Title :
A numerical method for spectral shaping of CPM signals
Author :
Freidhof, Markus ; Havezov, Peter
Author_Institution :
Inst. for Commun. Technol., Darmstadt Univ. of Technol., Germany
Abstract :
A new method for spectral shaping of the power density spectrum (PDS) of continuous phase modulation (CPM) is presented. The PDS is multiplied with a weighting function, integrated and minimized to control the shaping of the PDS. For an easy calculation of the PDS the CPM signal is disassembled into amplitude modulated pulses. A gradient search method is used for the optimization of the nonlinear set of equations. It is shown with some examples, that the optimization can shape the PDS in a purposeful manner. In the given examples the out-of-band power or the adjacent channel interference (ACI) is reduced. In order to control the trade-off between the power efficiency and the ACI, the object function of the optimization is expanded with a term which takes into account the free Euclidian distance. The results are compared to Gaussian minimum shift keying (GMSK) for various BT
Keywords :
adjacent channel interference; amplitude modulation; continuous phase modulation; nonlinear equations; optimisation; signal processing; spectral analysis; ACI; CPM signals; GMSK; Gaussian minimum shift keying; adjacent channel interference; amplitude modulated pulses; continuous phase modulation; free Euclidian distance; gradient search method; mobile communications systems; nonlinear equations optimization; nonlinear modulation; numerical method; out-of-band power; power density spectrum; power efficiency; spectral shaping; weighting function; Amplitude modulation; Assembly; Equations; Fourier transforms; Frequency; Phase modulation; Pulse modulation; Search methods;
Conference_Titel :
Global Telecommunications Conference, 1998. GLOBECOM 1998. The Bridge to Global Integration. IEEE
Conference_Location :
Sydney,NSW
Print_ISBN :
0-7803-4984-9
DOI :
10.1109/GLOCOM.1998.776593
