RTTY/AFSK terminal based on Web Audio API

Currently it's only able to transmit and receive UART messages (i.e. no real UI and RTTY).

Usage (using webpack-dev-server):

webpack serve

Navigate to shown location and use browser console to interact with application

startTx(); // connects oscillator to analyser and decoder input
startRx(); // connects microphone input to analyser and decoder input
send(byteNumber); // send byte to audio destination
setValueAtTime(-1|0|1); // manually set oscillator to space/silence/mark state
// decoded messages should also be logged to console

Future plans:

• Test against existing RTTY terminal
• Increase decoder quality (filter/DSP research & additional signal detection intelligence)
• Usable UI
• RTTY/baudot support
• Hardware FSK support via WebUSB or server backend