A multicarrier GMSK modulator

Author

Vankka, Jouko ; Honkanen, Mauri ; Halonen, Kari A I

Author_Institution

Electron. Circuit Design Lab., Helsinki Univ. of Technol., Finland

Volume

19

Issue

6

fYear

2001

fDate

6/1/2001 12:00:00 AM

Firstpage

1070

Lastpage

1079

Abstract

A multicarrier Gaussian minimum shift keying (GMSK) modulator has been developed and implemented. The design contains four GMSK modulators, which generate GMSK modulated carriers at the specified center frequencies. Utilization of the redundancy in the stored waveforms reduces the size of the GMSK trajectory look-up table to less than one-quarter of the original size in the modulator. Conventionally, the power ramping and output power level controlling are performed in the analog domain. A novel digital ramp generator and output power level controller perform both the burst ramping and the dynamic power control in the digital domain. The power control is realized by scaling the ramp curve, which follows a raised cosine/sine curve. The four GMSK modulated signals are combined together in the digital domain. The digital multicarrier GMSK modulator is designed to fulfil the spectrum and phase error specifications of the GSM 900 and DCS 1800 base stations

Keywords

cellular radio; direct digital synthesis; minimum shift keying; power control; redundancy; telecommunication control; DCS 1800; GSM 900; digital ramp generator; dynamic power control; look-up table; multicarrier GMSK modulator; multicarrier Gaussian minimum shift keying modulator; output power level controller; output power level controlling; power ramping; redundancy; stored waveforms; Base stations; Digital modulation; Distributed control; Frequency; GSM; Phase modulation; Power control; Power generation; Redundancy; Table lookup;

fLanguage

English

Journal_Title

Selected Areas in Communications, IEEE Journal on

Publisher

ieee

ISSN

0733-8716

Type

jour

DOI

10.1109/49.926363

Filename

926363