Updated readme.

README.md

@@ -1,3 +1,5 @@
 # rtty.js
 
-A FSK modulator implemented purely in Javascript. Requires a browser with reasonbly good support for Web Audio (Chrome, Safari).
+A FSK modulator implemented purely in Javascript. Requires a browser with reasonbly good support for Web Audio (Chrome, Safari).
+
+This was ported from a C implemetation of a FSK modulator that I created some years back. To keep things computationally simple, a wavetable is used to generate the audio tones. The method used to keep the baud rate in sync with the audio sample rate (a click track... read the source if you want to understand this a bit better) is a bit silly, but it makes things interesting.