DEMODULATION FILTERBANK, DOPPLER CORRECTION AND NON DECISION AIDED PHASE CORRECTION BLOCKS for GNU RADIO
Work done by Srinagesh Sharma, May 2012
srinag@umich.edu

for gnu radio version 3.5 onwards use gr-howto-write-a-block-3.5.1
for gnu radio version 3.6 onwards use gr-howto-write-a-block

I have incorporated the filterbank block and the Non Decision Aided Phase Correction block in the gr_digital folder. Replace your gnu radio gr_digital with this and install. Works for Gnuradio versions 3.6.1 and above.

Please read write up on cpm by Prof. Achilleas Anastasopoulos for the Rimoldi Decomposition implementation.
The Matlab implementation of the Rimoldi Decomposition is in the Matlab folder. The main program is cpmdecomposition.m

The Non-Decision Aided Phase correction block performs phase correction by nulling out the modulation on raising the nth power and then phase locks to it.
Please read the comments in the .cc file of the block for more details.

The doppler correction block takes the doppler correction from a TCP port. It is used for real time Intermediate frequency correction. It interfaces with predict or gpredict.

These blocks can be used for optimal decoding of CPM signals. I have tested these by decoding GMSK beacons from the RAX satellite.