sdrangel/ReadmeDevelopper.md

SDRangel Developper's notes

Build options

The release type can be specified with the -DBUILD_TYPE cmake option. It takes the following values:

• RELEASE (default): produces production release code i.e.optimized and no debug symbols
• RELEASEWITHDBGINFO: optimized with debug info
• DEBUG: unoptimized with debug info

You can specify whether or not you want to see debug messages printed out to the console with the -DDEBUG_OUTPUT cmake option:

• OFF (default): no debug output
• ON: debug output

You can add -Wno-dev on the cmake command line to avoid warnings.

Global code structure and flow

The existing receiving flow is represented with green boxes. The futrue Tx flow with red boxes. Some classes and file paths in the Rx part were renamed to avoid collision with future Tx names in this case the old name appears below the present name in italics.

Rx path

• The I/Q samples are collected from a physical device or UDP flow with a device plugin that derives from the DeviceSampleSource class.
• These I/Q samples are downsampled by a factor set in the device plugin GUI and fed into a BasebandSampleSink
• The DownChannelizerclass downsamples further down (or not) the baseband I/Q samples depending on the requirements of the Rx plugin. It cascades the downsampling from the center, left or right half of the baseband in order to fit the Rx plugin bandwidth. It contains the NCO to adjust to the Rx plugin center frequency.
• The special FileSource plugin reads a file that was recorded using the FileRecord class directly into the baseband as there is no downsampling from the sample rate at which the file was recorded.
• The baseband I/Q samples can be recorded to a file using the FileRecord class

Device sample source plugins

At present the following plugins are available:

• AirspyXxx classes in plugins/samplesource/airspy: Inteface with Airspy devices
• BladeRFXxx classes in plugins/samplesource/bladerf: Inteface with BladeRF devices
• BladeRFXxx classes in plugins/samplesource/bladerf: Inteface with BladeRF devices
• FCDProXxx classes in plugins/samplesource/fcdpro: Inteface with Funcube Pro devices
• FCDProPlusXxx classes in plugins/samplesource/fcdproplus: Inteface with Funcube Pro+ devices
• HackRFXxx classes in plugins/samplesource/hackrf: Inteface with HackRF devices
• RTLSDRXxx classes in plugins/samplesource/rtlsdr: Inteface with RTL-SDR devices
• SDRDaemonXxx classes in plugins/samplesource/sdrdaemon: Special inteface collecting I/Q samples from an UDP flow sent by a remote device using SDRdaemon.
• SDRDaemonFECXxx classes in plugins/samplesource/sdrdaemonfec: Special inteface collecting I/Q samples from an UDP flow sent by a remote device using SDRdaemon with FEC protection of blocks.
• FileSource classes in plugins/samplesource/filesource: Special inteface reading I/Q samples from a file directly into the baseband skipping the downsampling block

Device sample sink plugins

At present the following plugins are available:

• FileSink classes in plugins/samplesink/filesink: Special inteface writing baseband I/Q samples to a file skipping the final upsampling block

Channel receiver (Rx) plugins

At present the following plugins are available:

• ChannelAnalyzerXxx classes in plugins/channelrx/chanalyzer: Signal analysis tool pretty much like a DSA/DSO signal analyzer like the venerable HP 4406A (although still far from it!)
• AMDemodXxx classes in plugins/channelrx/demodam: AM demodulator with audio output
• BFMDemodXxx classes in plugins/channelrx/demodbfm: Broadcast FM demodulator with audio mono/stereo output and RDS
• DSDDemodXxx classes in plugins/channelrx/demoddsd: Digital Speech demodulator/decoder built on top of the DSDcc library. Produces audio output and some communication data from various digital voice standards: DMR, dPMR, D-Star, Yaesu System Fusion (YSF).
• LoraDemodXxx classes in plugins/channelrx/demodlora: Decodes LoRa transmissions. This is legacy code that is not very well maintained so it may or may not work.
• NFMDemodXxx classes in plugins/channelrx/demodnfm: Narrowband FM demodulator with audio output.
• SSBDemodXxx classes in plugins/channelrx/demodssb: SSB/DSB/CW demodulator with audio output.
• WFMDemodXxx classes in plugins/channelrx/demodwfm: Wideband FM demodulator with audio output. This is a basic demodulator.
• TCPSrcXxx classes in plugins/channelrx/tcpsrc: Sends channel I/Q samples via TCP
• UDPSrcXxx classes in plugins/channelrx/udpsrc: Sends channel I/Q or FM demodulated samples via UDP

