gr::digital::cpmmod_bc Class Reference

Generic CPM modulator. More...

#include <cpmmod_bc.h>

Inheritance diagram for gr::digital::cpmmod_bc:

List of all members.

Public Types
typedef boost::shared_ptr < cpmmod_bc >	sptr
Public Member Functions
virtual std::vector< float >	taps () const =0
	Return the phase response FIR taps.
virtual int	type () const =0
	Return the type of CPM modulator.
virtual float	index () const =0
	Return the modulation index of the modulator.
virtual int	samples_per_sym () const =0
	Return the number of samples per symbol.
virtual int	length () const =0
	Return the length of the phase duration (in symbols)
virtual double	beta () const =0
	Return the value of beta for the modulator.
Static Public Member Functions
static sptr	make (analog::cpm::cpm_type type, float h, int samples_per_sym, int L, double beta=0.3)
static sptr	make_gmskmod_bc (int samples_per_sym=2, int L=4, double beta=0.3)

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Detailed Description

Generic CPM modulator.

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.

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Member Typedef Documentation

typedef boost::shared_ptr<cpmmod_bc> gr::digital::cpmmod_bc::sptr

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Member Function Documentation

virtual double gr::digital::cpmmod_bc::beta

(

)

const [pure virtual]

Return the value of beta for the modulator.

virtual float gr::digital::cpmmod_bc::index

(

)

const [pure virtual]

Return the modulation index of the modulator.

virtual int gr::digital::cpmmod_bc::length

(

)

const [pure virtual]

Return the length of the phase duration (in symbols)

static sptr gr::digital::cpmmod_bc::make	(	analog::cpm::cpm_type	type,
		float	h,
		int	samples_per_sym,
		int	L,
		double	beta = 0.3
	)		[static]

Make CPM modulator block.

Parameters:

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

static sptr gr::digital::cpmmod_bc::make_gmskmod_bc	(	int	samples_per_sym = 2,
		int	L = 4,
		double	beta = 0.3
	)		[static]

Make GMSK modulator block.

The type is GAUSSIAN and the modulation index for GMSK is 0.5. This are populated automatically by this factory function.

Parameters:

samples_per_sym	Samples per symbol.
L	The length of the phase duration in symbols. For L=1, this yields full- response CPM symbols, for L > 1, partial-response.
beta	For LSRC, this is the rolloff factor. For Gaussian pulses, this is the 3 dB time-bandwidth product.

virtual int gr::digital::cpmmod_bc::samples_per_sym

(

)

const [pure virtual]

Return the number of samples per symbol.

virtual std::vector<float> gr::digital::cpmmod_bc::taps

(

)

const [pure virtual]

Return the phase response FIR taps.

virtual int gr::digital::cpmmod_bc::type

(

)

const [pure virtual]

Return the type of CPM modulator.

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

• cpmmod_bc.h