Real Time Spectrum Analyzer

- a summary or tutorial about the Real Time Spectrum Analyzer with operational details and how they work.

In recent years a form of spectrum analyser, termed a real-time spectrum analyser, RSA has grown in popularity.

These real-time spectrum analyzers are particularly useful in looking at waveforms where changes may be seen, and need to be captured. Often spectrum analysers that take time to process the waveforms may miss spurious signals and these can be particularly important when testing for compliance and out-of-band signals.

As the name implies, real-time spectrum analysers operate in real time.

Realtime spectrum analyser basics

A realtime spectrum analyser operates in a different way to that of a normal swept or superheterodyne spectrum analyser.

The analyser can acquire a particular bandwidth or span either side of a centre frequency. The analyser captures all the signals within the bandwidth and analyses them in real time.

To achieve their performance a real time spectrum analyser captures the waveform in memory and then uses a fast Fourier transform technology to analyse the waveform very quickly, i.e. in real-time.

By analysing the waveform in this way, transient effects that may not be visible on other forms of spectrum analyser can be captured and highlighted.

There are a number of characteristics of realtime spectrum analyzers:

  • They are based around an FFT - Fast Fourier Transform spectrum analyser. This will have a real-time - very fast - digital signal processing engine capable to processing the entire bandwidth with no gaps.
  • An ADC - analogue to digital converter capable of digitising he entire bandwidth of the passband.
  • Sufficient capture memory to enable continuous acquisition over the desired measurement period.

By Ian Poole

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Securing the future of IoT | Rutronik
Securing the future of IoT
Co-authored by Bernd Hantsche, Head of the GDPR Team of Excellence and Marketing Director Embedded & Wireless and Richard Ward, ‎Semiconductor Marketing Manager at Rutronik. is operated and owned by Adrio Communications Ltd and edited by Ian Poole. All information is © Adrio Communications Ltd and may not be copied except for individual personal use. This includes copying material in whatever form into website pages. While every effort is made to ensure the accuracy of the information on, no liability is accepted for any consequences of using it. This site uses cookies. By using this site, these terms including the use of cookies are accepted. More explanation can be found in our Privacy Policy