Difference between spectrum analyzer Vs network analyzer

Spectrum analyzers excel in signal strength and frequency analysis, while network analyzers provide comprehensive testing of RF networks through S-parameter measurements. Both spectrum analyzer and network analyzer inside use tuned receivers which operates over same or similar frequency range. The difference between spectrum analyzer and network analyzer mainly lies based on the measurement applications as described below. This page describes difference between spactrum analyzer Vs network analyzer.

Spectrum Analyzer basics

The figure-1 depicts spectrum analyzer using super-heterodyne architecture.
Refer Spectrum Analyzer basics for more.

• Network analyzer is used to measure reflection coefficients, transmission coefficients, insertion loss, return loss, S parameters and more. It takes care of measurement of components,devices and sub modules.
Spectrum analyzer is used to measure carrier power level, harmonics, spurious, sidebands, phase noise and more.

• Network analyzer is mainly designed to take care of measurements related to phase such as group delay which is not possible with spectrum analyzer. Spectrum Analyzer helps discover unwanted signals and network analyzer helps measure known signals.

network analyzer inside

The figure-2 depicts network analyzer inside modules. Refer Network Analyzer basics and types for more.

• Spectrum Analyzer is just a receiver which displays the signal fed to its RF input port from any RF transmitting device through cable or with antenna. Modern real time spectrum analyzers even decode and display complex broadband RF signals emitted/acquired using various wireless devices which for example include WLAN,WiMAX,GSM,Zigbee,LTE and more. To do so additional baseband circuitry is incorporated in the spectrum analyzer. Spectrum analyzer do not have source incorporated.
Network analyzer consists of source and multiple receivers and measures broadband frequency signal using techniques such as power and frequency sweep.

• The spectrum analyzers usually will have wider range IF bandwidths compare to most of the network analyzers. Network analyzer provides higher measurement accuracy compare to spectrum analyzer due to vector error correction feature.

•  While doing measurement with spectrum analyzer, it is easy to place a marker on the display, but interpretation of results are difficult.
While doing measurement with network analyzer, it is hard to place a marker on the display, but interpretation of results are very easy.

Compare spectrum analyzer Vs network analyzer

Following table provides comparison between spectrum Vs network analyzer with respect to various features.

Feature Spectrum analyzer Network analyzer
Primary Function Measures the magnitude of signals over a frequency range Measures both the amplitude and phase of signals (S-parameters) in a network
Purpose Frequency domain analysis (spectrum of signals) Analyzes the characteristics of RF networks (scattering parameters)
Type of Signals Analyzes a single input signal (passive measurement) Analyzes the relationship between input and output signals (active measurement)
Key Measurements Power spectral density, frequency, noise, harmonics S-parameters (S11, S21, etc.), reflection coefficient, return loss
Ports Typically single input port for signal measurement Usually has two or more ports for input and output network connections
Frequency Range Broad frequency range, typically from kHz to GHz Specific to the design, also in kHz to GHz range but used for network elements
Applications Signal strength, modulation analysis, EMC testing Device characterization (antennas, filters, amplifiers, etc.)
Complexity Relatively simpler to operate More complex due to phase and impedance measurement
Display Frequency vs. amplitude (power or voltage) Plots amplitude and phase (Smith chart, polar plot, etc.)
Example Instruments Keysight N9320B, R&S FSV Keysight PNA-X, R&S ZNB Network Analyzer

Conclusion

Understanding the difference between spectrum analyzer and network analyzer is crucial for RF and microwave engineering. A spectrum analyzer focuses on the magnitude of signals across frequencies, ideal for signal strength and interference analysis. In contrast, a network analyzer measures both amplitude and phase, making it essential for evaluating RF components' transmission and reflection properties.

RELATED LINKS

Spectrum Analyzer basics
SNA vs VNA - Network analyzer basics and difference between scalar network analyzer and vector network analyzer.

difference between

RF and Wireless Terminologies