along woth VSA software(89600), Frequency- 50MHz to 26.5GHz
Rohde and Schwarz - www.rohde-schwarz.co.in/	R&S ® SMU200A , R& S ® SMBV100A	R&S ® FS-K96 OFDM Vector Signal Analysis, R& S ® CMW500
Anritsu - www.anritsu.com/	MG3710A Vector Signal Generator	MT8870A, MS2830A Signal Analyzer
Litepoint-www.litepoint.com	IQview along with IQsignal ™ Signal Analysis Software Suite for WLAN VSG/VSA. IQflex ™ All in One for WLAN/bluetooth vector signal analysis

Conclusion

Both the RF Vector Signal Generator (VSG) and Vector Signal Analyzer (VSA) are essential in the development, testing and maintenance of RF systems. While the VSG excels in signal generation, the VSA provides invaluable insights through detailed signal analysis. By understanding their distinct functionalities and applications, RF professionals can effectively leverage these tools to ensure high performance and reliability in modern communication systems.