spectrumanalysers

A spectrum analyzer is a test and measurement instrument that displays the magnitude of a signal as a function of frequency. It is used to observe spectral content, determine occupied bandwidth, identify harmonics and spurious emissions, and assess modulation characteristics. Spectrum analyzers are essential in the design, verification, and troubleshooting of communications, radar, audio, and electronic systems.

Most modern analyzers use a mixer and local oscillator to translate frequencies to a fixed intermediate frequency, or they perform digital processing to derive the spectrum. In swept-tuned designs, the local oscillator is continuously varied over a specified span while the resulting RF signal is filtered and detected to produce a trace. Digital spectrum analyzers rely on fast Fourier transforms or real-time algorithms to generate the spectrum, often with selectable resolution bandwidth (RBW) and video bandwidth (VBW).

Common types include swept or analog spectrum analyzers, digital spectrum analyzers, real-time spectrum analyzers, and vector signal analyzers. Audio spectrum analyzers focus on acoustic signals, while RF and microwave analyzers cover high-frequency ranges. Some instruments combine spectrum analysis with vector measurements to display phase and amplitude relationships.

Applications include wireless and wired communications design, EMI/EMC testing, spectrum monitoring, radar development, and audio engineering. They help identify interference, verify regulatory compliance, characterize modulation schemes, and troubleshoot hardware or transmission chains.

The term is commonly written spectrum analyzer in American English and spectrumanalysers in British English.