GNU Radio 3.5.3.2 C++ API
digital_cpmmod_bc Class Reference

Generic CPM modulator. More...

#include <digital_cpmmod_bc.h>

Inheritance diagram for digital_cpmmod_bc:

List of all members.

Public Member Functions

std::vector< float > get_taps ()
 Return the phase response FIR taps.

Protected Member Functions

 digital_cpmmod_bc (gr_cpm::cpm_type type, float h, unsigned samples_per_sym, unsigned L, double beta)

Friends

DIGITAL_API digital_cpmmod_bc_sptr digital_make_cpmmod_bc (int type, float h, unsigned samples_per_sym, unsigned L, double beta)

Detailed Description

Generic CPM modulator.

Parameters:
typeThe modulation type. Can be one of LREC, LRC, LSRC, TFM or GAUSSIAN. See gr_cpm::phase_response() for a detailed description.
hThe modulation index. $ h \cdot \pi$ is the maximum phase change that can occur between two symbols, i.e., if you only send ones, the phase will increase by $ h \cdot \pi$ every samples_per_sym samples. Set this to 0.5 for Minimum Shift Keying variants.
samples_per_symSamples per symbol.
LThe length of the phase duration in symbols. For L=1, this yields full- response CPM symbols, for L > 1, partial-response.
betaFor LSRC, this is the rolloff factor. For Gaussian pulses, this is the 3 dB time-bandwidth product.

Examples:

  • Setting h = 0.5, L = 1, type = LREC yields MSK.
  • Setting h = 0.5, type = GAUSSIAN and beta = 0.3 yields GMSK as used in GSM.

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.


Constructor & Destructor Documentation

digital_cpmmod_bc::digital_cpmmod_bc ( gr_cpm::cpm_type  type,
float  h,
unsigned  samples_per_sym,
unsigned  L,
double  beta 
) [protected]

Member Function Documentation

std::vector<float> digital_cpmmod_bc::get_taps ( ) [inline]

Return the phase response FIR taps.


Friends And Related Function Documentation

DIGITAL_API digital_cpmmod_bc_sptr digital_make_cpmmod_bc ( int  type,
float  h,
unsigned  samples_per_sym,
unsigned  L,
double  beta 
) [friend]

The documentation for this class was generated from the following file: