Continuous Phase Modulation

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Generic CPM modulator.

The input of this block are symbols from an M-ary alphabet +/-1, +/-3, ..., +/-(M-1). Usually, M = 2 and therefore, the valid inputs are +/-1. The modulator will silently accept any other inputs, though. The output is the phase-modulated signal.


CPM Type
The modulation type. Can be one of LREC, LRC, LSRC, TFM or GAUSSIAN. See gr_cpm::phase_response() for a detailed description.
Modulation Index
Maximum phase change that can occur between two symbols, i.e., if you only send ones, the phase will increase by every samples. Set this to 0.5 for Minimum Shift Keying variants.
Samples per Symbol
Self explanatory
Pulse Duration (symbols)
The length of the phase duration in symbols. For L=1, this yields full- response CPM symbols, for L > 1, partial-response.
Phase Response Parameter (BT or beta)
For LSRC, this is the rolloff factor. For Gaussian pulses, this is the 3 dB time-bandwidth product.

Example Flowgraph[edit]

Insert description of flowgraph here, then show a screenshot of the flowgraph and the output if there is an interesting GUI. Currently we have no standard method of uploading the actual flowgraph to the wiki or git repo, unfortunately. The plan is to have an example flowgraph showing how the block might be used, for every block, and the flowgraphs will live in the git repo.

Source Files[edit]

C++ files
Header files
Public header files
Block definition