Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?


inspectrum is a tool for analysing captured signals, primarily from software-defined radio receivers.

inspectrum screenshot

Try it


  • cmake >= 3.1
  • fftw 3.x
  • liquid-dsp >= v1.3.0
  • pkg-config
  • qt5

Build instructions

Build instructions can be found here:


./inspectrum [filename]


inspectrum supports the following file types:

  • *.sigmf-meta, *.sigmf-data - SigMF recordings
  • *.cf32, *.cfile - Complex 32-bit floating point samples (GNU Radio, osmocom_fft)
  • *.cf64 - Complex 64-bit floating point samples
  • *.cs32 - Complex 16-bit signed integer samples (SDRAngel)
  • *.cs16 - Complex 16-bit signed integer samples (BladeRF)
  • *.cs8 - Complex 8-bit signed integer samples (HackRF)
  • *.cu8 - Complex 8-bit unsigned integer samples (RTL-SDR)
  • *.f32 - Real 32-bit floating point samples
  • *.f64 - Real 64-bit floating point samples (MATLAB)
  • *.s16 - Real 16-bit signed integer samples
  • *.s8 - Real 8-bit signed integer samples
  • *.u8 - Real 8-bit unsigned integer samples

If an unknown file extension is loaded, inspectrum will default to *.cf32.

Note: 64-bit samples will be truncated to 32-bit before processing, as inspectrum only supports 32-bit internally.


  • Large (100GB+) file support
  • Spectrogram with zoom/pan
  • Plots of amplitude, frequency, phase and IQ samples
  • Cursors for measuring period, symbol rate and extracting symbols
  • Export of selected time period, filtered samples and demodulated data