A spectrum analyzer measures how the energy of a signal is distributed across frequency, rather than how it changes over time. Where an oscilloscope shows «when» something happens, a spectrum analyzer shows «where» in the frequency spectrum it happens, making interference, harmonics, and noise visible that would otherwise stay hidden inside a time domain trace.
How a spectrum analyzer reads a signal
A spectrum analyzer plots power against frequency across a chosen «span». Within that span, the «Resolution Bandwidth» (RBW) determines how finely the instrument can separate two closely spaced signals: the narrower the RBW, the more detail becomes visible on screen, at the cost of a slower scan. Internally, the instrument converts incoming RF energy into a digitally processable signal, while continuously managing dynamic range and noise floor to keep weak signals visible next to strong ones.
Real-time versus swept analysis
A conventional, swept spectrum analyzer steps through its frequency range one point at a time, which can miss short or intermittent events that occur between steps. A «real-time spectrum analyzer» digitises the full span continuously, guaranteeing that transient interference, frequency hopping signals, and pulsed events are captured regardless of when they occur, a capability that matters directly for EMC pre-compliance and interference hunting.
Where spectrum analyzers are used
Spectrum analyzers are essential in telecommunications, electromagnetic compatibility testing, and Aerospace and Defense applications, where monitoring spectral purity is a requirement for secure, error free data transmission.
ALLdata's spectrum analyzer range
ALLdata's catalog spans cost effective swept analysis with the Rigol DSA815, up to full real-time capability with the Rigol RSA800 series, covering the needs of general bench work through demanding RF and EMC applications.
Need help matching frequency range, RBW, and real-time bandwidth to your application? Talk to an ALLdata engineer, or browse the spectrum analyzer range.