P25 Phase 1 and ProVoice vocoder

This source code is provided for educational purposes only.  It is
a written description of how certain voice encoding/decoding
algorythims could be implemented.  Executable objects compiled or
derived from this package MAY BE COVERED BY ONE OR MORE PATENTS.
Readers are strongly advised to check for any patent restrictions or
licencing requirements before compiling or using this source code.

mbelib supports the 7200x4400 bit/s codec used in P25 Phase 1,
the 7100x4400 bit/s codec used in ProVoice and the "Half Rate"
3600x2250 bit/s vocoder used in various radio systems.
