This paragraph here summarizies what Cubehub has done differently.

Currently this fork only exists because it seems that multimon-ng is quite picky about fsk9600 symbol rate. There is slight error in demod if input stream is converted to 22050 sps output stream. With this little error multimon-ng was unable to decode fsk9600 stream.

Anyway branch 48k-demod-fsk96 adds 48000 sps input stream support to fsk9600.

More information about demod and multimon-ng hack can be read from my blog.

sudo apt-get install libpulse-dev

git clone https://github.com/cubehub/multimon-ng.git
cd multimon-ng
git checkout 48k-demod-fsk96
mkdir build
cd build
qmake ../multimon-ng.pro
make
sudo make install

It is a fork of multimon. It decodes the following digital transmission modes:

• POCSAG512 POCSAG1200 POCSAG2400
• EAS
• UFSK1200 CLIPFSK AFSK1200 AFSK2400 AFSK2400_2 AFSK2400_3
• HAPN4800
• FSK9600
• DTMF
• ZVEI1 ZVEI2 ZVEI3 DZVEI PZVEI
• EEA EIA CCIR
• MORSE CW

The following changes have been made so far:

• Fixes for x64
• Basic functionality on Mac OS X 'Lion' (Soundcard/OSS input is unsupported)
• DUMMY_AUDIO "backend" (Gets rid of the OSS dependency, breaks audio in doing so)
• ONLY_RAW disables the format conversion while getting rid of posix dependencies
• Option NO_X11 to disable the X11 dependency since Apple will drop Xorg soon
• Override mode for POCSAG decoding (e.g. force text decoding)
• Brute-Force BCH implementation for POCSAG forward error correction
• Verbose mode is now listed in -h
• Continued EAS/SAME development. The decoder now works, but it should be considered "alpha" quality. Do not rely on it for the reception of emergency alerts!
• Portability is a major goal
• Compiles on Windows (MinGW or Cygwin) without format conversion
• PulseAudio support, contributed by inf_l00p_
• Windows native audio and a VisualStudio/MSVC project file, contributed by bzzt_ploink
• Now accepts raw samples as piped input

using qmake

mkdir build
cd build
qmake ../multimon-ng.pro
make
sudo make install

using cmake

mkdir build
cd build
cmake ../
make
make install

Files can be easily converted into multimon-ng's native raw format using sox. e.g: sox -t wav pocsag_short.wav -esigned-integer -b16 -r 22050 -t raw pocsag_short.raw

You can also "pipe" raw samples into multimon-ng using something like this sox -t wav pocsag_short.wav -esigned-integer -b16 -r 22050 -t raw - | ./multimon-ng - (note the trailing dash)