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IQ Power Spectrum

The IQ Power Spectrum block converts I/Q data via real-time FFT to SPECTRA:

IQ Power Spectrum Block

Left hand side Input:

  • IQ

Right hand side Output:



The IQ Power Spectrum block should be one of the most used ones. It converts I/Q data in real-time to SPECTRA using an highly optimized FFT algorithm. Using SPECTRA instead of I/Q highly reduces the CPU load of subsequent processing and visualization steps.

The FFT Size can be adjusted from 16 to 1 Million (depending on license). Optional the FFT size is also adjustable via the number of Bins.

Furter on you can switch the IQ Power Spectrum block to a more flexible multi adjustment mode (e.g. for control with further docked blocks):

  • Step & Frequency
  • RBW
  • RBW & FFT
  • Step & Frequency & RBW

The FFT Overlapping is fully adjustable (up to 99,9%) same for the power range (60 to 200dB).

The following FFT Window functions are available:

  • Hamming
  • Hann
  • Uniform
  • Blackmann
  • Blackmann Harris
  • Blackmann Harris 7
  • Flat Top
  • Lanczos
  • Gaussion 0.5
  • Gaussion 0.4
  • Gaussion 0.3
  • Gaussion 0.2
  • Gaussion 0.1
  • Kaiser 6
  • Kaiser 12
  • Kaiser 18
  • Kaiser 36
  • Kaiser 72
  • Tukey 0.1
  • Tukey 0.3
  • Tukey 0.5
  • Tukey 0.7
  • Tukey 0.9

Some interesting FFT tweaking features like FFT Skip Window (the opposite from FFT overlap, removes FFT windows e.g. if you need to save CPU power or if you can/want to reduce the SPECTRA data rate), Super Sample (our unique "oversampling", reducing the overal noise floor), Drop Partial (ignors I/Q data at the end of a segment that dosen't fit into a window (Hopping mode or IsoLOG)), an adjustable Processing Latency (100µs to 100ms), and a Noise Compensation are integrated:

IQ Power Spectrum Settings


A typical screenshot using the IQ Power Spectrum block:

IQ Power Spectrum Block in Action


Comparing our unique Super Sample and regular mode to see the reduced noise floor:

IQ Super Sample Mode reducing the Noise Floor

Typical Mission:

IQ Power Spectrum Typical Mission

FFT Super Sample Mode


could you please tell us about "FFT POI" and "FFT skip window" and "Drop Partial" options ?

With those features you can reduce data load by throwing away samples or packages.

Quote from AdminTC on 16/08/2023, 02:27

With those features you can reduce data load by throwing away samples or packages.

Dear admin,

Could you please provide more information? I mean, how can we find the best values for FFT Probability of Intercept (POI) and other settings?


Such values do not exist. Simpy change them to your needs depending on your use case.

You might want to use the HTTP feature for a setup test:

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