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go2signals go2DECODE

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The increasing density of signals, the growing complexity and the use of modified standard modems are posing a challenge. As every signal is a message, it is necessary to analyze new emissions and to automate the collection of information.
With go2DECODE you can analyze/decode signals, adjust demodulator parameters, develop new decoders and automate your monitoring tasks.
go2DECODE has numerous analysis tools as well as the PYTHON Decoder Development Tool (pyDDL).

Key Facts

  • Create and modify decoders with the advanced PYTHON Decoder Description Language (pyDDL)
  • Never again wait until a decoder comes on the market!
  • Automatic signal processing of radio data and voice signals, decoding, recording
  • Wide range of universal demodulators and standard decoders
  • Signal decoding from digital or analogous receivers, via streaming, from files or from the internal signal buffer
  • COTS hardware (computers, receivers)
  • Stay up-to-date with two updates per year
  • Windows or LINUX

Features

Recognition & Decoding

go2DECODE’s signal detection and production is a multi-level process. go2DECODE buffers the incoming signal continuously. Buffering allows loss-less demodulation in time respect. go2DECODE checks the signal for the predefined modem types in the steps:

  • Detection
  • Recognition
  • Demodulation and decoding.

Signal characteristics (e. g. center frequency and symbol rate) are determined and displayed. Decoded text will be displayed as plain text or as a formatted XML-stream.
Because of this multi-level process a modulation classification, a modem recognition and a complete production can be realized with go2DECODE. Thus even incomplete processing steps lead to partial results. Quality criterion's of all results are calculated and displayed.
For best results, code aided and soft-decision decoders are implemented in some decoders.

Processing of Voice Signals

A powerful voice detection module is integrated. The voice processing algorithms of go2DECODE are insensitive to interference's like wideband interference caused by a thunderstorm. The sensitivity level itself can be parameterized. In addition to the decision “voice yes or no” the module determines the values for nominal frequency, voice pitch and modulation type.
The voice transmission can be demodulated and stored in audio files for listening and further processing. All this is done in real-time and tailored to the typical COMINT signal scenario.

Recording

Besides demodulation and decoding of radio signals, signal recording is an important application in daily use. The signal recording not only provides the material for the manual technical analysis of unknown signals, but also for archiving the signals of interest. go2DECODE allows recording of both IF and AF during demodulation.
The recordings are started and stopped either via automatic triggers or manually by the operator. The triggers supported by go2DECODE are;

  • Configurable squelch
  • Signal detection
  • Modem recognition
  • Voice detection

go2DECODE can record the demodulated bit stream into a txt file or into a special go2DECODE file format that contains additional metadata such as the quality of each bit.

Signal Analysis

Precise measurements can be obtained with the displays provided by go2DECODE. All the important tools needed to determine the signal characteristics are available:

  • Spectrum display
  • Spectrum/Spectrogram display
  • Auto correlation display
  • Constellation display
  • Time display
  • Analysis display (for the simultaneous interpretation of magnitude, frequency and phase of a signal to get a first impression of the used modulation)
  • Hell display
  • Bit display

Hell and bit display show information about the used coding. In each display cross-hair or harmonic cursors are offered.
This powerful tool kit can be used to get the required parameters to setup new demodulators for decoders(modems).

DANA, Digital Analogue Audio Interface

Two signal sources are available:

  • Analogue signals from the sound card, mixing console or virtual audio cables
  • File, wav (IQ, real) .

Single files or a play list can be played back.

Various settings are available for:

  • Sampling rate conversion
  • Filtering
  • DC removal
  • Mirroring
  • Time source (real-time/file time)
  • Center frequency tuning
  • Sound card configuration
  • Automatic buffer flushing at the end of the file
  • Loop mode
  • FM demodulation.

PMO, Production Memory Observer

The PMO tool can be used to manage the output of the decoder. AF recordings, IF recordings, Binary results and production results are displayed in a structured list and lets the user select the specific data in a comfortable way. You can define which tools will be pop up if you call the context menu (right mouse click).

You can specify which external applications are used for  display or processing

  • Play audio recording
  • Display decoder output
  • Play IF-recordings (maybe with DANA)
  • Display binary data with a hex viewer

Options

SOMO Option

SOftware based generation of MOdulated signals. An advanced signal generator for operator training, simulation and testing

  • Wide range of modulation generators
  • Complex signal scenarios with several signals generated in parallel
  • Burst signals with burst shaping
  • Multi channel signals with up to 64 channels
  • Configurable modulation parameters
  • Variable coding standards with editable text or binary pattern for coding
  • Generator bandwidth of 20/40 kHz in online mode or several MHz in offline mode
  • Adjustable noise level
  • Running on COTS hardware
  • HF Channel Simulation (multi path fading and noise

pyDDL, Decoder programming

An important feature of the go2MONITOR/go2DECODE software is the capability for the user to extend on its own the existing decoder library by using go2DECODE-Professional.
The user can develop or modify decoders and use them with the supplied set of universal demodulators.

Decoder Description Language (pyDDL)

The user can define and create his own decoders, integrate existing ones or modify the integrated standard decoders. The evolutionary growing Decoder Description Language (pyDDL) is the most suitable toolbox for this task.

pyDDL offers many new features by using PYTHON language as base for future development. Decoder development is done with the enormous set of commands and libraries provided by PYTHON and the additional dedicated set of more than 100 special commands e.g. for pre-processing, searching, reading, transformation and output formatting. The instruction set is designed not only for basic recognition and synchronization tasks, but also for complex channel decoding techniques.

All supplied decoders were built on this basis. Where available, users can use these decoders as models for their own solutions.
The starting point is a demodulated bit stream supplied by an appropriately parameterized demodulator. pyDDL allows the analysis and processing of bit streams to generate decoded message content. In this way, even modern channel decoding methods can be applied in just a few steps.

The decoders can be used in other go2signals installations (e. g. go2MONITOR) as well as in other wireless monitoring systems with the same technology (PLATH). pyDDL ensures high decoding quality, i. e. fast synchronization, selectivity, correction capabilities, etc.

The powerful PYTHON programming language reduces the size of the decoder and thus the possible number of errors, which reduces the development time.
From the pyDDL it is also possible to call DLL's in C, C++ or other programming languages.

Spyder, Debugger

Decoders are preferably created and testedusing specialised tools. This way, decoder developers obtain the best possible insight into the entire modem function flow. go2DECODE’s pyDDL-based decoder development tools consist of Spyder as integrated editor and debugger.

Spyder is used to create and modify the pyDDL scripting source code. The editor offers automatic command completion and context sensitive help. Correct commands, functions and keywords are highlighted in color for visual checks. In the case of coding errors, the PYTHON scripting interpreter logs detailed error messages to help debugging code.

The debugger is used to verify the executable code. This application makes it possible to analyze the decoding process in detail. The large set of functionalities meet customers’ expectations on a modern development platform regarding:

  • Testing of isolated decoder sections
  • Verifying intermediate results
  • Stepping through the source code line by line
  • Monitoring variables and intermediated buffers with each step
  • Changing variable values at any step
  • Defining breakpoints within the program to stop continuous operation
  • Running decoders independent of real time baud rate (i.e. faster or slower)

go2DECODE

  • Record & decode signals (manually/automatic)
  • Analyze signals
  • Create new decoders (pyDDL)
  • SOMO, signal generator for testing and training
  • Export decoder's from go2DECODE to go2MONITOR