go2signals Signal Analyzer Features

"Signal Analyzer" allows the user to analyze unknown modulations easier and faster. This helps to identify signals or to create decoders/detectors for go2signals.

This application is intended for manual analysis of recorded signals. It is designed as a toolbox that contains the necessary signal processing and visualization functions for the study of emissions. "Signal Analyzer" results are visualized in plot displays that allow observing certain signal properties and determining some modulation parameters.

To use this application and interpret its results, knowledge and technical background of signal processing and modulation techniques are required.


  • For quick analysis of unknown signals
  • Equipment verification
  • Decoder development/setup
  • Analyzing transmission structures
  • Comparing signals
  • Offline Analysis



The Time Analysis module provides various time domain diagrams for manual analysis of basic emission characteristics, e.g. the modulation type of an emission.
The Time Analysis shows three diagrams that can contain:

  • Amplitude
  • Phase
  • Frequency
  • Amplitude (I+Q)
  • Real (in phase)
  • Imaginary (quadrature)
  • Power (squared magnitude, lin.)
  • Level (log. power)


Periodicity Analysis enables the detection of repetitive components, such as regularly sent synchronization sequences.
The analysis is performed depending on the selected metric and an auto-correlation is displayed.
Repeating sequences become visible in a circulation display.


The Classification Analysis module runs an automatic signal classification of a selected part of a signal.
All relevant signal parameters are displayed in a table if the classification was successful, otherwise only
generic parameters are displayed.


PSK Analysis can be used for manual analysis of PSK modulated signals.  
Several diagrams are displayed, which can be used to determine the following values:

  • Carrier frequency
  • Symbol rate
  • Version of the PSK modulation and order


FSK Analysis can be used for manual analysis of FSK modulated signals.  
Several diagrams are displayed which can be used to determine the following values:

  • modulation order, the number of tones
  • Symbol rate
  • Frequency-Offset aka center frequency
  • Shift, (the frequency spacing of the outer tones).


This module provides plots and measurements for the analysis of PSK/QAM multicarrier signals.
The following assumptions apply to a signal to be analyzed:

  • Carriers are equidistant in frequency
  • The symbol rate on all carriers is the same
  • The analyzed signal is coherent, i.e., it is taken from a single burst or continuous emission
  • Sufficient signal is available for processing, i.e., at least a few hundred symbols are recommended.
  • Automatic estimation of the parameters uses the statistical properties of the signal. The analysis works best with strong (high SNR), undistorted signals. Idle or repetitive symbol sequences can lead to confusing analysis results

The following parameters can be determined with the analysis:

  • Carrier spacing
  • Carrier frequency, i.e. center of the first (left) carrier
  • Symbol rate
  • Used constellation for each carrier

OFDM (Option)

OFDM signals are a special case of multicarrier modulated PSK/QAM signals.

The abbreviation stands for Orthogonal Frequency Division Multiplexing. In this modulation method, symbols that are defined as I/Q values (complex numbers) are distributed over several carriers. This modulation method places symbols that are defined as I/Q values (complex numbers) on multiple carriers.
The modulation and demodulation are usually performed by applying the Inverse Discrete Fourier Transform (IDFT) in the modulator and the Discrete Fourier Transform in the demodulator (DFT).
The analysis performs an automatic estimation of the basic modulation parameters of a modulated OFDM signal.
These parameters can be checked by the user and modified if necessary. Selected parameter values can be overwritten, allowing manually controlled demodulation. The results are shown on several displays.