Codec 2 on Android

  • FreeDC used to transmit codec2
    • Not GSM
    • Not VoIP
    • 1000 times more efficient than voice over WiFi
    • Free as in speech and beer
    • CPU cycles close to free

Building a SDR Digital Voice Radio

  1. Preamp to boost HF
  2. Local Oscillator added
  3. Mixer takes a difference of Local Oscillator and HF
  4. Baseband is the result of that, and is then Amp’d to normal audio jack levels.
  5. Uses USB sound card due to android not doing input sources correctly

SDR on android

  • Uses libusb-android in C/JNI mode
  • fdmdv2 and codec2 in C/JNI mode
  • Audio playback via Java/Android
  • Graphs for stats
  • Waterfall to come
  • Requires on the go USB host mode support