A spectrum analyzer measures and displays the amplitude of a signal as a function of frequency, rather than as a function of time. Where an oscilloscope shows how a signal changes over time, a spectrum analyzer answers a different question: what frequencies is this signal actually made of. That view makes individual carriers, harmonics, spurious emissions, and modulation sidebands visible, all of which would be invisible or indistinguishable on a time-domain trace.
Key specifications to consider
- Frequency range: how high in frequency the analyzer can measure, from a few kHz up into the microwave range.
- Resolution bandwidth (RBW): how finely the analyzer can separate two closely spaced signals.
- Displayed average noise level (DANL): how weak a signal the analyzer can still detect above its own noise floor.
- Real-time analysis: the ability to capture and display fast, transient, or frequency-hopping signals that a swept analyzer would miss entirely.
Typical applications
Spectrum analyzers are core instruments for RF and wireless product development, EMC pre-compliance emissions testing, spectrum monitoring, and troubleshooting interference in communication systems, from Wi-Fi and Bluetooth to cellular and satellite links.
Spectrum analyzers from ALLdata
Rigol's range spans entry-level swept analyzers to full «real-time analysis»: the Rigol DSA815 for cost-effective bench work, and the Rigol RSA800 series for capturing fast and intermittent RF events.
Need help matching frequency range and DANL to your application? Talk to an ALLdata engineer.