Channel transmitter (Tx) plugins

At present the following plugins are available:

• AMMmodXxx classes in plugins/channeltx/modam: AM modulator with simple sine

Source tree structure

At the first subdirectory level indclude and sdrbase contain the common core components include and source files respectively. They are further broken down in subdirectories corresponding to a specific area:

• audio contains the interface with the audio device(s)
• dsp contains the common blocks for Digital Signal Processing like filters, scope and spectrum analyzer internals
• gui contains the common Graphical User Interface components like the scope and spectrum analyzer controls and display
• plugin contains the common blocks for managing plugins
• settings contains components to manage presets and preferences
• util contains common utilities such as the message queue

The plugins subdirectory contains the associated plugins used to manage devices and channel components. Naming convention of various items depend on the usage and Rx (reception side) or Tx (transmission side) affinity. Transmission side is a work in progress.

• Receiver functions (Rx):

  • samplesource: Device managers:
    • xxx : Device manager (e.g. xxx = airspy)
      • xxxinput.h/cpp : Device interface
      • xxxgui.h/cpp : GUI
      • xxxplugin.h/cpp : Plugin interface
      • xxxsettings.h/cpp : Configuration manager
      • xxxthread.h/cpp : Reading samples
      • xxx.pro : Qt .pro file for Windows/Android build
  • channelrx: Channel handlers:
    • demodxxx : Demodulator internal handler (e.g xxx = demodam)
      • xxxdemod.h/cpp : Demodulator core
      • xxxdemodgui.h/cpp : Demodulator GUI
      • xxxdemodplugin.h/cpp : Plugin interface
      • demodxxx.pro : Qt .pro file for Windows/Android build
    • xxxanalyzer : Analyzer internal handler (e.g xxx = channel)
      • xxxanalyzer.h/cpp : Analyzer core
      • xxxanalyzergui.h/cpp : Analyzer GUI
      • xxxanalyzerplugin.h/cpp : Analyzer plugin manager
      • xxxanalyzer.pro : Qt .pro file for Windows/Android build
    • xxxsrc : Interface to the outside (e.g xxx = udp):
      • xxxsrc.h/cpp : Inteface core
      • xxxsrcgui.h/cpp : Interface GUI
      • xxxsrcplugin/h/cpp : Interface plugin manager
      • xxxsrc.pro : Qt .pro file for Windows/Android build

• Transmitter functions (Tx):

  • samplesink: Device managers:
    • xxx : Device manager (e.g. xxx = bladerf)
      • xxxsinkoutput.h/cpp : Device interface
      • xxxsinkgui.h/cpp : GUI
      • xxxsinkplugin.h/cpp : Plugin interface
      • xxxsinksettings.h/cpp : Configuration manager
      • xxxsinkthread.h/cpp : Writing samples
      • xxxsink.pro : Qt .pro file for Windows/Android build
  • channeltx: Channel handlers:
    • modxxx : Modulator internal handler (e.g xxx = modam)
      • xxxmod.h/cpp : Modulator core
      • xxxmodgui.h/cpp : Modulator GUI
      • xxxmodplugin.h/cpp : Plugin interface
      • modxxx.pro : Qt .pro file for Windows/Android build
    • xxxgenerator : Generator internal handler (e.g xxx = channel)
      • xxxgenerator.h/cpp : Generator core
      • xxxgeneratorgui.h/cpp : Generator GUI
      • xxxgeneratorplugin.h/cpp : Generator plugin manager
      • xxxgenerator.pro : Qt .pro file for Windows/Android build
    • xxxsink : Interface to the outside (e.g xxx = udp):
      • xxxsink.h/cpp : Inteface core
      • xxxsinkgui.h/cpp : Interface GUI
      • xxxsinklugin/h/cpp : Interface plugin manager
      • xxxsink.pro : Qt .pro file for Windows/Android build